Evaluation of Sources and Patterns of Elemental Composition of PM2.5 at Three Low-Income Neighborhood Schools and Residences in Quito, Ecuador

PubMed Central

Raysoni, Amit U.; Armijos, Rodrigo X.; Weigel, M. Margaret; Echanique, Patricia; Racines, Marcia; Pingitore, Nicholas E.; Li, Wen-Whai

2017-01-01

Elemental characterization of fine particulate matter was undertaken at schools and residences in three low income neighborhoods in Quito, Ecuador. The three zones were located in the northern (Cotocollao), south central (El Camal), and south east (Los Chillos) neighborhoods and were classified as zones 1–3, respectively. Forty elements were quantified via ICP-MS analysis. Amongst the geogenic elements, the concentration of Si was the most abundant followed by S, Al, and Ca. Elements with predominantly anthropogenic sources such as Zn, V, and Ni were higher in zone 3 school followed by zone 2 and zone 1 schools. Enrichment factors were calculated to study the role of crustal sources in the elemental concentrations. Geogenic elements, except K, all had values <10 and anthropogenic elements such as Ni, V, Zn, Pb, As, Cr had >10. Principal Component Analysis suggested that Ni and V concentrations were strongly attributable to pet coke and heavy oil combustion. Strong associations between As and Pb could be attributed to traffic and other industrial emissions. Resuspended dust, soil erosion, vehicular emissions (tailpipe, brake and tire wear, and engine abrasion), pet coke, heavy oil combustion, and heavy industrial operations were major contributors to air pollution. PMID:28644400

Evaluation of Sources and Patterns of Elemental Composition of PM2.5 at Three Low-Income Neighborhood Schools and Residences in Quito, Ecuador.

PubMed

Raysoni, Amit U; Armijos, Rodrigo X; Weigel, M Margaret; Echanique, Patricia; Racines, Marcia; Pingitore, Nicholas E; Li, Wen-Whai

2017-06-23

Elemental characterization of fine particulate matter was undertaken at schools and residences in three low income neighborhoods in Quito, Ecuador. The three zones were located in the northern (Cotocollao), south central (El Camal), and south east (Los Chillos) neighborhoods and were classified as zones 1-3, respectively. Forty elements were quantified via ICP-MS analysis. Amongst the geogenic elements, the concentration of Si was the most abundant followed by S, Al, and Ca. Elements with predominantly anthropogenic sources such as Zn, V, and Ni were higher in zone 3 school followed by zone 2 and zone 1 schools. Enrichment factors were calculated to study the role of crustal sources in the elemental concentrations. Geogenic elements, except K, all had values <10 and anthropogenic elements such as Ni, V, Zn, Pb, As, Cr had >10. Principal Component Analysis suggested that Ni and V concentrations were strongly attributable to pet coke and heavy oil combustion. Strong associations between As and Pb could be attributed to traffic and other industrial emissions. Resuspended dust, soil erosion, vehicular emissions (tailpipe, brake and tire wear, and engine abrasion), pet coke, heavy oil combustion, and heavy industrial operations were major contributors to air pollution.

Analysis of rare earth elements in coal fly ash using laser ablation inductively coupled plasma mass spectrometry and scanning electron microscopy

NASA Astrophysics Data System (ADS)

Thompson, Robert L.; Bank, Tracy; Montross, Scott; Roth, Elliot; Howard, Bret; Verba, Circe; Granite, Evan

2018-05-01

Reference standard NIST SRM 1633b and FA 345, a fly ash sample from an eastern U.S. coal power plant, were analyzed to determine and quantify the mineralogical association of rare earth elements (REE). These analyses were completed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and a scanning electron microscope, equipped with an energy-dispersive X-ray spectrometer (SEM-EDS). Internal standardization was avoided by quantifying elemental concentrations by normalizing to 100% oxides. Mineral grains containing elevated REE concentrations were found in diverse chemical environments, but were most commonly found in regions where Al and Si were predominant. Dividing the spot analyses into time segments yielded plots that showed the REE content changing over time as individual mineral grains were being ablated. SEM-EDS images of FA 345 confirmed the trends that were found in the LA-ICP-MS results. Small grains of apatite, monazite, or zircon were frequently observed as free mineral grains or embedded in amorphous aluminosilicate glass and were not associated with ferrous particles. This finding is consistent with previous reports that magnetic enrichment may be an effective way of concentrating non-magnetic REE phases. Furthermore, aggressive mechanical and chemical-based separation schemes will be required to separate and recover REE from aluminosilicate glass.

The Asian clam Corbicula fluminea as a biomonitor of trace element contamination: Accounting for different sources of variation using an hierarchical linear model

USGS Publications Warehouse

Shoults-Wilson, W. A.; Peterson, J.T.; Unrine, J.M.; Rickard, J.; Black, M.C.

2009-01-01

In the present study, specimens of the invasive clam, Corbicula fluminea, were collected above and below possible sources of potentially toxic trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) in the Altamaha River system (Georgia, USA). Bioaccumulation of these elements was quantified, along with environmental (water and sediment) concentrations. Hierarchical linear models were used to account for variability in tissue concentrations related to environmental (site water chemistry and sediment characteristics) and individual (growth metrics) variables while identifying the strongest relations between these variables and trace element accumulation. The present study found significantly elevated concentrations of Cd, Cu, and Hg downstream of the outfall of kaolin-processing facilities, Zn downstream of a tire cording facility, and Cr downstream of both a nuclear power plant and a paper pulp mill. Models of the present study indicated that variation in trace element accumulation was linked to distance upstream from the estuary, dissolved oxygen, percentage of silt and clay in the sediment, elemental concentrations in sediment, shell length, and bivalve condition index. By explicitly modeling environmental variability, the Hierarchical linear modeling procedure allowed the identification of sites showing increased accumulation of trace elements that may have been caused by human activity. Hierarchical linear modeling is a useful tool for accounting for environmental and individual sources of variation in bioaccumulation studies. ?? 2009 SETAC.

Trace and minor elements in sphalerite from metamorphosed sulphide deposits

NASA Astrophysics Data System (ADS)

Lockington, Julian A.; Cook, Nigel J.; Ciobanu, Cristiana L.

2014-12-01

Sphalerite is a common sulphide and is the dominant ore mineral in Zn-Pb sulphide deposits. Precise determination of minor and trace element concentrations in sulphides, including sphalerite, by Laser-Ablation Inductively-Coupled-Plasma Mass-Spectrometry (LA-ICP-MS) is a potentially valuable petrogenetic tool. In this study, LA-ICP-MS is used to analyse 19 sphalerite samples from metamorphosed, sphalerite-bearing volcanic-associated and sedimentary exhalative massive sulphide deposits in Norway and Australia. The distributions of Mn, Fe, Co, Cu, Ga, Se, Ag, Cd, In, Sn, Sb, Hg, Tl, Pb and Bi are addressed with emphasis on how concentrations of these elements vary with metamorphic grade of the deposit and the extent of sulphide recrystallization. Results show that the concentrations of a group of trace elements which are believed to be present in sphalerite as micro- to nano-scale inclusions (Pb, Bi, and to some degree Cu and Ag) diminish with increasing metamorphic grade. This is interpreted as due to release of these elements during sphalerite recrystallization and subsequent remobilization to form discrete minerals elsewhere. The concentrations of lattice-bound elements (Mn, Fe, Cd, In and Hg) show no correlation with metamorphic grade. Primary metal sources, physico-chemical conditions during initial deposition, and element partitioning between sphalerite and co-existing sulphides are dominant in defining the concentrations of these elements and they appear to be readily re-incorporated into recrystallized sphalerite, offering potential insights into ore genesis. Given that sphalerite accommodates a variety of trace elements that can be precisely determined by contemporary microanalytical techniques, the mineral has considerable potential as a geothermometer, providing that element partitioning between sphalerite and coexisting minerals (galena, chalcopyrite etc.) can be quantified in samples for which the crystallization temperature can be independently constrained.

Exploring bamboo leaf nutrient value in the US NPGS germplasm collection

USDA-ARS?s Scientific Manuscript database

Bamboo shoots and leaves are nutritious, providing food for both human and animal consumption. But their nutrient value may depend on the bamboo species, harvesting season, and growing location. Leaf crude protein content, amino acid composition, and mineral element concentration were quantified fro...

Quantifying Diffuse Contamination: Method and Application to Pb in Soil.

PubMed

Fabian, Karl; Reimann, Clemens; de Caritat, Patrice

2017-06-20

A new method for detecting and quantifying diffuse contamination at the continental to regional scale is based on the analysis of cumulative distribution functions (CDFs). It uses cumulative probability (CP) plots for spatially representative data sets, preferably containing >1000 determinations. Simulations demonstrate how different types of contamination influence elemental CDFs of different sample media. It is found that diffuse contamination is characterized by a distinctive shift of the low-concentration end of the distribution of the studied element in its CP plot. Diffuse contamination can be detected and quantified via either (1) comparing the distribution of the contaminating element to that of an element with a geochemically comparable behavior but no contamination source (e.g., Pb vs Rb), or (2) comparing the top soil distribution of an element to the distribution of the same element in subsoil samples from the same area, taking soil forming processes into consideration. Both procedures are demonstrated for geochemical soil data sets from Europe, Australia, and the U.S.A. Several different data sets from Europe deliver comparable results at different scales. Diffuse Pb contamination in surface soil is estimated to be <0.5 mg/kg for Australia, 1-3 mg/kg for Europe, and 1-2 mg/kg, or at least <5 mg/kg, for the U.S.A. The analysis presented here also allows recognition of local contamination sources and can be used to efficiently monitor diffuse contamination at the continental to regional scale.

Elements including metals in the atomizer and aerosol of disposable electronic cigarettes and electronic hookahs

PubMed Central

Williams, Monique; Bozhilov, Krassimir; Ghai, Sanjay; Talbot, Prue

2017-01-01

Objective Our purpose was to quantify 36 inorganic chemical elements in aerosols from disposable electronic cigarettes (ECs) and electronic hookahs (EHs), examine the effect of puffing topography on elements in aerosols, and identify the source of the elements. Methods Thirty-six inorganic chemical elements and their concentrations in EC/EH aerosols were determined using inductively coupled plasma optical emission spectroscopy, and their source was identified by analyzing disassembled atomizers using scanning electron microscopy and energy dispersive X-ray spectroscopy. Results Of 36 elements screened, 35 were detected in EC/EH aerosols, while only 15 were detected in conventional tobacco smoke. Some elements/metals were present in significantly higher concentrations in EC/EH aerosol than in cigarette smoke. Concentrations of particular elements/metals within EC/EH brands were sometimes variable. Aerosols generated at low and high air-flow rates produced the same pattern of elements, although the total element concentration decreased at the higher air flow rate. The relative amount of elements in the first and last 60 puffs was generally different. Silicon was the dominant element in aerosols from all EC/EH brands and in cigarette smoke. The elements appeared to come from the filament (nickel, chromium), thick wire (copper coated with silver), brass clamp (copper, zinc), solder joints (tin, lead), and wick and sheath (silicon, oxygen, calcium, magnesium, aluminum). Lead was identified in the solder and aerosol of two brands of EHs (up to 0.165 μg/10 puffs). Conclusion These data show that EC/EH aerosols contain a mixture of elements, including heavy metals, with concentrations often significantly higher than in conventional cigarette smoke. While the health effects of inhaling mixtures of heated metals is currently not known, these data will be valuable in future risk assessments involving EC/EH elements/metals. PMID:28414730

Investigation of Effects of Material Architecture on the Elastic Response of a Woven Ceramic Matrix Composite

NASA Technical Reports Server (NTRS)

Goldberg, Robert K.; Bonacuse, Peter J.; Mital, Subodh K.

2012-01-01

To develop methods for quantifying the effects of the microstructural variations of woven ceramic matrix composites on the effective properties and response of the material, a research program has been undertaken which is described in this paper. In order to characterize and quantify the variations in the microstructure of a five harness satin weave, CVI SiC/SiC, composite material, specimens were serially sectioned and polished to capture images that detailed the fiber tows, matrix, and porosity. Open source quantitative image analysis tools were then used to isolate the constituents and collect relevant statistics such as within ply tow spacing. This information was then used to build two dimensional finite element models that approximated the observed section geometry. With the aid of geometrical models generated by the microstructural characterization process, finite element models were generated and analyses were performed to quantify the effects of the microstructure and its variation on the effective stiffness and areas of stress concentration of the material. The results indicated that the geometry and distribution of the porosity appear to have significant effects on the through-thickness modulus. Similarly, stress concentrations on the outer surface of the composite appear to correlate to regions where the transverse tows are separated by a critical amount.

Major and trace elements in organically or conventionally produced milk.

PubMed

Hermansen, John E; Badsberg, Jens H; Kristensen, Troels; Gundersen, Vagn

2005-08-01

A total of 480 samples of milk from 10 organically and 10 conventionally producing dairy farms in Denmark and covering 8 sampling periods over 1 year (triplicate samplings) were analysed for 45 trace elements and 6 major elements by high-resolution inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry. Sampling, sample preparation, and analysis of the samples were performed under carefully controlled contamination-free conditions. The dairy cattle breeds were Danish-Holstein or Jersey. Sources of variance were quantified, and differences between production systems and breeds were tested. The major source of variation for most elements was week of sampling. Concentrations of Al, Cu, Fe, Mo, Rb, Se, and Zn were within published ranges. Concentrations of As, Cd, Cr, Mn and Pb were lower, and concentrations of Co and Sr were higher than published ranges. Compared with Holsteins, Jerseys produced milk with higher concentrations of Ba, Ca, Cu, Fe, Mg, Mn, Mo, P, Rh, and Zn and with a lower concentration of Bi. The organically produced milk, compared with conventionally produced milk, contained a significantly higher concentration of Mo (48 v. 37 ng/g) and a lower concentration of Ba (43 v. 62 ng/g), Eu (4 v. 7 ng/g), Mn (16 v. 20 ng/g) and Zn (4400 v. 5150 ng/g respectively). The investigation yielded typical concentrations for the following trace elements in milk, for which no or very few data are available: Ba, Bi, Ce, Cs, Eu, Ga, Gd, In, La, Nb, Nd, Pd, Pr, Rh, Sb, Sm, Tb, Te, Th, Ti, Tl, U, V, Y, and Zr.

Elemental concentrations in the seed of mutants and natural variants of Arabidopsis thaliana grown under varying soil conditions.

PubMed

McDowell, Stephen C; Akmakjian, Garo; Sladek, Chris; Mendoza-Cozatl, David; Morrissey, Joe B; Saini, Nick; Mittler, Ron; Baxter, Ivan; Salt, David E; Ward, John M; Schroeder, Julian I; Guerinot, Mary Lou; Harper, Jeffrey F

2013-01-01

The concentrations of mineral nutrients in seeds are critical to both the life cycle of plants as well as human nutrition. These concentrations are strongly influenced by soil conditions, as shown here by quantifying the concentration of 14 elements in seeds from Arabidopsis thaliana plants grown under four different soil conditions: standard, or modified with NaCl, heavy metals, or alkali. Each of the modified soils resulted in a unique change to the seed ionome (the mineral nutrient content of the seeds). To help identify the genetic networks regulating the seed ionome, changes in elemental concentrations were evaluated using mutants corresponding to 760 genes as well as 10 naturally occurring accessions. The frequency of ionomic phenotypes supports an estimate that as much as 11% of the A. thaliana genome encodes proteins of functional relevance to ion homeostasis in seeds. A subset of mutants were analyzed with two independent alleles, providing five examples of genes important for regulation of the seed ionome: SOS2, ABH1, CCC, At3g14280 and CNGC2. In a comparison of nine different accessions to a Col-0 reference, eight accessions were observed to have reproducible differences in elemental concentrations, seven of which were dependent on specific soil conditions. These results indicate that the A. thaliana seed ionome is distinct from the vegetative ionome, and that elemental analysis is a sensitive approach to identify genes controlling ion homeostasis, including those that regulate gene expression, phospho-regulation, and ion transport.

Seasonal determination of trace and ultra-trace content in Macrocystis pyrifera from San Jorge Gulf (Patagonia) by Total Reflection X-ray Fluorescence

NASA Astrophysics Data System (ADS)

Salomone, Vanesa N.; Riera, Marina; Cerchietti, Luciana; Custo, Graciela; Muniain, Claudia

2017-05-01

Seaweed have a great capacity to accumulate heavy metals in their tissues. The chemical characterization of seaweed is important due to their use in environmental monitoring and human or animal food. The aim of the present study was to evaluate the multi-elemental composition of seaweed from San Jorge Gulf (Patagonia, Argentina) by Total Reflection X-ray Fluorescence (TXRF). The elements As, Br, Cu, Cr, Fe, Mn, Ni, Pb, Rb, Sr, V and Zn were seasonally analyzed and quantified in blades of Macrocystis pyrifera. TXRF showed to be a suitable technique for simultaneous multi-element analysis in this kind of samples. The results revealed seasonal variations in the chemical content for some elements; arsenic content was maximum in summer and autumn, iron concentration increased to the winter and zinc concentration was maximum in autumn. The sum of principal micronutrients (Fe + Zn + Mn + Cu) varied between 114 and 171 mg k- 1 g dw. The total As concentration ranged between 36 and 66 mg kg- 1. Lead, nickel and copper were not detected.

Analysis of soil samples from Gebeng area using NAA technique

NASA Astrophysics Data System (ADS)

Elias, Md Suhaimi; Wo, Yii Mei; Hamzah, Mohd Suhaimi; Shukor, Shakirah Abd; Rahman, Shamsiah Ab; Salim, Nazaratul Ashifa Abdullah; Azman, Muhamad Azfar; Hashim, Azian

2017-01-01

Rapid development and urbanization will increase number of residence and industrial area. Without proper management and control of pollution, these will give an adverse effect to environment and human life. The objective of this study to identify and quantify key contaminants into the environment of the Gebeng area as a result of industrial and human activities. Gebeng area was gazetted as one of the industrial estate in Pahang state. Assessment of elemental pollution in soil of Gebeng area base on level of concentration, enrichment factor and geo-accumulation index. The enrichment factors (EFs) were determined by the elemental rationing method, whilst the geo-accumulation index (Igeo) by comparing of current to continental crustal average concentration of element. Twenty-seven of soil samples were collected from Gebeng area. Soil samples were analysed by using Neutron Activation Analyses (NAA) technique. The obtained data showed higher concentration of iron (Fe) due to abundance in soil compared to other elements. The results of enrichment factor showed that Gebeng area have enrich with elements of As, Br, Hf, Sb, Th and U. Base on the geo-accumulation index (Igeo) classification, the soil quality of Gebeng area can be classified as class 0, (uncontaminated) to Class 3, (moderately to heavily contaminated).

Quantitative chemical imaging of the intracellular spatial distribution of fundamental elements and light metals in single cells.

PubMed

Malucelli, Emil; Iotti, Stefano; Gianoncelli, Alessandra; Fratini, Michela; Merolle, Lucia; Notargiacomo, Andrea; Marraccini, Chiara; Sargenti, Azzurra; Cappadone, Concettina; Farruggia, Giovanna; Bukreeva, Inna; Lombardo, Marco; Trombini, Claudio; Maier, Jeanette A; Lagomarsino, Stefano

2014-05-20

We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10(6) atoms/μm(3). This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.

The effect of short-range spatial variability on soil sampling uncertainty.

PubMed

Van der Perk, Marcel; de Zorzi, Paolo; Barbizzi, Sabrina; Belli, Maria; Fajgelj, Ales; Sansone, Umberto; Jeran, Zvonka; Jaćimović, Radojko

2008-11-01

This paper aims to quantify the soil sampling uncertainty arising from the short-range spatial variability of elemental concentrations in the topsoils of agricultural, semi-natural, and contaminated environments. For the agricultural site, the relative standard sampling uncertainty ranges between 1% and 5.5%. For the semi-natural area, the sampling uncertainties are 2-4 times larger than in the agricultural area. The contaminated site exhibited significant short-range spatial variability in elemental composition, which resulted in sampling uncertainties of 20-30%.

Chemical Composition of Rainwater in Córdoba City, Argentina

NASA Astrophysics Data System (ADS)

López, M. L.; Asar, M. L.; Ceppi, S.; Bürgesser, R. E.; Avila, E.

2013-05-01

Sampling and chemical analysis of rainwater has proved to be a useful technique for studying its chemical composition and provides a greater understanding of local and regional dispersion of pollutants and their potential impacts to ecosystems through deposition processes. Samples of rainwater were collected during 2009-2012, in Córdoba city, Argentina. Two kind of sampling were performed: event-specific and sequential. The objective of the first of these was to determine the chemical concentration of the total rain, while the objective of the second one was to analyze the variability of the chemical concentration during an individual rain event. The total volume of each sample was divided in halves. One half was filtered through 0.45 μm membrane filter. After this, all the samples were reduced by evaporation to a final volume of 10 ml. The non-filtered samples were acidified and digested in accordance to the method 3050B of the Environmental Protection Agency (EPA) for acid digestion of sediments. Multi-elemental standard solutions in different concentrations were prepared by adequate dilutions. Gallium was added as an internal standard in all standard solutions and samples. Exactly 5 μL of these solutions were deposited on acrylic supports. When these droplets were dried, Synchrotron Radiation Total Reflection X-Ray Fluorescence technique was used for determining the chemical elements. Spectra were analyzed with the AXIL package for spectrum analysis. Due to the intrinsic characteristics of the total reflection technique, the background of the measurements is significantly reduced and there are no matrix effects, therefore quantification can be obtained from the linear correlation between fluorescence intensity and the concentration of the element of interest. The elements quantified were S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, and Pb. For all of them a calibration curve was performed in order to quantify their concentrations on the samples. The results show that the average pH in city rainwater was pH=6.5; the elements found in the samples were S, Ca, Cu, Cr, Sr, P, Fe, Mn, Pb, K, Ti, V, Zn and the average concentrations of these elements were below the limits established by World Health Organization for drinking water, and show a high natural variability. The temporal evolution of inorganic ion concentration during rain events was analyzed and the scavenging coefficients were calculated and compared with data from literature. A comparison was made between the rainwater chemical composition and chemical composition in the aerosols scavenging during the rain. This study is the first in Córdoba city to analyze the chemical composition of rainwater and constitute a base for future comparison of variability in pH and elemental composition.

Metal concentrations in the mussel Bathymodiolus platifrons from a cold seep in the South China Sea

NASA Astrophysics Data System (ADS)

Wang, Xiaocheng; Li, Chaolun; Zhou, Li

2017-11-01

Data regarding the concentration and distribution of various metals in different tissues of mussels from the cold seep is scant. We aimed to quantify the presence of twenty elements (Ca, K, Mg, Sr, Ag, Al, As, Ba, Cd, Co, Cr, Cu, Li, Fe, Mn, Mo, Ni, Pb, V, and Zn) in gills, mantles and shells of Bathymodiolus platifrons, a common mussel species in deep-sea cold seep and hydrothermal vent communities. Specimens of B. platifrons were sampled from a cold seep at the northern continental slope of the South China Sea and the elemental contents in its tissues were quantified. Our findings were compared to data from taxonomically similar species at hydrothermal vents and coastal waters. We found that most elements were significantly enriched in the gills, which could be related to food uptake and the existence of endosymbionts. In shells and mantles, Mn was particularly rich, possibly due to its replacement of Ca in the carbonate structure. A significant positive correlation among Ca, Sr, and Mg was found in both gills and mantles, consistent with relationships observed in vent and littoral mussel species. Concentrations of metals were highest in the new-growth outer edges of shells in comparison to older shell material, which suggests that trace metals have become more abundant in the ambient seawater in recent years. Compared with other deep-sea environments and coastal areas, metal accumulation showed local variability but similar overall patterns of uptake and accumulation, indicating that essential elemental requirements in different mussel species may be similar across taxa. The high bioconcentration factor (BCF) values of Mn and Ag suggest that their particular functions and regulation mechanisms are related to specific adaptations and life cycle processes.

The influence of atmospheric particles on the elemental content of vegetables in urban gardens of Sao Paulo, Brazil.

PubMed

Amato-Lourenco, Luís Fernando; Moreira, Tiana Carla Lopes; de Oliveira Souza, Vanessa Cristina; Barbosa, Fernando; Saiki, Mitiko; Saldiva, Paulo Hilário Nascimento; Mauad, Thais

2016-09-01

Although urban horticulture provides multiple benefits to society, the extent to which these vegetables are contaminated by the absorption of chemical elements derived from atmospheric deposition is unclear. This study was designed to evaluate the influence of air pollution on leafy vegetables in community gardens of Sao Paulo, Brazil. Vegetable seedlings of Brassica oleracea var. acephala (collard greens) and Spinacia oleracea (spinach) obtained in a non-polluted rural area and growing in vessels containing standard uncontaminated soil were exposed for three consecutive periods of 30, 60 and 90 days in 10 community gardens in Sao Paulo and in one control site. The concentrations of 17 chemical elements (traffic-related elements and those essential to plant biology) were quantified by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Tillandsia usneoides L. specimens were used as air plant biomonitors. The concentrations of As, Cd, Cr and Pb found in vegetables were compared to the recommended values for consumption. Principal Component Analysis (PCA) was used to cluster the elemental concentrations, and Generalized Linear Models (GLMs) were employed to evaluate the association of the factor scores from each PCA component with variables such as local weather, traffic burden and vertical barriers adjacent to the gardens. We found significant differences in the elemental concentrations of the vegetables in the different community gardens. These differences were related to the overall traffic burden, vertical obstacles and local weather. The Pb and Cd concentrations in both vegetables exceeded the limit values for consumption after 60 days of exposure. A strong correlation was observed between the concentration of traffic-related elements in vegetables and in Tillandsia usneoides L. An exposure response was observed between traffic burden and traffic-derived particles absorbed in the vegetables. Traffic-derived air pollution directly influences the absorption of chemical elements in leafy vegetables, and the levels of these elements may exceed the recommended values for consumption. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of sediment recycling on the trace element composition of primitive arc lavas

NASA Astrophysics Data System (ADS)

Collinet, M.; Jagoutz, O. E.

2017-12-01

Primitive calc-alkaline lavas from continental arcs are, on average, enriched in incompatible elements compared to those from intra-oceanic arcs. This relative enrichment is observed in different groups of trace elements: LILE (e.g. K, Rb), LREE to MREE (La-Dy) and HFSE (e.g.Zr, Nb) and is thought to result from (1) a transfer of material from the subducting slab to the mantle wedge at higher temperature than in intra-oceanic margins and/or (2) lower average degrees of melting in the mantle wedge, as a consequence of thicker overlying crusts and higher average pressures of melting. In addition to thicker overlying crusts and generally higher slab temperatures, continental margins are characterized by larger volumes of rock exposed above sea level and enhanced erosion rates compared to intra-oceanic arcs. As several geochemical signatures of arc lavas attest to the importance of sediment recycling in subduction zones, we explore the possibility that the high concentrations of incompatible elements in primitive lavas from continental arcs directly reflect a larger input of sediment to the subduction system. Previous efforts to quantify the sediment flux to oceanic trenches focused on the thickness of pelagic and hemipelagic sediments on top of the plate entering the subduction zone (Plank and Langmuir, 1993, Nature). These estimates primarily relied on the sediment layer drilled outboard from the subduction system and likely underestimate the volume of sediment derived from the arc itself. Accordingly, we find that such estimates of sediment flux do not correlate with the concentration of incompatible elements in primitive arc lavas. To account for regional contributions of coarser detrital sediments, usually delivered to oceanic trenches by turbidity currents, we apply to arc segments a model that quantifies the sediment load of rivers based on the average relief, area, temperature and runoff of their respective drainage areas (Syvitski et al., 2003, Sediment. Geol.). Our new estimates of sediment fluxes correlate positively with incompatible element concentrations in primitive arc lavas. We conclude that a large fraction of the local terrigenous sediments is subducted and contributes to the observed dichotomy in the trace element budget between primitive lavas from continental and oceanic margins.

The relationship between metal composition, phenolic acid and flavonoid content in Imleria badia from non-polluted and polluted areas.

PubMed

Gąsecka, Monika; Rzymski, Piotr; Mleczek, Mirosław; Siwulski, Marek; Budzyńska, Sylwia; Magdziak, Zuzanna; Niedzielski, Przemysław; Sobieralski, Krzysztof

2017-03-04

The aim of this study was to determine the elemental composition, phenolic content and composition and antioxidant properties of Imleria badia (Fr.) Vizzini (former names Boletus badius (Fr.) Fr., and Xerocomus badius (Fr.) E.-J. Gilbert) fruiting bodies collected from sites with different levels of pollution. Imleria badia was relatively tolerant to soil contamination with toxic elements and was able to grow in As, Cd, Hg and Pb concentrations exceeding 15, 2.9, 0.4 and 77 mg kg -1 , respectively. The concentration of elements in soil was reflected in the element content in I. badia. The fruiting bodies from polluted sites exhibited significantly higher content of all the analyzed elements. Among 21 individual phenolic compounds only protocatechiuc and caffeic acids, and quercetin were determined in fruiting bodies of I. badia. The differences between the concentration of the quantified phenolic compounds and the total flavonoid content in fruiting bodies of I. badia from unpolluted and polluted sites were not significant. However, the greatest total phenolic content was found in fruiting bodies from the polluted areas. The antioxidative capacity of mushrooms collected from heavily polluted sites was lower than those growing in unpolluted areas. The concentrations of some metals in soil and fruiting soil were positively correlated with phenolic content and IC 50 .

Differential patterns of accumulation and retention of dietary trace elements associated with coal ash during larval development and metamorphosis of an amphibian.

PubMed

Heyes, Andrew; Rowe, Christopher L; Conrad, Phillip

2014-01-01

We performed an experiment in which larval gray tree frogs (Hyla chrysoscelis) were raised through metamorphosis on diets increased with a suite of elements associated with coal combustion residues (silver [Ag], arsenic [As], cadmium [Cd], chromium [Cr], copper [Cu], mercury [Hg], lead [Pb], selenium [Se], vanadium [V], and zinc [Zn]) at "low" and "high" concentrations. We quantified accumulation of metals at three life stages (mid-larval development, initiation of metamorphosis, and completion of metamorphosis) as well as effects on survival, metabolic rate, size at metamorphosis, and duration and loss of weight during metamorphosis. Most elements were accumulated in a dose-dependent pattern by some or all life stages, although this was not the case for Hg. For most elements, larval body burdens exceeded those of later life stages in some or all treatments (control, low, or high). However for Se, As, and Hg, body burdens in control and low concentrations were increased in later compared with earlier life stages. A lack of dose-dependent accumulation of Hg suggests that the presence of high concentrations of other elements (possibly Se) either inhibited accumulation or increased depuration of Hg. The duration of metamorphosis (forelimb emergence through tail resorption) was lengthened in individuals exposed to the highest concentrations of elements, but there were no other statistically significant biological effects. This study shows that patterns of accumulation and possibly depuration of metals and trace elements are complex in animals possessing complex life cycles. Further study is required to determine specific interactions affecting these patterns, in particular which elements may be responsible for affecting accumulation or retention of Hg when organisms are exposed to complex mixtures of elements.

Elemental Concentrations in the Seed of Mutants and Natural Variants of Arabidopsis thaliana Grown under Varying Soil Conditions

PubMed Central

McDowell, Stephen C.; Akmakjian, Garo; Sladek, Chris; Mendoza-Cozatl, David; Morrissey, Joe B.; Saini, Nick; Mittler, Ron; Baxter, Ivan; Salt, David E.; Ward, John M.; Schroeder, Julian I.; Guerinot, Mary Lou; Harper, Jeffrey F.

2013-01-01

The concentrations of mineral nutrients in seeds are critical to both the life cycle of plants as well as human nutrition. These concentrations are strongly influenced by soil conditions, as shown here by quantifying the concentration of 14 elements in seeds from Arabidopsis thaliana plants grown under four different soil conditions: standard, or modified with NaCl, heavy metals, or alkali. Each of the modified soils resulted in a unique change to the seed ionome (the mineral nutrient content of the seeds). To help identify the genetic networks regulating the seed ionome, changes in elemental concentrations were evaluated using mutants corresponding to 760 genes as well as 10 naturally occurring accessions. The frequency of ionomic phenotypes supports an estimate that as much as 11% of the A. thaliana genome encodes proteins of functional relevance to ion homeostasis in seeds. A subset of mutants were analyzed with two independent alleles, providing five examples of genes important for regulation of the seed ionome: SOS2, ABH1, CCC, At3g14280 and CNGC2. In a comparison of nine different accessions to a Col-0 reference, eight accessions were observed to have reproducible differences in elemental concentrations, seven of which were dependent on specific soil conditions. These results indicate that the A. thaliana seed ionome is distinct from the vegetative ionome, and that elemental analysis is a sensitive approach to identify genes controlling ion homeostasis, including those that regulate gene expression, phospho-regulation, and ion transport. PMID:23671651

Human Geophagia, Calabash Chalk and Undongo: Mineral Element Nutritional Implications

PubMed Central

Abrahams, Peter W.; Davies, Theo C.; Solomon, Abiye O.; Trow, Amanda J.; Wragg, Joanna

2013-01-01

The prime aim of our work is to report and comment on the bioaccessible concentrations – i.e., the soluble content of chemical elements in the gastrointestinal environment that is available for absorption – of a number of essential mineral nutrients and potentially harmful elements (PHEs) associated with the deliberate ingestion of African geophagical materials, namely Calabash chalk and Undongo. The pseudo-total concentrations of 13 mineral nutrients/PHEs were quantified following a nitric-perchloric acid digestion of nine different Calabash chalk samples, and bioaccessible contents of eight of these chemical elements were determined in simulated saliva/gastric and intestinal solutions obtained via use of the Fed ORganic Estimation human Simulation Test (FOREhST) in vitro procedure. The Calabash chalk pseudo-total content of the chemical elements is often below what may be regarded as average for soils/shales, and no concentration is excessively high. The in vitro leachate solutions had concentrations that were often lower than those of the blanks used in our experimental procedure, indicative of effective adsorption: lead, a PHE about which concern has been previously raised in connection with the consumption of Calabash chalk, was one such chemical element where this was evident. However, some concentrations in the leachate solutions are suggestive that Calabash chalk can be a source of chemical elements to humans in bioaccessible form, although generally the materials appear to be only a modest supplier: this applies even to iron, a mineral nutrient that has often been linked to the benefits of geophagia in previous academic literature. Our investigations indicate that at the reported rates of ingestion, Calabash chalk on the whole is not an important source of mineral nutrients or PHEs to humans. Similarly, although Undongo contains elevated pseudo-total concentrations of chromium and nickel, this soil is not a significant source to humans for any of the bioaccessible elements investigated. PMID:23308189

Human geophagia, calabash chalk and undongo: mineral element nutritional implications.

PubMed

Abrahams, Peter W; Davies, Theo C; Solomon, Abiye O; Trow, Amanda J; Wragg, Joanna

2013-01-01

The prime aim of our work is to report and comment on the bioaccessible concentrations - i.e., the soluble content of chemical elements in the gastrointestinal environment that is available for absorption - of a number of essential mineral nutrients and potentially harmful elements (PHEs) associated with the deliberate ingestion of African geophagical materials, namely Calabash chalk and Undongo. The pseudo-total concentrations of 13 mineral nutrients/PHEs were quantified following a nitric-perchloric acid digestion of nine different Calabash chalk samples, and bioaccessible contents of eight of these chemical elements were determined in simulated saliva/gastric and intestinal solutions obtained via use of the Fed ORganic Estimation human Simulation Test (FOREhST) in vitro procedure. The Calabash chalk pseudo-total content of the chemical elements is often below what may be regarded as average for soils/shales, and no concentration is excessively high. The in vitro leachate solutions had concentrations that were often lower than those of the blanks used in our experimental procedure, indicative of effective adsorption: lead, a PHE about which concern has been previously raised in connection with the consumption of Calabash chalk, was one such chemical element where this was evident. However, some concentrations in the leachate solutions are suggestive that Calabash chalk can be a source of chemical elements to humans in bioaccessible form, although generally the materials appear to be only a modest supplier: this applies even to iron, a mineral nutrient that has often been linked to the benefits of geophagia in previous academic literature. Our investigations indicate that at the reported rates of ingestion, Calabash chalk on the whole is not an important source of mineral nutrients or PHEs to humans. Similarly, although Undongo contains elevated pseudo-total concentrations of chromium and nickel, this soil is not a significant source to humans for any of the bioaccessible elements investigated.

Residential metal contamination and potential health risks of ...

EPA Pesticide Factsheets

Potosí, Bolivia, is the site of centuries of historic and present-day mining of the Cerro Rico Mountain, known for its rich polymetallic deposits, and was the site of large-scale Colonial era silver refining operations, both of which have left a legacy of pollution. In this study, trace elements were quantified in adobe brick, dirt floor, and surface dust samples from 49 houses. Mean concentrations of total mercury (Hg), lead (Pb), and arsenic (As) were statistically significantly greater than concentrations measured in Sucre, Bolivia, a non-mining town used as a reference site, and exceeded US-based soil screening levels that are designed to be protective of human health. Adobe brick samples were analyzed for bioaccessible concentrations of elements using a simulated gastric fluid (GF) extraction. Mean GF extractable concentrations of Hg, As, and Pb were 0.841, 14.9, and 30.2 percent of the total concentration, respectively. Total and GF extractable concentrations of these elements were used to estimate exposure and potential health risks to children following incidental ingestion of adobe brick particles. Risks were assessed using a range of potential ingestion rates (50-1000 mg/day). Although the majority of households have total Hg, As, and Pb concentrations that represent a potential health risk, fewer are of concern when GF extractable concentrations are considered at lower ingestion rates. For Hg, only a small percentage of the sampled houses have GF ex

Trace Element and Cu Isotopic Tracers of Subsurface Flow and Transport in Wastewater Irrigated Soils

NASA Astrophysics Data System (ADS)

Carte, J.; Fantle, M. S.

2017-12-01

An understanding of subsurface flow paths is critical for quantifying the fate of contaminants in wastewater irrigation systems. This study investigates the subsurface flow of wastewater by quantifying the distribution of trace contaminants in wastewater irrigated soils. Soil samples were collected from the upper 1m of two wetlands at Penn State University's wastewater irrigation site, at which all effluent from the University's wastewater treatment plant has been sprayed since 1983. Major and trace element and Cu isotopic composition were determined for these samples, in addition to wastewater effluent and bedrock samples. The upper 20 cm of each wetland shows an enrichment of Bi, Cd, Cr, Cu, Mo, Ni, Pb, and Zn concentrations relative to deep (>1m) soils at the site by a factor of 1.7-3.5. Each wetland also has a subsurface clay rich horizon with Bi, Cu, Li, Ni, Pb, and Zn concentrations enriched by a factor of 1.4 to 5 relative to deep soils. These subsurface horizons directly underlie intervals that could facilitate preferential effluent flow: a gravel layer in one wetland, and a silty loam with visible mottling, an indication of dynamic water saturation, in the other. Trace metal concentrations in other horizons from both wetlands fall in the range of the deep soils. Significant variability in Cu isotopic composition is present in soils from both wetlands, with δ65Cu values ranging from 0.74‰ to 5.09‰. Soil δ65Cu correlates well with Cu concentrations, with lighter δ65Cu associated with higher concentrations. The Cu isotopic composition of the zones of metal enrichment are comparable to the ostensible average wastewater effluent δ65Cu value (0.61‰), while other horizons have considerably heavier δ65Cu values. We hypothesize that wastewater is the source of the metal enrichments, as each of the enriched elements are present as contaminants in wastewater, and the enrichments are located in clay-rich horizons conducive to trace metal immobilization due to adsorption. This hypothesis will be further tested by modeling with the reactive transport code CrunchTope. This study provides evidence that trace element and isotopic composition of soils can be useful tracers of subsurface hydrologic pathways and elemental fate and transport.

Trace elemental analysis of human breast cancerous blood by advanced PC-WDXRF technique

NASA Astrophysics Data System (ADS)

Singh, Ranjit; Kainth, Harpreet Singh; Prasher, Puneet; Singh, Tejbir

2018-03-01

The objective of this work is to quantify the trace elements of healthy and non-healthy blood samples by using advanced polychromatic source based wavelength dispersive X-ray fluorescence (PC-WDXRF) technique. The imbalances in trace elements present in the human blood directly or indirectly lead to the carcinogenic process. The trace elements 11Na, 12Mg, 15P, 16S, 17Cl, 19K, 20Ca, 26Fe, 29Cu and 30Zn are identified and their concentrations are estimated. The experimental results clearly discuss the variation and role of various trace elements present in the non-healthy blood samples relative to the healthy blood samples. These results establish future guidelines to probe the possible roles of essential trace elements in the breast carcinogenic processes. The instrumental sensitivity and detection limits for measuring the elements in the atomic range 11 ≤ Z ≤ 30 have also been discussed in the present work.

Trace elements distribution and post-mortem intake in human bones from Middle Age by total reflection X-ray fluorescence*1

NASA Astrophysics Data System (ADS)

Carvalho, M. L.; Marques, A. F.; Lima, M. T.; Reus, U.

2004-08-01

The purpose of the present work is to investigate the suitability of TXRF technique to study the distribution of trace elements along human bones of the 13th century, to conclude about environmental conditions and dietary habits of old populations and to study the uptake of some elements from the surrounding soil. In this work, we used TXRF to quantify and to make profiles of the elements through long bones. Two femur bones, one from a man and another from a woman, buried in the same grave were cross-sectioned in four different points at a distance of 1 cm. Microsamples of each section were taken at a distance of 1 mm from each other. Quantitative analysis was performed for Ca, Mn, Fe, Cu, Zn, Sr, Ba and Pb. Very high concentrations of Mn and Fe were obtained in the whole analysed samples, reaching values higher than 2% in some samples of trabecular tissue, very much alike to the concentrations in the burial soil. A sharp decrease for both elements was observed in cortical tissue. Zn and Sr present steady concentration levels in both kinds of bone tissues. Pb and Cu show very low concentrations in the inner tissue of cortical bone. However, these concentrations increase in the regions in contact to trabecular tissue and external surface in contact with the soil, where high levels of both elements were found. We suggest that contamination from the surrounding soil exists for Mn and Fe in the whole bone tissue. Pb can be both from post-mortem and ante-mortem origin. Inner compact tissue might represent in vivo accumulation and trabecular one corresponds to uptake during burial. The steady levels of Sr and Zn together with soil concentration lower levels for these elements may allow us to conclude that they are originated from in vivo incorporation in the hydroxyapatite bone matrix.

Concentrations of metallic elements in kidney, liver, and lung tissue of Indo-Pacific bottlenose dolphin Tursiops aduncus from coastal waters of Zanzibar, Tanzania.

PubMed

Mapunda, Edgar C; Othman, Othman C; Akwilapo, Leonard D; Bouwman, Hindrik; Mwevura, Haji

2017-09-15

Concentrations of metallic elements in kidney, liver and lung tissues of Indo-Pacific bottlenose dolphins Tursiops aduncus from coastal waters of Zanzibar were determined using inductively coupled plasma - optical emission spectroscopy. Cadmium, chromium, copper, and zinc were quantifiable in all tissues at concentration ranges of 0.10-150, 0.08-3.2, 1.1-88 and 14-210μg/g dry mass, respectively. Copper and zinc was significantly higher in liver, and females had significantly higher Cd in liver, and chromium in lung. Generally, T. aduncus dolphins from coastal waters around Zanzibar carry low concentrations of metals compared with dolphins from other areas. Cadmium increased significantly with age in kidney and lung. Copper decreased significantly with age in liver, probably due to foetal metallothionein. This study supplied baseline data against which future trends in marine mammals in the Indian Ocean, the world's third largest, can be assessed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laser ablation-laser induced breakdown spectroscopy for the measurement of total elemental concentration in soils.

PubMed

Pareja, Jhon; López, Sebastian; Jaramillo, Daniel; Hahn, David W; Molina, Alejandro

2013-04-10

The performances of traditional laser-induced breakdown spectroscopy (LIBS) and laser ablation-LIBS (LA-LIBS) were compared by quantifying the total elemental concentration of potassium in highly heterogeneous solid samples, namely soils. Calibration curves for a set of fifteen samples with a wide range of potassium concentrations were generated. The LA-LIBS approach produced a superior linear response different than the traditional LIBS scheme. The analytical response of LA-LIBS was tested with a large set of different soil samples for the quantification of the total concentration of Fe, Mn, Mg, Ca, Na, and K. Results showed an acceptable linear response for Ca, Fe, Mg, and K while poor signal responses were found for Na and Mn. Signs of remaining matrix effects for the LA-LIBS approach in the case of soil analysis were found and discussed. Finally, some improvements and possibilities for future studies toward quantitative soil analysis with the LA-LIBS technique are suggested.

Elevated serum MDA and depleted non-enzymatic antioxidants, macro-minerals and trace elements are associated with bipolar disorder.

PubMed

Chowdhury, Manjurul Islam; Hasan, Maimuna; Islam, Mohammad Safiqul; Sarwar, Md Shahid; Amin, Mohammad Nurul; Uddin, S M Naim; Rahaman, Md Zahedur; Banik, Sujan; Hussain, Md Saddam; Yokota, Kazushige; Hasnat, Abul

2017-01-01

Genetic and neurobiological factors are considered to be the major causes of mood and mental disorders. However, over the past few years, increased levels of serum malondialdehyde and altered levels of various non-enzymatic antioxidants and essential minerals involved in abnormal functional activity have been identified as major contributing factors to the pathogenesis of several neurological disorders. The aim of this study was to determine the levels of the serum lipid peroxidation product malondialdehyde (MDA), antioxidants (vitamin A, E and C), macro-minerals (calcium, potassium and sodium) and trace elements (zinc, iron and selenium) in patients with bipolar disorder and to explore their role in disease progression. This is a prospective case-control study that evaluated 55 patients with bipolar disorder and 55 healthy volunteers matched by age and sex. Serum MDA levels were determined by UV spectrophotometry as a marker of lipid peroxidation. RP-HPLC was employed to investigate the serum vitamin A and E concentrations, whereas UV spectrophotometry was used to quantify levels of vitamin C. Serum macro-minerals and trace elements were analyzed by atomic absorption spectroscopy (AAS). Statistical analysis was performed with independent sample t-tests and Pearson's correlation test. We found significantly higher concentrations of MDA (p<0.05) and significantly lower concentrations of antioxidants (vitamin A, E and C) (p<0.05) in the patient group compared with control group. Regarding trace elements and macro-minerals, lower concentrations of zinc, calcium, iron, selenium, sodium and potassium were found in the patient group compared with control subjects (p<0.05). Our study suggests that high serum MDA concentrations and low serum concentrations of antioxidants, macro-minerals and trace elements are strongly associated with bipolar disorder. Copyright © 2016 Elsevier GmbH. All rights reserved.

Comparative elemental analysis of fine particulate matter (PM2.5) from industrial and residential areas in Greater Cairo-Egypt by means of a multi-secondary target energy dispersive X-ray fluorescence spectrometer

NASA Astrophysics Data System (ADS)

Shaltout, Abdallah A.; Hassan, Salwa K.; Karydas, Andreas G.; Zaki, Z. I.; Mostafa, Nasser Y.; Kregsamer, Peter; Wobrauschek, Peter; Streli, Christina

2018-07-01

Fine aerosol particles with aerodynamic diameter equal or <2.5 μm (PM2.5) have been collected from industrial and residential areas of Greater Cairo, Egypt during two different seasons namely; autumn 2014 and winter 2014/2015. Energy dispersive X-ray fluorescence (EDXRF) analysis utilizing polarization geometry and three different secondary targets (CaF2, Ge, and Mo) was employed for the quantitative analysis of eighteen (18) elements in PM2.5 samples. Light elements like Na and Mg was possible to be quantified, whereas detection limits in the range of few ng m-3 were attained for the most of the detected elements. Although, the average mass concentrations of the PM2.5 collected from the residential area (27 ± 7 μg m-3) is close to the annual mean limit value, a significant number of the collected samples (33%) presented higher average mass concentrations. For the industrial location, the average mass concentration is equal to 55 ± 19 μg m-3, exceeded twofold the annual mean limit value of the European Commission. Remarkably high elemental concentrations were determined for the most of the detected elements from the industrial area samples, clearly indicating the significant influence of anthropogenic activities. The present optimized EDXRF analysis offered significantly improved analytical range and limits of detection with respect to previous similar studies, thus enhancing our knowledge and understanding on the contribution of different pollution sources.

Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird

Treesearch

Scott F. Pearson; Douglas J. Levey; Cathryn H. Greenberg; Carlos Martinez del Rio

2003-01-01

The use of stable isotopes to infer diet requires quantifying the relationship between diet and tissues and, in particular, knowing of how quickly isotopes turnover in different tissues and how isotopic concentrations of different food components change (discriminate) when incorporated into consumer tissues. We used feeding trials with wild-caught yellow-rumped...

Spatially resolved quantification of agrochemicals on plant surfaces using energy dispersive X-ray microanalysis.

PubMed

Hunsche, Mauricio; Noga, Georg

2009-12-01

In the present study the principle of energy dispersive X-ray microanalysis (EDX), i.e. the detection of elements based on their characteristic X-rays, was used to localise and quantify organic and inorganic pesticides on enzymatically isolated fruit cuticles. Pesticides could be discriminated from the plant surface because of their distinctive elemental composition. Findings confirm the close relation between net intensity (NI) and area covered by the active ingredient (AI area). Using wide and narrow concentration ranges of glyphosate and glufosinate, respectively, results showed that quantification of AI requires the selection of appropriate regression equations while considering NI, peak-to-background (P/B) ratio, and AI area. The use of selected internal standards (ISs) such as Ca(NO(3))(2) improved the accuracy of the quantification slightly but led to the formation of particular, non-typical microstructured deposits. The suitability of SEM-EDX as a general technique to quantify pesticides was evaluated additionally on 14 agrochemicals applied at diluted or regular concentration. Among the pesticides tested, spatial localisation and quantification of AI amount could be done for inorganic copper and sulfur as well for the organic agrochemicals glyphosate, glufosinate, bromoxynil and mancozeb. (c) 2009 Society of Chemical Industry.

Incorporating concentration dependence in stable isotope mixing models.

PubMed

Phillips, Donald L; Koch, Paul L

2002-01-01

Stable isotopes are often used as natural labels to quantify the contributions of multiple sources to a mixture. For example, C and N isotopic signatures can be used to determine the fraction of three food sources in a consumer's diet. The standard dual isotope, three source linear mixing model assumes that the proportional contribution of a source to a mixture is the same for both elements (e.g., C, N). This may be a reasonable assumption if the concentrations are similar among all sources. However, one source is often particularly rich or poor in one element (e.g., N), which logically leads to a proportionate increase or decrease in the contribution of that source to the mixture for that element relative to the other element (e.g., C). We have developed a concentration-weighted linear mixing model, which assumes that for each element, a source's contribution is proportional to the contributed mass times the elemental concentration in that source. The model is outlined for two elements and three sources, but can be generalized to n elements and n+1 sources. Sensitivity analyses for C and N in three sources indicated that varying the N concentration of just one source had large and differing effects on the estimated source contributions of mass, C, and N. The same was true for a case study of bears feeding on salmon, moose, and N-poor plants. In this example, the estimated biomass contribution of salmon from the concentration-weighted model was markedly less than the standard model estimate. Application of the model to a captive feeding study of captive mink fed on salmon, lean beef, and C-rich, N-poor beef fat reproduced very closely the known dietary proportions, whereas the standard model failed to yield a set of positive source proportions. Use of this concentration-weighted model is recommended whenever the elemental concentrations vary substantially among the sources, which may occur in a variety of ecological and geochemical applications of stable isotope analysis. Possible examples besides dietary and food web studies include stable isotope analysis of water sources in soils, plants, or water bodies; geological sources for soils or marine systems; decomposition and soil organic matter dynamics, and tracing animal migration patterns. A spreadsheet for performing the calculations for this model is available at http://www.epa.gov/wed/pages/models.htm.

Titanium dioxide in dental enamel as a trace element and its variation with bleaching

PubMed Central

Durán-Sedó, Randall; Herrera-Sancho, Óscar-Andrey

2018-01-01

Background Titanium is a less studied trace element in dental enamel. Literature relates an increased Titanium concentration with a decreased enamel crystal domain size, which in turn is related to a higher color value. The aim of our study was to analyze the effect of tooth bleaching agents on its concentration in dental enamel by means of confocal Raman spectroscopy. Material and Methods Human teeth were randomly distributed in six experimental groups (n=10) and submitted to different bleaching protocols according to the manufacturer´s instructions. Confocal Raman spectroscopy was carried out in order to identify and quantify the presence of titanium dioxide molecules in enamel prior to and during whitening. Statistical analysis included repeated measures analysis of variance (p≤0.05) and Bonferroni pairwise comparisons. Results Titanium dioxide concentration was negatively affected by the longer bleaching protocols (at-home bleaching gels). All in-office whitening products increased significantly the studied molecule (p≤0,05). Conclusions All dental specimens depicted the presence of titanium dioxide as a trace element in dental enamel. Bleaching gels that have to be applied at higher concentrations but for shorter periods of time increase the concentration of titanium dioxide, whilst at-home whitening gels used for longer periods of time despite the lower concentration caused a loss in titanium. Key words:Bleaching, whitening, hydrogen peroxide, carbamide peroxide, Raman spectroscopy, titanium dioxide. PMID:29930771

Titanium dioxide in dental enamel as a trace element and its variation with bleaching.

PubMed

Vargas-Koudriavtsev, Tatiana; Durán-Sedó, Randall; Herrera-Sancho, Óscar-Andrey

2018-06-01

Titanium is a less studied trace element in dental enamel. Literature relates an increased Titanium concentration with a decreased enamel crystal domain size, which in turn is related to a higher color value. The aim of our study was to analyze the effect of tooth bleaching agents on its concentration in dental enamel by means of confocal Raman spectroscopy. Human teeth were randomly distributed in six experimental groups (n=10) and submitted to different bleaching protocols according to the manufacturer´s instructions. Confocal Raman spectroscopy was carried out in order to identify and quantify the presence of titanium dioxide molecules in enamel prior to and during whitening. Statistical analysis included repeated measures analysis of variance ( p ≤0.05) and Bonferroni pairwise comparisons. Titanium dioxide concentration was negatively affected by the longer bleaching protocols (at-home bleaching gels). All in-office whitening products increased significantly the studied molecule ( p ≤0,05). All dental specimens depicted the presence of titanium dioxide as a trace element in dental enamel. Bleaching gels that have to be applied at higher concentrations but for shorter periods of time increase the concentration of titanium dioxide, whilst at-home whitening gels used for longer periods of time despite the lower concentration caused a loss in titanium. Key words: Bleaching, whitening, hydrogen peroxide, carbamide peroxide, Raman spectroscopy, titanium dioxide.

Quantifying sources of elemental carbon over the Guanzhong Basin of China: A consistent network of measurements and WRF-Chem modeling.

PubMed

Li, Nan; He, Qingyang; Tie, Xuexi; Cao, Junji; Liu, Suixin; Wang, Qiyuan; Li, Guohui; Huang, Rujin; Zhang, Qiang

2016-07-01

We conducted a year-long WRF-Chem (Weather Research and Forecasting Chemical) model simulation of elemental carbon (EC) aerosol and compared the modeling results to the surface EC measurements in the Guanzhong (GZ) Basin of China. The main goals of this study were to quantify the individual contributions of different EC sources to EC pollution, and to find the major cause of the EC pollution in this region. The EC measurements were simultaneously conducted at 10 urban, rural, and background sites over the GZ Basin from May 2013 to April 2014, and provided a good base against which to evaluate model simulation. The model evaluation showed that the calculated annual mean EC concentration was 5.1 μgC m(-3), which was consistent with the observed value of 5.3 μgC m(-3). Moreover, the model result also reproduced the magnitude of measured EC in all seasons (regression slope = 0.98-1.03), as well as the spatial and temporal variations (r = 0.55-0.78). We conducted several sensitivity studies to quantify the individual contributions of EC sources to EC pollution. The sensitivity simulations showed that the local and outside sources contributed about 60% and 40% to the annual mean EC concentration, respectively, implying that local sources were the major EC pollution contributors in the GZ Basin. Among the local sources, residential sources contributed the most, followed by industry and transportation sources. A further analysis suggested that a 50% reduction of industry or transportation emissions only caused a 6% decrease in the annual mean EC concentration, while a 50% reduction of residential emissions reduced the winter surface EC concentration by up to 25%. In respect to the serious air pollution problems (including EC pollution) in the GZ Basin, our findings can provide an insightful view on local air pollution control strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recurrence quantification analysis to characterize cyclical components of environmental elemental exposures during fetal and postnatal development

PubMed Central

Austin, Christine; Gennings, Chris; Tammimies, Kristiina; Bölte, Sven; Arora, Manish

2017-01-01

Environmental exposures to essential and toxic elements may alter health trajectories, depending on the timing, intensity, and mixture of exposures. In epidemiologic studies, these factors are typically analyzed as a function of elemental concentrations in biological matrices measured at one or more points in time. Such an approach, however, fails to account for the temporal cyclicity in the metabolism of environmental chemicals, which if perturbed may lead to adverse health outcomes. Here, we conceptualize and apply a non-linear method–recurrence quantification analysis (RQA)–to quantify cyclical components of prenatal and early postnatal exposure profiles for elements essential to normal development, including Zn, Mn, Mg, and Ca, and elements associated with deleterious health effects or narrow tolerance ranges, including Pb, As, and Cr. We found robust evidence of cyclical patterns in the metabolic profiles of nutrient elements, which we validated against randomized twin-surrogate time-series, and further found that nutrient dynamical properties differ from those of Cr, As, and Pb. Furthermore, we extended this approach to provide a novel method of quantifying dynamic interactions between two environmental exposures. To achieve this, we used cross-recurrence quantification analysis (CRQA), and found that elemental nutrient-nutrient interactions differed from those involving toxicants. These rhythmic regulatory interactions, which we characterize in two geographically distinct cohorts, have not previously been uncovered using traditional regression-based approaches, and may provide a critical unit of analysis for environmental and dietary exposures in epidemiological studies. PMID:29112980

Correlation and transport properties for mixtures at constant pressure and temperature

NASA Astrophysics Data System (ADS)

White, Alexander J.; Collins, Lee A.; Kress, Joel D.; Ticknor, Christopher; Clérouin, Jean; Arnault, Philippe; Desbiens, Nicolas

2017-06-01

Transport properties of mixtures of elements in the dense plasma regime play an important role in natural astrophysical and experimental systems, e.g., inertial confinement fusion. We present a series of orbital-free molecular dynamics simulations on dense plasma mixtures with comparison to a global pseudo ion in jellium model. Hydrogen is mixed with elements of increasingly high atomic number (lithium, carbon, aluminum, copper, and silver) at a fixed temperature of 100 eV and constant pressure set by pure hydrogen at 2 g/cm 3 , namely, 370 Mbars. We compute ionic transport coefficients, such as self-diffusion, mutual diffusion, and viscosity for various concentrations. Small concentrations of the heavy atoms significantly change the density of the plasma and decrease the transport coefficients. The structure of the mixture evidences a strong Coulomb coupling between heavy ions and the appearance of a broad correlation peak at short distances between hydrogen atoms. The concept of an effective one component plasma is used to quantify the overcorrelation of the light element induced by the admixture of a heavy element.

Correlation and transport properties for mixtures at constant pressure and temperature

DOE PAGES

White, Alexander J.; Collins, Lee A.; Kress, Joel D.; ...

2017-06-02

Transport properties of mixtures of elements in the dense plasma regime play an important role in natural astrophysical and experimental systems, e.g., inertial confinement fusion. In this paper, we present a series of orbital-free molecular dynamics simulations on dense plasma mixtures with comparison to a global pseudo ion in jellium model. Hydrogen is mixed with elements of increasingly high atomic number (lithium, carbon, aluminum, copper, and silver) at a fixed temperature of 100 eV and constant pressure set by pure hydrogen at 2g/cm 3, namely, 370 Mbars. We compute ionic transport coefficients, such as self-diffusion, mutual diffusion, and viscosity formore » various concentrations. Small concentrations of the heavy atoms significantly change the density of the plasma and decrease the transport coefficients. The structure of the mixture evidences a strong Coulomb coupling between heavy ions and the appearance of a broad correlation peak at short distances between hydrogen atoms. Finally, the concept of an effective one component plasma is used to quantify the overcorrelation of the light element induced by the admixture of a heavy element.« less

Correlation and transport properties for mixtures at constant pressure and temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, Alexander J.; Collins, Lee A.; Kress, Joel D.

Transport properties of mixtures of elements in the dense plasma regime play an important role in natural astrophysical and experimental systems, e.g., inertial confinement fusion. In this paper, we present a series of orbital-free molecular dynamics simulations on dense plasma mixtures with comparison to a global pseudo ion in jellium model. Hydrogen is mixed with elements of increasingly high atomic number (lithium, carbon, aluminum, copper, and silver) at a fixed temperature of 100 eV and constant pressure set by pure hydrogen at 2g/cm 3, namely, 370 Mbars. We compute ionic transport coefficients, such as self-diffusion, mutual diffusion, and viscosity formore » various concentrations. Small concentrations of the heavy atoms significantly change the density of the plasma and decrease the transport coefficients. The structure of the mixture evidences a strong Coulomb coupling between heavy ions and the appearance of a broad correlation peak at short distances between hydrogen atoms. Finally, the concept of an effective one component plasma is used to quantify the overcorrelation of the light element induced by the admixture of a heavy element.« less

Near-real-time trace element measurements in a rural, traffic-influenced environment with some fireworks

NASA Astrophysics Data System (ADS)

Furger, Markus; Slowik, Jay G.; Cruz Minguillón, María; Hueglin, Christoph; Koch, Chris; Prévôt, André S. H.; Baltensperger, Urs

2016-04-01

Aerosol-bound trace elements can affect the environment in significant ways especially when they are toxic. Characterizing the trace element spatial and temporal variability is a prerequisite for human exposure studies. The requirement for high time resolution and consequently the low sample masses asked for analysis methods not easily accessible, such as synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF). In recent years, instrumentation that samples and analyzes airborne particulate matter with time resolutions of less than an hour in near real time has entered the market. We present the results of a three-week campaign in a rural environment close to a freeway. The measurement period included the fireworks of the Swiss National Day. The XRF instrument was set up at the monitoring station Härkingen of the Swiss Monitoring Network for Air Pollution (NABEL). It was configured to sample and analyze ambient PM10 aerosols in 1-hour intervals. Sample analysis with XRF was performed by the instrument immediately after collection, i.e. during the next sampling interval. 24 elements were analyzed and quantified (Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sn, Sb, Ba, Pt, Hg, Pb, Bi). The element concentrations obtained by the XRF instrument were compared to those determined by ICP-AES and ICP-MS in PM10 samples collected by NABEL high volume samplers. The results demonstrate the capability of the instrument to measure over a wide range of concentrations, from a few ng m-3 to μg m-3, under ambient conditions. The time resolution allows for the characterization of diurnal variations of element concentrations, which provides information on the contribution of emission sources, such as road traffic, soil, or fireworks. Some elements (V, Co, As, Pt) were below their detection limit during most of the time, but As could be quantified during the fireworks. Transition metals Cr, Mn, Fe, Cu, Zn could be attributed to freeway traffic. K, S, Ba, and Bi were strongly linked to the fireworks. The field test provided good evidence for the applicability and ease of use of the instrument. It provided also an idea on the sensitivity of the method in realistic, ambient conditions, although the 3-week period was too short for a thorough assessment, e.g. for different weather conditions.

Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry.

PubMed

Richaud, R; Lazaro, M J; Lachas, H; Miller, B B; Herod, A A; Dugwell, D R; Kandiyoti, R

2000-01-01

1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were in the extract; for the coal, approximately 8% (at room temperature) and 23% (at 202 degrees C) were in the extract. For the ash, only 1.4% of the trace elements were extracted at 202 degrees C, comprising 25% of Cd but less than 1% of Pb. Copyright 2000 John Wiley & Sons, Ltd.

Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model

USGS Publications Warehouse

Bern, Carleton R.; Thompson, Aaron; Chadwick, Oliver A.

2015-01-01

Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies the contribution of aqueous versus colloidal element transfer. In the model, the high field strength elements Ti and Zr are assumed to be mobile only as suspended solids (colloids) and can therefore be used to distinguish elemental redistribution via colloids from redistribution via dissolved aqueous solutes. Calculations are based upon element concentrations in soil, parent material, and colloids dispersed from soil in the laboratory. We illustrate the utility of this model using a catena in South Africa. Traditional mass balance models systematically distort elemental gains and losses and changes in soil volume in this catena due to significant redistribution of Zr-bearing colloids. Applying the dual-phase model accounts for this colloidal redistribution and we find that the process accounts for a substantial portion of the major element (e.g., Al, Fe and Si) loss from eluvial soil. In addition, we find that in illuvial soils along this catena, gains of colloidal material significantly offset aqueous elemental loss. In other settings, processes such as accumulation of exogenous dust can mimic the geochemical effects of colloid redistribution and we suggest strategies for distinguishing between the two. The movement of clays and colloidal material is a major process in weathering and pedogenesis; the mass balance model presented here is a tool for quantifying effects of that process over time scales of soil development.

Exoskeleton Heterogeneity in Crustaceans: Quantifying Compositional and Structural Variations Across Body Parts

NASA Astrophysics Data System (ADS)

Ulrich, R. N.; Mergelsberg, S. T.; Dove, P. M.

2016-12-01

Crustacean exoskeletons are a complex biocomposite of organic macromolecules and calcium carbonate minerals. The highly divergent functions and diverse morphologies of these biominerals across taxa raise the question of whether these differences are systematically reflected in exoskeleton composition and structure. Previous studies that investigated element concentrations in exoskeletons used spectroscopic methods. However, the findings were largely inconclusive because of analytical limitations and most studies concluded that magnesium, phosphorus, and other trace elements are mostly contained in the mineral fraction because concentrations in the organic framework could not be resolved. This experimental study was designed to quantify the distributions of Ca, P, Mg, and Sr in the mineral versus organic fractions of exoskeletons from the American Lobster (H. americanus), Dungeness Crab (M. magister), and Red Rock Crab (M. productus). Samples of exoskeleton from 10 body parts were collected in triplicate and dissolved using three procedures specific to extracting the 1) mineral, 2) protein, and 3) chitin phases separately. Chemical analyses of the resulting effluents using ICP-OES show the mineral fraction of the skeleton can contain significant amounts of mineralized Mg and P particularly for body parts associated with a significant difference in mineral structural ordering. The protein fraction contains more Mg and P than expected based on estimates from previous studies (Hild et al., 2008). While the element distributions vary greatly depending on the location, in body parts with thicker cuticle (e.g. claw) the mineral component appears to control overall composition. The findings have implications for paleoenvironmental reconstructions based upon exoskeleton composition. First, the chemical composition of an exoskeleton cannot be assumed constant across the different body parts of an entire organism. This is particularly true when the exoskeleton of the claw is compared to other body parts. We also show a significant fraction of minor and trace elements contained in an exoskeleton are associated with the organic component. Element concentrations obtained from bulk measurements of exoskeletons cannot be assigned to the mineral fraction without imposing a bias on biomineral composition.

Study of the chemical composition of particulate matter from the Rio de Janeiro metropolitan region, Brazil, by inductively coupled plasma-mass spectrometry and optical emission spectrometry

NASA Astrophysics Data System (ADS)

Mateus, Vinícius Lionel; Monteiro, Isabela Luizi Gonçalves; Rocha, Rafael Christian Chávez; Saint'Pierre, Tatiana Dillenburg; Gioda, Adriana

2013-08-01

Air quality in the metropolitan region of Rio de Janeiro was evaluated by analysis of particulate matter (PM) in industrial (Santa Cruz) and rural (Seropédica) areas. Total suspended particles (TSP) and fine particulate matter (PM2.5) collected in filters over 24 h were quantified and their chemical composition determined. TSP exceeded Brazilian guidelines (80 μg m- 3) in Santa Cruz, while PM2.5 levels exceeded the World Health Organization guidelines (10 μg m- 3) in both locations. Filters were extracted with water and/or HNO3, and the concentrations of 20 elements, mostly metals, were determined by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP OES). Water soluble inorganic anions were determined by ion chromatography (IC). To estimate the proportion of these elements extracted, a certified reference material (NIST SRM 1648a, Urban Dust) was subjected to the same extraction process. Concordant results were obtained by ICP-MS and ICP OES for most elements. Some elements could not be quantified by both techniques; the most appropriate technique was chosen in each case. The urban dust was also analyzed by the United States Environmental Protection Agency (US EPA) method, which employs a combination of hydrochloric and nitric acids for the extraction, but higher extraction efficiency was obtained when only nitric acid was employed. The US EPA method gave better results only for Sb. In the PM samples, the elements found in the highest average concentrations by ICP were Zn and Al (3-6 μg m- 3). The anions found in the highest average concentrations were SO42 - in PM2.5 (2-4 μg m- 3) and Cl- in TSP (2-6 μg m- 3). Principal component analysis (PCA) in combination with enrichment factors (EF) indicated industrial sources in PM2.5. Analysis of TSP suggested both anthropogenic and natural sources. In conclusion, this work contributes data on air quality, as well as a method for the analysis of PM samples by ICP-MS.

Geosphere-biosphere circulation of chemical elements in soil and plant systems from a 100 km transect from southern central Norway.

PubMed

Reimann, Clemens; Fabian, Karl; Flem, Belinda; Andersson, Malin; Filzmoser, Peter; Englmaier, Peter

2018-05-17

Geochemical element separation is studied in 14 different sample media collected at 41 sites along an approximately 100-km long transect north of Oslo. At each site, soil C and O horizons and 12 plant materials (birch/spruce/cowberry/blueberry leaves/needles and twigs, horsetail, braken fern, pine bark and terrestrial moss) were sampled. The observed concentrations of 29 elements (K, Ca, P, Mg, Mn, S, Fe, Zn, Na, B, Cu, Mo, Co, Al, Ba, Rb, Sr, Ti, Ni, Pb, Cs, Cd, Ce, Sn, La, Tl, Y, Hg, Ag) were used to investigate soil-plant relations, and to evaluate the element differentiation between different plants, or between foliage and twigs of the same plant. In relation to the soil C horizon, the O horizon is strongly enriched (O/C ratio > 5) in Ag, Hg, Cd, Sn, S and Pb. Other elements (B, K, Ca, P, S, Mn) show higher concentrations in the plants than in the substrate represented by the C horizon, and often even higher concentrations than in the soil O horizon. Elements like B, K, Ca, S, Mg, P, Ba, and Cu are well tuned to certain concentration levels in most of the plants. This is demonstrated by their lower interquartile variability in the plants than in the soil. Cross-plots of element concentration, variance, and ratios, supported by linear discrimination analysis, establish that different plants are marked by their individual element composition, which is separable from, and largely independent of the natural substrate variability across the Gjøvik transect. Element allocation to foliage or twigs of the same plants can also be separated and thus dominantly depend on metabolism, physiology, and structure linked to biological functions, and only to a lesser degree on the substrate and environmental background. The results underline the importance of understanding the biological mechanisms of plant-soil interaction in order to correctly quantify anthropogenic impact on soil and plant geochemistry. Copyright © 2018 Elsevier B.V. All rights reserved.

Exposure assessment of carbon nanotubes at pilot factory focusing on quantitative determination of catalytic metals.

PubMed

Kato, Nobuyuki; Nagaya, Taiki; Matsui, Yasuto; Yoneda, Minoru

2017-11-25

The application of multiwall carbon nanotubes (MWCNTs) currently extends to various fields. However, it has been reported that exposure to CNT causes hazardous effects on animals and cells. The purpose of this study was to quantify the exposure to MWCNT in MWCNT/polymer composites for exposure assessment. We focused on catalytic metals included in the MWCNT and the diameter of dust released during the working processes. Although the Co in MWCNTs is not a common catalyst, it was used as a tracer in this study. A field survey was conducted in a MWCNT/polymer composite pilot factory. Airborne MWCNTs were monitored using black carbon monitors (BCMs) and optical particle sizers (OPSs) and collected on a filter. The MWCNT powder, all polymer resins used during the working processes, and the filter were analyzed in our lab using inductively coupled plasma mass spectrometry (ICP-MS) and electron microscopic observation. The mean concentration of airborne MWCNT contained in the collected dust was 0.92 μg/m 3 a few meters away from the extruder during the working processes (using elemental analysis). The maximum concentration measured using BCMs was shown to be seven times higher than the base concentration during the pelletizing process of polycarbonate (PC) and MWCNT composites. However, free, isolated, and unbound agglomerated MWCNTs were not detected using scanning electron microscopic (SEM) observation. The result obtained by elemental analysis indicated it was possible to quantify MWCNT in composites. The mean concentration at this factory was lower than the recommended exposure limit. However, additional studies during the pelletizing process are required in the future.

Biomonitoring of genotoxic effects and elemental accumulation derived from air pollution in community urban gardens.

PubMed

Amato-Lourenco, Luís Fernando; Lobo, Debora Jã A; Guimarães, Eliane T; Moreira, Tiana Carla Lopes; Carvalho-Oliveira, Regiani; Saiki, Mitiko; Saldiva, Paulo Hilário Nascimento; Mauad, Thais

2017-01-01

Urban gardening is a growing global phenomenon with a positive impact on society. Despite several associated benefits, growing vegetables in urban gardens that are localized in highly polluted areas poses questions about the safety of the produced food. Therefore, the identification of risk factors that result in possible deleterious effects to human health is important for realizing all of the benefits to society. We evaluated the use of two biomonitoring methods in ten urban gardens of Sao Paulo city and one control site: the micronuclei frequencies for early tetrads of Tradescantia pallida (Rose) Hunt. cv. "Purpurea" Boom (hereafter, Trad-MCN) as a short-term indicator of genotoxic response and tree barks to quantify the accumulation of traffic-related chemical elements as a long-term biomarker of air pollution in urban gardens. Mature plants of Tradescantia pallida were exposed in each garden, and their inflorescences were sampled over three months. A random set of 300 early tetrads in 13 to 21 slides per garden were evaluated for micronuclei frequencies. Elemental concentrations in 428 tree barks samples from 107 different trees in the areas surrounding urban gardens were quantified using an energy dispersive X-ray fluorescence spectrometer. The frequency of Trad-MCN has a significant correlation with traffic variables and chemical elements related to road dust and tailpipe emissions deposited in tree barks. Negative associations between Trad-MCN and both the distance through traffic and the presence of vertical obstacles were observed in the community gardens. The Mn/Zn concentrations in tree barks were associated with increased Trad-MCN. Copyright © 2016 Elsevier B.V. All rights reserved.

Concentrations of selected essential and non-essential elements in arctic fox (Alopex lagopus) and wolverines (Gulo gulo) from the Canadian Arctic.

PubMed

Hoekstra, P F; Braune, B M; Elkin, B; Armstrong, F A J; Muir, D C G

2003-06-20

Arctic fox (Alopex lagopus) and wolverine (Gulo gulo) tissues were collected in the Canadian Arctic from 1998 to 2001 and analyzed for various essential and non-essential elements. Several elements (Ag, Al, As, B, Ba, Be, Co, Cr, Mo, Ni, Sb, Sn, Sr, Tl, U and V) were near or below the detection limits in >95% arctic fox and wolverine samples. Concentrations of Cd, Cu, Fe, total Hg (THg), Mn, Pb, Se and Zn were quantifiable in >50% of the samples analyzed and reported herein. Hepatic elemental concentrations were not significantly different among arctic foxes collected at Ulukhaqtuuq (Holman), NT (n=13) and Arviat, NU (n=50), but were significantly greater than concentrations found in wolverine liver from Kugluktuk (Coppermine), NU (n=12). The mean (+/-1 S.E.) concentrations of Cd in kidney were also significantly greater in arctic fox (1.08+/-0.19 microg g(-1) wet wt.) than wolverine (0.67+/-0.18 microg g(-1) wet wt.). However, mean hepatic Cu concentrations (Ulukhaqtuuq: 5.5+/-0.64; Arviat: 7.1+/-0.49 microg g(-1) wet wt.) in arctic foxes were significantly lower than in wolverines (32+/-3.3 microg g(-1) wet wt.). Hepatic total Hg (THg) concentrations in arctic fox from this study were not significantly different from specimens collected in 1973, suggesting that THg concentrations have not changed dramatically over the past 30 years. The mono-methylmercury (MeHg) concentrations in selected (n=10) arctic fox liver samples from Arviat (0.14+/-0.07 microg g(-1) wet wt.) comprised 14% of THg. While the molar concentrations of THg were correlated with Se in arctic foxes and wolverines, the hepatic Hg/Se molar ratios were consistently lower than unity; suggesting that Se-mediated detoxification pathways of Hg are not overwhelmed at current exposure.

Serum protein measurement using a tapered fluorescent fibre-optic evanescent wave-based biosensor

NASA Astrophysics Data System (ADS)

Preejith, P. V.; Lim, C. S.; Chia, T. F.

2006-12-01

A novel method to measure the total serum protein concentration is described in this paper. The method is based on the principles of fibre-optic evanescent wave spectroscopy. The biosensor applies a fluorescent dye-immobilized porous glass coating on a multi-mode optical fibre. The evanescent wave's intensity at the fibre-optic core-cladding interface is used to monitor the protein-induced changes in the sensor element. The sensor offers a rapid, single-step method for quantifying protein concentrations without destroying the sample. This unique sensing method presents a sensitive and accurate platform for the quantification of protein.

Effect of Silicon on Activity Coefficients of Siderophile Elements (P, Au, Pd, As, Ge, Sb, and In) in Liquid Fe, with Application to Core Formation

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K.; Danielson, L. R.; Humayun, M.; Righter, M.; Lapen, T.; Boujibar, A.

2016-01-01

Earth's core contains approximately 10 percent light elements that are likely a combination of S, C, Si, and O, with Si possibly being the most abundant. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE) in Fe liquids, and thus the partitioning behavior of those elements between core and mantle. The effect of Si can be small such as for Ni and Co, or large such as for Mo, Ge, Sb, As. The effect of Si on many siderophile elements is unknown yet could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of P, Au, Pd, and many other SE between metal and silicate melt. The results will be applied to Earth, for which we have excellent constraints on the mantle siderophile element concentrations.

Characterization of elemental and polycyclic aromatic hydrocarbon compositions of urban air in Brisbane

NASA Astrophysics Data System (ADS)

Lim, McKenzie C. H.; Ayoko, Godwin A.; Morawska, Lidia

Characterization of the elemental and polycyclic aromatic hydrocarbons (PAHs) compositions of urban air was undertaken at three major sites in Brisbane, Australia. 17 elements and 16 US EPA priority PAHs were quantified at the sites. The most commonly detected elements in the TSP and PM 2.5 fractions were Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Si, Sn, Sr and Zn. Compared to the two other sites, PM 2.5 was found to contain higher concentrations of Zr, Mo, V, Al, Mn and Sr at the Queensland University of Technology (QUT) site. In contrast, the Woolloongabba sampling site, which was highly influenced by the vehicular emission and local industrial activities, has higher concentrations of Co, Sn, Cu, Zn and Mg while ANZ site has significantly lower concentration levels of most elements than the other sites; possibly due to the shielding effect of the nearby bush and forest. NAP, PHE, ANT, FLT, PYR and CRY were the most widespread PAHs found in all sites. But only QUT and Woolloongabba bus platform sites had detectable levels of the most carcinogenic US EPA PAH, BAP. The multi-criteria decision making procedures, Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Geometrical Analysis for Interactive Aid (GAIA) were used to rank the air samples and to identify the sources of the pollutants. Thus Woolloongabba bus platform was ranked as the most polluted site on the basis of the elemental and PAH compositions of its air samples while Woolloongabba bus platform and QUT sites were ranked as the worst polluted sites in terms of PAHs and PM 2.5 elemental contents, respectively.

Quantitative analysis of biomedical samples using synchrotron radiation microbeams

NASA Astrophysics Data System (ADS)

Ektessabi, Ali; Shikine, Shunsuke; Yoshida, Sohei

2001-07-01

X-ray fluorescence (XRF) using a synchrotron radiation (SR) microbeam was applied to investigate distributions and concentrations of elements in single neurons of patients with neurodegenerative diseases. In this paper we introduce a computer code that has been developed to quantify the trace elements and matrix elements at the single cell level. This computer code has been used in studies of several important neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and parkinsonism-dementia complex (PDC), as well as in basic biological experiments to determine the elemental changes in cells due to incorporation of foreign metal elements. The substantial nigra (SN) tissue obtained from the autopsy specimens of patients with Guamanian parkinsonism-dementia complex (PDC) and control cases were examined. Quantitative XRF analysis showed that neuromelanin granules of Parkinsonian SN contained higher levels of Fe than those of the control. The concentrations were in the ranges of 2300-3100 ppm and 2000-2400 ppm respectively. On the contrary, Zn and Ni in neuromelanin granules of SN tissue from the PDC case were lower than those of the control. Especially Zn was less than 40 ppm in SN tissue from the PDC case while it was 560-810 ppm in the control. These changes are considered to be closely related to the neuro-degeneration and cell death.

Trace analysis of high-purity graphite by LA-ICP-MS.

PubMed

Pickhardt, C; Becker, J S

2001-07-01

Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a very efficient and sensitive technique for the direct analysis of solids. In this work the capability of LA-ICP-MS was investigated for determination of trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose of quantifying the analytical results. Doped trace elements, concentration 0.5 microg g(-1), in a laboratory standard were determined with an accuracy of 1% to +/- 7% and a relative standard deviation (RSD) of 2-13%. Solution-based calibration was also used for quantitative analysis of high-purity graphite. It was found that such calibration led to analytical results for trace-element determination in graphite with accuracy similar to that obtained by use of synthetic laboratory standards for quantification of analytical results. Results from quantitative determination of trace impurities in a real reactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all elements of interest were determined in the low ng g(-1) concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite with LA-ICP-MS under wet plasma conditions, because the lower background signal and increased element sensitivity.

The influence of carbon, sulfur, and silicon on trace element partitioning in iron alloys

NASA Astrophysics Data System (ADS)

Han, J.; Van Orman, J. A.; Crispin, K. L.; Ash, R. D.

2014-12-01

Non-metallic light elements are important constituents of planetary cores and have a strong influence on the partitioning behavior of trace elements. Planetary cores may contain a wide range of non-metallic light elements, including H, N, S, P, Si, and C. Under highly reducing conditions, such as those that are thought to have pertained during the formation of Mercury's core, Si and C, in addition to sulfur, may be particularly important constituents. Each of these elements may strongly effect and have a different impact on the partitioning behavior of trace elements but their combined effects on trace element partitioning have not been quantified. We investigated the partitioning behavior of more than 25 siderophile trace elements within the Fe-S-C-Si system with varying concentrations of C, S, and Si. The experiments were performed under pressures varying from 1 atm to 2 GPa and temperatures ranging from 1200˚C to 1450˚C. All experiments produced immiscible liquids, one enriched in Si and C, and the other predominantly FeS. We found some highly siderophile elements including Os, Ru, Ir, and Re are much more enriched in Fe-Si-C phase than in Fe-S phase, whereas other trace elements like V, Co, Ag, Hf, and Pb are enriched in S-rich phase. However, not all the trace elements enriched in Fe-Si-C phase are repelled by sulfur. Elements like Re and Ru could have different partitioning trends if sulfur concentration in S-rich phase rises. The partitioning behavior of these trace elements could enhance our understanding of the differentiation of Mercury's core under oxygen-poor conditions.

Exposure assessment of carbon nanotubes at pilot factory focusing on quantitative determination of catalytic metals

PubMed Central

Kato, Nobuyuki; Nagaya, Taiki; Matsui, Yasuto; Yoneda, Minoru

2017-01-01

Objectives: The application of multiwall carbon nanotubes (MWCNTs) currently extends to various fields. However, it has been reported that exposure to CNT causes hazardous effects on animals and cells. The purpose of this study was to quantify the exposure to MWCNT in MWCNT/polymer composites for exposure assessment. We focused on catalytic metals included in the MWCNT and the diameter of dust released during the working processes. Although the Co in MWCNTs is not a common catalyst, it was used as a tracer in this study. Methods: A field survey was conducted in a MWCNT/polymer composite pilot factory. Airborne MWCNTs were monitored using black carbon monitors (BCMs) and optical particle sizers (OPSs) and collected on a filter. The MWCNT powder, all polymer resins used during the working processes, and the filter were analyzed in our lab using inductively coupled plasma mass spectrometry (ICP-MS) and electron microscopic observation. Results: The mean concentration of airborne MWCNT contained in the collected dust was 0.92 μg/m3 a few meters away from the extruder during the working processes (using elemental analysis). The maximum concentration measured using BCMs was shown to be seven times higher than the base concentration during the pelletizing process of polycarbonate (PC) and MWCNT composites. However, free, isolated, and unbound agglomerated MWCNTs were not detected using scanning electron microscopic (SEM) observation. Conclusions: The result obtained by elemental analysis indicated it was possible to quantify MWCNT in composites. The mean concentration at this factory was lower than the recommended exposure limit. However, additional studies during the pelletizing process are required in the future. PMID:28993572

Elemental assessment of vegetation via portable X-ray fluorescence (PXRF) spectrometry.

PubMed

McGladdery, Candice; Weindorf, David C; Chakraborty, Somsubhra; Li, Bin; Paulette, Laura; Podar, Dorina; Pearson, Delaina; Kusi, Nana Yaw O; Duda, Bogdan

2018-03-15

Elemental concentrations in vegetation are of critical importance, whether establishing plant essential element concentrations (toxicity vs. deficiency) or investigating deleterious elements (e.g., heavy metals) differentially extracted from the soil by plants. Traditionally, elemental analysis of vegetation has been facilitated by acid digestion followed by quantification via inductively coupled plasma (ICP) or atomic absorption (AA) spectroscopy. Previous studies have utilized portable X-ray fluorescence (PXRF) spectroscopy to quantify elements in soils, but few have evaluated the vegetation. In this study, a PXRF spectrometer was employed to scan 228 organic material samples (thatch, deciduous leaves, grasses, tree bark, and herbaceous plants) from smelter-impacted areas of Romania, as well as National Institute of Standards and Technology (NIST) certified reference materials, to demonstrate the application of PXRF for elemental determination in vegetation. Samples were scanned in three conditions: as received from the field (moist), oven dry (70 °C), and dried and powdered to pass a 2 mm sieve. Performance metrics of PXRF models relative to ICP atomic emission spectroscopy were developed to asses optimal scanning conditions. Thatch and bark samples showed the highest mean PXRF and ICP concentrations (e.g., Zn, Pb, Cd, Fe), with the exceptions of K and Cl. Validation statistics indicate that the stable validation predictive capacity of PXRF increased in the following order: oven dry intact < field moist < oven dried and powdered. Even under field moist conditions, PXRF could reasonably be used for the determination of Zn (coefficient of determination, R 2 val 0.86; residual prediction deviation, RPD 2.72) and Cu (R 2 val 0.77; RPD 2.12), while dried and powdered samples allowed for stable validation prediction of Pb (R 2 val 0.90; RPD 3.29), Fe (R 2 val 0.80; RPD 2.29), Cd (R 2 val 0.75; RPD 2.07) and Cu (R 2 val 0.98; RPD of 8.53). Summarily, PXRF was shown to be a useful approach for quickly assessing the elemental concentration in vegetation. Future PXRF/vegetation research should explore additional elements and investigate its usefulness in evaluating phytoremediation effectiveness. Copyright © 2018 Elsevier Ltd. All rights reserved.

Organic compounds and trace elements in the Pocomoke River and its tributaries

USGS Publications Warehouse

Miller, Cherie V.; Foster, Gregory D.; Huff, Thomas B.; Garbarino, John R.

1999-01-01

In response to concern about recent blooms of the dinoflagellate, Pfiesteria piscicida, samples of sediment and water were collected from the lower Pocomoke River Basin and were screened for trace elements, pesticides, and other organic compounds. A large group of steroid and fatty acid methyl-ester compounds was detected in streamwater using gas chromatography/mass spectroscopy in scan mode. Some of these steroid compounds have been identified and further quantified in bed-sediment extracts. Spatial patterns of the concentrations of cholesterol suggest that these compounds are linked to the runoff of animal wastes into the river. Many of the organic compounds found in the Pocomoke River sediments have not yet been identified, but at least several are in the class of hormone compounds related to estradiols and have the potential to promote endocrine-disrupting effects in aquatic life. Particulate forms of arsenic and zinc are slightly elevated above normal levels for streams, but the sources for these elements are still undetermined. Several pesticides were found in low, parts-per-trillion concentrations, but were within the ranges commonly found in streams of this region.

Trace element and isotope deposition across the air–sea interface: progress and research needs

PubMed Central

Landing, W. M.; Bucciarelli, E.; Cheize, M.; Fietz, S.; Hayes, C. T.; Kadko, D.; Morton, P. L.; Rogan, N.; Sarthou, G.; Shelley, R. U.; Shi, Z.; Shiller, A.; van Hulten, M. M. P.

2016-01-01

The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’. PMID:29035268

Trace element and isotope deposition across the air-sea interface: progress and research needs

NASA Astrophysics Data System (ADS)

Baker, A. R.; Landing, W. M.; Bucciarelli, E.; Cheize, M.; Fietz, S.; Hayes, C. T.; Kadko, D.; Morton, P. L.; Rogan, N.; Sarthou, G.; Shelley, R. U.; Shi, Z.; Shiller, A.; van Hulten, M. M. P.

2016-11-01

The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

Trace element and isotope deposition across the air-sea interface: progress and research needs.

PubMed

Baker, A R; Landing, W M; Bucciarelli, E; Cheize, M; Fietz, S; Hayes, C T; Kadko, D; Morton, P L; Rogan, N; Sarthou, G; Shelley, R U; Shi, Z; Shiller, A; van Hulten, M M P

2016-11-28

The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field will advance more rapidly by using a multi-tracer approach, and that aerosol deposition models should be ground-truthed against observed aerosol concentration data. It is also important to improve our understanding of the mechanisms and rates that control the fractional solubility of these tracers. Aerosol provenance and chemistry (humidity, acidity and organic ligand characteristics) play important roles in governing tracer solubility. Many of these factors are likely to be influenced by changes in atmospheric composition in the future. Intercalibration exercises for aerosol chemistry and fractional solubility are an essential component of the GEOTRACES programme.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2015 The Authors.

The geochemistry of environmentally important trace elements in UK coals, with special reference to the Parkgate coal in the Yorkshire-Nottinghamshire Coalfield, UK

USGS Publications Warehouse

Spears, D.A.; Tewalt, S.J.

2009-01-01

The Parkgate coal of Langsettian age in the Yorkshire-Nottinghamshire coalfield is typical of many coals in the UK in that it has a high sulphur (S) content. Detailed information on the distribution of the forms of S, both laterally and vertically through the seam, was known from previous investigations. In the present work, 38 interval samples from five measured sections of the coal were comprehensively analysed for major, minor and trace elements and the significance of the relationships established using both raw and centered log transformed data. The major elements are used to quantify the variations in the inorganic and organic coal components and determine the trace element associations. Pyrite contains nearly all of the Hg, As, Se, Tl and Pb and is also the major source of the Mo, Ni, Cd and Sb. The clays contain the following elements in decreasing order of association: Rb, Cs, Li, Ga, U, Cr, V, Sc, Y, Bi, Cu, Nb, Sn, Te and Th. Nearly all of the Rb is present in the clay fraction, whereas for elements such as V, Cu and U, a significant amount is thought to be present in the organic matter, based on the K vs trace element regression equations. Only Ge, and possibly Be, would appear to have a dominant organic source. The trace element concentrations are calculated for pyrite, the clay fraction and organic matter. For pyrite it is noted that concentrations agree with published data from the Yorkshire-Nottinghamshire coalfield and also that Tl concentrations (median of 0.33 ppm) in the pyrite are greater than either Hg or Cd. Unlike these elements, Tl has attracted less attention and possibly more information is needed on its anthropogenic distribution and impacts on man and the environment. A seawater source is thought to be responsible for the high concentrations of S, Cl and the non-detrital trace elements in the Parkgate coal. Indicative of the seawater control is the Th/U ratio, which expresses the detrital to non-detrital element contributions. Using other elements, similar ratios can be calculated, which in combination offer greater interpretative value. ?? 2009 Elsevier B.V.

Fish gelatin thin film standards for biological application of PIXE

NASA Astrophysics Data System (ADS)

Manuel, Jack E.; Rout, Bibhudutta; Szilasi, Szabolcs Z.; Bohara, Gyanendra; Deaton, James; Luyombya, Henry; Briski, Karen P.; Glass, Gary A.

2014-08-01

There exists a critical need to understand the flow and accumulation of metallic ions, both naturally occurring and those introduced to biological systems. In this paper the results of fabricating thin film elemental biological standards containing nearly any combination of trace elements in a protein matrix are presented. Because it is capable of high elemental sensitivity, particle induced X-ray emission spectrometry (PIXE) is an excellent candidate for in situ analysis of biological tissues. Additionally, the utilization of microbeam PIXE allows the determination of elemental concentrations in and around biological cells. However, obtaining elemental reference standards with the same matrix constituents as brain tissue is difficult. An excellent choice for simulating brain-like tissue is Norland® photoengraving glue which is derived from fish skin. Fish glue is water soluble, liquid at room temperature, and resistant to dilute acid. It can also be formed into a thin membrane which dries into a durable, self-supporting film. Elements of interest are introduced to the fish glue in precise volumetric additions of well quantified atomic absorption standard solutions. In this study GeoPIXE analysis package is used to quantify elements intrinsic to the fish glue as well as trace amounts of manganese added to the sample. Elastic (non-Rutherford) backscattered spectroscopy (EBS) and the 1.734 MeV proton-on-carbon 12C(p,p)12C resonance is used for a normalization scheme of the PIXE spectra to account for any discrepancies in X-ray production arising from thickness variation of the prepared standards. It is demonstrated that greater additions of the atomic absorption standard cause a viscosity reduction of the liquid fish glue resulting in thinner films but the film thickness can be monitored by using simultaneous PIXE and EBS proton data acquisition.

Effect of Silicon on Activity Coefficients of Platinum in Liquid Fe-Si, With Application to Core Formation

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K.; Danielson, L. R.; Humayun, M.

2017-01-01

Earth's core contains approximately 10% of a light element that is likely a combination of S, C, Si, and O, with Si possibly being the most abundant light element. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE) in Fe liquids, and thus the partitioning behavior of those elements between core and mantle. The effect of Si can be small such as for Ni and Co, or large such as for Mo, Ge, Sb, As. The effect of Si on many siderophile elements is unknown yet could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of Pt (with Re and Ru in progress or planned) between metal and silicate melt. The results will be applied to Earth, for which we have excellent constraints on the mantle Pt concentrations.

Heavy metal analysis in commercial Spirulina products for human consumption

PubMed Central

Al-Dhabi, Naif Abdullah

2013-01-01

For consumption of health foods of Spirulina, by the general public, health food stores are increasingly offering more exotic products. Though Spirulina consumption is growing worldwide, relatively few studies have reported on the quantities of heavy metals/minerals they contain and/or their potential effects on the population’s health. This study reveals the concentrations of six typical heavy metals/minerals (Ni, Zn, Hg, Pt, Mg, and Mn) in 25 Spirulina products commercialized worldwide for direct human consumption. Samples were ground, digested and quantified by Coupled Plasma Mass Spectroscopy (ICP–MS). The concentrations (mg/kg d.w.) were range from 0.001 to 0.012 (Pt) followed by 0.002–0.028 (Hg), 0.002–0.042 (Mg), 0.005–2.248 (Mn), 0.211–4.672 (Ni) and 0.533–6.225 (Zn). The inorganic elements of the present study were significantly lower than the recommended daily intake (RDI) level of heavy metal elements (mg/daily) Ni (0.4), Zn (13), Hg (0.01), Pt (0.002), Mg (400) and Mn (4). Based on this study the concentration of inorganic elements was not found to exceed the present regulation levels, and they can be considered as safe food. PMID:24235875

Potential of fly ash for neutralisation of acid mine drainage.

PubMed

Qureshi, Asif; Jia, Yu; Maurice, Christian; Öhlander, Björn

2016-09-01

Lignite (PK), bituminous (FI) and biomass (SE) fly ashes (FAs) were mineralogically and geochemically characterised, and their element leachability was studied with batch leaching tests. The potential for acid neutralisation (ANP) was quantified by their buffering capacity, reflecting their potential for neutralisation of acid mine drainage. Quartz was the common mineral in FAs detected by XRD with iron oxide, anhydrite, and magnesioferrite in PK, mullite and lime in FI, and calcite and anorthite in SE. All the FAs had high contents of major elements such as Fe, Si, Al and Ca. The Ca content in SE was six and eight times higher compared to PK and FI, respectively. Sulphur content in PK and SE was one magnitude higher than FI. Iron concentrations were higher in PK. The trace element concentrations varied between the FAs. SE had the highest ANP (corresponding to 275 kg CaCO3 tonne(-1)) which was 15 and 10 times higher than PK and FI, respectively. The concentrations of Ca(2+), SO4 (2-), Na(+) and Cl(-) in the leachates were much higher compared to other elements from all FA samples. Iron, Cu and Hg were not detected in any of the FA leachates because of their mild to strong alkaline nature with pH ranging from 9 to 13. Potassium leached in much higher quantity from SE than from the other ashes. Arsenic, Mn and Ni leached from PK only, while Co and Pb from SE only. The concentrations of Zn were higher in the leachates from SE. The FAs used in this study have strong potential for the neutralisation of AMD due to their alkaline nature. However, on the other hand, FAs must be further investigated, with scaled-up experiments before full-scale application, because they might leach pronounced concentrations of elements of concern with decreasing pH while neutralising AMD.

Identification, quantification of bioactive constituents, evaluation of antioxidant and in vivo acute toxicity property from the methanol extract of Vernonia cinerea leaf extract.

PubMed

Rajamurugan, R; Selvaganabathy, N; Kumaravel, S; Ramamurthy, Ch; Sujatha, V; Suresh Kumar, M; Thirunavukkarasu, C

2011-12-01

Vernonia cinerea (L.) Less [Compositae (Asteraceae)] is used traditionally for several medical purposes such as inflammation, pain, fever, and cancer. The present study identified the bioactive constituents in the methanol extract of Vernonia cinerea leaf and evaluated its antioxidant activity and acute toxicity. The identification of phytochemicals was accomplished by GC-MS and the major antioxidant phenolic compounds in the extract were quantified by HPTLC analysis. To quantify the essential elements, atomic absorption spectrophotometeric analysis was carried out. Total phenol and flavonoid content was measured by Folin-Ciocalteau reagent and 2% aluminium chloride, respectively. GC-MS analysis identified the presence of 27 phytoconstituents. The predominant phenolic compound in the extract as quantified by HPTLC was gallic acid (1.92 mg/g) followed by rutin (0.705 mg/g), quercetin (0.173 mg/g), caffeic acid (0.082 mg/g) and ferulic acid (0.033 mg/g). The following elements were quantified: Fe (0.050 ppm), Mn (0.022 ppm), Co (0.0180 ppm), Pb (0.029 ppm), Hg (3.885 ppm) and Se (4.5240 ppm). The antioxidant activity of the extract increased with increasing concentration and the correlation (r²) for all in vitro assays were satisfactory. V. cinerea extract has significant (p < 0.05) antiradical activity. Hence, V. cinerea may have potential medicinal value and can be used in the formulation of pharmacological products for degenerative diseases.

Highly-sensitive open-cell LA-ICPMS approaches for the quantification of rare earth elements in natural carbonates at parts-per-billion levels.

PubMed

Wu, Chung-Che; Burger, Marcel; Günther, Detlef; Shen, Chuan-Chou; Hattendorf, Bodo

2018-08-14

This work presents a high-sensitivity approach to quantify ultra-trace concentrations of rare earth elements (REEs) in speleothem carbonates using open-cell laser ablation-sector field-inductively coupled plasma mass spectrometry (open-cell LA-SF-ICPMS). Specifically, open-cell LA in combination with a gas exchange device enabled sampling of large-scale carbonate specimens in an ambient environment. The use of a "jet" vacuum interface and the addition of small amounts of N 2 gas allowed for a 20-40 fold sensitivity enhancement compared to the conventional interface configuration. Mass load effects, quantification capabilities and detection power were investigated in analyses of reference materials using various combinations of spot sizes and laser repetition rates. From a 160 μm diameter circular laser spot and 10 Hz ablation frequency, limits of detection were in the low or sub-ng g -1 range for REEs. Little dependence of Ca normalized sensitivity factors on the amount of material introduced into the plasma was observed. Relative deviations of quantified concentrations from USGS MACS-3 preferred values were smaller than 12%. The analytical approach enabled the determination of REE concentration profiles at the single digit ng g -1 level. Application to a 15-cm piece stalagmite collected from East Timor revealed at least two abrupt elevations in light rare earth elements (LREEs) within a scanning distance of 8 mm. These anomaly regions extended over a distance of ≈200 μm and showed LREE abundances elevated by at least one order of magnitude. This high-resolution open-cell LA-SF-ICPMS method has the potential to be applied in micro-domain analyses of other natural carbonates, such as travertine, tufa, and flowstones. This is promising for a better understanding of earth and environmental sciences. Copyright © 2018 Elsevier B.V. All rights reserved.

Influence of other rare earth ions on the optical refrigeration efficiency in Yb:YLF crystals.

PubMed

Di Lieto, Alberto; Sottile, Alberto; Volpi, Azzurra; Zhang, Zhonghan; Seletskiy, Denis V; Tonelli, Mauro

2014-11-17

We investigated the effect of rare earth impurities on the cooling efficiency of Yb³⁺:LiYF₄ (Yb:YLF). The refrigeration performance of two single crystals, doped with 5%-at. Yb and with identical history but with different amount of contaminations, have been compared by measuring the cooling efficiency curves. Spectroscopic and elemental analyses of the samples have been carried out to identify the contaminants, to quantify their concentrations and to understand their effect on the cooling efficiencies. A model of energy transfer processes between Yb and other rare earth ions is suggested, identifying Erbium and Holmium as elements that produce a detrimental effect on the cooling performance.

Catastrophic Failure Modes Assessment of the International Space Station Alpha

NASA Technical Reports Server (NTRS)

Lutz, B. E. P.; Goodwin, C. J.

1996-01-01

This report summarizes a series of analyses to quantify the hazardous effects of meteoroid/debris penetration of Space Station Alpha manned module protective structures. These analyses concentrate on determining (a) the critical crack length associated with six manned module pressure wall designs that, if exceeded, would lead to unstopped crack propagation and rupture of manned modules, and (b) the likelihood of crew or station loss following penetration of unsymmetrical di-methyl hydrazine tanks aboard the proposed Russian FGB ('Tug') propulsion module and critical elements aboard the control moment gyro module (SPP-1). Results from these quantified safety analyses are useful in improving specific design areas, thereby reducing the overall likelihood of crew or station loss following orbital debris penetration.

Measuring lanthanide concentrations in molten salt using laser-induced breakdown spectroscopy (LIBS).

PubMed

Weisberg, Arel; Lakis, Rollin E; Simpson, Michael F; Horowitz, Leo; Craparo, Joseph

2014-01-01

The versatility of laser-induced breakdown spectroscopy (LIBS) as an analytical method for high-temperature applications was demonstrated through measurement of the concentrations of the lanthanide elements europium (Eu) and praseodymium (Pr) in molten eutectic lithium chloride-potassium chloride (LiCl-KCl) salts at a temperature of 500 °C. Laser pulses (1064 nm, 7 ns, 120 mJ/pulse) were focused on the top surface of the molten salt samples in a laboratory furnace under an argon atmosphere, and the resulting LIBS signals were collected using a broadband Echelle-type spectrometer. Partial least squares (PLS) regression using leave-one-sample-out cross-validation was used to quantify the concentrations of Eu and Pr in the samples. The root mean square error of prediction (RMSEP) for Eu was 0.13% (absolute) over a concentration range of 0-3.01%, and for Pr was 0.13% (absolute) over a concentration range of 0-1.04%.

Manganese and Mn/Ca ratios in soil and vegetation in forests across the northeastern US: Insights on spatial Mn enrichment.

PubMed

Richardson, J B

2017-03-01

Manganese (Mn) cycling in the Critical Zone is important because of its role as an essential nutrient and potential toxicity to plants and organisms. Quantifying Mn enrichment in terrestrial environments has been limited since Mn is monoisotopic. However, elemental ratios of Mn/Ca ratios may be used to determine spatial Mn enrichment and in aboveground and belowground pools. The objectives of this study were to quantify the spatial variation in Mn concentrations and Mn/Ca ratios in foliage, bolewood, forest floor, and mineral soil horizons across the northeastern United States and compare Mn/Ca ratios to estimate enrichment. Forest floor and mineral soil samples were collected from 26 study sites across the northeastern United States and analyzed by strong acid digestion. Foliage and bolewood was collected from 12 of the 26 sites and analyzed for total Mn and Ca. Our results show forest floor and mineral soil horizon Mn concentrations and Mn/Ca ratios were higher at Pennsylvania and New York sites than New Hampshire and Vermont sites. Using a modified isotope equation, enrichment factors (EF) for Mn/Ca ratios were calculated to be ~3.6 in the forest floor, upper and lower mineral soil horizons at sites in New York and Pennsylvania compared to reference sites in New Hampshire and Vermont. Foliar and bolewood Mn concentrations also decreased from Pennsylvania towards New Hampshire. Moreover, foliar and bolewood Mn concentrations were strongly correlated to forest floor, upper, and lower mineral soil Mn concentrations. It was hypothesized that internal cycling (uptake, throughfall, and litterfall) of Mn controls retention of enriched Mn in forests. Geologic influences from a lithologic gradient and soil pH gradient could also influence Mn enrichment in addition to Mn pollution. Ratios of Mn/Ca and other elemental ratios hold promise as geochemical tracers but require further development. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of Metal Element Distributions in Rice (Oryza sativa L.) Seeds and Relocation during Germination Based on X-Ray Fluorescence Imaging of Zn, Fe, K, Ca, and Mn

PubMed Central

Lu, Lingli; Tian, Shengke; Liao, Haibing; Zhang, Jie; Yang, Xiaoe; Labavitch, John M.; Chen, Wenrong

2013-01-01

Knowledge of mineral localization within rice grains is important for understanding the role of different elements in seed development, as well as for facilitating biofortification of seed micronutrients in order to enhance seeds’ values in human diets. In this study, the concentrations of minerals in whole rice grains, hulls, brown rice, bran and polished rice were quantified by inductively coupled plasma mass spectroscopy. The in vivo mineral distribution patterns in rice grains and shifts in those distribution patterns during progressive stages of germination were analyzed by synchrotron X-ray microfluorescence. The results showed that half of the total Zn, two thirds of the total Fe, and most of the total K, Ca and Mn were removed by the milling process if the hull and bran were thoroughly polished. Concentrations of all elements were high in the embryo regions even though the local distributions within the embryo varied between elements. Mobilization of the minerals from specific seed locations during germination was also element-specific. High mobilization of K and Ca from grains to growing roots and leaf primordia was observed; the flux of Zn to these expanding tissues was somewhat less than that of K and Ca; the mobilization of Mn or Fe was relatively low, at least during the first few days of germination. PMID:23451212

Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allegrini, Elisa, E-mail: elia@env.dtu.dk; Maresca, Alberto; Olsson, Mikael Emil

2014-09-15

Highlights: • Ferrous and non-ferrous metals were quantified in MSWI bottom ashes. • Metal recovery system efficiencies for bottom ashes were estimated. • Total content of critical elements was determined in bottom ash samples. • Post-incineration recovery is not viable for most critical elements. - Abstract: Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based onmore » a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2 mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.« less

Rutile solubility in NaF–NaCl–KCl-bearing aqueous fluids at 0.5–2.79GPa and 250–650°C

DOE PAGES

Tanis, Elizabeth A.; Simon, Adam; Zhang, Youxue; ...

2016-01-14

The complex nature of trace element mobility in subduction zone environments is thought to be primarily controlled by fluid-rock interactions, episodic behavior of fluids released, mineral assemblages, and element partitioning during phase transformations and mineral breakdown throughout the transition from hydrated basalt to blueschist to eclogite. Quantitative data that constrain the partitioning of trace elements between fluid(s) and mineral(s) are required in order to model trace element mobility during prograde and retrograde metamorphic fluid evolution in subduction environments. The stability of rutile has been proposed to control the mobility of HFSE during subduction, accounting for the observed depletion of Nbmore » and Ta in arc magmas. Recent experimental studies demonstrate that the solubility of rutile in aqueous fluids at temperatures >700 degrees C and pressures <2 GPa increases by several orders of magnitude relative to pure H2O as the concentrations of ligands (e.g., F and Cl) in the fluid increase. Considering that prograde devolatilization in arcs begins at similar to 300 degrees C, there is a need for quantitative constraints on rutile solubility and the partitioning of HFSE between rutile and aqueous fluid over a wider range of temperature and pressure than is currently available. In this study, new experimental data are presented that quantify the solubility of rutile in aqueous fluids from 0.5 to 2.79 GPa and 250 to 650 degrees C. Rutile solubility was determined by using synchrotron X-ray fluorescence to measure the concentration of Zr in an aqueous fluid saturated with a Zr-bearing rutile crystal within a hydrothermal diamond anvil cell. At the PT conditions of the experiments, published diffusion data indicate that Zr is effectively immobile (log D-Zr similar to 10(-25) m(2)/s at 650 degrees C and similar to 10(-30) m(2)/s at 250 degrees C) with diffusion length-scales of <0.2 mu m in rutile for our run durations (<10 h). Hence, the Zr/Ti ratio of the starting rutile, which was quantified, does not change during the experiment, and the measured concentration of Zr in the fluid was used to calculate the concentration of Ti (i.e., the solubility of rutile) in the fluid. The salts NaF, NaCl, and KCl were systematically added to the aqueous fluid, and the relative effects of fluid composition, pressure, and temperature on rutile solubility were quantified. The results indicate that fluid composition exerts the greatest control on rutile solubility in aqueous fluid, consistent with previous studies, and that increasing temperature has a positive, albeit less pronounced, effect. The solubility of Zr-rutile in aqueous fluid increases with the addition of halides in the following order: 2 wt% NaF < 30 wt% KCl < 30 wt% NaCl < 3 wt% NaF < (10 wt% NaCl + 2 wt% NaF) < 4 wt% NaF. The solubility of rutile in the fluid increases with the 2nd to 3rd power of the Cl- concentration, and the 3rd to 4th power of the F- concentration. These new data are consistent with observations from field studies of exhumed terranes that indicate that rutile is soluble in complex aqueous fluids, and that fluid composition is the primary control on rutile solubility and HFSE mobility« less

Rutile solubility in NaF-NaCl-KCl-bearing aqueous fluids at 0.5-2.79 GPa and 250-650 °C

NASA Astrophysics Data System (ADS)

Tanis, Elizabeth A.; Simon, Adam; Zhang, Youxue; Chow, Paul; Xiao, Yuming; Hanchar, John M.; Tschauner, Oliver; Shen, Guoyin

2016-03-01

The complex nature of trace element mobility in subduction zone environments is thought to be primarily controlled by fluid-rock interactions, episodic behavior of fluids released, mineral assemblages, and element partitioning during phase transformations and mineral breakdown throughout the transition from hydrated basalt to blueschist to eclogite. Quantitative data that constrain the partitioning of trace elements between fluid(s) and mineral(s) are required in order to model trace element mobility during prograde and retrograde metamorphic fluid evolution in subduction environments. The stability of rutile has been proposed to control the mobility of HFSE during subduction, accounting for the observed depletion of Nb and Ta in arc magmas. Recent experimental studies demonstrate that the solubility of rutile in aqueous fluids at temperatures >700 °C and pressures <2 GPa increases by several orders of magnitude relative to pure H2O as the concentrations of ligands (e.g., F and Cl) in the fluid increase. Considering that prograde devolatilization in arcs begins at ∼300 °C, there is a need for quantitative constraints on rutile solubility and the partitioning of HFSE between rutile and aqueous fluid over a wider range of temperature and pressure than is currently available. In this study, new experimental data are presented that quantify the solubility of rutile in aqueous fluids from 0.5 to 2.79 GPa and 250 to 650 °C. Rutile solubility was determined by using synchrotron X-ray fluorescence to measure the concentration of Zr in an aqueous fluid saturated with a Zr-bearing rutile crystal within a hydrothermal diamond anvil cell. At the PT conditions of the experiments, published diffusion data indicate that Zr is effectively immobile (log DZr ∼10-25 m2/s at 650 °C and ∼10-30 m2/s at 250 °C) with diffusion length-scales of <0.2 μm in rutile for our run durations (<10 h). Hence, the Zr/Ti ratio of the starting rutile, which was quantified, does not change during the experiment, and the measured concentration of Zr in the fluid was used to calculate the concentration of Ti (i.e., the solubility of rutile) in the fluid. The salts NaF, NaCl, and KCl were systematically added to the aqueous fluid, and the relative effects of fluid composition, pressure, and temperature on rutile solubility were quantified. The results indicate that fluid composition exerts the greatest control on rutile solubility in aqueous fluid, consistent with previous studies, and that increasing temperature has a positive, albeit less pronounced, effect. The solubility of Zr-rutile in aqueous fluid increases with the addition of halides in the following order: 2 wt% NaF < 30 wt% KCl < 30 wt% NaCl < 3 wt% NaF < (10 wt% NaCl + 2 wt% NaF) < 4 wt% NaF. The solubility of rutile in the fluid increases with the 2nd to 3rd power of the Cl- concentration, and the 3rd to 4th power of the F- concentration. These new data are consistent with observations from field studies of exhumed terranes that indicate that rutile is soluble in complex aqueous fluids, and that fluid composition is the primary control on rutile solubility and HFSE mobility.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanis, Elizabeth A.; Simon, Adam; Zhang, Youxue

The complex nature of trace element mobility in subduction zone environments is thought to be primarily controlled by fluid-rock interactions, episodic behavior of fluids released, mineral assemblages, and element partitioning during phase transformations and mineral breakdown throughout the transition from hydrated basalt to blueschist to eclogite. Quantitative data that constrain the partitioning of trace elements between fluid(s) and mineral(s) are required in order to model trace element mobility during prograde and retrograde metamorphic fluid evolution in subduction environments. The stability of rutile has been proposed to control the mobility of HFSE during subduction, accounting for the observed depletion of Nbmore » and Ta in arc magmas. Recent experimental studies demonstrate that the solubility of rutile in aqueous fluids at temperatures >700 degrees C and pressures <2 GPa increases by several orders of magnitude relative to pure H2O as the concentrations of ligands (e.g., F and Cl) in the fluid increase. Considering that prograde devolatilization in arcs begins at similar to 300 degrees C, there is a need for quantitative constraints on rutile solubility and the partitioning of HFSE between rutile and aqueous fluid over a wider range of temperature and pressure than is currently available. In this study, new experimental data are presented that quantify the solubility of rutile in aqueous fluids from 0.5 to 2.79 GPa and 250 to 650 degrees C. Rutile solubility was determined by using synchrotron X-ray fluorescence to measure the concentration of Zr in an aqueous fluid saturated with a Zr-bearing rutile crystal within a hydrothermal diamond anvil cell. At the PT conditions of the experiments, published diffusion data indicate that Zr is effectively immobile (log D-Zr similar to 10(-25) m(2)/s at 650 degrees C and similar to 10(-30) m(2)/s at 250 degrees C) with diffusion length-scales of <0.2 mu m in rutile for our run durations (<10 h). Hence, the Zr/Ti ratio of the starting rutile, which was quantified, does not change during the experiment, and the measured concentration of Zr in the fluid was used to calculate the concentration of Ti (i.e., the solubility of rutile) in the fluid. The salts NaF, NaCl, and KCl were systematically added to the aqueous fluid, and the relative effects of fluid composition, pressure, and temperature on rutile solubility were quantified. The results indicate that fluid composition exerts the greatest control on rutile solubility in aqueous fluid, consistent with previous studies, and that increasing temperature has a positive, albeit less pronounced, effect. The solubility of Zr-rutile in aqueous fluid increases with the addition of halides in the following order: 2 wt% NaF < 30 wt% KCl < 30 wt% NaCl < 3 wt% NaF < (10 wt% NaCl + 2 wt% NaF) < 4 wt% NaF. The solubility of rutile in the fluid increases with the 2nd to 3rd power of the Cl- concentration, and the 3rd to 4th power of the F- concentration. These new data are consistent with observations from field studies of exhumed terranes that indicate that rutile is soluble in complex aqueous fluids, and that fluid composition is the primary control on rutile solubility and HFSE mobility« less

QEEN Workshop: "Quantifying Exposure to Engineered Nano ...

EPA Pesticide Factsheets

The measurement and characterization of nanomaterials in biological tissues is complicated by a number of factors including: the sensitivity of the assay to small sized particles or low concentrations of materials; the ability to distinguish different forms and transformations of the materials related to the biological matrix; distinguishing exogenous nanomaterials, which may be composed of biologically common elements such as carbon,from normal biological tissues; differentiating particle from ionic phases for materials that dissolve; localization of sparsely distributed materials in a complex substrate (the

Impact of snow deposition on major and trace element concentrations and elementary fluxes in surface waters of the Western Siberian Lowland across a 1700 km latitudinal gradient

NASA Astrophysics Data System (ADS)

Shevchenko, Vladimir P.; Pokrovsky, Oleg S.; Vorobyev, Sergey N.; Krickov, Ivan V.; Manasypov, Rinat M.; Politova, Nadezhda V.; Kopysov, Sergey G.; Dara, Olga M.; Auda, Yves; Shirokova, Liudmila S.; Kolesnichenko, Larisa G.; Zemtsov, Valery A.; Kirpotin, Sergey N.

2017-11-01

In order to better understand the chemical composition of snow and its impact on surface water hydrochemistry in the poorly studied Western Siberia Lowland (WSL), the surface layer of snow was sampled in February 2014 across a 1700 km latitudinal gradient (ca. 56.5 to 68° N). We aimed at assessing the latitudinal effect on both dissolved and particulate forms of elements in snow and quantifying the impact of atmospheric input to element storage and export fluxes in inland waters of the WSL. The concentration of dissolved+colloidal (< 0.45 µm) Fe, Co, Cu, As and La increased by a factor of 2 to 5 north of 63° N compared to southern regions. The pH and dissolved Ca, Mg, Sr, Mo and U in snow water increased with the rise in concentrations of particulate fraction (PF). Principal component analyses of major and trace element concentrations in both dissolved and particulate fractions revealed two factors not linked to the latitude. A hierarchical cluster analysis yielded several groups of elements that originated from alumino-silicate mineral matrix, carbonate minerals and marine aerosols or belonging to volatile atmospheric heavy metals, labile elements from weatherable minerals and nutrients. The main sources of mineral components in PF are desert and semi-desert regions of central Asia. The snow water concentrations of DIC, Cl, SO4, Mg, Ca, Cr, Co, Ni, Cu, Mo, Cd, Sb, Cs, W, Pb and U exceeded or were comparable with springtime concentrations in thermokarst lakes of the permafrost-affected WSL zone. The springtime river fluxes of DIC, Cl, SO4, Na, Mg, Ca, Rb, Cs, metals (Cr, Co, Ni, Cu, Zn, Cd, Pb), metalloids (As, Sb), Mo and U in the discontinuous to continuous permafrost zone (64-68° N) can be explained solely by melting of accumulated snow. The impact of snow deposition on riverine fluxes of elements strongly increased northward, in discontinuous and continuous permafrost zones of frozen peat bogs. This was consistent with the decrease in the impact of rock lithology on river chemical composition in the permafrost zone of the WSL, relative to the permafrost-free regions. Therefore, the present study demonstrates significant and previously underestimated atmospheric input of many major and trace elements to their riverine fluxes during spring floods. A broader impact of this result is that current estimations of river water fluxes response to climate warming in high latitudes may be unwarranted without detailed analysis of winter precipitation.

Measurement of Trace Constituents by Electron-Excited X-Ray Microanalysis with Energy-Dispersive Spectrometry.

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2016-06-01

Electron-excited X-ray microanalysis performed with scanning electron microscopy and energy-dispersive spectrometry (EDS) has been used to measure trace elemental constituents of complex multielement materials, where "trace" refers to constituents present at concentrations below 0.01 (mass fraction). High count spectra measured with silicon drift detector EDS were quantified using the standards/matrix correction protocol embedded in the NIST DTSA-II software engine. Robust quantitative analytical results for trace constituents were obtained from concentrations as low as 0.000500 (mass fraction), even in the presence of significant peak interferences from minor (concentration 0.01≤C≤0.1) and major (C>0.1) constituents. Limits of detection as low as 0.000200 were achieved in the absence of peak interference.

Residual levels of rare earth elements in freshwater and marine fish and their health risk assessment from Shandong, China.

PubMed

Yang, Luping; Wang, Xining; Nie, Hongqian; Shao, Lijun; Wang, Guoling; Liu, Yongjun

2016-06-15

The total concentrations of rare earth elements (ΣREE) were quantified in 251 samples from 10 common species of freshwater and marine fish in seventeen cities of Shandong, China. ΣREE obtained from the freshwater fish ranged from 34.0 to 37.9ngg(-1) (wet weight) and marine fish from 12.7 to 37.6ngg(-1). The ratio of LREE to HREE was 13.7:1 and 10:1 for freshwater and marine fish, respectively. This suggests that freshwater fish exhibit greater REE concentrations than marine fish and the biological effects of LREE are higher than HREE. Results revealed a similar REE distribution pattern between those fish and coastal sediments, abiding the "abundance law". The health risk assessment demonstrated the EDIs of REEs in fish were significantly lower than the ADI, indicating that the consumption of these fish presents little risk to human health. Copyright © 2016 Elsevier Ltd. All rights reserved.

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

P. Bernot

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this activity is to predict dissolved concentrations or solubility limits for elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) relevant to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are provided in the form of tabulated functions with pH andmore » log fCO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. Even though selection of an appropriate set of radionuclides documented in Radionuclide Screening (BSC 2002 [DIRS 160059]) includes actinium, transport of Ac is not modeled in the total system performance assessment for the license application (TSPA-LA) model because of its extremely short half-life. Actinium dose is calculated in the TSPA-LA by assuming secular equilibrium with {sup 231}Pa (Section 6.10); therefore, Ac is not analyzed in this report. The output data from this report are fundamental inputs for TSPA-LA used to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for the actinides discussed in this report. These models cover broad ranges of environmental conditions so they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.« less

Local phase method for designing and optimizing metasurface devices.

PubMed

Hsu, Liyi; Dupré, Matthieu; Ndao, Abdoulaye; Yellowhair, Julius; Kanté, Boubacar

2017-10-16

Metasurfaces have attracted significant attention due to their novel designs for flat optics. However, the approach usually used to engineer metasurface devices assumes that neighboring elements are identical, by extracting the phase information from simulations with periodic boundaries, or that near-field coupling between particles is negligible, by extracting the phase from single particle simulations. This is not the case most of the time and the approach thus prevents the optimization of devices that operate away from their optimum. Here, we propose a versatile numerical method to obtain the phase of each element within the metasurface (meta-atoms) while accounting for near-field coupling. Quantifying the phase error of each element of the metasurfaces with the proposed local phase method paves the way to the design of highly efficient metasurface devices including, but not limited to, deflectors, high numerical aperture metasurface concentrators, lenses, cloaks, and modulators.

Irrigation drainage studies of the Angostura Reclamation Unit and the Belle Fourche Reclamation Project, western South Dakota : results of 1994 sampling and comparisons with 1988 data

USGS Publications Warehouse

Sando, Steven K.; Williamson, Joyce E.; Dickerson, Kimberly K.; Wesolowski, Edwin A.

2001-01-01

The U.S. Department of the Interior started the National Irrigation Water Quality Program in 1985 to identify the nature and extent of irrigation-induced water-quality problems that might exist in the western U.S. The Angostura Reclamation Unit (ARU) and Belle Fourche Reclamation Project (BFRP) in western South Dakota were included as part of this program. The ARU and BFRP reconnaissance studies were initiated in 1988, during below-normal streamflow conditions in both study areas. Surface water, bottom sediment, and fish were resampled in 1994 at selected sites in both study areas during generally near-normal streamflow conditions to compare with 1988 study results. Concentrations of major ions in water for both the ARU and BFRP study areas are high relative to national baseline levels. Major-ion concentrations for both areas generally are lower for 1994 than for 1988, when low-flow conditions prevailed, but ionic proportions are similar between years. For ARU, dissolved-solids concentrations probably increase slightly downstream from Angostura Reservoir; however, the available data sets are insufficient to confidently discern effects of ARU operations on dissolved-solids loading. For BFRP, dissolved-solids concentrations are slightly higher at sites that are affected by irrigation drainage; again, however, the data are inconclusive to determine whether BFRP operations increase dissolved-solids loading. Most trace-element concentrations in water samples for both study areas are similar between 1988 and 1994, and do not show strong relations with discharge. ARU operations probably are not contributing discernible additional loads of trace elements to the Cheyenne River. For BFRP, concentrations of some trace elements are slightly higher at sites downstream from irrigation operations than at a site upstream from irrigation operations. BFRP operations might contribute to trace-element concentrations in the Belle Fourche River, but available data are insufficient to quantify increases. For both study areas, concentrations of several trace elements occasionally exceed National Irrigation Water Quality Program guidelines. Selenium routinely occurs in concentrations that could be problematic at sites upstream and downstream from both study areas. Elevated selenium concentrations at sites upstream from irrigation operations indicate that naturally occurring selenium concentrations are relatively high in and near the study areas. While ARU operations probably do not contribute discernible additional loads of selenium to the Cheyenne River, BFRP operations might contribute additional selenium loads to the Belle Fourche River. Concentrations of most trace elements in bottom sediment, except arsenic and selenium, are similar to typical concentrations for western U.S. soils for both study areas. Bottom-sediment arsenic and selenium (1988) concentrations in both study areas can reach levels that might be of concern; however, there is insufficient information to determine whether irrigation operations contribute to these elevated concentrations. Concentrations of most trace elements in fish in both study areas are less than values known to adversely affect fish or birds, although there are occasional exceedances of established criteria. However, selenium concentrations in fish samples routinely are within the National Irrigation Water Quality Program level of concern, and also commonly exceed the dietary guideline for avian consumers for both study areas. Selenium concentrations in fish samples generally are higher at sites downstream from irrigation operations. For BFRP, arsenic and mercury concentrations are elevated in fish samples from site B-18, which is influenced by mine tailings.

Verification of radionuclide transfer factors to domestic-animal food products, using indigenous elements and with emphasis on iodine.

PubMed

Sheppard, S C; Long, J M; Sanipelli, B

2010-11-01

Recent reviews have established benchmark values for transfer factors that describe radionuclide transfer from plants to animal food product such as milk, eggs and meat. They also illustrate the paucity of data for some elements and some food products. The present study quantified transfer data using indigenous elements measured in dairy, poultry and other livestock farms in Canada. Up to 62 elements are reported, with particular emphasis on iodine (I) because of the need to accurately assess the behaviour of (129)I from disposal of nuclear fuel waste. There was remarkable agreement with the literature values, and for many elements the present study involved many more observations than were previously available. Perhaps the most important observation was that product/substrate concentration ratios (CR) were quite consistent across species, whereas the traditional fractional transfer factors (TF, units of d kg(-1) or d L(-1)) necessarily vary with body mass (feed intake). This suggests that for long-term assessments, it may be advisable to change the models to use CR rather than TF.

Spatial and Temporal Distribution of Polycyclic Aromatic Hydrocarbons and Elemental Carbon in Bakersfield, California

PubMed Central

Noth, Elizabeth M.; Lurmann, Fred; Northcross, Amanda; Perrino, Charles; Vaughn, David; Hammond, S. Katharine

2016-01-01

Despite increasing evidence that airborne polycyclic aromatic hydrocarbon (PAH) exposures contribute to adverse health outcomes for sensitive populations, limited data are available on short-term intraurban spatial distributions for use in epidemiologic research. Exposure assessments for airborne PAHs are uncommon because air sampling for PAHs is a labor-, equipment-, and time-intensive task. To address this gap we measured wintertime PAH concentrations during 2010-2011 in Bakersfield, California, USA, a major city in the Southern San Joaquin Valley. Specifically, 58 96-hour integrated PAH samples were collected during 4 time periods at 14 locations from November 2010 to January 2011; duplicates were collected at two sites. We also collected elemental carbon (EC) at the same 14 sites and analyzed the two time periods with the highest ambient PAH pollution. We used linear regression models to quantify the relationship between potential spatial and temporal predictors of PAH concentrations. We found that wintertime PAH concentrations in Bakersfield, CA, are best predicted by meteorological variables and traffic proximity. Our model explains a moderate amount of the variability in the data (R2=0.58), likely reflecting the major sources of PAHs in Bakersfield. We also observed that PAH concentrations were more spatially variable than EC concentrations. Comparing our data to historical monitoring data at one location in Bakersfield showed that the relatively low PAH concentrations during the 2010-2011 winter in Bakersfield is part of a long-term trend in decreasing PAH concentrations. PMID:28083077

Concentrations and loads of suspended sediment and trace element pollutants in a small semi-arid urban tributary, San Francisco Bay, California.

PubMed

McKee, Lester J; Gilbreath, Alicia N

2015-08-01

Water-quality policy documents throughout the world often identify urban stormwater as a large and controllable impact to sensitive ecosystems, yet there is often limited data to characterize concentrations and loads especially for rare and more difficult to quantify pollutants. In response, concentrations of suspended sediments and silver, mercury and selenium including speciation, and other trace elements were measured in dry and wet weather stormwater flow from a 100% urban watershed near San Francisco. Suspended sediment concentrations ranged between 1.4 and 2700 mg/L and varied with storm intensity. Turbidity was shown to correlate strongly with suspended sediments and most trace elements and was used as a surrogate with regression to estimate concentrations during unsampled periods and to compute loads. Mean suspended sediment yield was 31.5 t/km(2)/year. Total mercury ranged between 1.4 and 150 ng/L and was, on average, 92% particulate, 0.9% methylated, and 1.2% acid labile. Total mercury yield averaged 5.7 μg/m(2)/year. Total selenium ranged between non-detect and 2.9 μg/L and, on average, the total load (0.027 μg/m(2)/year) was 61% transported in dissolved phase. Selenate (Se(VI)) was the dominant species. Silver concentrations ranged between non-detect and 0.11 μg/L. Concentrations and loads of other trace elements were also highly variable and were generally similar to other urban systems with the exceptions of Ag and As (seldom reported) and Cr and Zn which exhibited concentrations and loads in the upper range of those reported elsewhere. Consistent with the semi-arid climatic setting, >95% of suspended sediment, 94% of total Hg, and 85-95 % of all other trace element loads were transported during storm flows with the exception of selenium which showed an inverse relationship between concentration and flow. Treatment of loads is made more challenging in arid climate settings due to low proportions of annual loads and greater dissolved phase during low flow conditions. This dataset fills an important local data gap for highly urban watersheds of San Francisco Bay. The field and interpretative methods, the uniqueness of the analyte list, and resulting information have general applicability for managing pollutant concentrations and loads in urban watersheds in other parts of the world and may have particularly useful application in more arid climates.

Aerosol Pollution from Small Combustors in a Village

PubMed Central

Zwozdziak, A.; Samek, L.; Sowka, I.; Furman, L.; Skrętowicz, M.

2012-01-01

Urban air pollution is widely recognized. Recently, there have been a few projects that examined air quality in rural areas (e.g., AUPHEP project in Austria, WOODUSE project in Denmark). Here we present the results within the International Cooperation Project RER/2/005 targeted at studying the effect of local combustion processes to air quality in the village of Brzezina in the countryside north-west of Wroclaw (south western Poland). We identified the potential emission sources and quantified their contributions. The ambient aerosol monitoring (PM10 and elemental concentrations) was performed during 4 measurement cycles, in summer 2009, 2010 and in winter 2010, 2011. Some receptor modeling techniques, factor analysis-multiple linear regression analysis (FA-MLRA) and potential source localization function (PSLF), have been used. Different types of fuel burning along with domestic refuse resulted in an increased concentration of PM10 particle mass, but also by an increased in various other compounds (As, Pb, Zn). Local combustion sources contributed up to 80% to PM10 mass in winter. The effect of other sources was small, from 6 to 20%, dependently on the season. Both PM10 and elemental concentrations in the rural settlement were comparable to concentrations at urban sites in summer and were much higher in winter, which can pose asignificant health risk to its inhabitants. PMID:22629226

Compositional variability of the aerosols collected on Kerkennah Islands (central Tunisia)

NASA Astrophysics Data System (ADS)

Trabelsi, A.; Masmoudi, M.; Quisefit, J. P.; Alfaro, S. C.

2016-03-01

The aim of the present study is to investigate the seasonal variability of the aerosol concentrations and origins in central Tunisia. Four field campaigns were carried out in 2010/2011 to collect air-suspended particles on the Kerkennah Islands. The elemental composition (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Pb, Ni, V, and As) of the particles collected in summer (June and July), autumn (September and November), winter (February and March), and spring (April and May) is determined by X-ray fluorescence analysis. Examination of the enrichment factors (EF) of all elements indicate that Al, Fe, Si, Ca, Ti, Mn, and Cr are mainly derived from soil sources, whereas Na and Cl are mostly of marine origin. Other elements such as K and Mg or S and P have multiple origins (Marine/crustal and crustal/anthropogenic, respectively). Finally, V, Cu, Ni, As, and Pb appear to be produced by anthropogenic activities. Based on the inter-elemental correlations, the mass concentrations of mineral dust (MD), sea-salt (SS) and anthropogenic (non-crustal and non-marine) sulfates (NSS) are quantified. MD, SS and NSS display significant inter-seasonal differences: on the one hand, MD and SS are the highest in spring and the lowest in winter, probably because of the seasonal change in meteorological conditions. On the other hand, NSS and Cu concentrations are above their autumn and winter values in spring and summer, which suggests the existence of a common source of the combustion type for these two pollutants.

Temporal stability and rates of post-depositional change in geochemical signatures of brown trout Salmo trutta scales.

PubMed

Ryan, D; Shephard, S; Kelly, F L

2016-09-01

This study investigates temporal stability in the scale microchemistry of brown trout Salmo trutta in feeder streams of a large heterogeneous lake catchment and rates of change after migration into the lake. Laser-ablation inductively coupled plasma mass spectrometry was used to quantify the elemental concentrations of Na, Mg, Mn, Cu, Zn, Ba and Sr in archived (1997-2002) scales of juvenile S. trutta collected from six major feeder streams of Lough Mask, County Mayo, Ireland. Water-element Ca ratios within these streams were determined for the fish sampling period and for a later period (2013-2015). Salmo trutta scale Sr and Ba concentrations were significantly (P < 0·05) correlated with stream water sample Sr:Ca and Ba:Ca ratios respectively from both periods, indicating multi-annual stability in scale and water-elemental signatures. Discriminant analysis of scale chemistries correctly classified 91% of sampled juvenile S. trutta to their stream of origin using a cross-validated classification model. This model was used to test whether assumed post-depositional change in scale element concentrations reduced correct natal stream classification of S. trutta in successive years after migration into Lough Mask. Fish residing in the lake for 1-3 years could be reliably classified to their most likely natal stream, but the probability of correct classification diminished strongly with longer lake residence. Use of scale chemistry to identify natal streams of lake S. trutta should focus on recent migrants, but may not require contemporary water chemistry data. © 2016 The Fisheries Society of the British Isles.

Anthrobiogeochemical platinum, palladium and rhodium cycles of earth: Emerging environmental contamination

NASA Astrophysics Data System (ADS)

Mitra, Arijeet; Sen, Indra Sekhar

2017-11-01

Anthrobiogeochemical cycles have been a subject of scientific research for many decades as they are important for identifying possible sources, sinks, and pathways of an element in the environment. In this study, we quantified global cycles for the platinum group elements (PGE; platinum (Pt), palladium (Pd) and rhodium (Rh)). We quantified the stocks of Pt, Pd, and Rh in Earth's various reservoirs, such as the core, mantle, consolidated crust, biomass, seawater, unconsolidated sediments, and atmosphere, as well as coal and petroleum deposits. We further quantified their fluxes, both natural and anthropogenic, between each reservoir, by identifying the flows across the hydrosphere, geosphere, biosphere, atmosphere and anthroposphere, including from mining activities, fossil fuel and biomass burning, construction activities, soil erosion, human contributions to net primary productivity, riverine transport, aeolian dust movement, primary production, volcanic eruption, sea-salt spray, crustal subduction, crust formation at mid ocean ridges, PGE recovery from recycling processes, and cosmic dust inputs at the Earth's surface. Stocks of PGEs were quantified by multiplying the mass of the reservoir by the average Pt, Pd and Rh concentration in the reservoir, whereas Pt, Pd and Rh fluxes were calculated by multiplying the rate of mass movement across the reservoirs with the Pt, Pd and Rh concentrations of the material. Uncertainties were explicitly incorporated in stock and flow estimations through Monte Carlo simulations. Our calculations reveal that the total surficial anthropogenic Pt, Pd, and Rh mobilizations were greater than their corresponding natural surficial mobilizations. We show that crustal subduction and crustal formation is the most important natural flow and contributes 21-42% of total PGE mobilization. When Earth's surficial processes are considered, soil erosion is the dominant flow for Rh and Pt mobilization, comprising 33% and 13%, respectively, of the total mobilization on Earth's surface, whereas NPP dominates the natural Pd mobilization. On the other hand, mining activities, fossil fuel burning and automobile emissions are the most important anthropogenic flows. Therefore, our qualitative and quantitative assessment indicates that mining activities contribute almost 60-80% of the total anthropogenic flow on Earth, and crustal subduction and production dominates the total global PGE cycle.

The potential of inductively coupled plasma mass spectrometry (ICP-MS) for the simultaneous determination of trace elements in whole blood, plasma and serum.

PubMed

Krachler, M; Irgolic, K J

1999-11-01

The advantages accruing to biochemical and clinical investigations from a method that allows the simultaneous quantification (RSD < or = 10%) of many elements in blood, plasma, and serum at concentrations equal to one-hundredth of the lower limits of the normal ranges are undeniable. The suitability of inductively coupled argon plasma low-resolution quadrupole mass spectrometry (ICP-MS), a simultaneous method with low detection limits, is evaluated for the quantification of inorganic constituents in whole blood, plasma, and serum with consideration of the dilution associated with the mineralization of the samples, of isobaric and polyatomic interferences and of normal ranges. Of the 3 bulk elements, the 3 major electrolytes, the 15 essential elements, the 8 toxic elements, the 4 therapeutic elements, and the 14 elements of potential interest (total of 47 elements) only 7 elements (Ca, Cu, K, Mg, Rb, Sr, Zn) can be simultaneously quantified under these rigorous conditions in serum and only 8 elements (additional element Pb) in whole blood. Quantification of elements in the Seronorm Standards "Whole Blood" and "Serum" showed, that this list of simultaneously determinable elements in these matrices is reasonable. Although this list is disappointingly short, the number of elements determinable simultaneously by ICP-MS is still larger than that by ICP-AES or GFAAS. Improved detectors, more efficient nebulizers, avoidance of interferences, better instrument design, and high-resolution mass spectrometers promise to increase the number of elements that can be determined simultaneously.

Determination of toxic inorganic elements pollution in ground waters of Kahuta Industrial Triangle Islamabad, Pakistan using inductively coupled plasma mass spectrometry.

PubMed

Kausar, Rubina; Ahmad, Zulfiqar

2009-10-01

The present study deals with the ground water quality assessment in Kahuta Industrial Triangle Islamabad, Pakistan. The objective of the study was to assess ground water quality against the drinking water standards for various toxic inorganic elements. Representative groundwater samples were collected and analyzed in the Water Quality Laboratory of Pakistan Council of Research in Water Resources (PCRWR) at Islamabad, Pakistan. The samples were run on ICP-MS (Inductively coupled plasma mass spectrometry), which has the capability to separate and quantify 70 elements at a time. One of the finding of study is that ICP-MS is a very good tool to analyze broad range of toxic inorganic elements to the level of parts per billion (ppb). World Health Organization drinking water standards shows that these toxic inorganic elements such as heavy metals even at this concentration level (ppb) are injurious to human health. This analysis indicated pollution of various toxic elements including Selenium. Vertical leachate through industrial waste septic tanks is identified as major cause of groundwater pollution in the Industrial Triangle. Monitoring of the septic tanks and groundwater quality in study area is suggested along with remedial measures.

Long-term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

NASA Astrophysics Data System (ADS)

Gelado-Caballero, MaríA. D.; López-GarcíA, Patricia; Prieto, Sandra; Patey, Matthew D.; Collado, Cayetano; HéRnáNdez-Brito, José J.

2012-02-01

There are very few sets of long-term measurements of aerosol concentrations over the North Atlantic Ocean, yet such data is invaluable in quantifying atmospheric dust inputs to this ocean region. We present an 8-year record of total suspended particles (TSP) collected at three stations on Gran Canaria Island, Spain (Taliarte at sea level, Tafira 269 m above sea level (a.s.l.) and Pico de la Gorra 1930 m a.s.l.). Using wet and dry deposition measurements, the mean dust flux was calculated at 42.3 mg m-2 d-1. Air mass back trajectories (HYSPLIT, NOAA) suggested that the Sahara desert is the major source of African dust (dominant during 32-50% of days), while the Sahel desert was the major source only 2-10% of the time (maximum in summer). Elemental composition ratios of African samples indicate that, despite the homogeneity of the dust in collected samples, some signatures of the bedrocks can still be detected. Differences were found for the Sahel, Central Sahara and North of Sahara regions in Ti/Al, Mg/Al and Ca/Al ratios, respectively. Elements often associated with pollution (Pb, Cd, Ni, Zn) appeared to share a common origin, while Cu may have a predominantly local source, as suggested by a decrease in the enrichment factor (EF) of Cu during dust events. The inter-annual variability of dust concentrations is investigated in this work. During winter, African dust concentration measurements at the Pico de la Gorra station were found to correlate with the North Atlantic Oscillation (NAO) index.

Simulated Nitrogen Deposition has Minor Effects on Ecosystem Pools and Fluxes of Energy, Elements, and Biochemicals in a Northern Hardwoods Forest

NASA Astrophysics Data System (ADS)

Talhelm, A. F.; Pregitzer, K. S.; Burton, A. J.; Xia, M.; Zak, D. R.

2017-12-01

The elemental and biochemical composition of plant tissues is an important influence on primary productivity, decomposition, and other aspects of biogeochemistry. Human activity has greatly altered biogeochemical cycles in ecosystems downwind of industrialized regions through atmospheric nitrogen deposition, but most research on these effects focuses on individual elements or steps in biogeochemical cycles. Here, we quantified pools and fluxes of biomass, the four major organic elements (carbon, oxygen, hydrogen, nitrogen), four biochemical fractions (lignin, structural carbohydrates, cell walls, and soluble material), and energy in a mature northern hardwoods forest in Michigan. We sampled the organic and mineral soil, fine and coarse roots, leaf litter, green leaves, and wood for chemical analyses. We then combined these data with previously published and archival information on pools and fluxes within this forest, which included replicated plots receiving either ambient deposition or simulated nitrogen deposition (3 g N m-2 yr-1 for 18 years). Live wood was the largest pool of energy and all elements and biochemical fractions. However, the production of wood, leaf litter, and fine roots represented similar fluxes of carbon, hydrogen, oxygen, cell wall material, and energy, while nitrogen fluxes were dominated by leaf litter and fine roots. Notably, the flux of lignin via fine roots was 70% higher than any other flux. Experimental nitrogen deposition had relatively few significant effects, increasing foliar nitrogen, increasing the concentration of lignin in the soil organic horizon and decreasing pools of all elements and biochemical fractions in the soil organic horizon except nitrogen, lignin, and structural carbohydrates. Overall, we found that differences in tissue chemistry concentrations were important determinants of ecosystem-level pools and fluxes, but that nitrogen deposition had little effect on concentrations, pools, or fluxes in this mature forest. Disclaimer: The views expressed in this poster are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

Radiolytic hydrogen production in basaltic basement of the South Pacific Gyre

NASA Astrophysics Data System (ADS)

Dzaugis, M. E.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; Kelley, K. A.; D'Hondt, S. L.

2013-12-01

Water radiolysis is the decomposition of water molecules due to interactions with ionizing radiation from the natural decay of radioactive elements, such as uranium (238U, 235U), thorium (232Th) and potassium (40K). This abiotic process produces electron donors (e.g., H2) and acceptors (e.g., O2) that microorganisms can metabolize for energy. Although water radiolysis has been examined in deep continental crust (Lin et al., 2005) and marine sediment (Blair et al., 2007), it has not been rigorously addressed in oceanic basement. The submarine depth to which life extends on Earth, and the potential for life in basaltic aquifers of other worlds (such as Mars and Europa), may depend on radiolytic production of electron donors and acceptors. In order to quantify the extent to which water radiolysis occurs in the subseafloor basaltic basement, we (i) quantified radioactive element concentrations of basement samples from Integrated Ocean Drilling Program (IODP) Expedition 329 and (ii) developed a quantitative model of H2 production by water radiolysis in the basement aquifer. Modeling radiolytic production of H2 in oceanic basement is difficult because the basement is a heterogeneous environment. Microscale changes in physical properties and chemical composition cause microscale variation in water radiolysis within the basement. During radioactive decay, alpha particles, beta particles and gamma rays are emitted, each with a spectrum of characteristic energies. The distance over which radiation is attenuated depends on the kind of radiation (alpha, beta or gamma), initial energy, and the absorbing material. These properties and the concentration of radioactive elements provide the basis for our preliminary model. We are using inductively coupled plasma emission spectroscopy (ICP-ES), mass spectrometry (ICP-MS) and laser ablation (LA ICP-MS) to map variation in radioelement concentrations from phase to phase (e.g., across successive alteration halos to unaltered rock). The last step in our model combines (i) the rate at which radiation energy is transferred to the water with (ii) published H2 yields per rate of energy transfer.

Enhancing Induction Coil Reliability

NASA Astrophysics Data System (ADS)

Kreter, K.; Goldstein, R.; Yakey, C.; Nemkov, V.

2014-12-01

In induction hardening, thermal fatigue is one of the main copper failure modes of induction heat treating coils. There have been papers published that describe this failure mode and others that describe some good design practices. The variables previously identified as the sources of thermal fatigue include radiation from the part surface, frequency, current, concentrator losses, water pressure and coil wall thickness. However, there is very little quantitative data on the factors that influence thermal fatigue in induction coils is available in the public domain. By using finite element analysis software this study analyzes the effect of common design variables of inductor cooling, and quantifies the relative importance of these variables. A comprehensive case study for a single shot induction coil with Fluxtrol A concentrator applied is used for the analysis.

Bioavailability assessment of toxic metals using the technique "acid-volatile sulfide (AVS)-simultaneously extracted metals (SEM)" in marine sediments collected in Todos os Santos Bay, Brazil.

PubMed

Silva, Jucelino B; Nascimento, Rodrigo A; de Oliva, Sergio T; de Oliveira, Olívia M C; Ferreira, Sergio L C

2015-10-01

This paper reports the bioavailability of the metals (cadmium, copper, zinc, lead, and nickel) in sediment samples collected in seven stations from the São Paulo Estuary, Todos os Santos Bay, Brazil. The bioavailability was determined by employing the technique "acid-volatile sulfide (AVS) and simultaneously extracted metal (SEM)". The elements cadmium, copper, lead, and zinc were determined using differential pulse anodic stripping voltammetry (DPASV), while nickel was quantified utilizing electrothermal atomic absorption spectrometry (ET AAS). The accuracy of these methods was confirmed using a certified reference material of estuarine sediment (NIST 1646). The sulfide was quantified using potentiometry with selective electrode and the organic matter determination employing an indirect volumetric method using potassium dichromate and iron(II) sulfate solutions. The bioavailability of the metals was estimated by relationship between the concentration of AVS and the sum of the concentrations of the simultaneously extracted metals (ΣSEM), considering a significant toxicity when (ΣSEM)/(AVS) is higher than 1. The bioavailability values in the seven stations studied varied from 0.93 to 1.31 (June, 2014) and from 0.34 to 0.58 (September, 2014). These results demonstrated a critical condition of toxicity (bioavailability >1) in six of the seven sediment samples collected during the rainy season (June, 2014). In the other period (September, 2014), the bioavailability was always lower than 1 for all sediment samples collected in the seven stations. The individual values of the concentrations of the five metals were compared with the parameters PEL (probable effects level) and TEL (threshold effects level), which are commonly employed for characterization of ecological risk in environmental systems. This comparison revealed that all metals have concentrations lower than the PEL and only zinc and lead in some stations have contents higher than the TEL. The bioavailability evaluation and the concentrations achieved for the five elements in the sediments samples analyzed demonstrated that the ecosystem studied does not present an environmental risk.

Experimental Investigations of Boron, Lithium, and Halogens During High-Temperature Water-Rock Interaction: Insights into the Yellowstone Hydrothermal System

NASA Astrophysics Data System (ADS)

Cullen, J. T.; Hurwitz, S.; Thordsen, J. J.; Barnes, J.

2017-12-01

B, Li, and halogens (Cl, F, Br) are used extensively in studies of thermal waters to infer fluid equilibrium conditions with the host reservoir lithology, and quantify the possible fraction of a magmatic component in thermal waters. Apart from fluorine, the limited number of minerals that incorporate these elements support the notion that they preferentially partition into an aqueous fluid during high temperature water-rock interaction. Although limited experimental work is largely consistent with these observations, a rigorous experimental investigation is required to quantify the mobility of these elements under conditions emulating a silicic hydrothermal system. Here we present the results from water-rhyolite interaction batch experiments conducted over a range of temperatures between 150 °C and 350 °C and 250 bar. Powdered obsidian from Yellowstone was reacted with MiliQ water and sampled intermittently throughout the duration of the 90 day experiment. The experimental data show that at temperatures ≤ 200 °C, B, Cl, Br, and Li are not readily leached from the rhyolite, whereas aqueous F- concentration increases by a factor of 3.5 when the temperature was increased from 150 °C to 200 °C. Between 200 °C and 250 °C, B concentration increased by more than an order of magnitude and Cl- concentration increased by a factor of 5. F- concentration increased by a factor of 3. Between 250 °C and 300 °C the opposite trend was observed, in which F- concentration decreased by 60%, Br- concentration increased by a factor of 5, and Cl- and B concentrations increased by more than an order of magnitude. The progressive decrease of aqueous F- at T ≥ 300 °C is likely controlled by precipitation into a fluorine bearing secondary mineral(s). Our experimental results demonstrate that leaching of B, Li, Cl, F, and Br from rhyolite is highly temperature-dependent between 150 °C and 350 °C. These results can provide context to infer the sources of solutes discharged at thermal springs and the subsurface water-rhyolite equilibrium temperatures in the Yellowstone hydrothermal system. Work to characterize the alteration mineralogy and the temperature-dependent stable Cl, Li, and B isotope fractionation is currently ongoing. Keywords: Yellowstone, hydrothermal, halogens, experiments, water-rock interaction

Experimental Investigations of Boron, Lithium, and Halogens During High-Temperature Water-Rock Interaction: Insights into the Yellowstone Hydrothermal System

NASA Astrophysics Data System (ADS)

Cullen, J. T.; Hurwitz, S.; Thordsen, J. J.; Barnes, J.

2016-12-01

B, Li, and halogens (Cl, F, Br) are used extensively in studies of thermal waters to infer fluid equilibrium conditions with the host reservoir lithology, and quantify the possible fraction of a magmatic component in thermal waters. Apart from fluorine, the limited number of minerals that incorporate these elements support the notion that they preferentially partition into an aqueous fluid during high temperature water-rock interaction. Although limited experimental work is largely consistent with these observations, a rigorous experimental investigation is required to quantify the mobility of these elements under conditions emulating a silicic hydrothermal system. Here we present the results from water-rhyolite interaction batch experiments conducted over a range of temperatures between 150 °C and 350 °C and 250 bar. Powdered obsidian from Yellowstone was reacted with MiliQ water and sampled intermittently throughout the duration of the 90 day experiment. The experimental data show that at temperatures ≤ 200 °C, B, Cl, Br, and Li are not readily leached from the rhyolite, whereas aqueous F- concentration increases by a factor of 3.5 when the temperature was increased from 150 °C to 200 °C. Between 200 °C and 250 °C, B concentration increased by more than an order of magnitude and Cl- concentration increased by a factor of 5. F- concentration increased by a factor of 3. Between 250 °C and 300 °C the opposite trend was observed, in which F- concentration decreased by 60%, Br- concentration increased by a factor of 5, and Cl- and B concentrations increased by more than an order of magnitude. The progressive decrease of aqueous F- at T ≥ 300 °C is likely controlled by precipitation into a fluorine bearing secondary mineral(s). Our experimental results demonstrate that leaching of B, Li, Cl, F, and Br from rhyolite is highly temperature-dependent between 150 °C and 350 °C. These results can provide context to infer the sources of solutes discharged at thermal springs and the subsurface water-rhyolite equilibrium temperatures in the Yellowstone hydrothermal system. Work to characterize the alteration mineralogy and the temperature-dependent stable Cl, Li, and B isotope fractionation is currently ongoing. Keywords: Yellowstone, hydrothermal, halogens, experiments, water-rock interaction

Measurement of atmospheric mercury species with manual sampling and analysis methods in a case study in Indiana

USGS Publications Warehouse

Risch, M.R.; Prestbo, E.M.; Hawkins, L.

2007-01-01

Ground-level concentrations of three atmospheric mercury species were measured using manual sampling and analysis to provide data for estimates of mercury dry deposition. Three monitoring stations were operated simultaneously during winter, spring, and summer 2004, adjacent to three mercury wet-deposition monitoring stations in northern, central, and southern Indiana. The monitoring locations differed in land-use setting and annual mercury-emissions level from nearby sources. A timer-controlled air-sampling system that contained a three-part sampling train was used to isolate reactive gaseous mercury, particulate-bound mercury, and elemental mercury. The sampling trains were exchanged every 6 days, and the mercury species were quantified in a laboratory. A quality-assurance study indicated the sampling trains could be held at least 120 h without a significant change in reactive gaseous or particulate-bound mercury concentrations. The manual sampling method was able to provide valid mercury concentrations in 90 to 95% of samples. Statistical differences in mercury concentrations were observed during the project. Concentrations of reactive gaseous and elemental mercury were higher in the daytime samples than in the nighttime samples. Concentrations of reactive gaseous mercury were higher in winter than in summer and were highest at the urban monitoring location. The results of this case study indicated manual sampling and analysis could be a reliable method for measurement of atmospheric mercury species and has the capability for supplying representative concentrations in an effective manner from a long-term deposition-monitoring network. ?? 2007 Springer Science+Business Media B.V.

Spectral analysis of rare earth elements using laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Martin, Madhavi Z.; Fox, Robert V.; Miziolek, Andrzej W.; DeLucia, Frank C.; André, Nicolas

2015-06-01

There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W

2015-01-01

There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to bemore » able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.« less

Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W

2015-01-01

There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to bemore » able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.« less

Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Madhavi Z. Martin; Robert V. Fox; Andrzej W. Miziolek

2001-05-01

There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to bemore » able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.« less

Arsenic Uptake by Muskmelon (Cucumis melo) Plants from Contaminated Water.

PubMed

Hettick, Bryan E; Cañas-Carrell, Jaclyn E; Martin, Kirt; French, Amanda D; Klein, David M

2016-09-01

Arsenic is a carcinogenic element that occurs naturally in the environment. High levels of arsenic are found in water in some parts of the world, including Texas. The aims of this study were to determine the distribution of arsenic in muskmelon (Cucumis melo) plants accumulated from arsenic spiked water and to observe effects on plant biomass. Plants were grown and irrigated using water spiked with variable concentrations of arsenic. Inductively coupled plasma mass spectrometry was used to quantify arsenic in different parts of the plant and fruit. Under all conditions tested in this study, the highest concentrations of arsenic were found in the leaves, soil, and roots. Arsenic in the water had no significant effect on plant biomass. Fruits analyzed in this study had arsenic concentrations of 101 μg/kg or less. Consuming these fruits would result in less arsenic exposure than drinking water at recommended levels.

Application of ICP-OES for evaluating energy extraction and production wastewater discharge impacts on surface waters in Western Pennsylvania.

PubMed

Pancras, Joseph Patrick; Norris, Gary A; Landis, Matthew S; Kovalcik, Kasey D; McGee, John K; Kamal, Ali S

2015-10-01

Oil and gas extraction and coal-fired electrical power generating stations produce wastewaters that are treated and discharged to rivers in Western Pennsylvania with public drinking water system (PDWS) intakes. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to quantify inorganic species in wastewater and river samples using a method based on EPA Method 200.7 rev4.4. A total of 53 emission lines from 30 elements (Al, As, B, Ba, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Se, Si, Sn, Sr, Ti, Tl, V, and Zn) were investigated. Samples were prepared by microwave-assisted acid digestion using a mixture of 2% HNO3 and 0.5% HCl. Lower interferences and better detection characteristics resulted in selection of alternative wavelengths for Al, As, Sb, Mg, Mo, and Na. Radial view measurements offered accurate determinations of Al, Ba, K, Li, Na, and Sr in high-brine samples. Spike recovery studies and analyses of reference materials showed 80-105% recoveries for most analytes. This method was used to quantify species in samples with high to low brine concentrations with method detection limits a factor of 2 below the maximum contaminant limit concentrations of national drinking water standards. Elements B, Ca, K, Li, Mg, Na, and Sr were identified as potential tracers for the sources impacting PDWS intakes. Usability of the ICP-OES derived data for factor analytic model applications was also demonstrated. Published by Elsevier B.V.

Suitability of Tillandsia usneoides and Aechmea fasciata for biomonitoring toxic elements under tropical seasonal climate.

PubMed

Giampaoli, Patricia; Wannaz, Eduardo D; Tavares, Armando R; Domingos, Marisa

2016-04-01

Aechmea fasciata was evaluated for the first time as a biomonitor of toxic elements, in comparison to the biomonitoring capacity of Tillandsia usneoides, a well-established biomonitor bromeliad species. Plants of both species were exposed to air pollutants from industrial, urban, and agricultural sources, under the tropical seasonal climate, from June/2011 to April/2013, in five sites of São Paulo State, Brazil, for 8 consecutive exposure periods of 12 weeks each. The levels of essential and non-essential elements, including trace metals, were quantified at the end of each exposure. T. usneoides and A. fasciata indicated N, Fe, Zn, Co, Cr, and V as air contaminants in the studied sites, during wet and dry seasons and both species were recommended for qualitative biomonitoring. Concentration levels of N, Ca, S, Fe, Zn, Cu, B, Co, and Ni were significantly higher in T. usneoides than in A. fasciata. However, A. fasciata showed a higher effective retention capacity of Ni, Pb, V, Cu, Fe, Cr, and Co during field exposure, as indicated by the estimate of enrichment factor relative to basal concentrations. This species is more suitable for detecting the atmospheric pollution level of those metals than the T. usneoides. Both species indicated adequately the seasonal differences in the pollution levels of several elements, but T. usneoides presented higher ability for biomonitoring the spatial variations and for indicating more properly the sources of each element in the studied region than the A. fasciata. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metallic elements and isotope of Pb in wet precipitation in urban area, South America

NASA Astrophysics Data System (ADS)

Migliavacca, Daniela Montanari; Teixeira, Elba Calesso; Gervasoni, Fernanda; Conceição, Rommulo Vieira; Raya Rodriguez, Maria Teresa

2012-04-01

The atmosphere of urban areas has been the subject of many studies to show the atmospheric pollution in large urban centers. By quantifying wet precipitation through the analysis of metallic elements (ICP/AES) and Pb isotopes, the wet precipitation of the Metropolitan Area of the Porto Alegre (MAPA), Brazil, was characterized. The samples were collected between July 2005 and December 2007. Zn, Fe and Mn showed the highest concentration in studied sites. Sapucaia do Sul showed the highest average for Zn, due to influence by the steel plant located near the sampling site. The contribution of anthropogenic emissions from vehicular activity and steel plants in wet precipitation and suspended particulate matter in the MAPA was identified by the isotopic signatures of 208Pb/207Pb and 206Pb/207Pb. Moreover the analyses of the metallic elements allowed also to identify the contribution of other anthropic sources, such as steel plants and oil refinery.

Leaves of Phragmites australis as potential atmospheric biomonitors of Platinum Group Elements.

PubMed

Bonanno, Giuseppe; Pavone, Pietro

2015-04-01

The increasing emissions of Platinum Group Elements (PGEs), namely Pt, Pd and Rh, may pose a significant risk to ecosystem processes and human health. A periodic assessment of PGEs distribution in the environment is thus of the utmost importance for the implementation of timely measures of mitigation. Although several studies have quantified PGEs in different life forms such as mammals, birds, fish, crustaceans, algae, mosses and even human beings, data about vascular plants need further surveys. This study aimed to test the suitability of the grass Phragmites australis (common reed) as a biomonitor of PGEs atmospheric pollution. The results showed that Pd and Pt concentrations in leaves are significantly higher in urban areas. In particular, Pd showed the highest range of values in line with current studies that consider palladium as the main element of traffic-related pollution. Overall, the leaves of Phragmites australis reflected the different gradient of PGEs emissions, and may thus be considered as potential biomonitors of atmospheric pollution. Copyright © 2015 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelli Kazuberns; Sushil Gupta; Mihaela Grigore

Blast furnace efficiency may be improved by optimizing coke reactivity. Some but not all forms of mineral matter in the coke modify its reactivity, but changes in mineral matter that occur within coke while in the blast furnace have not been fully quantified. To determine changes in mineral matter forms in the blast furnace, coke samples from a dissection study in the LKAB experimental blast furnace (EBF) were characterized using SEM/EDS analysis, EPMA (microprobe), and low-temperature ashing/quantitative XRD analysis. Variations in alkali concentration, particularly potassium, dominated the compositional changes. At high concentrations of potassium, the mineral matter was largely potassium-bearingmore » but even more potassium was diffused throughout the coke and not associated with mineral matter. There was little difference in potassium concentration between the core and surface of the coke pieces, suggesting that potassium diffused rapidly through the whole coke. Iron, calcium, silicon, and aluminum concentrations were relatively constant in comparison, although the mineralogy of all elements changed significantly with changing temperature. 23 refs., 20 figs., 9 tabs.« less

Decadal Comparisons of Particulate Matter in Repeat Transects in the Atlantic, Pacific, and Indian Ocean Basins

NASA Astrophysics Data System (ADS)

Gardner, W. D.; Mishonov, A. V.; Richardson, M. J.

2018-01-01

Basin-wide sections of beam cp (proxy for particle concentration) in ocean basins collected during numerous oceanographic programs over the last four decades record variable concentrations in euphotic surface waters, very low concentrations through most of the water column, and very low to very high concentrations near the seafloor. Sections resampled at decadal intervals show that intense benthic nepheloid layers (BNLs) recur in the same general locations in these repeat sections, most often where eddy kinetic energy (EKE: cm2 s-2) is high in overlying waters. Areas beneath regions of low surface EKE consistently have weak to no BNLs. The decadal persistence of the close connection between surface and benthic EKE and presence or absence of BNLs is clear. Understanding the location and causes of intense versus weak BNLs helps in assessing scavenging of adsorption-prone elements in the deep sea and quantifying the impact of deep ocean sediment dynamics on sediment redistribution.

Effect of nitrogen species supply and mycorrhizal colonization on organosulfur and phenolic compounds in onions.

PubMed

Perner, Henrike; Rohn, Sascha; Driemel, Gregor; Batt, Natalie; Schwarz, Dietmar; Kroh, Lothar W; George, Eckhard

2008-05-28

The aim of the present study was to test whether variations in the root environment affect the content of health-related organosulfur compounds, total phenolic compounds, and flavonol glycoside concentrations in onions. For this purpose, greenhouse-grown onions ( Allium cepa L.) were either inoculated with a commercial arbuscular mycorrhizal inoculum or a sterile inoculum and were provided with two NH(4)(+):NO(3)(-) ratios as a nitrogen source. Onion growth, arbuscular mycorrhizal colonization rate, sugars, and nutrient element concentrations were also quantified. The plant antioxidant activity and quercetin monoglucoside and organosulfur compound concentrations increased with dominant nitrate supply. Furthermore, mycorrhizal colonization increased the antioxidant activity and also concentrations of the major quercetin glucosides. The present study provides clear evidence that antioxidant activity, quercetin glycosides, and organosulfur compounds can be increased in sufficiently supplied onion plants by dominant nitrate supply or application of arbuscular mycorrhizal fungi. This was probably due to increased precursor production and induced defense mechanisms.

Co-inoculation of Lolium perenne with Funneliformis mosseae and the dark septate endophyte Cadophora sp. in a trace element-polluted soil.

PubMed

Berthelot, Charlotte; Blaudez, Damien; Beguiristain, Thierry; Chalot, Michel; Leyval, Corinne

2018-04-01

The presence of dark septate endophytes (DSEs) or arbuscular mycorrhizal fungi (AMF) in plant roots and their effects on plant fitness have been extensively described. However, little is known about their interactions when they are simultaneously colonizing a plant root, especially in trace element (TE)-polluted soils. We therefore investigated the effects of Cadophora sp. and Funneliformis mosseae on ryegrass (Lolium perenne) growth and element uptake in a Cd/Zn/Pb-polluted soil. The experiment included four treatments, i.e., inoculation with Cadophora sp., inoculation with F. mosseae, co-inoculation with Cadophora sp. and F. mosseae, and no inoculation. Ryegrass biomass and shoot Na, P, K, and Mg concentrations significantly increased following AMF inoculation as compared to non-inoculated controls. Similarly, DSE inoculation increased shoot Na concentration, whereas dual inoculation significantly decreased shoot Cd concentration. Moreover, oxidative stress determined by ryegrass leaf malondialdehyde concentration was alleviated both in the AMF and dual inoculation treatments. We used quantitative PCR and microscope observations to quantify colonization rates. They demonstrated that DSEs had no effect on AMF colonization, while AMF colonization slightly decreased DSE frequency. We also monitored fluorescein diacetate (FDA) hydrolysis and alkaline phosphatase (AP) activity in the rhizosphere soils. FDA hydrolysis remained unchanged in the three inoculated treatments, but AMF colonization increased AP activity and P mobility in the soil whereas DSE colonization did not alter AP activity. In this experiment, we unveiled the interactions between two ecologically important fungal groups likely to occur in roots which involved a decrease of oxidative stress and Cd accumulation in shoots. These results open promising perspectives on the fungal-based phytomanagement of TE-contaminated sites by the production of uncontaminated and marketable plant biomass.

Ablative and transport fractionation of trace elements during laser sampling of glass and copper

NASA Astrophysics Data System (ADS)

Outridge, P. M.; Doherty, W.; Gregoire, D. C.

1997-12-01

The fractionation of trace elements due to ablation and transport processes was quantified during Q-switched infrared laser sampling of glass and copper reference materials. Filter-trapping of the ablated product at different points in the sample introduction system showed ablation and transport sometimes caused opposing fractionation effects, leading to a confounded measure of overall (ablative + transport) fractionation. An unexpected result was the greater ablative fractionation of some elements (Au, Ag, Bi, Te in glass and Au, Be, Bi, Ni, Te in copper) at a higher laser fluence of 1.35 × 10 4W cm -2 than at 0.62 × 10 4W cm -2, which contradicted predictions from modelling studies of ablation processes. With glass, there was an inverse logarithmic relationship between the extent of ablative and overall fractionation and element oxide melting point (OMPs), with elements with OMPs < 1000° C exhibiting overall concentration increases of 20-1340%. Fractionation during transport was quantitatively important for most certified elements in copper, and for the most volatile elements (Au, Ag, Bi, Te) in glass. Elements common to both matrices showed 50-100% higher ablative fractionation in copper, possibly because of greater heat conductance away from the ablation site causing increased element volatilisation or zone refinement. These differences between matrices indicate that non-matrix-matched standardisation is likely to provide inaccurate calibration of laser ablation inductively coupled plasma-mass spectrometry analyses of at least some elements.

Phytoextraction of potentially toxic elements by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil.

PubMed

Shaheen, Sabry M; Rinklebe, Jörg

2015-12-01

The objective of this study was to quantify the phytoextraction of the potentially toxic elements Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Se, V, and Zn by Indian mustard, rapeseed, and sunflower from a contaminated riparian soil. To achieve this goal, a greenhouse pot experiment was established using a highly contaminated grassland soil collected at the Wupper River (Germany). The impact of ethylene-diamine-tetra-acetic acid (EDTA), humate (HK), and phosphate potassium (PK) on the mobility and uptake of the elements by rapeseed also was investigated. Indian mustard showed the highest efficiency for phytoextraction of Al, Cr, Mo, Se, and V; sunflower for Cd, Ni, Pb, and Zn, and rapeseed for Cu. The bioconcentration ratios were higher than 1 for the elements (except As and Cu), indicating the suitability of the studied plants for phytoextraction. Application of EDTA to the soil increased significantly the solubility of Cd, Co, Cr, Ni, and Pb and decreased the solubility of Al, As, Se, V, and Mo. Humate potassium decreased significantly the concentrations of Al and As in rapeseed but increased the concentrations of Cu, Se, and Zn. We may conclude that HK can be used for immobilization of Al and As, while it can be used for enhancing the phytoextraction of Cu, Se, and Zn by rapeseed. Phosphate potassium immobilized Al, Cd, Pb, and Zn, but enhanced phytoextraction of As, Cr, Mo, and Se by rapeseed.

Evaluation of two models for predicting elemental accumulation by arthropods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Webster, J.R.; Crossley, D.A. Jr.

1978-06-15

Two different models have been proposed for predicting elemental accumulation by arthropods. Parameters of both models can be quantified from radioisotope elimination experiments. Our analysis of the 2 models shows that both predict identical elemental accumulation for a whole organism, though differing in the accumulation in body and gut. We quantified both models with experimental data from /sup 134/Cs and /sup 85/Sr elimination by crickets. Computer simulations of radioisotope accumulation were then compared with actual accumulation experiments. Neither model showed exact fit to the experimental data, though both showed the general pattern of elemental accumulation.

SR-TXRF analysis of trace elements in whole blood and heart of rats: effects of irradiation with low and high doses

NASA Astrophysics Data System (ADS)

Mota, C. L.; Pickler, A.; Braz, D.; Barroso, R. C.; Mantuano, A.; Salata, C.; Ferreira-Machado, S. C.; Lau, C. C.; de Almeida, C. E.

2018-04-01

In the last decades, studies showed that the exposure to low doses of ionizing radiation of the body could sense and activate the cell signaling pathways needed to respond to any induced cellular damage. This procedure reduces cell killing compared with a single dose of high radiation dose. Damage to the vasculature can affect the function of most body organs by restricting blood flow and oxygen to tissues; however, the heart and brain are of main concern. The precise relationship between long-term health effects and low-dose exposures remain poorly understood. Biological markers are powerful tools that can be used to determine dose- response relationships and to estimate risk, especially when dealing with, the effects of low dose exposures in humans. These markers should be specific, sensitive, as well as easy and fast to quantify. Various types of biologic specimens are potential candidates for identifying biomarkers but blood has the advantage of being minimally invasive to obtain. In this study, we propose to apply total reflection X-ray fluorescence to quantify possible chemical elemental concentration (sulfer, iron, zinc, potassium and calcium) changes in blood and heart tissues of Wistar rats after total body irradiation with low (0.1 Gy) and high (2.5 Gy) doses. The fluorescence measurements were carried out at the X-ray Fluorescence beamline in the Brazilian Synchrotron Light Laboratory. The results showed that the irradiated animals with low doses have significant alterations in blood and cardiac tissue when compared with animals that received high doses of radiation. Taken together the analysis of all the elements, we can observe that the radiation induced oxidative stress may be the leading cause for alteration of the elemental level in the studied samples.

Laboratory calibration and field testing of the Chemcatcher-Metal for trace levels of rare earth elements in estuarine waters.

PubMed

Petersen, Jördis; Pröfrock, Daniel; Paschke, Albrecht; Broekaert, Jose A C; Prange, Andreas

2015-10-01

Little knowledge is available about water concentrations of rare earth elements (REEs) in the marine environment. The direct measurement of REEs in coastal waters is a challenging task due to their ultra-low concentrations as well as the high salt content in the water samples. To quantify these elements at environmental concentrations (pg L(-1) to low ng L(-1)) in coastal waters, current analytical techniques are generally expensive and time consuming, and require complex chemical preconcentration procedures. Therefore, an integrative passive sampler was tested as a more economic alternative sampling approach for REE analysis. We used a Chemcatcher-Metal passive sampler consisting of a 3M Empore Chelating Disk as the receiving phase, as well as a cellulose acetate membrane as the diffusion-limiting layer. The effect of water turbulence and temperature on the uptake rates of REEs was analyzed during 14-day calibration experiments by a flow-through exposure tank system. The sampling rates were in the range of 0.42 mL h(-1) (13 °C; 0.25 m s(-1)) to 4.01 mL h(-1) (13 °C; 1 m s(-1)). Similar results were obtained for the different REEs under investigation. The water turbulence was the most important influence on uptake. The uptake rates were appropriate to ascertain time-weighted average concentrations of REEs during a field experiment in the Elbe Estuary near Cuxhaven Harbor (exposure time 4 weeks). REE concentrations were determined to be in the range 0.2 to 13.8 ng L(-1), where the highest concentrations were found for neodymium and samarium. In comparison, most of the spot samples measured along the Chemcatcher samples had REE concentrations below the limit of detection, in particular due to necessary dilution to minimize the analytical problems that arise with the high salt content in marine water samples. This study was among the first efforts to measure REE levels in the field using a passive sampling approach. Our results suggest that passive samplers could be an effective tool to monitor ultra-trace concentrations of REEs in coastal waters with high salt content.

Quantification of nitrogen in the liquid fraction and in vitro assessment of lysine bioavailability in the solid fraction of soybean meal hydrolysates.

PubMed

Luján-Rhenals, D; Morawicki, R; Shi, Z; Ricke, S C

2018-01-02

Soybean meal (SBM) is a product generated from the manufacture of soybean oil and has the potential for use as a source of fermentable sugars for ethanol production or as a protein source for animal feeds. Knowing the levels of nitrogen available from ammonium is a necessary element of the ethanolic fermentation process while identifying the levels of essential amino acids such as lysine is important in determining usage as a feed source. As such the purpose of this study was to quantify total nitrogen and ammonium in the liquid fraction of hydrolyzed SBM and to evaluate total and bioavailable lysine in the solid fraction of the hydrolyzed SBM. The effects of acid concentration, cellulase and β-glucosidase on total and ammonium nitrogen were studied with analysis indicating that higher acid concentrations increased nitrogen compounds with ammonium concentrations ranging from 0.20 to 1.24 g L -1 while enzymatic treatments did not significantly increase nitrogen levels. Total and bioavailable lysine was quantified by use of an auxotrophic gfpmut3 E.coli whole-cell bioassay organism incapable of lysine biosynthesis. Acid and enzymatic treatments were applied with lysine bioavailability increasing from a base of 82% for untreated SBM to up to 97%. Our results demonstrated that SBM has the potential to serve in ethanolic fermentation and as an optimal source essential amino acid lysine.

Elemental imaging at the nanoscale: NanoSIMS and complementary techniques for element localisation in plants.

PubMed

Moore, Katie L; Lombi, Enzo; Zhao, Fang-Jie; Grovenor, Chris R M

2012-04-01

The ability to locate and quantify elemental distributions in plants is crucial to understanding plant metabolisms, the mechanisms of uptake and transport of minerals and how plants cope with toxic elements or elemental deficiencies. High-resolution secondary ion mass spectrometry (SIMS) is emerging as an important technique for the analysis of biological material at the subcellular scale. This article reviews recent work using the CAMECA NanoSIMS to determine elemental distributions in plants. The NanoSIMS is able to map elemental distributions at high resolution, down to 50 nm, and can detect very low concentrations (milligrams per kilogram) for some elements. It is also capable of mapping almost all elements in the periodic table (from hydrogen to uranium) and can distinguish between stable isotopes, which allows the design of tracer experiments. In this review, particular focus is placed upon studying the same or similar specimens with both the NanoSIMS and a wide range of complementary techniques, showing how the advantages of each technique can be combined to provide a fuller data set to address complex scientific questions. Techniques covered include optical microscopy, synchrotron techniques, including X-ray fluorescence and X-ray absorption spectroscopy, transmission electron microscopy, electron probe microanalysis, particle-induced X-ray emission and inductively coupled plasma mass spectrometry. Some of the challenges associated with sample preparation of plant material for SIMS analysis, the artefacts and limitations of the technique and future trends are also discussed.

μPIXE for a μBrain: The vinegar fly's brain, antenna, sensilla hairs and eye ion concentrations

NASA Astrophysics Data System (ADS)

Reinert, Anja; Barapatre, Nirav; Sachse, Silke; Reinert, Tilo

2011-10-01

The vinegar fly Drosophila melanogaster is used as model organism to study a variety of different scientific purposes. Thus, our laboratory studies the olfactory system by neurobiological experiments. These techniques are often disruptive and need to compensate or exchange the body fluid, the lymph, with an artificial Ringer's solution in defined compartments of the fly. The solution mainly contains Na, Cl, K and Ca and is to keep physiological conditions. Therefore, the knowledge about the ion concentrations in the respective Drosophila lymph is required for a correct mixture of the ions. This paper presents the spatially resolved concentrations of P, S, Cl, K, Ca, Fe, Cu and Zn in lyophilised head cryosections of Drosophila by using quantitative μPIXE at the ion beam facility LIPSION in Leipzig. The PIXE maps enable a detailed analysis of particular regions of interest down to a spatial resolution of 0.5 μm. We quantified the ion concentrations especially in the brain, the antenna and its sensilla hairs acting as the olfactory organ of the fly, in the compound eye and in the mouthparts. The averaged element concentrations of these main compartments are (in descending order): P: 90 mM, K: 81 mM, S: 38 mM, Cl: 18 mM, Ca: 4.9 mM, Fe: 1.4 mM, Zn: 1.2 mM, Cu: 0.06 mM. Certain structures or cavities possess a remarkably high concentration of particular elements and might reflect the different functions of the compartments. An example presented in more detail is the composition of the compound eye. Conclusively, our findings on the ion concentrations might be useful for the mixture of the Drosophila Ringer's solution to ensure physiological conditions in experiments.

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound

PubMed Central

Mercado, Karla P.; Helguera, María; Hocking, Denise C.

2015-01-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13–47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices. PMID:25517512

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound.

PubMed

Mercado, Karla P; Helguera, María; Hocking, Denise C; Dalecki, Diane

2015-07-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13-47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices.

Diesel exhaust exposures in port workers.

PubMed

Debia, Maximilien; Neesham-Grenon, Eve; Mudaheranwa, Oliver C; Ragettli, Martina S

2016-07-01

Exposure to diesel engine exhaust has been linked to increased cancer risk and cardiopulmonary diseases. Diesel exhaust is a complex mixture of chemical substances, including a particulate fraction mainly composed of ultrafine particles, resulting from the incomplete combustion of fuel. Diesel trucks are known to be an important source of diesel-related air pollution, and areas with heavy truck traffic are associated with higher air pollution levels and increased public health problems. Several indicators have been proposed as surrogates for estimating exposures to diesel exhaust but very few studies have focused specifically on monitoring the ultrafine fraction through the measurement of particle number concentrations. The aim of this study is to assess occupational exposures of gate controllers at the port of Montreal, Canada, to diesel engine emissions from container trucks by measuring several surrogates through a multimetric approach which includes the assessment of both mass and number concentrations and the use of direct reading devices. A 10-day measurement campaign was carried out at two terminal checkpoints at the port of Montreal. Respirable elemental and organic carbon, PM1, PM2.5, PMresp (PM4), PM10, PMtot (inhalable fraction), particle number concentrations, particle size distributions, and gas concentrations (NO2, NO, CO) were monitored. Gate controllers were exposed to concentrations of contaminants associated with diesel engine exhaust (elemental carbon GM = 1.6 µg/m(3); GSD = 1.6) well below recommended occupational exposure limits. Average daily particle number concentrations ranged from 16,544-67,314 particles/cm³ (GM = 32,710 particles/cm³; GSD = 1.6). Significant Pearson correlation coefficients were found between daily elemental carbon, PM fractions and particle number concentrations, as well as between total carbon, PM fractions and particle number concentrations. Significant correlation coefficients were found between particle number concentrations and the number of trucks and wind speed (R(2) = 0.432; p < 0.01). The presence of trucks with cooling systems and older trucks with older exhaust systems was associated with peak concentrations on the direct reading instruments. The results highlight the relevance of direct reading instruments in helping to identify sources of exposure and suggest that monitoring particle number concentrations improves understanding of workers' exposures to diesel exhaust. This study, by quantifying workers' exposure levels through a multimetric approach, contributes to the further understanding of occupational exposures to diesel engine exhaust.

Mineral Composition and Nutritive Value of Isotonic and Energy Drinks.

PubMed

Leśniewicz, Anna; Grzesiak, Magdalena; Żyrnicki, Wiesław; Borkowska-Burnecka, Jolanta

2016-04-01

Several very popular brands of isotonic and energy drinks consumed for fluid and electrolyte supplementation and stimulation of mental or physical alertness were chosen for investigation. Liquid beverages available in polyethylene bottles and aluminum cans as well as products in the form of tablets and powder in sachets were studied. The total concentrations of 21 elements (Ag, Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, Ti, V, and Zn), both essential and toxic, were simultaneously determined in preconcentrated drink samples by inductively coupled plasma-optical emission spectrometry (ICP-OES) equipped with pneumatic and ultrasonic nebulizers. Differences between the mineral compositions of isotonic and energy drinks were evaluated and discussed. The highest content of Na was found in both isotonic and energy drinks, whereas quite high concentrations of Mg were found in isotonic drinks, and the highest amount of calcium was quantified in energy drinks. The concentrations of B, Co, Cu, Ni, and P were higher in isotonic drinks, but energy drinks contained greater quantities of Ag, Cr, Zn, Mn, and Mo and toxic elements, as Cd and Pb. A comparison of element contents with micronutrient intake and tolerable levels was performed to evaluate contribution of the investigated beverages to the daily diet. The consumption of 250 cm(3) of an isotonic drink provides from 0.32% (for Mn) up to 14.8% (for Na) of the recommended daily intake. For the energy drinks, the maximum recommended daily intake fulfillment ranged from 0.02% (for V) to 19.4 or 19.8% (for Mg and Na).

The influence of microtopography on soil nutrients in created mitigation wetlands

USGS Publications Warehouse

Moser, K.F.; Ahn, C.; Noe, G.B.

2009-01-01

This study explores the relationship between microtopography and soil nutrients (and trace elements), comparing results for created and reference wetlands in Virginia, and examining the effects of disking during wetland creation. Replicate multiscale tangentially conjoined circular transects were used to quantify microtopography both in terms of elevation and by two microtopographic indices. Corresponding soil samples were analyzed for moisture content, total C and N, KCl-extractable NH4-N and NO3-N, and Mehlich-3 extractable P, Ca, Mg, K, Al, Fe, and Mn. Means and variances of soil nutrient/element concentrations were compared between created and natural wetlands and between disked and nondisked created wetlands. Natural sites had higher and more variable soil moisture, higher extractable P and Fe, lower Mn than created wetlands, and comparatively high variability in nutrient concentrations. Disked sites had higher soil moisture, NH4-N, Fe, and Mn than did nondisked sites. Consistently low variances (Levene test for inequality) suggested that nondisked sites had minimal nutrient heterogeneity. Across sites, low P availability was inferred by the molar ratio (Mehlich-3 [P/(Al + Fe)] < 0.06); strong intercorrelations among total C, total N, and extractable Fe, Al, and P suggested that humic-metal-P complexes may be important for P retention and availability. Correlations between nutrient/element concentrations and microtopographic indices suggested increased Mn and decreased K and Al availability with increased surface roughness. Disking appears to enhance water and nutrient retention, as well as nutrient heterogeneity otherwise absent from created wetlands, thus potentially promoting ecosystem development. ?? 2008 Society for Ecological Restoration International.

Dramatic fluctuations in liver mass and metal content of eared grebes (Podiceps nigricollis) during autumnal migration

USGS Publications Warehouse

Rattner, B.A.; Jehl, J.R.

1997-01-01

Adult eared grebes exhibit threefold fluctuation in body mass and up to a fivefold variation in liver weight during the course of their annual breeding and migratory cycle. Concentrations of 20 metals or metalloids were quantified in the liver from eared grebes obtained at three phases of their annual cycle: newly arrived migrants (July-August-September), staging (October-November), and immediate post-migration (December-January). Values for twelve elements (Al, B, Cd, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Se, and Zn) that were detected in more than one-half of the samples were low. Hepatic concentrations of elements known to be toxic to free-ranging birds (e.g., Cd, Hg, Pb, Se) were well below known effect thresholds. No differences in metal concentrations were observed between newly arrived migrants and staging birds despite the large increases in body and liver mass. However, in the immediate post-migration period after body and liver mass have rapidly declined, Al values decreased, whereas Se and Zn concentrations actually increased. Total liver burdens of elements tended to be greatest in staging grebes compared to other collection periods, and paralleled changes in body and liver mass. The need for temporally- and physiologically-matched reference birds, and at least knowledge of circannual organ mass fluctuations, appears to be a requirement for ecotoxicological exposure assessments in species such as the eared grebe. Generation of additional avian toxicity data from controlled dosing studies during potentially vulnerable phases of their annual cycle (e.g., molt, post-migration) seems warranted. Although it is commonly accepted that hepatic metal concentrations are principally affected by contaminant exposure, we have shown differential alterations related to the stage of the annual cycle. Our findings may be of broad significance, as well as of immediate importance in resolving the cause of the die-off of approximately 150,000 eared grebes (perhaps 7% of the North American population) at the Salton Sea in 1991-1992.

Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

NASA Astrophysics Data System (ADS)

Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

2016-04-01

The Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are areas in particular where forest sources have elevated concentrations and may require some attention in the decontamination and monitoring of potential radiocesium downstream transfers.

3D element imaging using NSECT for the detection of renal cancer: a simulation study in MCNP.

PubMed

Viana, R S; Agasthya, G A; Yoriyaz, H; Kapadia, A J

2013-09-07

This work describes a simulation study investigating the application of neutron stimulated emission computed tomography (NSECT) for noninvasive 3D imaging of renal cancer in vivo. Using MCNP5 simulations, we describe a method of diagnosing renal cancer in the body by mapping the 3D distribution of elements present in tumors using the NSECT technique. A human phantom containing the kidneys and other major organs was modeled in MCNP5. The element composition of each organ was based on values reported in literature. The two kidneys were modeled to contain elements reported in renal cell carcinoma (RCC) and healthy kidney tissue. Simulated NSECT scans were executed to determine the 3D element distribution of the phantom body. Elements specific to RCC and healthy kidney tissue were then analyzed to identify the locations of the diseased and healthy kidneys and generate tomographic images of the tumor. The extent of the RCC lesion inside the kidney was determined using 3D volume rendering. A similar procedure was used to generate images of each individual organ in the body. Six isotopes were studied in this work - (32)S, (12)C, (23)Na, (14)N, (31)P and (39)K. The results demonstrated that through a single NSECT scan performed in vivo, it is possible to identify the location of the kidneys and other organs within the body, determine the extent of the tumor within the organ, and to quantify the differences between cancer and healthy tissue-related isotopes with p ≤ 0.05. All of the images demonstrated appropriate concentration changes between the organs, with some discrepancy observed in (31)P, (39)K and (23)Na. The discrepancies were likely due to the low concentration of the elements in the tissue that were below the current detection sensitivity of the NSECT technique.

Monte Carlo Simulation to Determine Geometry Effects on Quantitative X-ray Microanalysis in Plant Cell Walls Using Gelatin Standards

NASA Astrophysics Data System (ADS)

Tylko, Grzegorz; Dubchak, Sergyi; Banach, Zuzanna; Turnau, Katarzyna

2010-04-01

Monte Carlo simulations of gelatin matrices with known elemental concentrations confirmed the suitability of protein standards to quantify elements of cellulose material in x-ray microanalysis. However, gelatin standards and cellulose plant cell walls differ in structure, what influences x-ray generation and emission in both specimens. The goal of the project was to establish the influence of gelatin structure on x-ray generation and its usefulness to calculate elemental concentrations in plant cell walls of different width. Roots of Medicago truncatula as well as gelatin standards with known elemental composition were prepared according to freeze-drying protocols. The thermanox polymer was chosen to establish background formation for flat and compact organic materials. All analyses were performed with the scanning electron microscope operated at 10 keV and probe current of 350 pA. The Monte Carlo code Casino was applied to calculate the intensities of the generated and the emitted x-rays from biological matrix of different width. No topography effects of gelatin structure were visible when the raster mode of electron impact was applied to the specimen. Monte Carlo simulations of gelatin of different width revealed that a significant decrease of the generated x-ray intensity appears at the width of the specimen around 3.5 μm. However, an increase of emission of low energy x-ray intensities (Na, Mg) was noted at 3.5 μm size with constant emission of higher energy x-rays (Cl, K) down to 2.5 μm width. It determines the minimal size of plant specimen useful for comparison to bulk gelatin standard when quantitative analysis is performed for biologically important elements.

Elemental Redistribution at the Onset of Soil Genesis from Basalt as Measured in a Soil Lysimeter System

NASA Astrophysics Data System (ADS)

Wang, Y.; Umanzor, M.; Alves Meira Neto, A.; Sengupta, A.; Amistadi, M. K.; Root, R.; Troch, P.; Chorover, J.

2017-12-01

Elemental translocation, resulting in enrichment or depletion relative to parent rock, is a consequence of mineral dissolution and precipitation reactions of soil genesis. Accurate measurement of translocation in natural systems is complicated by factors such as parent material heterogeneity and dust deposition. In the present work, a fully controlled and monitored 10° sloping soil lysimeter with known homogeneous initial conditions, was utilized to investigate initial stages of soil genesis from 1 m3 of crushed basalt. Throughout the two-year experiment, periodic irrigation coupled with sensor measurements enabled monitoring of changes in internal moisture states. A total 15-meter water influx resulted in distinct efflux patterns, wetting and drying cycles, as well as high volume water storage. Biological changes, such as algal and grass emergence, were visible on the soil surface, and microbial colonization throughout the profile was measured in a companion study, suggesting that biogeochemical hotspots may have formed. Forensic excavation and sampling of 324 voxels captured the final state heterogeneity of the lysimeter with respect to length and depth. Total elemental concentrations and a five-step sequential extraction (SE) scheme quantified elemental redistributions into operationally-defined pools including exchangeable, poorly-crystalline (hydr)oxides, and crystalline (hydr)oxides. Data were correlated to water flux and storage that was determined from sensor and tracer data over the two years of rock-water interaction; then used to map 2D cross-sections and identify geochemical hotspots. Total and SE Fe concentrations were used to establish a governing mass balance equation, and sub mass balance equations with unique partitioning coefficients of Fe were developed for each SE pool, respectively. The results help to explain elemental (e.g., Fe) lability and redistribution due to physical and geochemical weathering during the initial stages of soil genesis.

Assessment of heavy metals in the particulate matter of two Brazilian metropolitan areas by using Tillandsia usneoides as atmospheric biomonitor.

PubMed

Vianna, Nelzair A; Gonçalves, Daniel; Brandão, Flavia; de Barros, Roberta P; Amado Filho, Gilberto M; Meire, Rodrigo O; Torres, João Paulo M; Malm, Olaf; D'Oliveira Júnior, Argemiro; Andrade, Leonardo R

2011-03-01

The aims of this paper were to quantify the heavy metals (HM) in the air of different sites in Rio de Janeiro (RJ) and Salvador (SA) using Tillandsia usneoides (Bromeliaceae) as a biomonitor, and to study the morphology and elemental composition of the air particulate matter (PM) retained on the Tillandsia surface. Tillandsia samples were collected in a noncontaminated area and exposed to the air of five sites in RJ State and seven in SA for 45 days, in two seasons. Samples were prepared to HM quantification by flame atomic absorption spectrophotometry, while morphological and elemental characterizations were studied by using scanning electron microscopy. HM concentrations were significantly higher when compared to control sites. We found an increasing metal concentration as follows: Cd < Cr < Pb < Cu < Zn. PM exhibited a morphology varying from amorphous- to polygonal-shaped particles. Size measurements indicated that more than 80% of particles were less than 10 μm. PM contained aluminosilicates iron-rich particles, but Zn, Cu, Cr, and Ba were also detected. HM input in the atmosphere was mainly associated with anthropogenic sources such as vehicle exhaust. Elemental analysis detected HM in the inhalable particles, indicating that those HMs may intensify the toxic effects of PM on human health. Our results indicated T. usneoides as an adequate biomonitor of HM in the PM belonging to the inhalable fraction.

LA-ICP-MS trace element mapping: insights into the crystallisation history of a metamorphic garnet population

NASA Astrophysics Data System (ADS)

George, Freya; Gaidies, Fred

2017-04-01

In comparison to our understanding of major element zoning, relatively little is known about the incorporation of trace elements into metamorphic garnet. Given their extremely slow diffusivities and sensitivity to changing mineral assemblages, the analysis of the distribution of trace elements in garnet has the potential to yield a wealth of information pertaining to interfacial attachment mechanisms during garnet crystallisation, the mobility of trace elements in both garnet and the matrix, and trace element geochronology. Due to advances in the spatial resolution and analytical precision of modern microbeam techniques, small-scale trace element variations can increasingly be documented and used to inform models of metamorphic crystallisation. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in particular, can be used to rapidly quantify a wide range of elemental masses as a series of laser rasters, producing large volumes of spatially constrained trace element data. In this study, we present LA-ICP-MS maps of trace element concentrations from numerous centrally-sectioned garnets representative of the crystal size-distribution of a single sample's population. The study sample originates from the garnet-grade Barrovian zone of the Lesser Himalayan Sequence in Sikkim, northeast India, and has been shown to have crystallised garnet within a single assemblage between 515 ˚C and 565˚C, with no evidence for accessory phase reaction over the duration of garnet growth. Previous models have indicated that the duration of garnet crystallisation was extremely rapid (<1 Myr), with negligible diffusional homogenisation of major divalent cations. Consequently, the trace element record likely documents the primary zonation generated during garnet growth. In spite of straightforward (i.e. concentrically-zoned) major element garnet zonation, trace elements maps are characterised by significant complexity and variability. Y and the heavy rare earth elements are strongly enriched in crystal cores, where there is overprinting of the observed internal fabric, and exhibit numerous concentric annuli towards crystal rims. Conversely, the medium rare earth elements (e.g. Gd, Eu and Sm) exhibit bowl-shaped zoning from core to rim, with no annuli, and core and rim compositions of the medium rare earth elements are the same throughout the population within crystals of differing size. Cr exhibits pronounced spiral zoning, and the average Cr content increases towards garnet rims. In all cases, spirals are centered on the geometric core of the crystals. These LA-ICP-MS maps highlight the complexity of garnet growth over a single prograde event, and indicate that there is still much to be learnt from the analysis of garnet using ever-improving analytical methods. We explore the potential causes of the variations in the distribution of trace elements in garnet, and assess how these zoning patterns may be used to refine our understanding of the intricacies of garnet crystallisation and the spatial and temporal degree of trace element equilibration during metamorphism.

Reconstructing paleosalinity in the Sacramento-San Joaquin Delta of California using major elements in peat

NASA Astrophysics Data System (ADS)

Drexler, J. Z.; Alpers, C. N.; Taylor, H. E.; Windham-Myers, L.; Neymark, L. A.; Paces, J. B.

2010-12-01

Marshes in the Sacramento-San Joaquin Delta, the most landward extent of the San Francisco Estuary, started forming around ~6,700 years ago. Currently, Delta marshes are classified as tidal freshwater, however it is unknown to what degree the salinity regime has varied between brackish and fresh conditions since marsh development. This information is important to managers considering major changes to the flow regime in the Delta, because such changes could impact the future sustainability of endangered species such as the Delta smelt (Hypomesus transpacificus), which live in or just upstream of the mixing zone between fresh and brackish water. The main goal of the Rates and Evolution of PEat Accretion through Time project (REPEAT II) is to reconstruct paleosalinity regimes in the Delta. We are using elemental concentrations of Na, Ca, K, and Mg (the major cations in ocean water) in peat profiles to develop a quantitative index of salinity for the past 6000+ years. We are normalizing the elemental concentrations to Ti (a proxy for inorganic sediment content because it is inversely correlated with loss on ignition, a measure of peat organic content) to correct for bias in elemental concentrations caused by variations in the inorganic sediment content of peat through time. Plots of Ti-normalized element concentration vs. peat depth (or age) indicate that Browns Island, a brackish marsh on the western edge of the Delta, has experienced significant variations in salinity through the millennia. Vertical peat profiles show a spatial trend of decreasing salinity from west (bay-side) to east (landward) (i.e., Browns Island > Sherman Island > Franks Wetland ≧ Bacon Channel Island). During the period from 2300 to 500 calibrated years before present, Na concentrations in peat at Browns Island indicate a particularly saline period, with peat containing up to 3 wt. % Na. In the last 100 years or so, salinity at Browns Island has apparently decreased and the Na content of peat has stabilized at between 0.6 and 1 wt. % Na. We are currently analyzing the roots of live plants collected along a salinity gradient (range of means from ~0.2 to 20 ppt) in the San Francisco Estuary to determine concentrations of Na, Ca, K, and Mg in root material and the empirical relationships between root chemistry and ambient salinity levels. Because the organic component of peat is largely made up of roots that have decomposed in situ, we anticipate using these empirical relationships to quantify salinity regimes in the Delta through time.

Monitoring of toxic elements present in sludge of industrial waste using CF-LIBS.

PubMed

Kumar, Rohit; Rai, Awadhesh K; Alamelu, Devanathan; Aggarwal, Suresh K

2013-01-01

Industrial waste is one of the main causes of environmental pollution. Laser-induced breakdown spectroscopy (LIBS) was applied to detect the toxic metals in the sludge of industrial waste water. Sludge on filter paper was obtained after filtering the collected waste water samples from different sections of a water treatment plant situated in an industrial area of Kanpur City. The LIBS spectra of the sludge samples were recorded in the spectral range of 200 to 500 nm by focusing the laser light on sludge. Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique was used for the quantitative measurement of toxic elements such as Cr and Pb present in the sample. We also used the traditional calibration curve approach to quantify these elements. The results obtained from CF-LIBS are in good agreement with the results from the calibration curve approach. Thus, our results demonstrate that CF-LIBS is an appropriate technique for quantitative analysis where reference/standard samples are not available to make the calibration curve. The results of the present experiment are alarming to the people living nearby areas of industrial activities, as the concentrations of toxic elements are quite high compared to the admissible limits of these substances.

Effect of Silicon on Activity Coefficients of P, Bl, CD, SN, and AG in Liquid Fe-Si, and Implications for Differentiation and Core Formation

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K.; Ross, D. K.

2017-01-01

Cores of differentiated bodies (Earth, Mars, Mercury, Moon, Vesta) contain light elements such as S, C, Si, and O. We have previously measured small effects of Si on metal-silicate partitioning of Ni and Co [1,2], and larger effects for Mo, Ge, Sb, As [2]. The effect of Si on many siderophile elements could be an important, and as yet unquantified, influence on the core-mantle partitioning of SE. Here we report new experiments designed to quantify the effect of Si on the partitioning of Bi, Cd, Sn, Ag, and P between metal and silicate melt. The results will be applied to Earth, Mars, Mercury, Moon, and Vesta, for which we have excellent constraints on the mantle Bi, Cd, Sn, Ag, and P concentrations from mantle and/or basalt samples.

Gunshot residue (GSR) analysis by single particle inductively coupled plasma mass spectrometry (spICP-MS).

PubMed

Heringer, Rodrigo D; Ranville, James F

2018-05-25

Single particle inductively coupled plasma mass spectrometry (spICP-MS) was investigated as a screening-level technique for the analysis and characterization of inorganic gunshot residue (IGSR) nanoparticles. spICP-MS works with undigested samples whereby nanoparticles (NPs) in a suspension are individually atomized and ionized as they reach the plasma, each resulting in a pulse of analyte ions that can be quantified. The method is rapid, and signals from hundreds of NPs can be collected in 1-2min per sample. The technique is quantitative for NP mass and number concentration when only one element (single element mode) is measured using a quadrupole MS. Likewise, a qualitative elemental fingerprint can be obtained for individual NPs when peak-hopping between two elements (dual element mode). For this proof of concept study, each shooter's hand was sampled with ultrapure water or swab to obtain NPs suspensions. Measurements of antimony, barium, and lead were performed using both analysis modes. With no sample preparation and fully automated sample introduction, it is possible to analyze more than 100 samples in a day. Results show that this technique opens a new perspective for future research on GSR sample identification and characterization and can complement SEM/EDX analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Sub-micron Hard X-ray Fluorescence Imaging of Synthetic Elements

PubMed Central

Jensen, Mark P.; Aryal, Baikuntha P.; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E.

2013-01-01

Synchrotron-based X-ray fluorescence microscopy (SXFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurement such as μ-XANES (X-ray absorption near edge structure). We have used SXFM to image and simultaneously quantify the transuranic element plutonium at the L3 or L2 edge as well as lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope 242Pu. Elemental maps reveal that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions for an average 202 μm2 cell is 1.4 fg Pu/cell or 2.9 × 10−20 moles Pu/μm2, which is similar to the detection limit of K-edge SXFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its Lα X-ray emission. PMID:22444530

Physico-chemical characterisation of material fractions in residual and source-segregated household waste in Denmark.

PubMed

Götze, R; Pivnenko, K; Boldrin, A; Scheutz, C; Astrup, T Fruergaard

2016-08-01

Physico-chemical waste composition data are paramount for the assessment and planning of waste management systems. However, the applicability of data is limited by the regional, temporal and technical scope of waste characterisation studies. As Danish and European legislation aims for higher recycling rates evaluation of source-segregation and recycling chains gain importance. This paper provides a consistent up-to-date dataset for 74 physico-chemical parameters in 49 material fractions from residual and 24 material fractions from source-segregated Danish household waste. Significant differences in the physico-chemical properties of residual and source-segregated waste fractions were found for many parameters related to organic matter, but also for elements of environmental concern. Considerable differences in potentially toxic metal concentrations between the individual recyclable fractions within one material type were observed. This indicates that careful planning and performance evaluation of recycling schemes are important to ensure a high quality of collected recyclables. Rare earth elements (REE) were quantified in all waste fractions analysed, with the highest concentrations of REE found in fractions with high content of mineral raw materials, soil materials and dust. The observed REE concentrations represent the background concentration level in non-hazardous waste materials that may serve as a reference point for future investigations related to hazardous waste management. The detailed dataset provided here can be used for assessments of waste management solutions in Denmark and for the evaluation of the quality of recyclable materials in waste. Copyright © 2016 Elsevier Ltd. All rights reserved.

A double medium model for diffusion in fluid-bearing rock

NASA Astrophysics Data System (ADS)

Wang, H. F.

1993-09-01

The concept of a double porosity medium to model fluid flow in fractured rock has been applied to model diffusion in rock containing a small amount of a continuous fluid phase that surrounds small volume elements of the solid matrix. The model quantifies the relative role of diffusion in the fluid and solid phases of the rock. The fluid is the fast diffusion path, but the solid contains the volumetrically significant amount of the diffusing species. The double medium model consists of two coupled differential equations. One equation is the diffusion equation for the fluid concentration; it contains a source term for change in the average concentration of the diffusing species in the solid matrix. The second equation represents the assumption that the change in average concentration in a solid element is proportional to the difference between the average concentration in the solid and the concentration in the fluid times the solid-fluid partition coefficient. The double medium model is shown to apply to laboratory data on iron diffusion in fluid-bearing dunite and to measured oxygen isotope ratios at marble-metagranite contacts. In both examples, concentration profiles are calculated for diffusion taking place at constant temperature, where a boundary value changes suddenly and is subsequently held constant. Knowledge of solid diffusivities can set a lower bound to the length of time over which diffusion occurs, but only the product of effective fluid diffusivity and time is constrained for times longer than the characteristic solid diffusion time. The double medium results approach a local, grain-scale equilibrium model for times that are large relative to the time constant for solid diffusion.

Serum trace element differences between Schizophrenia patients and controls in the Han Chinese population.

PubMed

Cai, Lei; Chen, Tianlu; Yang, Jinglei; Zhou, Kejun; Yan, Xiaomei; Chen, Wenzhong; Sun, Liya; Li, Linlin; Qin, Shengying; Wang, Peng; Yang, Ping; Cui, Donghong; Burmeister, Margit; He, Lin; Jia, Wei; Wan, Chunling

2015-10-12

Little is known about the trace element profile differences between Schizophrenia patients and healthy controls; previous studies about the association of certain elements with Schizophrenia have obtained conflicting results. To identify these differences in the Han Chinese population, inductively coupled plasma-mass spectrometry was used to quantify the levels of 35 elements in the sera of 111 Schizophrenia patients and 110 healthy participants, which consisted of a training (61/61 for cases/controls included) and a test group including remaining participants. An orthogonal projection to latent structures model was constructed from the training group (R(2)Y = 0.465, Q(2)cum = 0.343) had a sensitivity of 76.0% and a specificity of 71.4% in the test group. Single element analysis indicated that the concentrations of cesium, zinc, and selenium were significantly reduced in patients with Schizophrenia in both the training and test groups. The meta-analysis including 522 cases and 360 controls supported that Zinc was significantly associated with Schizophrenia (standardized mean difference [SMD], -0.81; 95% confidence intervals [CI], -1.46 to -0.16, P = 0.01) in the random-effect model. Information theory analysis indicated that Zinc could play roles independently in Schizophrenia. These results suggest clear element profile differences between patients with Schizophrenia and healthy controls, and reduced Zn level is confirmed in the Schizophrenia patients.

The chemical behavior of the transuranic elements and the barrier function in natural aquifer systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jewett, J.R.

1997-09-17

In a geological repository for long-lived radioactive wastes, such as actinides and certain fission products, most of the stored radionuclides remain immobile in the particular geological formation. If any of these could possibly become mobile, only trace concentrations of a few radionuclides would result. Nevertheless, with an inventory in the repository of many tonnes of transuranic elements, the amounts that could disperse cannot be neglected. A critical assessment of the chemical behavior of these nuclides, especially their migration properties in the aquifer system around the repository site, is mandatory for analysis of the long-term safety. The chemistry requited for thismore » includes many geochemical multicomponent reactions that are so far only partially understood and [which] therefore can be quantified only incompletely. A few of these reactions have been discussed in this paper based on present knowledge. If a comprehensive discussion of the subject is impossible because of this [lack of information], then an attempt to emphasize the importance of the predominant geochemical reactions of the transuranic elements in various aquifer systems should be made.« less

Particulate Matter Sources and Composition near a Shrinking Saline Lake (Salton Sea)

NASA Astrophysics Data System (ADS)

Frie, A. L.; Dingle, J. H.; Garrison, A.; Ying, S.; Bahreini, R.

2017-12-01

Dried lake beds (playas) are large dust sources in arid regions, and with increased global water demand many large lakes are shrinking. The Salton Sea is an example of one such lake in the early stages of desiccation, with about 15,000 acres of exposed playa. To quantify the impacts of the shrinking lake on airborne particulate matter(PM) composition, PM samples were collected in August of 2015 and February of 2016 near the Salton Sea, CA. These samples were analyzed for total elemental concentration of 15 elements. For these elements, enrichment factors relative to aluminum were calculated and PMF modeling was applied to deconvolve source factors. From these data, desert-like and playa-like sources were estimated to accounted for 45% and 9% of PM10 mass during these sampling periods. PMF results also revealed that playa sources account for 70% of PM10 Na, evidencing playa-driven PM compositional changes. Additionally, PM Se displayed strong seasonal variation, which is thought to be driven by Se volatilization within Salton Sea sediments, playas, or waters.

Assessing human metal accumulations in an urban superfund site.

PubMed

Hailer, M Katie; Peck, Christopher P; Calhoun, Michael W; West, Robert F; James, Kyle J; Siciliano, Steven D

2017-09-01

Butte, Montana is part of the largest superfund site in the continental United States. Open-pit mining continues in close proximity to Butte's urban population. This study seeks to establish baseline metal concentrations in the hair and blood of individuals living in Butte, MT and possible routes of exposure. Volunteers from Butte (n=116) and Bozeman (n=86) were recruited to submit hair and blood samples and asked to complete a lifestyle survey. Elemental analysis of hair and blood samples was performed by ICP-MS. Three air monitors were stationed in Butte to collect particulate and filters were analyzed by ICP-MS. Soil samples from the yards of Butte volunteers were quantified by ICP-MS. Hair analysis revealed concentrations of Al, As, Cd, Cu, Mn, Mo, and U to be statistically elevated in Butte's population. Blood analysis revealed that the concentration of As was also statistically elevated in the Butte population. Multiple regression analysis was performed for the elements As, Cu, and Mn for hair and blood samples. Soil samples revealed detectable levels of As, Pb, Cu, Mn, and Cd, with As and Cu levels being higher than expected in some of the samples. Air sampling revealed consistently elevated As and Mn levels in the larger particulate sampled as compared to average U.S. ambient air data. Copyright © 2017 Elsevier B.V. All rights reserved.

[Atmospheric depositions of biogenic elements and their ecological effects on marine ecosystem of Jiaozhou Bay: A review].

PubMed

Xing, Jian Wei; Song, Jin Ming; Yuan, Hua Mao; Li, Xue Gang; Li, Ning; Duan, Li Qin; Qu, Bao Xiao; Kang, Xu Ming

2017-01-01

As a typical semi-closed bay, Jiaozhou Bay, is remarkably affected by human activities. Biogenic elements transported into the oceans by the atmospheric deposition of anthropogenic particles can lead to profound impacts on the ecosystem of Jiaozhou Bay. In this paper, the researches of atmospheric dry and wet depositions in the Jiaozhou Bay were systematically summarized from the following three aspects: study methods, variation characteristics of the fluxes and their influencing factors and the ecological effects of atmospheric deposition. The concentrations and fluxes of nitrogen species in atmospheric dry and wet depositions were very high in the Jiaozhou Bay compared with other bays, estuaries and marginal seas around the world. The dissolved inorganic nitrogen (DIN) was the main component of the total dissolved nitrogen (TDN) and the dissolved organic nitrogen (DON) accounted for 22%-31% of TDN. However, the concentrations and fluxes of phosphate and silicate species were very low. The atmospheric deposition fluxes of (NO 3 - -N+NO 2 - -N) were slightly higher than terrestrial inputs, while the fluxes of NH 4 + -N, PO 4 3- -P and SiO 3 2- -Si were very low compared with terrestrial inputs. The concentration of total suspended particulates (TSP) in the air, the intensity of the emission sources, precipitation amount and meteorological conditions are the major factors influencing the atmospheric depositions of biogenic elements, which can increase the primary productivity, change the structure of nutrients and the structure of phytoplankton communities in surface seawater and further promote the succession of phytoplankton dominant species from diatom to dinoflagellate in the Jiaozhou Bay. On that basis, the future research should be focused on constructing the monitoring network for atmospheric dry and wet depositions, accurately quantifying the deposition rates of aerosol particles of different forms and sizes, recognizing the ecological effects and biogeochemical mechanisms of atmospheric depositions of biogenic elements and discriminating the mechanisms, fluxes and influencing factors of atmospheric deposition biogenic elements via indirect approaches such as overland runoff, sheetflood and permeation etc. It is significant for illuminating the effects of anthropogenic activities on the coastal waters as well as understanding the bio-geochemical processes of biogenic elements in marginal seas by elucidating atmospheric depositions of biogenic elements in the Jiaozhou Bay.

Attomole quantitation of protein separations with accelerator mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vogel, J S; Grant, P G; Buccholz, B A

2000-12-15

Quantification of specific proteins depends on separation by chromatography or electrophoresis followed by chemical detection schemes such as staining and fluorophore adhesion. Chemical exchange of short-lived isotopes, particularly sulfur, is also prevalent despite the inconveniences of counting radioactivity. Physical methods based on isotopic and elemental analyses offer highly sensitive protein quantitation that has linear response over wide dynamic ranges and is independent of protein conformation. Accelerator mass spectrometry quantifies long-lived isotopes such as 14C to sub-attomole sensitivity. We quantified protein interactions with small molecules such as toxins, vitamins, and natural biochemicals at precisions of 1-5% . Micro-proton-induced-xray-emission quantifies elemental abundancesmore » in separated metalloprotein samples to nanogram amounts and is capable of quantifying phosphorylated loci in gels. Accelerator-based quantitation is a possible tool for quantifying the genome translation into proteome.« less

Laser-induced plasma characterization through self-absorption quantification

NASA Astrophysics Data System (ADS)

Hou, JiaJia; Zhang, Lei; Zhao, Yang; Yan, Xingyu; Ma, Weiguang; Dong, Lei; Yin, Wangbao; Xiao, Liantuan; Jia, Suotang

2018-07-01

A self-absorption quantification method is proposed to quantify the self-absorption degree of spectral lines, in which plasma characteristics including electron temperature, elemental concentration ratio, and absolute species number density can be deduced directly. Since there is no spectral intensity involved in the calculation, the analysis results are independent of the self-absorption effects and the additional spectral efficiency calibration is not required. In order to evaluate the practicality, the limitation for application and the precision of this method are also discussed. Experimental results of aluminum-lithium alloy prove that the proposed method is qualified to realize semi-quantitative measurements and fast plasma characteristics diagnostics.

Identification of an exposure risk to heavy metals from pharmaceutical-grade rubber stoppers.

PubMed

Li, Xianghui; Qian, Pingping

2017-07-01

Exposure to low concentrations of heavy metals and metalloids represents a well-documented risk to animal and human health. However, current standards (European Pharmacopeia [EP], United States Pharmacopoeia [USP], International Organization for Standardization [ISO], YBB concerned with rubber closures) only require testing for Zn in pharmaceutical-grade rubber stoppers and then using only pure water as a solvent. We extracted and quantified heavy metals and trace elements from pharmaceutical-grade rubber stoppers under conditions that might occur during the preparation of drugs. Pure water, saline, 10% glucose, 3% acetic acid (w/v), 0.1 mol/L hydrochloric acid, and diethylenetriaminepentaacetic acid (4 mg/mL, 0.4 mg/mL, and 0.04 mg/mL) were used as extraction agents. We quantified the extracted arsenic, lead, antimony, iron, magnesium, aluminum, and zinc using inductively coupled plasma mass spectrometry. The concentration of extracted metals varied depending on the different extraction solutions used and between the different rubber stopper manufacturers. Rubber stoppers are ubiquitously used in the pharmaceutical industry for the storage and preparation of drugs. Extraction of heavy metals during the manufacturing and preparation of drugs represents a significant risk, suggesting a need for industry standards to focus on heavy metal migration from rubber stoppers. Copyright © 2016. Published by Elsevier B.V.

Targeted quantification of functional enzyme dynamics in environmental samples for microbially mediated biogeochemical processes: Targeted quantification of functional enzyme dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Minjing; Gao, Yuqian; Qian, Wei-Jun

Microbially mediated biogeochemical processes are catalyzed by enzymes that control the transformation of carbon, nitrogen, and other elements in environment. The dynamic linkage between enzymes and biogeochemical species transformation has, however, rarely been investigated because of the lack of analytical approaches to efficiently and reliably quantify enzymes and their dynamics in soils and sediments. Herein, we developed a signature peptide-based technique for sensitively quantifying dissimilatory and assimilatory enzymes using nitrate-reducing enzymes in a hyporheic zone sediment as an example. Moreover, the measured changes in enzyme concentration were found to correlate with the nitrate reduction rate in a way different frommore » that inferred from biogeochemical models based on biomass or functional genes as surrogates for functional enzymes. This phenomenon has important implications for understanding and modeling the dynamics of microbial community functions and biogeochemical processes in environments. Our results also demonstrate the importance of enzyme quantification for the identification and interrogation of those biogeochemical processes with low metabolite concentrations as a result of faster enzyme-catalyzed consumption of metabolites than their production. The dynamic enzyme behaviors provide a basis for the development of enzyme-based models to describe the relationship between the microbial community and biogeochemical processes.« less

Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pearson, Scott, F.; Levey, Douglas, J.; Greenberg, Catheryn, H.

2003-02-28

Pearson, S.F., D.J. Levey, C.H. Greenberg, and C.M. del Rio. 2003. Effects of elemental composition on the incorporation of dietary nitrogen and carbon isotopic signatures in an omnivorous songbird. Oecologia. 135:516-523. The use of stable isotopes to infer diet requires quantifying the relationship between diet and tissues and, in particular, knowing of how quickly isotopes turnover in different tissues and how isotopic concentrations of different food components change (discriminate) when incorporated into consumer tissues. We used feeding trials with wild-caught yellow-rumped warblers (Dendroica coronata) to determine d15N and d13C turnover rates for blood, d15N and d13C diet-tissue discrimination factors, andmore » diet-tissue relationships for blood and feathers. After 3 weeks on a common diet, 36 warblers were assigned to one of four diets differing in the relative proportion of fruit and insects. Plasma half-life estimates ranged from 0.4 to 0.7 days for d13C and from 0.5 to 1.7 days for d15N. Half-life did not differ among diets. Whole blood half-life for d13C ranged from 3.9 to 6.1 days. Yellow-rumped warbler tissues were enriched relative to diet by 1.7.3.6% for nitrogen isotopes and by 1.2 to 4.3% for carbon isotopes, depending on tissue and diet. Consistent with previous studies, feathers were the most enriched and whole blood and plasma were the least enriched or, in the case of carbon, slightly depleted relative to diet. In general, tissues were more enriched relative to diet for birds with high percentages of insects. For all tissues, carbon and nitrogen isotope discrimination factors increased with carbon and nitrogen concentrations of diets. The isotopic signature of plasma increased linearly with the sum of the isotopic signature of the diet and the discrimination factor. Because the isotopic signature of tissues depends on both elemental concentration and isotopic signature of the diet, attempts to reconstruct diet from stable isotope signatures require mixing models that incorporate elemental concentration.« less

Analysis of coke beverages by total-reflection X-ray fluorescence

NASA Astrophysics Data System (ADS)

Fernández-Ruiz, Ramón; von Bohlen, Alex; Friedrich K, E. Josue; Redrejo, M. J.

2018-07-01

The influence of the organic content, sample preparation process and the morphology of the depositions of two types of Coke beverage, traditional and light Coke, have been investigated by mean of Total-reflection X-ray Fluorescence (TXRF) spectrometry. Strong distortions of the nominal concentration values, up to 128% for P, have been detected in the analysis of traditional Coke by different preparation methods. These differences have been correlated with the edge X-ray energies of the elements analyzed being more pronounced for the lighter elements. The influence of the organic content (mainly sugar) was evaluated comparing traditional and light Coke analytical TXRF results. Three sample preparation methods have been evaluated as follows: direct TXRF analysis of the sample only adding internal standard, TXRF analysis after open vessel acid digestion and TXRF analysis after high pressure and temperature microwave-assisted acid digestion. Strong correlations were detected between quantitative results, methods of preparation and energies of the X-ray absorption edges of quantified elements. In this way, a decay behavior for the concentration differences between preparation methods and the energies of the X-ray absorption edges of each element were observed. The observed behaviors were modeled with exponential decay functions obtaining R2 correlation coefficients from 0.989 to 0.992. The strong absorption effect observed, and even possible matrix effect, can be explained by the inherent high organic content of the evaluated samples and also by the morphology and average thickness of the TXRF depositions observed. As main conclusion of this work, the analysis of light elements in samples with high organic content by TXRF, i.e. medical, biological, food or any other organic matrixes should be taken carefully. In any case, the direct analysis is not recommended and a previous microwave-assisted acid digestion, or similar, is mandatory, for the correct elemental quantification by TXRF.

Reduced trace element concentrations in fast-growing juvenile Atlantic salmon in natural streams.

PubMed

Ward, Darren M; Nislow, Keith H; Chen, Celia Y; Folt, Carol L

2010-05-01

To assess the effect of rapid individual growth on trace element concentrations in fish, we measured concentrations of seven trace elements (As, Cd, Cs, Hg, Pb, Se, Zn) in stream-dwelling Atlantic salmon (Salmo salar) from 15 sites encompassing a 10-fold range in salmon growth. All salmon were hatched under uniform conditions, released into streams, and sampled approximately 120 days later for trace element analysis. For most elements, element concentrations in salmon tracked those in their prey. Fast-growing salmon had lower concentrations of all elements than slow growers, after accounting for prey concentrations. This pattern held for essential and nonessential elements, as well as elements that accumulate from food and those that can accumulate from water. At the sites with the fastest salmon growth, trace element concentrations in salmon were 37% (Cs) to 86% (Pb) lower than at sites where growth was suppressed. Given that concentrations were generally below levels harmful to salmon and that the pattern was consistent across all elements, we suggest that dilution of elements in larger biomass led to lower concentrations in fast-growing fish. Streams that foster rapid, efficient fish growth may produce fish with lower concentrations of elements potentially toxic for human and wildlife consumers.

Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes.

PubMed

Allegrini, Elisa; Maresca, Alberto; Olsson, Mikael Emil; Holtze, Maria Sommer; Boldrin, Alessio; Astrup, Thomas Fruergaard

2014-09-01

Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based on a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration.

PubMed

Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

2007-01-07

A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO(2)) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO(2)) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO(2) and HHb, total haemoglobin concentration and SO(2). The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of +/-3.8 g l(-1) (+/-58 microM) and +/-4.4 g l(-1) (+/-68 microM) for the HbO(2) and HHb concentrations respectively and +/-4% for SO(2) with an accuracy in the latter in the range -6%-+7%.

Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

NASA Astrophysics Data System (ADS)

Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

2007-01-01

A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO2) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO2) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO2 and HHb, total haemoglobin concentration and SO2. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l-1 (±58 µM) and ±4.4 g l-1 (±68 µM) for the HbO2 and HHb concentrations respectively and ±4% for SO2 with an accuracy in the latter in the range -6%-+7%.

Analyzing Solutions High in Total Dissolved Solids for Rare Earth Elements (REEs) Using Cation Exchange and Online Pre-Concentration with the seaFAST2 Unit; NETL-TRS-7-2017; NETL Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory: Albany, OR, 2017; p 32

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, J.; Torres, M.; Verba, C.

The accurate quantification of the rare earth element (REE) dissolved concentrations in natural waters are often inhibited by their low abundances in relation to other dissolved constituents such as alkali, alkaline earth elements, and dissolved solids. The high abundance of these constituents can suppress the overall analytical signal as well as create isobaric interferences on the REEs during analysis. Waters associated with natural gas operations on black shale plays are characterized by high salinities and high total dissolved solids (TDS) contents >150,000 mg/L. Methods used to isolate and quantify dissolved REEs in seawater were adapted in order to develop themore » capability of analyzing REEs in waters that are high in TDS. First, a synthetic fluid based on geochemical modelling of natural brine formation fluids was created within the Marcellus black shale with a TDS loading of 153,000 mg/L. To this solution, 1,000 ng/mL of REE standards was added based on preliminary analyses of experimental fluids reacted at high pressure and temperature with Marcellus black shale. These synthetic fluids were then run at three different dilution levels of 10, 100, and 1,000–fold dilutions through cation exchange columns using AG50-X8 exchange resin from Eichrom Industries. The eluent from the cation columns were then sent through a seaFAST2 unit directly connected to an inductively coupled plasma mass spectrometer (ICP-MS) to analyze the REEs. Percent recoveries of the REEs ranged from 80–110% and fell within error for the external reference standard used and no signal suppression or isobaric interferences on the REEs were observed. These results demonstrate that a combined use of cation exchange columns and seaFAST2 instrumentation are effective in accurately quantifying the dissolved REEs in fluids that are >150,000 mg/L in TDS and have Ba:Eu ratios in excess of 380,000.« less

Uncertainties in detecting decadal change in extractable soil elements in Northern Forests

NASA Astrophysics Data System (ADS)

Bartlett, O.; Bailey, S. W.; Ducey, M. J.

2016-12-01

Northern Forest ecosystems have been or are being impacted by land use change, forest harvesting, acid deposition, atmospheric CO2 enrichment, and climate change. Each of these has the potential to modify soil forming processes, and the resulting chemical stocks. Horizontal and vertical variations in concentrations complicate determination of temporal change. This study evaluates sample design, sample size, and differences among observers as sources of uncertainty when quantifying soil temporal change over regional scales. Forty permanent, northern hardwood, monitoring plots were established on the White Mountain National Forest in central New Hampshire and western Maine. Soil pits were characterized and sampled by genetic horizon at plot center in 2001 and resampled again in 2014 two-meters on contour from the original sampling location. Each soil horizon was characterized by depth, color, texture, structure, consistency, boundaries, coarse fragments, and roots from the forest floor to the upper C horizon, the relatively unaltered glacial till parent material. Laboratory analyses included pH in 0.01 M CaCl2 solution and extractable Ca, Mg, Na, K, Al, Mn, and P in 1 M NH4OAc solution buffered at pH 4.8. Significant elemental differences were identified by genetic horizon from paired t-tests (p ≤ 0.05) indicate temporal change across the study region. Power analysis, 0.9 power (α = 0.05), revealed sampling size was appropriate within this region to detect concentration change by genetic horizon using a stratified sample design based on topographic metrics. There were no significant differences between observers' descriptions of physical properties. As physical properties would not be expected to change over a decade, this suggests spatial variation in physical properties between the pairs of sampling pits did not detract from our ability to detect temporal change. These results suggest that resampling efforts within a site, repeated across a region, to quantify elemental change by carefully described genetic horizons is an appropriate method of detecting soil temporal change in this region. Sample size and design considerations from this project will have direct implications for future monitoring programs to characterize change in soil chemistry.

Dexamethasone concentration gradients along scala tympani after application to the round window membrane.

PubMed

Plontke, Stefan K; Biegner, Thorsten; Kammerer, Bernd; Delabar, Ursular; Salt, Alec N

2008-04-01

Local application of dexamethasone-21-dihydrogen-phosphate (Dex-P) to the round window (RW) membrane of guinea pigs produces a substantial basal-apical concentration gradient in scala tympani (ST) perilymph. In recent years, intratympanically applied glucocorticoids are increasingly being used for the treatment of inner ear disease. Although measurements of intracochlear concentrations after RW application exist, there is limited information on the distribution of these drugs in the inner ear fluids. It has been predicted from computer simulations that substantial concentration gradients will occur after RW application, with lower concentrations expected in apical turns. Concentration gradients of other substances along the cochlea have recently been confirmed using a sequential apical sampling method to obtain perilymph. Dexamethasone-21-dihydrogen-phosphate (10 mg/ml) was administered to the RW membrane of guinea pigs (n = 9) in vivo for 2 to 3 hours. Perilymph was then collected using a protocol in which 10 samples, each of approximately 1 mul, were taken sequentially from the cochlear apex into capillary tubes. Dexamethasone-21-dihydrogen-phosphate concentration of the samples was analyzed by high-performance liquid chromatography. Interpretation of sample data using a finite element model allowed the longitudinal gradients of Dex-P in ST to be quantified. The Dex-P content of the first sample in each experiment (dominated by perilymph from apical regions) was substantially lower than that of the third and fourth sample (dominated by basal turn perilymph). These findings qualitatively demonstrated the existence of a concentration gradient along ST. After detailed analysis of the measured sample concentrations using an established finite element computer model, the mean basal-apical concentration gradient was estimated to be 17,000. Both absolute concentrations of Dex-P in ST and the basal-apical gradients were found to vary substantially. The existence of substantial basal-apical concentration gradients of Dex-P in ST perilymph were demonstrated experimentally. If the variability in peak concentration and gradient is also present under clinical conditions, this may contribute to the heterogeneity of outcome that is observed after intratympanic application of glucocorticoids for various inner ear diseases.

Dexamethasone concentration gradients along scala tympani after application to the round window membrane

PubMed Central

Salt, Alec N

2008-01-01

Hypothesis Local application of dexamethasone-21-dihydrogene-phosphate (Dex-P) to the round window membrane (RWM) of guinea pigs produces a substantial basal-apical concentration gradient in scala tympani (ST) perilymph. Background In recent years, intratympanically-applied glucocorticoids are increasingly being used for the treatment of inner ear disease. Although measurements of intracochlear concentrations after round window (RW) application exist, there is limited information on the distribution of these drugs in the inner ear fluids. It has been predicted from computer simulations that substantial concentration gradients will occur with lower concentrations expected in apical turns after RW application. Concentration gradients of other substances along the cochlea have recently been confirmed using a sequential apical sampling method to obtain perilymph. Methods Dex-P (10mg/ml) was administered to the RWM of guinea pigs (n=9) in vivo for 2 to 3 hours. Perilymph was then collected using a protocol in which ten samples, each of approximately 1μl, were taken sequentially from the cochlear apex into capillary tubes. Dex-P concentration of the samples was determined by HPLC. Interpretation of sample data using a finite element model allowed the longitudinal gradients of Dex-P in scala tympani to be quantified. Results The Dex-P content of the first sample in each experiment (dominated by perilymph from apical regions) was substantially lower than that of the third and fourth sample (dominated by basal turn perilymph). These findings qualitatively demonstrated the existence of a concentration gradient along scala tympani (ST). After detailed analysis of the measured sample concentrations using an established finite element computer model, the mean basal-apical concentration gradient was estimated to be 17•103. Both absolute concentrations of Dex-P in ST and the basal-apical gradients were found to vary substantially. Conclusion The existence of substantial basal-apical concentration gradients of Dex-P in ST perilymph was demonstrated experimentally. If the variability in peak concentration and gradient is also present under clinical conditions this may contribute to the heterogeneity of outcome that is observed after intratympanic application of glucocorticoids for various inner ear diseases. PMID:18277312

Contributions of diesel truck emissions to indoor elemental carbon concentrations in homes in proximity to Ambassador Bridge

NASA Astrophysics Data System (ADS)

Baxter, Lisa K.; Barzyk, Timothy M.; Vette, Alan F.; Croghan, Carry; Williams, Ronald W.

Ambassador Bridge, connecting Detroit, Michigan and Windsor, Ontario, is the busiest international commercial vehicle crossing in North America, with a large percentage of heavy duty diesel trucks. This study seeks to examine the contribution of diesel truck traffic across Ambassador Bridge to indoor exposure patterns of elemental carbon (EC), a common surrogate for diesel exhaust particles, in homes in close proximity to the bridge. We also aim to understand the relative importance of home ventilation characteristics and wind speed. Measurements were collected as part of the Detroit Exposure and Aerosol Research Study (DEARS). Residential indoor and outdoor EC measurements were collected over five consecutive 24 h periods in both the summer and winter at 16 homes in close proximity to Ambassador Bridge. Ambient concentrations and meteorological data were collected at a central-site monitor, and home air exchange rates were estimated using a perfluorocarbon tracer. The contributions of ambient concentrations and Ambassador Bridge, and potential effect modification by wind speed and home ventilation status were quantified with regression analyses. Both ambient concentrations and the percentage of time a home was downwind from the bridge were associated with an increase in indoor concentrations. Ambient concentrations significantly contributed to indoor concentrations regardless of wind speed category but were a greater influence in home experiencing calm winds. The effect of the percent of time downwind variable on indoor levels was only significant in homes where the ventilation status was high. The distance a home was from the bridge tollbooth complex was not significantly associated with indoor concentrations. We conclude that diesel traffic emissions related to Ambassador Bridge may have an impact on indoor EC exposures. Given that people spend the majority of their time indoors, it is important to evaluate the impact of traffic-related pollution in the home environment.

Predicting residential indoor concentrations of nitrogen dioxide, fine particulate matter, and elemental carbon using questionnaire and geographic information system based data

NASA Astrophysics Data System (ADS)

Baxter, Lisa K.; Clougherty, Jane E.; Paciorek, Christopher J.; Wright, Rosalind J.; Levy, Jonathan I.

Previous studies have identified associations between traffic-related air pollution and adverse health effects. Most have used measurements from a few central ambient monitors and/or some measure of traffic as indicators of exposure, disregarding spatial variability and factors influencing personal exposure-ambient concentration relationships. This study seeks to utilize publicly available data (i.e., central site monitors, geographic information system, and property assessment data) and questionnaire responses to predict residential indoor concentrations of traffic-related air pollutants for lower socioeconomic status (SES) urban households. As part of a prospective birth cohort study in urban Boston, we collected indoor and outdoor 3-4 day samples of nitrogen dioxide (NO 2) and fine particulate matter (PM 2.5) in 43 low SES residences across multiple seasons from 2003 to 2005. Elemental carbon (EC) concentrations were determined via reflectance analysis. Multiple traffic indicators were derived using Massachusetts Highway Department data and traffic counts collected outside sampling homes. Home characteristics and occupant behaviors were collected via a standardized questionnaire. Additional housing information was collected through property tax records, and ambient concentrations were collected from a centrally located ambient monitor. The contributions of ambient concentrations, local traffic and indoor sources to indoor concentrations were quantified with regression analyses. PM 2.5 was influenced less by local traffic but had significant indoor sources, while EC was associated with traffic and NO 2 with both traffic and indoor sources. Comparing models based on covariate selection using p-values or a Bayesian approach yielded similar results, with traffic density within a 50 m buffer of a home and distance from a truck route as important contributors to indoor levels of NO 2 and EC, respectively. The Bayesian approach also highlighted the uncertanity in the models. We conclude that by utilizing public databases and focused questionnaire data we can identify important predictors of indoor concentrations for multiple air pollutants in a high-risk population.

Water-quality assessment of the Kentucky River Basin, Kentucky; distribution of metals and other trace elements in sediment and water, 1987-90

USGS Publications Warehouse

Porter, Stephen D.; White, Kevin D.; Clark, J.R.

1995-01-01

The U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program is designed to provide a nationally consistent description of the current status of water quality, to define water-quality trends, and to relate past and present water-quality conditions to natural features, uses of land and water, and other water-quality effects from human activities. The Kentucky River Basin is one of four NAWQA pilot projects that focused primarily on the quality of surface water. Water, sediment, and bedrock samples were collected in the Kentucky River Basin during 1987-90 for the purpose of (1) describing the spatial distribution, transport, and temporal variability of metals and other trace elements in streams of the basin; (2) estimating mean annual loads, yields, and trends of constituent concentrations and identifying potential causes (or sources) of spatial patterns; (3) providing baseline information for concentrations of metals in streambed and suspended sediments; (4) identifying stream reaches in the Kentucky River Basin with chronic water-quality problems; and (5) evaluating the merits of the NAWQA pilot study-approach for the assessment of metals and other trace elements in a river system. The spatial distribution of metals and other trace elements in streambed sediments of the Kentucky River Basin is associated with regional differences of geology, land use and cover, and the results of human activities. Median concentrations of constituents differed significantly among physiographic regions of the basin because of relations to bedrock geochemistry and land disturbance. Concentrations of potentially toxic metals were large in urban and industrial areas of the basin. Elevated concentrations of certain metals were also found in streambed sediments of the Knobs Region because of the presence of Devonian shale bedrock. Elevated concentrations of lead and zinc found in streambed sediments of the Bluegrass Region are likely associated with urban stormwater runoff, point-source discharges, and waste-management practices. Concentrations of cadmium, chromium, copper, mercury, and silver were elevated in streambed sediments downstream from wastewater-treatment plant discharges. Streambed-sediment concentrations of barium, chromium, and lithium were elevated in streams that receive brine discharges from oil production. Elevated concentrations of antimony, arsenic, molybdenum, selenium, strontium, uranium, and vanadium in streambed sediments of the Kentucky River Basin were generally associated with natural sources. Concentrations of metals and other trace elements in water samples from fixed stations (stations where water-quality samples were collected for 3.5 years) in the Kentucky River Basin were generally related to stream discharge and the concentration of suspended sediment, whereas constituent concentrations in the suspended-sediment matrix were indicative of natural and human sources. Estimated mean annual loads and yields for most metals and other trace elements were associated with the transport of suspended sediment. Land disturbance, such as surface mining and agriculture, contribute to increased transport of sediment in streams, thereby increasing concentrations of metals in water samples during periods of intense or prolonged rainfall and increased stream discharge. Concentrations of many metals and trace elements were reduced during low streamflow. Although total-recoverable and dissolved concentrations of certain metals and trace elements were large in streams affected by land disturbance, concentrations of constituents in the suspendedsediment matrix were commonly large in streams in the Knobs and Eastern Coal Field Regions (because of relations with bedrock geochemistry) and in streams that receive wastewater or oil-well-brine discharges. Concentrations and mean annual load estimates for aluminum, chromium, copper, iron, lead, manganese, and mercury were larger than those obtained from data collected by a State agency, probably because of differences in sample-collection methodology, the range of discharge associated with water-quality samples, and laboratory analytical procedures. However, concentrations, loads, and yields of arsenic, barium, and zinc were similar to those determined from the State data. Significant upward trends in the concentrations of aluminum, iron, magnesium, manganese, and zinc were indicated at one or more fixed stations in the Kentucky River Basin during the past 10 to 15 years. Upward trends for concentrations of aluminum, iron, and manganese were found at sites that receive drainage from coal mines in the upper Kentucky River Basin, whereas upward trends for zinc may be associated with urban sources. Water-quality criteria established by the U.S. Environmental Protection Agency (USEPA) or the State of Kentucky for concentrations of aluminum, beryllium, cadmium, chromium, copper, iron, manganese, nickel, silver, and zinc were exceeded at one or more fixed stations in the Kentucky River Basin. On a qualitative basis, dissolved concentrations of certain metals and trace elements were large during low streamflow at sites where (1) concentrations of these constituents in underlying streambed sediments were large, or (2) dissolvedoxygen concentrations were small. Concentrations of barium, lithium, and strontium were large during low streamflow, which indicates the influence of ground-water baseflows on the quality of surface water during low flow. The effects of point-source discharges, landfills, and other wastemanagement practices are somewhat localized in the Kentucky River Basin and are best indicated by the spatial distribution of metals and other trace elements in streambed sediments and in the suspended-sediment fraction of water samples at stream locations near the source. It was not possible to quantify the contribution of point sources to the total transport of metals and other trace elements at fixed stations because data were not available for wastewater effluents. Quantification of baseline concentrations of metals and other trace elements in streambed sediments provides a basis for the detection of water-quality changes that may result from improvements in wastewater treatment or the implementation of best-management practices for controlling contamination from nonpoint sources in the Kentucky River Basin.

Accelerator mass spectrometry in biomedical research

NASA Astrophysics Data System (ADS)

Vogel, J. S.; Turteltaub, K. W.

1994-06-01

Biological effects occur in natural systems at chemical concentrations of parts per billion (1:10 9) or less. Affected biomolecules may be separable in only milligram or microgram quantities. Quantification at attomole sensitivity is needed to study these interactions. AMS measures isotope concentrations to parts per 10 13-15 on milligram-sized samples and is ideal for quantifying long-lived radioisotopic labels for tracing biochemical pathways in natural systems. 14C-AMS has now been coupled to a variety of organic separation and definition technologies. Our primary research investigates pharmacokinetics and genotoxicities of toxins and drugs at very low doses. Human subjects research using AMS includes nutrition, toxicity and elemental balance studies. 3H, 41Ca and 26Al are also traced by AMS for fundamental biochemical kinetic research. Expansion of biomedical AMS awaits further development of biochemical and accelerator technologies designed specifically for these applications.

Heterogeneity in mantle carbon content from CO2-undersaturated basalts

PubMed Central

Le Voyer, M.; Kelley, K.A.; Cottrell, E.; Hauri, E.H.

2017-01-01

The amount of carbon present in Earth's mantle affects the dynamics of melting, volcanic eruption style and the evolution of Earth's atmosphere via planetary outgassing. Mantle carbon concentrations are difficult to quantify because most magmas are strongly degassed upon eruption. Here we report undegassed carbon concentrations from a new set of olivine-hosted melt inclusions from the Mid-Atlantic Ridge. We use the correlations of CO2 with trace elements to define an average carbon abundance for the upper mantle. Our results indicate that the upper mantle carbon content is highly heterogeneous, varying by almost two orders of magnitude globally, with the potential to produce large geographic variations in melt fraction below the volatile-free solidus. Such heterogeneity will manifest as variations in the depths at which melt becomes interconnected and detectable, the CO2 fluxes at mid-ocean ridges, the depth of the lithosphere-asthenosphere boundary, and mantle conductivity. PMID:28082738

Accretion rate of extraterrestrial matter: Iridium deposited over the last 70 million years

NASA Technical Reports Server (NTRS)

Kyte, Frank T.

1988-01-01

In order to quantify the accretion rate of extraterrestrial matter during the Cenozoic, Ir concentrations were measured in a continuous series of 450 samples across most of the length of piston core LL44-GPC3. LL44-GPC3 is a 25-meter-long, large-diameter piston core of abyssal clay from the central North Pacific. This core contains a nearly continuous record of sedimentation over the last 70 Ma, as this site migrated from a region near the Equator in the late Cretaceous to its present position north of Hawaii. The first-cut survey across the core is nearing completion, and all of the conclusions of the earlier study, in which was reported the concentrations of Ir, Co, and Sb across 9 meters of this core, remain unchanged. The only strongly enhanced Ir concentrations occur at the Cretaceous-Tertiary (K-T) boundary and outside the K-T boundary Ir correlates well with Co, a terrestrial element which is largely present in hydrogenous ferromanganese oxide precipitates from seawater. Concentrations of both elements appear to be inversely correlated with the sedimentation rate. Although the K-T Ir anomaly is unique in magnitude in this core, there are several small bumps in the Ir profile which may reflect smaller accretionary events. The most promising Ir enhancement was observed in a 30 cm section approximately 1 m below the K-T boundary. Preliminary data suggest deposition of an excess across this interval at a time estimate to be approximate 1 Ma before the K-T impact event, but there is insufficient evidence at present to prove that this reflects enhanced accretion of extraterrestrial matter. A detailed model is being prepared of the chemical record of sedimentation in this core using a combined database of 39 elements in approximately 450 samples across the Cenozoic. Preliminary working model indicates that the only sedimentary sources which contribute significantly to the Ir budget in this core are the hydrogenous precipitates and extraterrestrial particulates.

Comparison of Highly Resolved Model-Based Exposure ...

EPA Pesticide Factsheets

Human exposure to air pollution in many studies is represented by ambient concentrations from space-time kriging of observed values. Space-time kriging techniques based on a limited number of ambient monitors may fail to capture the concentration from local sources. Further, because people spend more time indoors, using ambient concentration to represent exposure may cause error. To quantify the associated exposure error, we computed a series of six different hourly-based exposure metrics at 16,095 Census blocks of three Counties in North Carolina for CO, NOx, PM2.5, and elemental carbon (EC) during 2012. These metrics include ambient background concentration from space-time ordinary kriging (STOK), ambient on-road concentration from the Research LINE source dispersion model (R-LINE), a hybrid concentration combining STOK and R-LINE, and their associated indoor concentrations from an indoor infiltration mass balance model. Using a hybrid-based indoor concentration as the standard, the comparison showed that outdoor STOK metrics yielded large error at both population (67% to 93%) and individual level (average bias between −10% to 95%). For pollutants with significant contribution from on-road emission (EC and NOx), the on-road based indoor metric performs the best at the population level (error less than 52%). At the individual level, however, the STOK-based indoor concentration performs the best (average bias below 30%). For PM2.5, due to the relatively low co

Accelerator-based chemical and elemental analysis of atmospheric aerosols

NASA Astrophysics Data System (ADS)

Mentes, Besim

Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is forbidden at certain times when the meteorological conditions are unfavourable. Aerosols play an important role in the climate, and may have both direct and indirect effect which cause cooling of the planet surface, in contrast to the so-called greenhouse gases. During this work a technique for chemical and elemental analysis of atmospheric aerosols and an elemental analysis methodology for upper tropospheric aerosols have been developed. The elemental analysis is performed by the ion beam analysis (IBA) techniques, PIXE (elements heavier than Al). PESA (C, N and O), cPESA (H) and pNRA (Mg and Na). The chemical speciation of atmospheric aerosols is obtained by ion beam thermography (IBT). During thermography the sample temperature is stepwise increased and the IBA techniques are used to continuously monitor the elemental concentration. A thermogram is obtained for each element. The vaporisation of the compounds in the sample appears as a concentration decrease in the thermograms at characteristic vaporisation temperatures (CVTs). Different aspects of IBT have been examined in Paper I to IV. The features of IBT are: almost total elemental speciation of the aerosol mass, chemical speciation of the inorganic compounds, carbon content obtained as volatile and non-volatile fractions, analysis of acidic aerosols is possible, aerosols can be size-fractionated using a cascade impactor as collection device, total analysis time for a sample is around 45 min, the sample mass load is from around 1 to 30 μg/cm2. An intercomparison of IBT and ion chromatography (IC) when a DMPS system was used as a reference instrument has been performed (Paper IV). Ions of K, Na, SO4, NO3 and NH4 were determined and quantified by both IBT and IC. The intercomparison showed that the procedure used in IBT does not suffer from any selective losses, especially not from the NO3 and NH4 compounds, which exhibit an appreciable interaction with the gas phase as NH3 and HNO3. An impactor-based aerosol sampler for upper tropospheric conditions has been developed (Paper V). Despite the low aerosol concentration at that altitude the sulphur concentration can be measured, with a detection limit of 1 ng/m 3 for one hour sampling by optimising parameters in the use of PIXE analysis.

Submicron hard X-ray fluorescence imaging of synthetic elements.

PubMed

Jensen, Mark P; Aryal, Baikuntha P; Gorman-Lewis, Drew; Paunesku, Tatjana; Lai, Barry; Vogt, Stefan; Woloschak, Gayle E

2012-04-13

Synchrotron-based X-ray fluorescence microscopy (XFM) using hard X-rays focused into sub-micron spots is a powerful technique for elemental quantification and mapping, as well as microspectroscopic measurements such as μ-XANES (X-ray absorption near edge structure). We have used XFM to image and simultaneously quantify the transuranic element plutonium at the L(3) or L(2)-edge as well as Th and lighter biologically essential elements in individual rat pheochromocytoma (PC12) cells after exposure to the long-lived plutonium isotope (242)Pu. Elemental maps demonstrate that plutonium localizes principally in the cytoplasm of the cells and avoids the cell nucleus, which is marked by the highest concentrations of phosphorus and zinc, under the conditions of our experiments. The minimum detection limit under typical acquisition conditions with an incident X-ray energy of 18 keV for an average 202 μm(2) cell is 1.4 fg Pu or 2.9×10(-20) moles Pu μm(-2), which is similar to the detection limit of K-edge XFM of transition metals at 10 keV. Copper electron microscopy grids were used to avoid interference from gold X-ray emissions, but traces of strontium present in naturally occurring calcium can still interfere with plutonium detection using its L(α) X-ray emission. Copyright © 2012 Elsevier B.V. All rights reserved.

Discrete elements for 3D microfluidics.

PubMed

Bhargava, Krisna C; Thompson, Bryant; Malmstadt, Noah

2014-10-21

Microfluidic systems are rapidly becoming commonplace tools for high-precision materials synthesis, biochemical sample preparation, and biophysical analysis. Typically, microfluidic systems are constructed in monolithic form by means of microfabrication and, increasingly, by additive techniques. These methods restrict the design and assembly of truly complex systems by placing unnecessary emphasis on complete functional integration of operational elements in a planar environment. Here, we present a solution based on discrete elements that liberates designers to build large-scale microfluidic systems in three dimensions that are modular, diverse, and predictable by simple network analysis techniques. We develop a sample library of standardized components and connectors manufactured using stereolithography. We predict and validate the flow characteristics of these individual components to design and construct a tunable concentration gradient generator with a scalable number of parallel outputs. We show that these systems are rapidly reconfigurable by constructing three variations of a device for generating monodisperse microdroplets in two distinct size regimes and in a high-throughput mode by simple replacement of emulsifier subcircuits. Finally, we demonstrate the capability for active process monitoring by constructing an optical sensing element for detecting water droplets in a fluorocarbon stream and quantifying their size and frequency. By moving away from large-scale integration toward standardized discrete elements, we demonstrate the potential to reduce the practice of designing and assembling complex 3D microfluidic circuits to a methodology comparable to that found in the electronics industry.

Quantification of HIV-1 DNA using real-time recombinase polymerase amplification.

PubMed

Crannell, Zachary Austin; Rohrman, Brittany; Richards-Kortum, Rebecca

2014-06-17

Although recombinase polymerase amplification (RPA) has many advantages for the detection of pathogenic nucleic acids in point-of-care applications, RPA has not yet been implemented to quantify sample concentration using a standard curve. Here, we describe a real-time RPA assay with an internal positive control and an algorithm that analyzes real-time fluorescence data to quantify HIV-1 DNA. We show that DNA concentration and the onset of detectable amplification are correlated by an exponential standard curve. In a set of experiments in which the standard curve and algorithm were used to analyze and quantify additional DNA samples, the algorithm predicted an average concentration within 1 order of magnitude of the correct concentration for all HIV-1 DNA concentrations tested. These results suggest that quantitative RPA (qRPA) may serve as a powerful tool for quantifying nucleic acids and may be adapted for use in single-sample point-of-care diagnostic systems.

Aerosol Emission Monitoring and Assessment of Potential Exposure to Multi-walled Carbon Nanotubes in the Manufacture of Polymer Nanocomposites

PubMed Central

Thompson, Drew; Chen, Sheng-Chieh; Wang, Jing; Pui, David Y.H.

2015-01-01

Recent animal studies have shown that carbon nanotubes (CNTs) may pose a significant health risk to those exposed in the workplace. To further understand this potential risk, effort must be taken to measure the occupational exposure to CNTs. Results from an assessment of potential exposure to multi-walled carbon nanotubes (MWCNTs) conducted at an industrial facility where polymer nanocomposites were manufactured by an extrusion process are presented. Exposure to MWCNTs was quantified by the thermal-optical analysis for elemental carbon (EC) of respirable dust collected by personal sampling. All personal respirable samples collected (n = 8) had estimated 8-h time weighted average (TWA) EC concentrations below the limit of detection for the analysis which was about one-half of the recommended exposure limit for CNTs, 1 µg EC/m3 as an 8-h TWA respirable mass concentration. Potential exposure sources were identified and characterized by direct-reading instruments and area sampling. Area samples analyzed for EC yielded quantifiable mass concentrations inside an enclosure where unbound MWCNTs were handled and near a pelletizer where nanocomposite was cut, while those analyzed by electron microscopy detected the presence of MWCNTs at six locations throughout the facility. Through size selective area sampling it was identified that the airborne MWCNTs present in the workplace were in the form of large agglomerates. This was confirmed by electron microscopy where most of the MWCNT structures observed were in the form of micrometer-sized ropey agglomerates. However, a small fraction of single, free MWCNTs was also observed. It was found that the high number concentrations of nanoparticles, ~200000 particles/cm3, present in the manufacturing facility were likely attributable to polymer fumes produced in the extrusion process. PMID:26209597

Quantifying trace elements in the emitted particulate matter during cooking and health risk assessment.

PubMed

Gorjinezhad, Soudabeh; Kerimray, Aiymgul; Amouei Torkmahalleh, Mehdi; Keleş, Melek; Ozturk, Fatma; Hopke, Philip K

2017-04-01

Particulate matter (PM) measurements were conducted during heating corn oil, heating corn oil mixed with the table salt and heating low fat ground beef meat using a PTFE-coated aluminum pan on an electric stove with low ventilation. The main objectives of this study were to measure the size segregated mass concentrations, emission rates, and fluxes of 24 trace elements emitted during heating cooking oil or oil with salt and cooking meat. Health risk assessments were performed based on the resulting exposure to trace elements from such cooking activities. The most abundant elements (significantly different from zero) were Ba (24.4 ug m -3 ) during grilling meat and Ti during heating oil with salt (24.4 ug m -3 ). The health assessment indicates that the cooking with an electric stove with poor ventilation leading to chronic exposures may pose the risk of significant adverse health effects. Carcinogenic risk exceeded the acceptable level (target cancer risk 1 × 10 -6 , US EPA 2015) by four orders of magnitude, while non-carcinogenic risk exceeded the safe level (target HQ = 1, US EPA 2015) by a factor of 5-20. Cr and Co were the primary contributors to the highest carcinogenic and non-carcinogenic risks, respectively.

Quantifying the impact of riverine particulate dissolution in seawater on ocean chemistry

NASA Astrophysics Data System (ADS)

Jones, Morgan T.; Gislason, Sigurður R.; Burton, Kevin W.; Pearce, Christopher R.; Mavromatis, Vasileios; Pogge von Strandmann, Philip A. E.; Oelkers, Eric H.

2014-06-01

The quantification of the sources and sinks of elements to the oceans forms the basis of our understanding of global geochemical cycles and the chemical evolution of the Earth's surface. There is, however, a large imbalance in the current best estimates of the global fluxes to the oceans for many elements. In the case of strontium (Sr), balancing the input from rivers would require a much greater mantle-derived component than is possible from hydrothermal water flux estimates at mid-ocean ridges. Current estimates of riverine fluxes are based entirely on measurements of dissolved metal concentrations, and neglect the impact of riverine particulate dissolution in seawater. Here we present 87Sr/86Sr isotope data from an Icelandic estuary, which demonstrate rapid Sr release from the riverine particulates. We calculate that this Sr release is 1.1-7.5 times greater than the corresponding dissolved riverine flux. If such behaviour is typical of volcanic particulates worldwide, this release could account for 6-45% of the perceived marine Sr budget imbalance, with continued element release over longer timescales further reducing the deficit. Similar release from particulate material will greatly affect the marine budgets of many other elements, changing our understanding of coastal productivity, and anthropogenic effects such as soil erosion and the damming of rivers.

Cycles of selected elements in the frame of Globalization and Global Change in the environment of Tenerife (Canary Islands, Spain)

NASA Astrophysics Data System (ADS)

Heidak, Markus O.; Glasmacher, Ulrich A.; Schöler, Heinfried; Trieloff, Mario; Kober, Bernd

2010-05-01

The Laurel Forest is an important and sensitive ecosystem with particular element cycling mechanisms. On Tenerife the distribution is straitened to some parts in the north, north-west and northeast. The NE trade wind ensures a permanently humid climate in the north. Major urban and industrial development is centred on Tenerife, and as a touristy hotspot the Island is exposed to heavy air traffic. Furthermore, the short distance to the African coastline and, therefore, to the Sahara, contribute a regular influence of African Dust emissions. In summary, Laurel Forest is exposed to different climatic conditions, variations in lithology and soils, and aerosols caused by local anthropogenic emissions, Saharan dust, and sea spray. The present study aims to understand geogenic and anthropogenic element transports of K, P, N, and organic components between soils and Laurel Forest. In addition, the element contribution from the aerosols such as the Sahara dust has to be quantified to understand the rock - soil - vegetation coupling system. The Sahara dust as one of the important aerosols has been studied by various researchers (Bustos et al., 1998; Rodrıguez, 1999; Torres et al., 2001; Viana et al., 2002). Viana et al.,(2002) quantified the impacts of African dust outbreaks for Tenerife and Gran Canaria, after the interpretation of the PM10 (thoracis particulate matter) from nineteen air quality monitoring stations. Three types of African dust contributions were identified and characterized (winter, summer and autumn-winter dust outbreaks). Collected samples with and without African dust influence proved that: (a) for the intensive winter African dust outbreaks (daily PM10 levels up to 191 mg/m3) at least 76% of the bulk PM10 levels may be attributable to dust load, whereas the anthropogenic input accounts for only 3-14% and (b) SiO2, Al2O3, Ca, K, Fe, Ti, V, Mn and Ba concentrations are excellent tracers of African origin (Viana et al., 2002).

Partitioning of light lithophile elements during basalt eruptions on Earth and application to Martian shergottites

NASA Astrophysics Data System (ADS)

Edmonds, Marie

2015-02-01

An enigmatic record of light lithophile element (LLE) zoning in pyroxenes in basaltic shergottite meteorites, whereby LLE concentrations decrease dramatically from the cores to the rims, has been interpreted as being due to partitioning of LLE into a hydrous vapor during magma ascent to the surface on Mars. These trends are used as evidence that Martian basaltic melts are water-rich (McSween et al., 2001). Lithium and boron are light lithophile elements (LLE) that partition into volcanic minerals and into vapor from silicate melts, making them potential tracers of degassing processes during magma ascent to the surface of Earth and of other planets. While LLE degassing behavior is relatively well understood for silica-rich melts, where water and LLE concentrations are relatively high, very little data exists for LLE abundance, heterogeneity and degassing in basaltic melts. The lack of data hampers interpretation of the trends in the shergottite meteorites. Through a geochemical study of LLE, volatile and trace elements in olivine-hosted melt inclusions from Kilauea Volcano, Hawaii, it can be demonstrated that lithium behaves similarly to the light to middle rare Earth elements during melting, magma mixing and fractionation. Considerable heterogeneity in lithium and boron is inherited from mantle-derived primary melts, which is dominant over the fractionation and degassing signal. Lithium and boron are only very weakly volatile in basaltic melt erupted from Kilauea Volcano, with vapor-melt partition coefficients <0.1. Degassing of LLE is further inhibited at high temperatures. Pyroxene and associated melt inclusion LLE concentrations from a range of volcanoes are used to quantify lithium pyroxene-melt partition coefficients, which correlate negatively with melt H2O content, ranging from 0.13 at low water contents to <0.08 at H2O contents >4 wt%. The observed terrestrial LLE partitioning behavior is extrapolated to Martian primitive melts through modeling. The zoning observed in the shergottite pyroxenes is only consistent with degassing of LLE from a Martian melt near its liquidus temperature if the vapor-melt partition coefficient was an order of magnitude larger than observed on Earth. The range in LLE and trace elements observed in shergottite pyroxenes are instead consistent with concurrent mixing and fractionation of heterogeneous melts from the mantle.

Trace element-protein interactions in endolymph from the inner ear of fish: implications for environmental reconstructions using fish otolith chemistry.

PubMed

Thomas, Oliver R B; Ganio, Katherine; Roberts, Blaine R; Swearer, Stephen E

2017-03-22

Otoliths, the biomineralised hearing "ear stones" from the inner ear of fish, grow throughout the lifespan of an individual, with deposition of alternating calciferous and proteinaceous bands occurring daily. Trace element : calcium ratios within daily increments measured by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are often used in fisheries science to reconstruct environmental histories. There is, however, considerable uncertainty as to which elements are interacting with either the proteinaceous or calciferous zones of the otolith, and thus their utility as indicators of environmental change. To answer this, we used size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) of endolymph, the otolith growth medium, to determine the binding interactions for a range of elements. In addition, we used solution ICP-MS to quantify element concentrations in paired otolith and endolymph samples and determined relative enrichment factors for each. We found 12 elements that are present only in the proteinaceous fraction, 6 that are present only in the salt fraction, and 4 that are present in both. These findings have important implications for the reconstruction of environmental histories based on changes in otolith elemental composition: (1) elements occurring only in the salt fraction are most likely to reflect changes in the physico-chemical environment experienced during life; (2) elements occurring only in the proteinaceous fraction are more likely to reflect physiological rather than environmental events; and (3) elements occurring in both the salt and proteinaceous fractions are likely to be informative about both endogenous and exogenous processes, potentially reducing their utility in environmental reconstructions.

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activationmore » analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.« less

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

NASA Astrophysics Data System (ADS)

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.; Tuskan, Gerald A.; Gunter, Lee E.; Engle, Nancy L.; Wymore, Ann M.; Weston, David J.

2017-12-01

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activation analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.

Correlating laser-induced breakdown spectroscopy with neutron activation analysis to determine the elemental concentration in the ionome of the Populus trichocarpa leaf

DOE PAGES

Martin, Madhavi Z.; Glasgow, David C.; Tschaplinski, Timothy J.; ...

2017-10-17

The black cottonwood poplar (Populus trichocarpa) leaf ionome (inorganic trace elements and mineral nutrients) is an important aspect for determining the physiological and developmental processes contributing to biomass production. A number of techniques are used to measure the ionome, yet characterizing the leaf spatial heterogeneity remains a challenge, especially in solid samples. Laser-induced breakdown spectroscopy (LIBS) has been used to determine the elemental composition of leaves and is able to raster across solid matrixes at 10 μm resolution. Here, we evaluate the use of LIBS for solid sample leaf elemental characterization in relation to neutron activation. In fact, neutron activationmore » analysis is a laboratory-based technique which is used by the National Institute of Standards and Technology (NIST) to certify trace elements in candidate reference materials including plant leaf matrices. Introduction to the techniques used in this research has been presented in this manuscript. Neutron activation analysis (NAA) data has been correlated to the LIBS spectra to achieve quantification of the elements or ions present within poplar leaves. The regression coefficients of calibration and validation using multivariate analysis (MVA) methodology for six out of seven elements have been determined and vary between 0.810 and 0.998. LIBS and NAA data has been presented for the elements such as, calcium, magnesium, manganese, aluminum, copper, and potassium. Chlorine was also detected but it did not show good correlation between the LIBS and NAA techniques. This research shows that LIBS can be used as a fast, high-spatial resolution technique to quantify elements as part of large-scale field phenotyping projects.« less

On the Applications of IBA Techniques to Biological Samples Analysis: PIXE and RBS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falcon-Gonzalez, J. M.; Bernal-Alvarado, J.; Sosa, M.

2008-08-11

The analytical techniques based on ion beams or IBA techniques give quantitative information on elemental concentration in samples of a wide variety of nature. In this work, we focus on PIXE technique, analyzing thick target biological specimens (TTPIXE), using 3 MeV protons produced by an electrostatic accelerator. A nuclear microprobe was used performing PIXE and RBS simultaneously, in order to solve the uncertainties produced in the absolute PIXE quantifying. The advantages of using both techniques and a nuclear microprobe are discussed. Quantitative results are shown to illustrate the multielemental resolution of the PIXE technique; for this, a blood standard wasmore » used.« less

Ridge to reef assessment of metal concentration and mineralogy in rocks and sediments on St. John, U.S. Virgin Islands

NASA Astrophysics Data System (ADS)

Harrington, R. J.; Gray, S. C.; Ramos-Scharron, C. E.; O'Shea, B.

2012-12-01

Land development on the island of St. John, US Virgin Islands is increasing terrigenous sediment loads into coastal bays and this is adversely affecting its sensitive, near-shore coral reef systems. Accelerated erosion of by-products originating from igneous bedrock may contribute metal-rich sediment to ephemeral streams and bays around St. John. In order to determine how development is affecting the production and transportation of land-based metals from watersheds to reef environments, we compare the chemistry and mineralogy of bedrock and sediment of both an undeveloped and a developed watershed and their corresponding bays. Both watersheds are comprised of bedrock of similar lithology (Water Island Formation: plagiorhyolite and basalt). Our study objectives are to: 1) determine what metal elements could serve as reliable stable geochemical tracers to track the transport of land-derived sediments to reefs; 2) document the total change in metal concentrations from in-situ bedrock and sediment along travel paths as the sediment gets transported from the watersheds to the reefs; and 3) estimate erosion rates from active sediment sources and metal accumulation rates within the marine environment. Whole rock, soil, stream, shore and reef sediment samples were collected from both study areas to represent a ridge to reef progression of material as it is eroded from the bedrock and transported to the reefs. Samples of in-situ rock and sediments were collected by hand, while material representing sediment being eroded from the watersheds and settling in the ephemeral streams and bays was captured by terrestrial and marine sediment traps. Major and trace element concentrations and the mineralogy of rock and sediments were analyzed using X-ray fluorescence, petrography and X-ray diffraction. Analyses of bedrock samples reveal mineral and elemental compositions typical of basalt and plagiorhyolite. In hydrothermally altered bedrock Ba and K concentrations elevated above non-hydrothermally altered bedrock are detected. A chemical weathering index of bedrock and adjacent C and B soil horizons suggests that some major elements, such as Ca, K and Na, are chemically weathering from bedrock and soils. However, some major and trace elements that derive from terrigenous sources (FeO, Al2O3, TiO2, Cu, Zr) resist chemical weathering and are transported to the shore and reef within eroded terrestrial sediment. The concentrations of these metals in marine trap sediments are strongly correlated with percent terrigenous material (R2= 0.80 - 0.94, p: <0.0001). This suggests these elements can be used as tracers for sediment derived from terrestrial environments. Watershed terrestrial metals concentrations do not show a consistent pattern of change from ridge to reef, but are generally higher in the watershed than the shore and reef sites. Higher concentrations (5 to 50 times higher depending on the element) of terrigenous derived metals are detected below the developed watershed compared to the undeveloped watershed. These data support previous research showing higher rates of terrigenous sedimentation in the marine environments of developed bays. These geochemical data will be compared to a watershed-scale erosion analysis of both study areas to quantify metal flux rates in this type of sub-tropical island system.

Granulometric selectivity in Liza ramado and potential contamination resulting from heavy metal load in feeding areas

NASA Astrophysics Data System (ADS)

Pedro, Sílvia; Canastreiro, Vera; Caçador, Isabel; Pereira, Eduarda; Duarte, Armando C.; Raposo de Almeida, Pedro

2008-11-01

The stomach contents of thin-lipped grey mullets Liza ramado were analysed in terms of granulometric composition and compared to the sediment of potential feeding areas in the Tagus estuary. Total organic matter (TOM) content and heavy metal content were determined in the surface sediment of three areas and eight trace elements were quantified: Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn. The three sampled areas did not differ in TOM; and the heavy metal content was below Effects Range-Low level for most elements. The mean observed concentrations were present in the following sequence: Zn > Pb > Cr > Cu ≈ Ni > Co > Cd > Hg. Stomach contents granulometric composition provided information about the feeding selectivity of the mullets. Sediment fractions with particle size between 20 and 50 μm are preferred, independently of the fishes' length. Smaller standard length (SL) fishes have a higher positive selection of fine grained sediments than those with a larger SL. Finer fractions usually have higher concentration of heavy metals, which makes younger specimens of the thin-lipped grey mullet potentially more exposed to heavy metal load in the estuary. Metal concentration was not independent from the sampling point, presenting higher values near the margins and the estuary tidal drainage system. This means that during the first period of each tidal cycle, the mullets will feed first on the most contaminated areas, as a consequence of their movement following the rising tide to feed on previously exposed areas.

Neutron activation analysis of certified samples by the absolute method

NASA Astrophysics Data System (ADS)

Kadem, F.; Belouadah, N.; Idiri, Z.

2015-07-01

The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

Emergy of the Global Biogeochemical Cycles of Biologically Active Elements

EPA Science Inventory

Accurate estimates of the emergy of elemental flows are needed to accurately evaluate the far field effects of anthropogenic wastes. The transformity and specific emergy of the elements and of their different chemical species is also needed to quantify the inputs to many producti...

A locally conservative non-negative finite element formulation for anisotropic advective-diffusive-reactive systems

NASA Astrophysics Data System (ADS)

Mudunuru, M. K.; Shabouei, M.; Nakshatrala, K.

2015-12-01

Advection-diffusion-reaction (ADR) equations appear in various areas of life sciences, hydrogeological systems, and contaminant transport. Obtaining stable and accurate numerical solutions can be challenging as the underlying equations are coupled, nonlinear, and non-self-adjoint. Currently, there is neither a robust computational framework available nor a reliable commercial package known that can handle various complex situations. Herein, the objective of this poster presentation is to present a novel locally conservative non-negative finite element formulation that preserves the underlying physical and mathematical properties of a general linear transient anisotropic ADR equation. In continuous setting, governing equations for ADR systems possess various important properties. In general, all these properties are not inherited during finite difference, finite volume, and finite element discretizations. The objective of this poster presentation is two fold: First, we analyze whether the existing numerical formulations (such as SUPG and GLS) and commercial packages provide physically meaningful values for the concentration of the chemical species for various realistic benchmark problems. Furthermore, we also quantify the errors incurred in satisfying the local and global species balance for two popular chemical kinetics schemes: CDIMA (chlorine dioxide-iodine-malonic acid) and BZ (Belousov--Zhabotinsky). Based on these numerical simulations, we show that SUPG and GLS produce unphysical values for concentration of chemical species due to the violation of the non-negative constraint, contain spurious node-to-node oscillations, and have large errors in local and global species balance. Second, we proposed a novel finite element formulation to overcome the above difficulties. The proposed locally conservative non-negative computational framework based on low-order least-squares finite elements is able to preserve these underlying physical and mathematical properties. Several representative numerical examples are discussed to illustrate the importance of the proposed numerical formulations to accurately describe various aspects of mixing process in chaotic flows and to simulate transport in highly heterogeneous anisotropic media.

Towards a better understanding of long-term wood-chemistry variations in old-growth forests: A case study on ancient Pinus uncinata trees from the Pyrenees.

PubMed

Hevia, Andrea; Sánchez-Salguero, Raúl; Camarero, J Julio; Buras, Allan; Sangüesa-Barreda, Gabriel; Galván, J Diego; Gutiérrez, Emilia

2018-06-01

Dendrochemical studies in old forests are still underdeveloped. Old trees growing in remote high-elevation areas far from direct human influence constitute a promising biological proxy for the long-term reconstructions of environmental changes using tree-rings. Furthermore, centennial-long chronologies of multi-elemental chemistry at inter- and intra-annual resolution are scarce. Here, we use a novel non-destructive method by applying Micro X-ray fluorescence (μXRF) to wood samples of old Pinus uncinata trees from two Pyrenean high-elevation forests growing on acidic and basic soils. To disentangle ontogenetic (changes in tree age and diameter) from environmental influences (e.g., climate warming) we compared element patterns in sapwood (SW) and heartwood (HW) during the pre-industrial (1700-1849) and industrial (1850-2008) periods. We quantified tree-ring growth, wood density and relative element concentrations at annual (TRW, tree-ring) to seasonal resolution (EW, earlywood; LW, latewood) and related them to climate variables (temperature and precipitation) and volcanic eruptions in the 18th and 19th centuries. We detected differences for most studied elements between SW and HW along the stem and also between EW and LW within rings. Long-term positive and negative trends were observed for Ca and K, respectively. Cl, P and S showed positive trends during the industrial period. However, differences between sites were also notable. Higher values of Mg, Al, Si and the Ca/Mn ratio were observed at the site with acidic soil. Growing-season temperatures were positively related to growth, maximum wood density and to the concentration of most elements. Peaks in S, Fe, Cl, Zn and Ca were linked to major volcanic eruptions (e.g., Tambora in 1815). Our results reveal the potential of long-term wood-chemistry studies based on the μXRF non-destructive technique to reconstruct environmental changes. Copyright © 2017 Elsevier B.V. All rights reserved.

Speciation analysis of antimony in extracts of size-classified volcanic ash by HPLC-ICP-MS.

PubMed

Miravet, R; López-Sánchez, J F; Rubio, R; Smichowski, P; Polla, G

2007-03-01

Although there is concern about the presence of toxic elements and their species in environmental matrices, for example water, sediment, and soil, speciation analysis of volcanic ash has received little attention. Antimony, in particular, an emerging element of environmental concern, has been less studied than other potentially toxic trace elements. In this context, a study was undertaken to assess the presence of inorganic Sb species in ash emitted from the Copahue volcano (Argentina). Antimony species were extracted from size-classified volcanic ash (<36 microm, 35-45 microm, 45-150 microm, and 150-300 microm) by use of 1 mol L(-1) citrate buffer at pH 5. Antimony(III) and (V) in the extracts were separated and quantified by high-performance liquid chromatography combined on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Antimony species concentrations (microg g(-1)) in the four fractions varied from 0.14 to 0.67 for Sb(III) and from 0.02 to 0.03 for Sb(V). The results reveal, for the first time, the occurrence of both inorganic Sb species in the extractable portion of volcanic ash. Sb(III) was always the predominant species.

[Development and validation of an analytical method to quantify residues of cleaning products able to inactivate prion].

PubMed

Briot, T; Robelet, A; Morin, N; Riou, J; Lelièvre, B; Lebelle-Dehaut, A-V

2016-07-01

In this study, a novel analytical method to quantify prion inactivating detergent in rinsing waters coming from the washer-disinfector of a hospital sterilization unit has been developed. The final aim was to obtain an easy and functional method in a routine hospital process which does not need the cleaning product manufacturer services. An ICP-MS method based on the potassium dosage of the washer-disinfector's rinsing waters was developed. Potassium hydroxide is present on the composition of the three prion inactivating detergent currently on the French market. The detergent used in this study was the Actanios LDI(®) (Anios laboratories). A Passing and Bablok regression compares concentrations measured with this developed method and with the HPLC-UV manufacturer method. According to results obtained, the developed method is easy to use in a routine hospital process. The Passing and Bablok regression showed that there is no statistical difference between the two analytical methods during the second rinsing step. Besides, both methods were linear on the third rinsing step, with a 1.5ppm difference between the concentrations measured for each method. This study shows that the ICP-MS method developed is nonspecific for the detergent, but specific for the potassium element which is present in all prion inactivating detergent currently on the French market. This method should be functional for all the prion inactivating detergent containing potassium, if the sensibility of the method is sufficient when the potassium concentration is very low in the prion inactivating detergent formulation. Copyright © 2016. Published by Elsevier Masson SAS.

Controls on foliar nutrient and aluminium concentrations in a tropical tree flora: phylogeny, soil chemistry and interactions among elements.

PubMed

Metali, Faizah; Abu Salim, Kamariah; Tennakoon, Kushan; Burslem, David F R P

2015-01-01

Foliar elemental concentrations are predictors of life-history variation and contribute to spatial patterns in biogeochemical cycling. We examined the contributions of habitat association, local soil environment, and elemental interactions to variation in foliar elemental concentrations in tropical trees using methods that account for phylogeny. We sampled top-soils and leaves of 58 tropical trees in heath forest (HF) on nutrient-poor sand and mixed dipterocarp forest (MDF) on nutrient-rich clay soils. A phylogenetic generalized least squares method was used to determine how foliar nutrient and aluminium (Al) concentrations varied in response to habitat distribution, soil chemistry and other elemental concentrations. Foliar nitrogen (N) and Al concentrations were greater for specialists of MDF than for specialists of HF, while foliar calcium (Ca) concentrations showed the opposite trend. Foliar magnesium (Mg) concentrations were lower for generalists than for MDF specialists. Foliar element concentrations were correlated with fine-scale variation in soil chemistry in phylogenetically controlled analyses across species, but there was limited within-species plasticity in foliar elemental concentrations. Among Al accumulators, foliar Al concentration was positively associated with foliar Ca and Mg concentrations, and negatively associated with foliar phosphorus (P) concentrations. The Al-accumulation trait and relationships between foliar elemental and Al concentrations may contribute to species habitat partitioning and ecosystem-level differences in biogeochemical cycles. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Time of Day Does Not Modulate Improvements in Motor Performance following a Repetitive Ballistic Motor Training Task

PubMed Central

Sale, Martin V.; Ridding, Michael C.; Nordstrom, Michael A.

2013-01-01

Repetitive performance of a task can result in learning. The neural mechanisms underpinning such use-dependent plasticity are influenced by several neuromodulators. Variations in neuromodulator levels may contribute to the variability in performance outcomes following training. Circulating levels of the neuromodulator cortisol change throughout the day. High cortisol levels inhibit neuroplasticity induced with a transcranial magnetic stimulation (TMS) paradigm that has similarities to use-dependent plasticity. The present study investigated whether performance changes following a motor training task are modulated by time of day and/or changes in endogenous cortisol levels. Motor training involving 30 minutes of repeated maximum left thumb abduction was undertaken by twenty-two participants twice, once in the morning (8 AM) and once in the evening (8 PM) on separate occasions. Saliva was assayed for cortisol concentration. Motor performance, quantified by measuring maximum left thumb abduction acceleration, significantly increased by 28% following training. Neuroplastic changes in corticomotor excitability of abductor pollicis brevis, quantified with TMS, increased significantly by 23% following training. Training-related motor performance improvements and neuroplasticity were unaffected by time of day and salivary cortisol concentration. Although similar neural elements and processes contribute to motor learning, training-induced neuroplasticity, and TMS-induced neuroplasticity, our findings suggest that the influence of time of day and cortisol differs for these three interventions. PMID:23577271

Incorporating both physical and kinetic limitations in quantifying dissolved oxygen flux to aquatic sediments

USGS Publications Warehouse

O'Connor, B.L.; Hondzo, Miki; Harvey, J.W.

2009-01-01

Traditionally, dissolved oxygen (DO) fluxes have been calculated using the thin-film theory with DO microstructure data in systems characterized by fine sediments and low velocities. However, recent experimental evidence of fluctuating DO concentrations near the sediment-water interface suggests that turbulence and coherent motions control the mass transfer, and the surface renewal theory gives a more mechanistic model for quantifying fluxes. Both models involve quantifying the mass transfer coefficient (k) and the relevant concentration difference (??C). This study compared several empirical models for quantifying k based on both thin-film and surface renewal theories, as well as presents a new method for quantifying ??C (dynamic approach) that is consistent with the observed DO concentration fluctuations near the interface. Data were used from a series of flume experiments that includes both physical and kinetic uptake limitations of the flux. Results indicated that methods for quantifying k and ??C using the surface renewal theory better estimated the DO flux across a range of fluid-flow conditions. ?? 2009 ASCE.

Serum Concentrations of Trace Elements in Patients with Tuberculosis and Its Association with Treatment Outcome

PubMed Central

Choi, Rihwa; Kim, Hyoung-Tae; Lim, Yaeji; Kim, Min-Ji; Kwon, O Jung; Jeon, Kyeongman; Park, Hye Yun; Jeong, Byeong-Ho; Koh, Won-Jung; Lee, Soo-Youn

2015-01-01

Deficiencies in essential trace elements are associated with impaired immunity in tuberculosis infection. However, the trace element concentrations in the serum of Korean patients with tuberculosis have not yet been investigated. This study aimed to compare the serum trace element concentrations of Korean adult patients with tuberculosis with noninfected controls and to assess the impact of serum trace element concentration on clinical outcome after antituberculosis treatment. The serum concentrations of four trace elements in 141 consecutively recruited patients with tuberculosis and 79 controls were analyzed by inductively coupled plasma-mass spectrometry. Demographic characteristics were also analyzed. Serum cobalt and copper concentrations were significantly higher in patients with tuberculosis compared with controls, while zinc and selenium concentrations were significantly lower (p < 0.01). Moreover, serum selenium and zinc concentrations were positively correlated (ρ = 0.41, p < 0.05). A high serum copper concentration was associated with a worse clinical outcome, as assessed after one month of antituberculosis therapy. Specifically, culture-positive patients had higher serum copper concentrations than culture-negative patients (p < 0.05). Patients with tuberculosis had altered serum trace element concentrations. Further research is needed to elucidate the roles of individual trace elements and to determine their clinical impact on patients with tuberculosis. PMID:26197334

Quantifying Post-Fire Aeolian Sediment Transport Using Rare Earth Element Tracers.

NASA Astrophysics Data System (ADS)

Dukes, D.; Ravi, S.; Grandstaff, D. E.; Gonzales, H. B.; Li, J. J.; Sankey, J. B.; Wang, G.; Van Pelt, R. S.

2016-12-01

Grasslands and rangelands in arid and semi-arid regions of the world, which provide fundamental ecosystem services, are undergoing rapid increases in fire activity and are highly susceptible to post-fire accelerated soil erosion by wind. A quantitative assessment that integrates fire-wind erosion feedbacks is therefore critically needed in understanding vegetation change, soil biogeochemical cycling, air quality, and landscape evolution. We investigated the applicability of a novel tracer technique - the use of rare earth element (REE) tracers - to quantify soil erosion by wind and to identify sources and sinks of wind-blown sediments in both a burned and unburned shrub-grass transition zone within the Chihuahuan desert (New Mexico, USA). At the beginning of the windy season, March 2016, silt and sand sized particles in shrub, grass, and bare microsites were each tagged with a unique REE oxide, Ho, Eu, and Yb respectively. Samples were then taken directly after application prior to a prescribed fire and again at the end of the windy season in June 2016. All REE tracers showed signs of depletion and mixing, with the depletion in the burned site up to 20% greater than the unburned. REE concentration comparisons between the burned and unburned plots reveal a shift in the source and sink dynamics of sediment post fire. In unburned plots, changes in microsite REE concentrations indicate that sediment moved from the bare to vegetated microsites, whereas the opposite occurred in burned plots. However, burned plot grass microsites acted as a sink for sediment from shrub microsites, whereas unburned plot grass microsites exhibited no enrichment from shrub microsite-sourced sediment. Though fires are known to immediately increase aeolian sediment transport, accompanying changes in the sources and sinks of wind borne sediment may influence biogeochemical cycling and vegetation shifts possibly providing a feedback mechanism for land degradation in dryland ecosystems.

Petrology, mineralogy and geochemistry of mined coals, western Venezuela

USGS Publications Warehouse

Hackley, Paul C.; Warwick, Peter D.; González, Eligio

2005-01-01

Upper Paleocene to middle Miocene coal samples collected from active mines in the western Venezuelan States of Táchira, Mérida and Zulia have been characterized through an integrated geochemical, mineralogical and petrographic investigation. Proximate, ultimate, calorific and forms of sulfur values, major and trace element, vitrinite reflectance, maceral concentrations and mineral matter content have been determined for 16 channel samples from 14 mines. Ash yield generally is low, ranging from < 1 to 17 wt.% (mean = 5 wt.%) on a dry basis (db). Total sulfur content is low to moderate, ranging from 1 to 6 wt.%, db (average = 1.7 wt.%). Calorific value ranges from 25.21 to 37.21 MJ/kg (10,840–16,000 Btu/lb) on a moist, mineral-matter-free basis (average = 33.25 MJ/kg, 14,300 Btu/lb), placing most of the coal samples in the apparent rank classification of high-volatile bituminous. Most of the coal samples exhibit favorable characteristics on the various indices developed to predict combustion and coking behavior and concentrations of possible environmentally sensitive elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, Th and U) generally are similar to the concentrations of these elements in most coals of the world, with one or two exceptions. Concentrations of the liptinite maceral group range from < 1% to 70 vol.%. Five samples contain > 20 vol.% liptinite, dominated by the macerals bituminite and sporinite. Collotelinite dominates the vitrinite group; telinite was observed in quantities of ≤ 1 vol.% despite efforts to better quantify this maceral by etching the sample pellets in potassium permanganate and also by exposure in an oxygen plasma chamber. Inertinite group macerals typically represent < 10 vol.% of the coal samples and the highest concentrations of inertinite macerals are found in distantly spaced (> 400 km) upper Paleocene coal samples from opposite sides of Lago de Maracaibo, possibly indicating tectonic controls on subsidence related to construction of the Andean orogen. Values of maximum reflectance of vitrinite in oil (Ro max) range between 0.42% and 0.85% and generally are consistent with the high-volatile bituminous rank classification obtained through ASTM methods. X-ray diffraction analyses of low-temperature ash residues indicate that kaolinite, quartz, illite and pyrite dominate the inorganic fraction of most samples; plagioclase, potassium feldspar, calcite, siderite, ankerite, marcasite, rutile, anatase and apatite are present in minor or trace concentrations. Semiquantitative values of volume percent pyrite content show a strong correlation with pyritic sulfur and some sulfide-hosted trace element concentrations (As and Hg). This work provides a modern quality dataset for the western Venezuela coal deposits currently being exploited and will serve as the foundation for an ongoing coal quality research program in Venezuela.

Loess as an environmental archive of atmospheric trace element deposition

NASA Astrophysics Data System (ADS)

Blazina, T.; Winkel, L. H.

2013-12-01

Environmental archives such as ice cores, lake sediment cores, and peat cores have been used extensively to reconstruct past atmospheric deposition of trace elements. These records have provided information about how anthropogenic activities such as mining and fossil fuel combustion have disturbed the natural cycles of various atmospherically transported trace elements (e.g. Pb, Hg and Se). While these records are invaluable for tracing human impacts on such trace elements, they often provide limited information about the long term natural cycles of these elements. An assumption of these records is that the observed variations in trace element input, prior to any assumed anthropogenic perturbations, represent the full range of natural variations. However, records such as those mentioned above which extend back to a maximum of ~400kyr may not capture the potentially large variations of trace element input occurring over millions of years. Windblown loess sediments, often representing atmospheric deposition over time scales >1Ma, are the most widely distributed terrestrial sediments on Earth. These deposits have been used extensively to reconstruct continental climate variability throughout the Quaternary and late Neogene periods. In addition to being a valuable record of continental climate change, loess deposits may represent a long term environmental archive of atmospheric trace element deposition and may be combined with paleoclimate records to elucidate how fluctuations in climate have impacted the natural cycle of such elements. Our research uses the loess-paleosol deposits on the Chinese Loess Plateau (CLP) to quantify how atmospheric deposition of trace elements has fluctuated in central China over the past 6.8Ma. The CLP has been used extensively to reconstruct past changes of East Asian monsoon system (EAM). We present a suite of trace element concentration records (e.g. Pb, Hg, and Se) from the CLP which exemplifies how loess deposits can be used as an environmental archive to reconstruct long term natural variations in atmospheric trace element input. By comparing paleomonsoon proxy data with geochemical data we can directly correlate variations in atmospheric trace element input to fluctuations in the EAM. For example we are able to link Se input into the CLP to EAM derived precipitation. In interglacial climatic periods from 2.3-1.56Ma and 1.50-1.29Ma, we find very strong positive correlations between Se concentration and the summer monsoon index, a proxy for effective precipitation. In later interglacial periods from 1.26-0.83Ma and 0.78-0.16Ma, we find dust input plays a greater role. Our findings demonstrate that the CLP is a valuable environmental archive of atmospheric trace element deposition and suggest that other loess deposits worldwide may serve as useful records for investigating long term natural variations in atmospheric trace element cycling.

Metrics for Assessing the Quality of Groundwater Used for Public Supply, CA, USA: Equivalent-Population and Area.

PubMed

Belitz, Kenneth; Fram, Miranda S; Johnson, Tyler D

2015-07-21

Data from 11,000 public supply wells in 87 study areas were used to assess the quality of nearly all of the groundwater used for public supply in California. Two metrics were developed for quantifying groundwater quality: area with high concentrations (km(2) or proportion) and equivalent-population relying upon groundwater with high concentrations (number of people or proportion). Concentrations are considered high if they are above a human-health benchmark. When expressed as proportions, the metrics are area-weighted and population-weighted detection frequencies. On a statewide-scale, about 20% of the groundwater used for public supply has high concentrations for one or more constituents (23% by area and 18% by equivalent-population). On the basis of both area and equivalent-population, trace elements are more prevalent at high concentrations than either nitrate or organic compounds at the statewide-scale, in eight of nine hydrogeologic provinces, and in about three-quarters of the study areas. At a statewide-scale, nitrate is more prevalent than organic compounds based on area, but not on the basis of equivalent-population. The approach developed for this paper, unlike many studies, recognizes the importance of appropriately weighting information when changing scales, and is broadly applicable to other areas.

Recent Rainfall and Aerosol Chemistry From Bermuda

NASA Astrophysics Data System (ADS)

Landing, W. M.; Shelley, R.; Kadko, D. C.

2014-12-01

This project was devoted to testing the use of Be-7 as a tracer for quantifying trace element fluxes from the atmosphere to the oceans. Rainfall and aerosol samples were collected between June 15, 2011 and July 27, 2013 at the Bermuda Institute of Ocean Sciences (BIOS) located near the eastern end of the island of Bermuda. Collectors were situated near ground level, clear of surrounding vegetation, at a meteorological monitoring station in front of the BIOS laboratory, about 10 m above sea level. This is a Bermuda Air Quality Program site used for ambient air quality monitoring. To quantify the atmospheric deposition of Be-7, plastic buckets were deployed for collection of fallout over ~3 week periods. Wet deposition was collected for trace element analysis using a specially modified "GEOTRACES" N-CON automated wet deposition collector. Aerosol samples were collected with a Tisch TE-5170V-BL high volume aerosol sampler, modified to collect 12 replicate samples on acid-washed 47mm diameter Whatman-41 filters, using procedures identical to those used for the US GEOTRACES aerosol program (Morton et al., 2013). Aerosol and rainfall samples were analyzed for total Na, Mg, Al, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Zr, Cd, Sb, Ba, La, Ce, Nd, Pb, Th, and U using ICPMS. Confirming earlier data from Bermuda, strong seasonality in rainfall and aerosol loading and chemistry was observed, particularly for aerosol and rainfall Fe concentrations when Saharan dust arrives in July/August with SE trajectories.

Impact of Santiago de Chile urban atmospheric pollution on anthropogenic trace elements enrichment in snow precipitation at Cerro Colorado, Central Andes

NASA Astrophysics Data System (ADS)

Cereceda-Balic, F.; Palomo-Marín, M. R.; Bernalte, E.; Vidal, V.; Christie, J.; Fadic, X.; Guevara, J. L.; Miro, C.; Pinilla Gil, E.

2012-02-01

Seasonal snow precipitation in the Andes mountain range is evaluated as an environmental indicator of the composition of atmospheric emissions in Santiago de Chile metropolitan area, by measuring a set of representative trace elements in snow samples by ICP-MS. Three late winter sampling campaigns (2003, 2008 and 2009) were conducted in three sampling areas around Cerro Colorado, a Central Andes mountain range sector NE of Santiago (36 km). Nevados de Chillán, a sector in The Andes located about 500 km south from the metropolitan area, was selected as a reference area. The experimental results at Cerro Colorado and Nevados de Chillán were compared with previously published data of fresh snow from remote and urban background sites. High snow concentrations of a range of anthropogenic marker elements were found at Cerro Colorado, probably derived from Santiago urban aerosol transport and deposition combined with the effect of mining and smelting activities in the area, whereas Nevados de Chillán levels roughly correspond to urban background areas. Enhanced concentrations in surface snow respect to deeper samples are discussed. Significant differences found between the 2003, 2008 and 2009 anthropogenic source markers profiles at Cerro Colorado sampling points were correlated with changes in emission sources at the city. The preliminary results obtained in this study, the first of this kind in the southern hemisphere, show promising use of snow precipitation in the Central Andes as a suitable matrix for receptor model studies aimed at identifying and quantifying pollution sources in Santiago de Chile.

Space Radiation Program Element

NASA Technical Reports Server (NTRS)

Krenek, Sam

2008-01-01

This poster presentation shows the various elements of the Space Radiation Program. It reviews the program requirements: develop and validate standards, quantify space radiation human health risks, mitigate risks through countermeasures and technologies, and treat and monitor unmitigated risks.

Quantifying Elements of a Lunar Economy Based on Resource Needs

NASA Astrophysics Data System (ADS)

Greenblatt, J. B.

2017-10-01

We model a simplified lunar economy from human life support, Earth materials consumption, and energy and propulsion requirement estimates, constrained by lunar elemental abundances; estimate likely imports/exports and "gross interplanetary product."

Lead in the environment

USGS Publications Warehouse

Pattee, Oliver H.; Pain, Deborah J.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

2003-01-01

Anthropogenic uses of lead have probably altered its availability and environmental distribution more than any other toxic element. Consequently, lead concentrations in many living organisms may be approaching thresholds of toxicity for the adverse effects of lead. Such thresholds are difficult to define, as they vary with the chemical and physical form of lead, exposure regime, other elements present and also vary both within and between species. The technological capability to accurately quantify low lead concentrations has increased over the last decade, and physiological and behavioral effects have been measured in wildlife with tissue lead concentrations below those previously considered safe for humans.s.236 Consequently. lead criteria for the protection of wildlife and human health are frequently under review, and 'thresholds' of lead toxicity are being reconsidered. Proposed lead criteria for the protection of natural resources have been reviewed by Eisler. Uptake of lead by plants is limited by its generally low availability in soils and sediments, and toxicity may be limited by storage mechanisms and its apparently limited translocation within most plants. Lead does not generally accumulate within the foliar parts of plants, which limits its transfer to higher trophic levels. Although lead may concentrate in plant and animal tissues, no evidence of biomagnification exists. Acid deposition onto surface waters and soils with low buffering capacity may influence the availability of lead for uptake by plants and animals, and this may merit investigation at susceptible sites. The biological significance of chronic low-level lead exposure to wildlife is sometimes difficult to quantify. Animals living in urban environments or near point sources of lead emission are inevitably subject to greater exposure to lead and enhanced risk of lead poisoning. Increasingly strict controls on lead emissions in many countries have reduced exposure to lead from some sources. and the .reduction of lead in gasoline has resulted in lower tissue lead concentrations in humans and wildlife from many, particularly urban, locations. However, it has been suggested that increasing use of organic lead compounds as catalysts for the production of plastics and as wood preservatives and biocides could adversely affect wildlife. The most significant source of direct wildlife mortality from lead is spent gunshot and fishing sinkers. Elevated mortality from shot ingestion in avian species resulted in the introduction of nontoxic (steel) shot zones along certain flyways in the United States in the mid-1970s and a total ban on the use of lead for waterfowl and coot hunting nationwide by 1992. Several other countries are now following suit and have either banned or are in the process of restricting the use of lead shot for waterfowl hunting. In the United States it has been estimated that since the 1986 hunting season. when the use of nontoxic shot became widespread. over 6 million ducks have not been lost to lead poisoning. Raptors, especially eagles, have also apparently benefited. although lead poisoning from ingestion of bullet fragments remains a problem for the critically threatened California condor. Quantifying reductions in lead mortality rates would be difficult since eagle populations throughout North America are rapidly recovering from other anthropogenic perturbations, especially organochlorine pesticides.

Noninvasive imaging of absolute PpIX concentration distribution in nonmelanoma skin tumors at pre-PDT

NASA Astrophysics Data System (ADS)

Sunar, Ulas; Rohrbach, Daniel; Morgan, Janet; Zeitouni, Natalie

2013-03-01

Photodynamic Therapy (PDT) has proven to be an effective treatment option for nonmelanoma skin cancers. The ability to quantify the concentration of drug in the treated area is crucial for effective treatment planning as well as predicting outcomes. We utilized spatial frequency domain imaging for quantifying the accurate concentration of protoporphyrin IX (PpIX) in phantoms and in vivo. We correct fluorescence against the effects of native tissue absorption and scattering parameters. First we quantified the absorption and scattering of the tissue non-invasively. Then, we corrected raw fluorescence signal by compensating for optical properties to get the absolute drug concentration. After phantom experiments, we used basal cell carcinoma (BCC) model in Gli mice to determine optical properties and drug concentration in vivo at pre-PDT.

Biomineralisation by earthworms - an investigation into the stability and distribution of amorphous calcium carbonate.

PubMed

Hodson, Mark E; Benning, Liane G; Demarchi, Bea; Penkman, Kirsty E H; Rodriguez-Blanco, Juan D; Schofield, Paul F; Versteegh, Emma A A

Many biominerals form from amorphous calcium carbonate (ACC), but this phase is highly unstable when synthesised in its pure form inorganically. Several species of earthworm secrete calcium carbonate granules which contain highly stable ACC. We analysed the milky fluid from which granules form and solid granules for amino acid (by liquid chromatography) and functional group (by Fourier transform infrared (FTIR) spectroscopy) compositions. Granule elemental composition was determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and electron microprobe analysis (EMPA). Mass of ACC present in solid granules was quantified using FTIR and compared to granule elemental and amino acid compositions. Bulk analysis of granules was of powdered bulk material. Spatially resolved analysis was of thin sections of granules using synchrotron-based μ-FTIR and EMPA electron microprobe analysis. The milky fluid from which granules form is amino acid-rich (≤ 136 ± 3 nmol mg -1 (n = 3; ± std dev) per individual amino acid); the CaCO 3 phase present is ACC. Even four years after production, granules contain ACC. No correlation exists between mass of ACC present and granule elemental composition. Granule amino acid concentrations correlate well with ACC content (r ≥ 0.7, p ≤ 0.05) consistent with a role for amino acids (or the proteins they make up) in ACC stabilisation. Intra-granule variation in ACC (RSD = 16%) and amino acid concentration (RSD = 22-35%) was high for granules produced by the same earthworm. Maps of ACC distribution produced using synchrotron-based μ-FTIR mapping of granule thin sections and the relative intensity of the ν 2 : ν 4 peak ratio, cluster analysis and component regression using ACC and calcite standards showed similar spatial distributions of likely ACC-rich and calcite-rich areas. We could not identify organic peaks in the μ-FTIR spectra and thus could not determine whether ACC-rich domains also had relatively high amino acid concentrations. No correlation exists between ACC distribution and elemental concentrations determined by EMPA. ACC present in earthworm CaCO 3 granules is highly stable. Our results suggest a role for amino acids (or proteins) in this stability. We see no evidence for stabilisation of ACC by incorporation of inorganic components. Graphical abstractSynchrotron-based μ-FTIR mapping was used to determine the spatial distribution of amorphous calcium carbonate in earthworm-produced CaCO 3 granules.

X-ray fluorescence microscopy reveals the role of selenium in spermatogenesis

PubMed Central

Kehr, Sebastian; Malinouski, Mikalai; Finney, Lydia; Vogt, Stefan; Labunskyy, Vyacheslav M.; Kasaikina, Marina V.; Carlson, Bradley A.; Zhou, You; Hatfield, Dolph L.; Gladyshev, Vadim N.

2009-01-01

Selenium (Se) is a trace element with important roles in human health. Several selenoproteins have essential functions in development. However, the cellular and tissue distribution of Se remains largely unknown because of the lack of analytical techniques that image this element with sufficient sensitivity and resolution. Herein, we report that X-ray fluorescence microscopy (XFM) can be used to visualize and quantify the tissue, cellular and subcellular topography of Se. We applied this technique to characterize the role of Se in spermatogenesis and identified a dramatic Se enrichment specifically in late spermatids, a pattern that was not seen in any other elemental maps. This enrichment was due to elevated levels of the mitochondrial form of glutathione peroxidase 4 and was fully dependent on the supplies of Se by Selenoprotein P. High-resolution scans revealed that Se concentrated near the lumen side of elongating spermatids, where structural components of sperm are formed. During spermatogenesis, maximal Se associated with decreased phosphorus, whereas Zn did not change. In sperm, Se was primarily in the midpiece and co-localized with Cu and Fe. XFM allowed quantification of Se in the midpiece (0.8 fg) and head (0.14 fg) of individual sperm cells, revealing the ability of sperm cells to handle the amounts of this element well above its toxic levels. Overall, the use of XFM allowed visualization of tissue and cellular Se and provided important insights in the role of this and other trace elements in spermatogenesis. PMID:19379757

Faults and foibles of quantitative scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDS)

NASA Astrophysics Data System (ADS)

Newbury, Dale E.; Ritchie, Nicholas W. M.

2012-06-01

Scanning electron microscopy with energy dispersive x-ray spectrometry (SEM/EDS) is a powerful and flexible elemental analysis method that can identify and quantify elements with atomic numbers > 4 (Be) present as major constituents (where the concentration C > 0.1 mass fraction, or 10 weight percent), minor (0.01<= C <= 0.1) and trace (C < 0.01, with a minimum detectable limit of ~+/- 0.0005 - 0.001 under routine measurement conditions, a level which is analyte and matrix dependent ). SEM/EDS can select specimen volumes with linear dimensions from ~ 500 nm to 5 μm depending on composition (masses ranging from ~ 10 pg to 100 pg) and can provide compositional maps that depict lateral elemental distributions. Despite the maturity of SEM/EDS, which has a history of more than 40 years, and the sophistication of modern analytical software, the method is vulnerable to serious shortcomings that can lead to incorrect elemental identifications and quantification errors that significantly exceed reasonable expectations. This paper will describe shortcomings in peak identification procedures, limitations on the accuracy of quantitative analysis due to specimen topography or failures in physical models for matrix corrections, and quantitative artifacts encountered in xray elemental mapping. Effective solutions to these problems are based on understanding the causes and then establishing appropriate measurement science protocols. NIST DTSA II and Lispix are open source analytical software available free at www.nist.gov that can aid the analyst in overcoming significant limitations to SEM/EDS.

Levels of selected metals in ambient air PM10 in an urban site of Zaragoza (Spain).

PubMed

López, J M; Callén, M S; Murillo, R; García, T; Navarro, M V; de la Cruz, M T; Mastral, A M

2005-09-01

An assessment of the air quality of Zaragoza (Spain) was performed by determining the trace element content in airborne PM10 in a sampling campaign from July 2001 to July 2002. Samples were collected in a heavy traffic area with a high volume air sampler provided with a PM10 cutoff inlet. The levels of 16 elements (Al, Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were quantified after collecting the PM10 on Teflon-coated glass fiber filters (GFF). Regarding the PM10, 32% exceedance of the proposed PM10 daily limit was obtained, some of them corresponding to summer and autumn periods. The limit values of toxic trace elements from US-EPA, WHO, and EC were not exceeded, considering Zaragoza as a moderately polluted city under the current air quality guidelines. The contribution of anthropogenic sources to atmospheric elemental levels was reflected by the high values of enrichment factors for Zn, Pb, and Cu compared to the average crustal composition. Statistical analyses also determined the contribution of different sources to the PM10, finding that vehicle traffic and anthropogenic emissions related to combustion and industrial processes were the main pollutant sources as well as natural sources associated with transport of dust from Africa for specific dates. Regarding the influence of meteorological conditions on PM10 and trace elements concentrations, it was found that calm weather conditions with low wind speed favor the PM10 collection and the pollution for trace elements, suggesting the influence of local sources.

Measurement of Trace Elements During the Development and Immune Response of Heliothis virescens Larvae

USDA-ARS?s Scientific Manuscript database

While many studies have examined the effect of microbial infections on the status of trace elements in mammalian tissues, similar studies have not been performed in insects. We used inductively coupled plasma-mass spectrometry (ICP-MS) to quantify changes in trace elements of Mg, Mn, Fe, Cu, Zn and ...

Impacts of sampling design and estimation methods on nutrient leaching of intensively monitored forest plots in the Netherlands.

PubMed

de Vries, W; Wieggers, H J J; Brus, D J

2010-08-05

Element fluxes through forest ecosystems are generally based on measurements of concentrations in soil solution at regular time intervals at plot locations sampled in a regular grid. Here we present spatially averaged annual element leaching fluxes in three Dutch forest monitoring plots using a new sampling strategy in which both sampling locations and sampling times are selected by probability sampling. Locations were selected by stratified random sampling with compact geographical blocks of equal surface area as strata. In each sampling round, six composite soil solution samples were collected, consisting of five aliquots, one per stratum. The plot-mean concentration was estimated by linear regression, so that the bias due to one or more strata being not represented in the composite samples is eliminated. The sampling times were selected in such a way that the cumulative precipitation surplus of the time interval between two consecutive sampling times was constant, using an estimated precipitation surplus averaged over the past 30 years. The spatially averaged annual leaching flux was estimated by using the modeled daily water flux as an ancillary variable. An important advantage of the new method is that the uncertainty in the estimated annual leaching fluxes due to spatial and temporal variation and resulting sampling errors can be quantified. Results of this new method were compared with the reference approach in which daily leaching fluxes were calculated by multiplying daily interpolated element concentrations with daily water fluxes and then aggregated to a year. Results show that the annual fluxes calculated with the reference method for the period 2003-2005, including all plots, elements and depths, lies only in 53% of the cases within the range of the average +/-2 times the standard error of the new method. Despite the differences in results, both methods indicate comparable N retention and strong Al mobilization in all plots, with Al leaching being nearly equal to the leaching of SO(4) and NO(3) with fluxes expressed in mol(c) ha(-1) yr(-1). This illustrates that Al release, which is the clearest signal of soil acidification, is mainly due to the external input of SO(4) and NO(3).

Near-road enhancement and solubility of fine and coarse ...

EPA Pesticide Factsheets

Communities near major roadways are disproportionately affected by traffic-related air pollution which can contribute to adverse health outcomes. The specific role of particulate matter (PM) from traffic sources is not fully understood due to complex emissions processes and physical/chemical properties of PM in the near-road environment. To investigate the spatial profile and water solubility of elemental PM species near a major roadway, filter-based measurements of fine (PM2.5) and coarse (PM10-2.5) PM were simultaneously collected at multiple distances (10 m, 100 m, and 300 m) from Interstate I-96 in Detroit, Michigan during September–November 2010. Filters were extracted in water, followed by a hot acid extraction, and analyzed by magnetic sector field high resolution inductively coupled plasma mass spectrometry (HR-ICPMS) to quantify water-soluble and acid-soluble trace elements for each PM size fraction. PM2.5 and PM10-2.5 species measured in the near-road samples included elements associated with traffic activity, local industrial sources, and regional pollution. Metals indicative of brake wear (Ba, Cu) were dramatically enriched near the roadway during downwind conditions (factor of 5 concentration increase), with the largest increase within 100 m of the roadway. Moderate near-roadway increases were observed for crustal elements and other traffic-related PM (Fe, Ca), and the lowest increases observed for regional PM species (S). Water solubility varied

Elemental Gains/Losses Associated with Alteration Fractures in an Eolian Sandstone, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Ming, D. W.; Yen, A. S.; Gellert, R.; Sutter, B.; Berger, J. A.; Thompson, L. M.; Schmidt, M. E.; Morris, R. V.; Treiman, A. H.

2016-01-01

The Mars Science Laboratory rover Curiosity has traversed up section through approximately 100 m of sedimentary rocks deposited in fluvial, deltaic, lacustrine, and eolian environments (Bradbury group and overlying Mount Sharp group). The Stimson formation unconformably overlies a lacustrine mudstone at the base of the Mount Sharp group and has been interpreted to be a cross-bedded sandstone of lithified eolian dunes. Unaltered Stimson sandstone has a basaltic composition similar to the average Mars crustal composition, but is more variable and ranges to lower K and higher Al. Fluids passing through alteration "halos" adjacent to fractures have altered the chemistry and mineralogy of the sandstone. Elemental mass gains and losses in the alteration halos were quantified using immobile element concentrations, i.e., Ti (taus). Alteration halos have elemental gains in Si, Ca, S, and P and large losses in Al, Fe, Mn, Mg, Na, K, Ni, and Zn. Mineralogy of the altered Stimson is dominated by Ca-sulfates, Si-rich X-ray amorphous materials along with plagioclase feldspar, magnetite, and pyroxenes. The igneous phases were less abundant in the altered sandstone with a lower pyroxene/plagioclase feldspar. Large elemental losses suggest acidic fluids initially removed these elements (Al mobile under acid conditions). Enrichments in Si, Ca, and S suggest secondary fluids (possibly alkaline) passed through these fractures leaving behind X-ray amorphous Si and Ca-sulfates. The mechanism for the large elemental gains in P is unclear. The geochemistry and mineralogy of the altered sandstone suggests a complicated diagenetic history with multiple episodes of aqueous alteration under a variety of environmental conditions (e.g., acidic, alkaline).

Anthropogenic disturbance of element cycles at the Earth's surface.

PubMed

Sen, Indra S; Peucker-Ehrenbrink, Bernhard

2012-08-21

The extent to which humans are modifying Earth's surface chemistry can be quantified by comparing total anthropogenic element fluxes with their natural counterparts (Klee and Graedel, 2004). We quantify anthropogenic mass transfer of 77 elements from mining, fossil fuel burning, biomass burning, construction activities, and human apportionment of terrestrial net primary productivity, and compare it to natural mass transfer from terrestrial and marine net primary productivity, riverine dissolved and suspended matter fluxes to the ocean, soil erosion, eolian dust, sea-salt spray, cosmic dust, volcanic emissions, and for helium, hydrodynamic escape from the Earth's atmosphere. We introduce an approach to correct for losses during industrial processing of elements belonging to geochemically coherent groups, and explicitly incorporate uncertainties of element mass fluxes through Monte Carlo simulations. We find that at the Earth's surface anthropogenic fluxes of iridium, osmium, helium, gold, ruthenium, antimony, platinum, palladium, rhenium, rhodium and chromium currently exceed natural fluxes. For these elements mining is the major factor of anthropogenic influence, whereas petroleum burning strongly influences the surficial cycle of rhenium. Our assessment indicates that if anthropogenic contributions to soil erosion and eolian dust are considered, anthropogenic fluxes of up to 62 elements surpass their corresponding natural fluxes.

Identification of specific sources of airborne particles emitted from within a complex industrial (steelworks) site

NASA Astrophysics Data System (ADS)

Beddows, D. C. S.; Harrison, Roy M.

2018-06-01

A case study is provided of the development and application of methods to identify and quantify specific sources of emissions from within a large complex industrial site. Methods include directional analysis of concentrations, chemical source tracers and correlations with gaseous emissions. Extensive measurements of PM10, PM2.5, trace gases, particulate elements and single particle mass spectra were made at sites around the Port Talbot steelworks in 2012. By using wind direction data in conjunction with real-time or hourly-average pollutant concentration measurements, it has been possible to locate areas within the steelworks associated with enhanced pollutant emissions. Directional analysis highlights the Slag Handling area of the works as the most substantial source of elevated PM10 concentrations during the measurement period. Chemical analyses of air sampled from relevant wind directions is consistent with the anticipated composition of slags, as are single particle mass spectra. Elevated concentrations of PM10 are related to inverse distance from the Slag Handling area, and concentrations increase with increased wind speed, consistent with a wind-driven resuspension source. There also appears to be a lesser source associated with Sinter Plant emissions affecting PM10 concentrations at the Fire Station monitoring site. The results are compared with a ME2 study using some of the same data, and shown to give a clearer view of the location and characteristics of emission sources, including fugitive dusts.

Fluid-related inclusions in Alpine high-pressure peridotite reveal trace element recycling during subduction-zone dehydration of serpentinized mantle (Cima di Gagnone, Swiss Alps)

NASA Astrophysics Data System (ADS)

Scambelluri, Marco; Pettke, Thomas; Cannaò, Enrico

2015-11-01

Serpentinites release at sub-arc depths volatiles and several fluid-mobile trace elements found in arc magmas. Constraining element uptake in these rocks and defining the trace element composition of fluids released upon serpentinite dehydration can improve our understanding of mass transfer across subduction zones and to volcanic arcs. The eclogite-facies garnet metaperidotite and chlorite harzburgite bodies embedded in paragneiss of the subduction melange from Cima di Gagnone derive from serpentinized peridotite protoliths and are unique examples of ultramafic rocks that experienced subduction metasomatism and devolatilization. In these rocks, metamorphic olivine and garnet trap polyphase inclusions representing the fluid released during high-pressure breakdown of antigorite and chlorite. Combining major element mapping and laser-ablation ICP-MS bulk inclusion analysis, we characterize the mineral content of polyphase inclusions and quantify the fluid composition. Silicates, Cl-bearing phases, sulphides, carbonates, and oxides document post-entrapment mineral growth in the inclusions starting immediately after fluid entrapment. Compositional data reveal the presence of two different fluid types. The first (type A) records a fluid prominently enriched in fluid-mobile elements, with Cl, Cs, Pb, As, Sb concentrations up to 103 PM (primitive mantle), ∼102 PM Tl, Ba, while Rb, B, Sr, Li, U concentrations are of the order of 101 PM, and alkalis are ∼2 PM. The second fluid (type B) has considerably lower fluid-mobile element enrichments, but its enrichment patterns are comparable to type A fluid. Our data reveal multistage fluid uptake in these peridotite bodies, including selective element enrichment during seafloor alteration, followed by fluid-rock interaction along with subduction metamorphism in the plate interface melange. Here, infiltration of sediment-equilibrated fluid produced significant enrichment of the serpentinites in As, Sb, B, Pb, an enriched trace element pattern that was then transferred to the fluid released at greater depth upon serpentine dehydration (type A fluid). The type B fluid hosted by garnet may record the composition of the chlorite breakdown fluid released at even greater depth. The Gagnone study-case demonstrates that serpentinized peridotites acquire water and fluid-mobile elements during ocean floor hydration and through exchange with sediment-equilibrated fluids in the early subduction stages. Subsequent antigorite devolatilization at subarc depths delivers aqueous fluids to the mantle wedge that can be prominently enriched in sediment-derived components, potentially triggering arc magmatism without the need of concomitant dehydration/melting of metasediments or altered oceanic crust.

Measurement of Rare Earth and Uranium Elements Using Laser-Induced Breakdown Spectroscopy (LIBS) in an Aerosol System for Nuclear Safeguards Applications

NASA Astrophysics Data System (ADS)

Williams, Ammon Ned

The primary objective of this research is to develop an applied technology and provide an assessment for remotely measuring and analyzing the real time or near real time concentrations of used nuclear fuel (UNF) elements in electroreners (ER). Here, Laser-Induced Breakdown Spectroscopy (LIBS) in UNF pyroprocessing facilities was investigated. LIBS is an elemental analysis method, which is based on the emission from plasma generated by focusing a laser beam into the medium. This technology has been reported to be applicable in solids, liquids (includes molten metals), and gases for detecting elements of special nuclear materials. The advantages of applying the technology for pyroprocessing facilities are: (i) Rapid real-time elemental analysis; (ii) Direct detection of elements and impurities in the system with low limits of detection (LOD); and (iii) Little to no sample preparation is required. One important challenge to overcome is achieving reproducible spectral data over time while being able to accurately quantify fission products, rare earth elements, and actinides in the molten salt. Another important challenge is related to the accessibility of molten salt, which is heated in a heavily insulated, remotely operated furnace in a high radiation environment within an argon gas atmosphere. This dissertation aims to address these challenges and approaches in the following phases with their highlighted outcomes: 1. Aerosol-LIBS system design and aqueous testing: An aerosol-LIBS system was designed around a Collison nebulizer and tested using deionized water with Ce, Gd, and Nd concentrations from 100 ppm to 10,000 ppm. The average %RSD values between the sample repetitions were 4.4% and 3.8% for the Ce and Gd lines, respectively. The univariate calibration curve for Ce using the peak intensities of the Ce 418.660 nm line was recommended and had an R 2 value, LOD, and RMSECV of 0.994, 189 ppm, and 390 ppm, respectively. The recommended Gd calibration curve was generated using the peak areas of the Gd 409.861 nm line and had an R2, LOD, and RMSECV of 0.992, 316 ppm, and 421 ppm, respectively. The partial least squares (PLS) calibration curves yielded similar results with RMSECV of 406 ppm and 417 ppm for the Ce and Gd curves, respectively. 2. High temperature aerosol-LIBS system design and CeCl3 testing: The aerosol-LIBS system was transitioned to a high temperature and used to measure Ce in molten LiCl-KCl salt within a glovebox environment. The concentration range studied was from 0.1 wt% to 5 wt% Ce. Normalization was necessary due to signal degradation over time; however, with the normalization the %RSD values averaged 5% for the mid and upper concentrations studied. The best univariate calibration curve was generated using the peak areas of the Ce 418.660 nm line. The LOD for this line was 148 ppm with the RMSECV of 647 ppm. The PLS calibration curve was made using 7 latent variables (LV) and resulting in the RMSECV of 622 ppm. The LOD value was below the expected rare earth concentration within the ER. 3. Aerosol-LIBS testing using UCl3: Samples containing UCl 3 with concentrations ranging from 0.3 wt% to 5 wt% were measured. The spectral response in this range was linear. The best univariate calibration curves were generated using the peak areas of the U 367.01 nm line and had an R2 value of 0.9917. Here, the LOD was 647 ppm and the RMSECV was 2,290 ppm. The PLS model was substantially better with a RMSECV of 1,110 ppm. The LOD found here is below the expected U concentrations in the ER. The successful completion of this study has demonstrated the feasibility of using an aerosol-LIBS analytical technique to measure rare earth elements and actinides in the pyroprocessing salt.

Major and trace element geochemistry and background concentrations for soils in Connecticut

USGS Publications Warehouse

Brown, Craig; Thomas, Margaret A.

2014-01-01

Soil samples were collected throughout Connecticut (CT) to determine the relationship of soil chemistry with the underlying geology and to better understand background concentrations of major and trace elements in soils. Soil samples were collected (1) from the upper 5 cm of surficial soil at 100 sites, (2) from the A horizon at 86 of these sites, and (3) from the deeper horizon, typically the C horizon, at 79 of these sites. The <2-millimeter fraction of each sample was analyzed for 44 elements by methods that yield the total or near-total elemental content. Sample sites were characterized by glacial setting, underlying bedrock geology, and soil type. These spatial data were used with element concentrations in the C-horizon to relate geologic factors to soil chemistry. Concentrations of elements in C-horizon soils varied with grain size in surficial glacial materials and with underlying rock types, as determined using nonparametric statistical procedures. Concentrations of most elements in C-horizon soils showed a positive correlation with silt and (or) clay content and were higher in surficial materials mapped as till, thick till, and (or) fines. Element concentrations in C-horizon soils showed significant differences among the underlying geologic provinces and were highest overlying the Grenville Belt and (or) the Grenville Shelf Sequence Provinces in western CT. These rocks consist mainly of carbonates and the relatively high element concentrations in overlying soils likely result from less influence of dilution by quartz compared to other provinces. Element concentrations in C-horizon soils in CT were compared with those in samples from other New England states overlying similar lithologic bedrock types. The upper range of As concentrations in C-horizon soils overlying the New Hampshire-Maine (NH-ME) Sequence in CT was 15 mg/kg, lower than the upper range of 24 mg/kg in C-horizon soils overlying the same sequence in ME. In CT, U concentration means were significantly higher in C-horizon soils overlying Avalonian granites, and U concentrations ranged as high as 14 mg/kg, compared to those in C-horizon soil samples collected from other New England states, which ranged as high as 6.1 mg/kg in a sample in NH overlying the NH-ME Sequence. Element concentrations in C-horizon soils in CT were compared with those in samples collected from shallower depths. Concentrations of most major elements were highest in C-horizon soil samples, including Al, Ca, Fe, K, Na, and Ti, but element concentrations showed a relatively similar pattern in A-horizon and surficial soil samples among the underlying geologic provinces. Trace element concentrations, including Ba, W, Ga, Ni, Cs, Rb, Sr, Th, Sc, and U, also were higher in C-horizon soil samples than in overlying soil samples. Concentrations of Mg, and several trace elements, including Mn, P, As, Nb, Sn, Be, Bi, Hg, Se, Sb, La, Co, Cr, Pb, V, Y, Cu, Pb, and Zn were highest in some A-horizon or surficial soils, and indicate possible contributions from anthropogenic sources. Because element concentrations in soils above the C horizon are more likely to be affected by anthropogenic factors, concentration ranges in C-horizon soils and their spatially varying geologic associations should be considered when estimating background concentrations of elements in CT soils.

Estimation of Throughfall and Stemflow Bacterial Flux in a Subtropical Oak-Cedar Forest

NASA Astrophysics Data System (ADS)

Bittar, Thais B.; Pound, Preston; Whitetree, Ansley; Moore, L. Dean; Van Stan, John T.

2018-02-01

Transport pathways of microbes between ecosystem spheres (atmosphere, phyllosphere, and pedosphere) represent major fluxes in nutrient cycles and have the potential to affect microbially mediated biogeochemical processes. Novel data on bacterial fluxes from the phyllosphere to the pedosphere during rainfall via throughfall (rain dripping from/through the canopy) and stemflow (rain funneled down tree stems) are reported. Bacterial concentrations were quantified using flow cytometry and validated with quantitative polymerase chain reaction assays in rainfall samples from an oak-cedar forest in coastal Georgia (southeastern U.S.). Bacteria concentrations (cells mL-1) and storm-normalized fluxes (cells m-2 h-1, cells m-2 mm-1) were greater for cedar versus oak. Total bacterial flux was 1.5 × 1016 cells ha-1 yr-1. These previously unexamined bacterial fluxes are interpreted in the context of major elemental pools and fluxes in forests and could represent inoculum-level sources of bacteria (if alive), and organic matter and inorganic solute inputs (if lysed) to soils.

Ubiquity of microplastics in coastal seafloor sediments.

PubMed

Ling, S D; Sinclair, M; Levi, C J; Reeves, S E; Edgar, G J

2017-08-15

Microplastic pollutants occur in marine environments globally, however estimates of seafloor concentrations are rare. Here we apply a novel method to quantify size-graded (0.038-4.0mm diam.) concentrations of plastics in marine sediments from 42 coastal and estuarine sites spanning pollution gradients across south-eastern Australia. Acid digestion/density separation revealed 9552 individual microplastics from 2.84l of sediment across all samples; equating to a regional average of 3.4 microplastics·ml -1 sediment. Microplastics occurred as filaments (84% of total) and particle forms (16% of total). Positive correlations between microplastic filaments and wave exposure, and microplastic particles with finer sediments, indicate hydrological/sediment-matrix properties are important for deposition/retention. Contrary to expectations, positive relationships were not evident between microplastics and other pollutants (heavy metals/sewage), nor were negative relationships with neighbouring reef biota detected. Rather, microplastics were ubiquitous across sampling sites. Positive associations with some faunal-elements (i.e. invertebrate species richness) nevertheless suggest high potential for microplastic ingestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laser-induced breakdown spectroscopy (LIBS) for rapid analysis of ash, potassium and magnesium in gluten free flours.

PubMed

Markiewicz-Keszycka, Maria; Casado-Gavalda, Maria P; Cama-Moncunill, Xavier; Cama-Moncunill, Raquel; Dixit, Yash; Cullen, Patrick J; Sullivan, Carl

2018-04-01

Gluten free (GF) diets are prone to mineral deficiency, thus effective monitoring of the elemental composition of GF products is important to ensure a balanced micronutrient diet. The objective of this study was to test the potential of laser-induced breakdown spectroscopy (LIBS) analysis combined with chemometrics for at-line monitoring of ash, potassium and magnesium content of GF flours: tapioca, potato, maize, buckwheat, brown rice and a GF flour mixture. Concentrations of ash, potassium and magnesium were determined with reference methods and LIBS. PCA analysis was performed and presented the potential for discrimination of the six GF flours. For the quantification analysis PLSR models were developed; R 2 cal were 0.99 for magnesium and potassium and 0.97 for ash. The study revealed that LIBS combined with chemometrics is a convenient method to quantify concentrations of ash, potassium and magnesium and present the potential to classify different types of flours. Copyright © 2017 Elsevier Ltd. All rights reserved.

Particulate matters collected from ceramic factories in Lampang Province affecting rat lungs.

PubMed

Fongmoon, Duriya; Pongnikorn, Surathat; Chaisena, Aphiruk; Iamsaard, Sitthichai

2014-01-01

Lung cancer ranks as the fifth largest of all cancer cases in Thailand. However, it is the first leading cancer in the northern part of Thailand (data from 2003-2007). There are several predisposing causes that lead to lung cancer and one important inducement is particulate matters (PMs). Lampang Province in Thailand is famous for the ceramic industry, where there are over 200 ceramic industrial factories. PMs are produced during the ceramic manufacturing process and spread throughout all of the working areas. It is very possible that workers could directly inhale PM-contaminated air during working hours. This study focuses on the toxic effects of PMs collected from ceramic factories on genes and lungs of rats. PMs collected from six ceramic factories in Lampang Province were extracted using dimethyl sulfoxide (DMSO). The inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to analyze the chemical elements at lower and higher concentrations, respectively. Then, the toxicity of PMs on the genes was examined by the Ames test, and subsequently, the effect of PMs on DNA was examined by quantifying the amount of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Finally, the toxicity of the PMs on rat's lungs was examined by histology. As chemical elements of lower concentrations, cadmium, chromium, nickel, copper, and lead were detected by ICP-MS. As chemical elements of higher concentrations, manganese, magnesium, zinc, iron, potassium, calcium, and sodium were detected by ICP-OES. No mutagenicity in Salmonella typhimurium was found in the PM extracts from all six factories by utilizing the Ames test. In the histological study, the reduction in spaces of alveolar ducts and sacs, and terminal bronchioles, the thickening of interstitial connective tissues were noted by PM extracts in high amounts (100 and 350 µg). Female rats were more sensitive to PM extracts than males in terms of their pulmonary damages. PMs were not mutagenic to S. typhimurium but can damage the lung tissue of rats.

Unified framework for information integration based on information geometry

PubMed Central

Oizumi, Masafumi; Amari, Shun-ichi

2016-01-01

Assessment of causal influences is a ubiquitous and important subject across diverse research fields. Drawn from consciousness studies, integrated information is a measure that defines integration as the degree of causal influences among elements. Whereas pairwise causal influences between elements can be quantified with existing methods, quantifying multiple influences among many elements poses two major mathematical difficulties. First, overestimation occurs due to interdependence among influences if each influence is separately quantified in a part-based manner and then simply summed over. Second, it is difficult to isolate causal influences while avoiding noncausal confounding influences. To resolve these difficulties, we propose a theoretical framework based on information geometry for the quantification of multiple causal influences with a holistic approach. We derive a measure of integrated information, which is geometrically interpreted as the divergence between the actual probability distribution of a system and an approximated probability distribution where causal influences among elements are statistically disconnected. This framework provides intuitive geometric interpretations harmonizing various information theoretic measures in a unified manner, including mutual information, transfer entropy, stochastic interaction, and integrated information, each of which is characterized by how causal influences are disconnected. In addition to the mathematical assessment of consciousness, our framework should help to analyze causal relationships in complex systems in a complete and hierarchical manner. PMID:27930289

[Exposure to metals in dental laboratories].

PubMed

Apostoli, P; Ferioli, A; Crippa, M; Redaelli, P; Braga Marcazzan, G; Alessio, L

1988-11-01

Dental care includes handling of different types of metal alloys usually classified as "noble" and "base" in relation to the presence or absence of either gold or other precious metals. It must be born in mind that exposure to metals in this activities is due not only to those metals present in the alloys but also to those contained in the other materials used during the processes of casting and finishing. The most important metals are the following: Al, Be, Cd, Cr, Co, Cu, Au, In, Hg, Mo, Ni, Pd, Pt, Si, Ag, Sn, Ti, W, Zn. In this paper we investigated the environmental exposure to metals in dental laboratories studying the environmental air concentration of metals in casting and finishing processes estimating the "quality" of the elements present by Particle Induces X-ray Emission (PIXE) and the "quantity" of the elements by electro thermic atomic absorption spectrophotometry (ET-AAS) and the concentration of the main metals in the blood and in the urine of exposed technicians by ET-AAS. These analyses permitted to detect all the metals present in the work environment and to quantify their concentration, which always resulted to be low (except some metals during short time operations). The biological monitoring revealed the existence of moderate absorption of these metals in the exposed workers but it is not possible for us to affirm if this phenomenon represents a real risk for the health of the technicians. Hence further epidemiological and health surveillance investigations are needed to verify morbidity and mortality of the subjects employed in this activity.

Concentrations of selected trace elements in fish tissue and streambed sediment in the Clark Fork-Pend Oreille and Spokane River basins, Washington, Idaho, and Montana, 1998

USGS Publications Warehouse

Maret, Terry R.; Skinner, K.D.

2000-01-01

Fish tissue and bed sediment samples were collected from 16 stream sites in the Northern Rockies Intermontane Basins study area in 1998 as part of the U.S. Geological Survey National Water-Quality Assessment Program. Bed sediment samples were analyzed for 45 trace elements, and fish livers and sportfish fillets were analyzed for 22 elements to characterize the occurrence and distribution of these elements in relation to stream characteristics and land use activities. Nine trace elements of environmental concern—arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc—were detected in bed sediment, but not all of these elements were detected in fish tissue. Trace-element concentrations were highest in bed sediment samples collected at sites downstream from significant natural mineral deposits and (or) mining activities. Arsenic, cadmium, copper, lead, mercury, and zinc in bed sediment at some sites were elevated relative to national median concentrations, and some concentrations were at levels that can adversely affect aquatic biota. Although trace-element concentrations in bed sediment exceeded various guidelines, no concentrations in sportfish fillets exceeded U.S. Environmental Protection Agency screening values for the protection of human health. Correlations between most trace-element concentrations in bed sediment and fish tissue (liver and fillet) were not significant (r0.05). Concentrations of arsenic, cadmium, copper, lead, mercury, nickel, selenium, and zinc in bed sediment were significantly correlated (r=0.53 to 0.88, p2=0.95 and 0.99, p<0.001) that corresponded to trace-element enrichment categories. These strong relations warrant further study using mine density as an explanatory variable to predict trace-element concentrations in bed sediment.

Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana

USGS Publications Warehouse

Rusk, B.G.; Reed, M.H.; Dilles, J.H.; Kent, A.J.R.

2006-01-01

Textures of hydrothermal quartz revealed by cathodoluminescence using a scanning electron microscope (SEM-CL) reflect the physical and chemical environment of quartz formation. Variations in intensity of SEM-CL can be used to distinguish among quartz from superimposed mineralization events in a single vein. In this study, we present a technique to quantify the cathodoluminescent intensity of quartz within individual and among multiple samples to relate luminescence intensity to specific mineralizing events. This technique has been applied to plutonic quartz and three generations of hydrothermal veins at the porphyry copper deposit in Butte, Montana. Analyzed veins include early quartz-molybdenite veins with potassic alteration, pyrite-quartz veins with sericitic alteration, and Main Stage veins with intense sericitic alteration. CL intensity of quartz is diagnostic of each mineralizing event and can be used to fingerprint quartz and its fluid inclusions, isotopes, trace elements, etc., from specific mineralizing episodes. Furthermore, CL intensity increases proportional to temperature of quartz formation, such that plutonic quartz from the Butte quartz monzonite (BQM) that crystallized at temperatures near 750 ??C luminesces with the highest intensity, whereas quartz that precipitated at ???250 ??C in Main Stage veins luminesces with the least intensity. Trace-element analyses via electron microprobe and laser ablation-ICP-MS indicate that plutonic quartz and each generation of hydrothermal quartz from Butte is dominated by characteristic trace amounts of Al, P, Ti, and Fe. Thus, in addition to CL intensity, each generation of quartz can be distinguished based on its unique trace-element content. Aluminum is generally the most abundant element in all generations of quartz, typically between 50 and 200 ppm, but low-temperature, Main Stage quartz containing 400 to 3600 ppm Al is enriched by an order of magnitude relative to all other quartz generations. Phosphorous is present in abundances between 25 and 75 ppm, and P concentrations in quartz show little variation among quartz generations. Iron is the least abundant of these elements in most quartz types and is slightly enriched in CL-dark quartz in pyrite-quartz veins with sericitic alteration. Titanium is directly correlated with both temperature of quartz precipitation, and intensity of quartz luminescence, such that BQM quartz contains hundreds of ppm Ti, whereas Main Stage quartz contains less than 10 ppm Ti. Our results suggest that Ti concentration in quartz is controlled by temperature of quartz precipitation and that increased Ti concentrations in quartz may be responsible for increased CL intensities.

Potentially toxic trace element contamination, sources, and pollution assessment in farmlands, Bijie City, southwestern China.

PubMed

Yuan, Zhimin; Yao, Jun; Wang, Fei; Guo, Zunwei; Dong, Zeqin; Chen, Feng; Hu, Yu; Sunahara, Geoffrey

2017-01-01

Artisanal zinc smelting activities, which had been widely applied in Bijie City, Guizhou Province, southwestern of China, can pollute surrounding farmlands. In the present study, 177 farmland topsoil samples of Bijie City were collected and 11 potentially toxic trace elements (PTEs), namely Pb, Zn, Cu, Ni, Co, Mn, Cr, V, Hg, As, and Cd were tested to characterize the concentrations, sources, and ecological risks. Mean concentrations of these PTEs in soils were (mg/kg) as follows: Pb (127), Zn (379), Cu (93.1), Ni (54.6), Co (26.2), Mn (1095), Cr (133), V (206), Hg (0.15), As (16.2), and Cd (3.08). Pb, Zn, and Cd had coefficients of variation greater than 100% and showed a high uneven distribution and spatial variability in the study area. Correlation coefficient analysis and principal component analysis (PCA) were used to quantify potential pollution sources. Results showed that Cu, Ni, Co, Mn, and V came from natural sources, whereas Pb, Zn, Hg, As, and Cd came from anthropogenic pollution sources. Geoaccumulation index and potential ecological risk indices were employed to study the pollution degree of PTEs, which revealed that Pb and Cd shared the greatest contamination and would pose serious ecological risks to the surrounding environment. The results of this study could help the local government managers to establish pollution control strategies and to secure food safety.

Abnormal chemical element concentrations in lichens of Isle Royale National Park

USGS Publications Warehouse

Bennett, J.P.

1995-01-01

Lichens have been used for many years to monitor changes in deposited airborne chemical elements in many areas, but few studies have focused on areas suspected of experiencing slightly elevated pollution. Detection of subtle patterns of slightly elevated pollutants calls for developing several lines of evidence as opposed to single line studies used in heavily polluted areas. This study of two lichen species, Hypogymnia physodes and Evernia mesomorpha, in Isle Royale National Park, Michigan compares the concentrations and ranks of elements with the concentrations and ranks of the elements in the earth's crust, changes in element concentrations over a nine year period, and the geography of element concentrations in the park. S, Zn, Pb, Cd and Se were elevated in both species and higher in rank compared to the concentrations and ranks in the earth's crust. Toxic elements increased 123% in Hypogymnia and 62% in Evernia over 9 years, compared to increases of 45% and 59% for non-toxic elements in each species, respectively. Geographically, the lichens at certain localities with higher exposures experienced higher than average element concentrations. Finally, tissue concentrations of Mn, S and Se at some localities were above levels known to be either toxic or similar to those found in polluted areas. These four lines of evidence suggest that Isle Royale National Park is experiencing the onset of chronic air pollution stress from a number of sources.

Behavior of the main sources that contribute to ambient PM2.5 in Santiago since 1998

NASA Astrophysics Data System (ADS)

Barraza, F.; Lambert, F.; Jorquera, H.; Villalobos, A. M.; Gallardo, L.

2016-12-01

Santiago's inhabitants have been exposed to high concentrations of fine particle matter (PM2.5) for decades. To contribute to a solution for this long-standing problem it is necessary to clearly identify and quantify the agents that contribute to ambient levels of PM2.5. We present an analysis of a long historical elemental concentrations database measured in air filter particles taken in central Santiago from April 1998 to August 2012 (1243 daily samples). We identify and quantify the main sources that contribute to PM2.5 levels using the source-receptor models PMF 5.0 and UNMIX 6.0. . The 6 main sources that contribute to outdoor PM2.5 levels were: vehicles (13.26±0.42 µg/m3), industrial sulfates (6.60±0.0.47 µg/m3), copper smelters (5.12±0.29 µg/m3), residential wood burning (4.38±0.36 µg/m3), marine aerosols (3.39±0.24 µg/m3), and urban dust (1.07±0.42 µg/m3). The unexplained fraction amounts to 1.76±0.90 µg/m3). The similar results obtained with both receptor models suggest a robust estimation of the main Santiago PM2.5 source apportionment. The analysis of the time series of these sources shows that their absolute contribution to PM2.5 levels has been decreasing during the last decade (except for urban dust which is increasing), and shows the effectiveness of government emission reduction policies. However, these improvements have not been sufficient to reduce PM2.5 concentrations to daily levels below the Chilean standard of 50 µg/m3, let alone the WHO standard of 25 µg/m3.

Investigation of element distributions in Luna-16 regolith

NASA Astrophysics Data System (ADS)

Kuznetsov, R. A.; Lure, B. G.; Minevich, V. Ia.; Stiuf, V. I.; Pankratov, V. B.

1981-03-01

The concentrations of 32 elements in fractions of different grain sizes in the samples of the lunar regolith brought back by Luna-16 are determined by means of neutron activation analysis. Four groups of elements are distinguished on the basis of the variations of their concentration with grain size, and concentration variations of the various elements with sample depth are also noted. Chemical leaching of the samples combined with neutron activation also reveals differences in element concentrations in the water soluble, metallic, sulphide, phosphate, rare mineral and rock phases of the samples. In particular, the rare earth elements are observed to be depleted in the regolith with respect to chondritic values, and to be concentrated in the phase extracted with 14 M HNO3.

Grain-size distribution and selected major and trace element concentrations in bed-sediment cores from the Lower Granite Reservoir and Snake and Clearwater Rivers, eastern Washington and northern Idaho, 2010

USGS Publications Warehouse

Braun, Christopher L.; Wilson, Jennifer T.; Van Metre, Peter C.; Weakland, Rhonda J.; Fosness, Ryan L.; Williams, Marshall L.

2012-01-01

Fifty subsamples from 15 cores were analyzed for major and trace elements. Concentrations of trace elements were low, with respect to sediment quality guidelines, in most cores. Typically, major and trace element concentrations were lower in the subsamples collected from the Snake River compared to those collected from the Clearwater River, the confluence of the Snake and Clearwater Rivers, and Lower Granite Reservoir. Generally, lower concentrations of major and trace elements were associated with coarser sediments (larger than 0.0625 millimeter) and higher concentrations of major and trace elements were associated with finer sediments (smaller than 0.0625 millimeter).

Frozen Scope and Grammatical Optimization

ERIC Educational Resources Information Center

Freedman, Michael

2014-01-01

The literature on quantifier scope has repeatedly observed that some otherwise expected permutations of scope taking elements are unavailable. Various methods have been proffered explaining these facts. This thesis aims to unify three disparate areas where the scope of operators seems to be frozen: the interaction of universal quantifiers with…

Cytotoxic, phytotoxic, and mutagenic appraisal to ascertain toxicological potential of particulate matter emitted from automobiles.

PubMed

Anwar, Khaleeq; Ejaz, Sohail; Ashraf, Muhammad; Altaf, Imran; Anjum, Aftab Ahmad

2013-07-01

Vehicular air pollution is a mounting health issue of the modern age, particularly in urban populations of the developing nations. Auto-rickshaws are not considered eco-friendly as to their inefficient engines producing large amount of particulate matter (PM), thus posing significant environmental threat. The present study was conducted to ascertain the cytotoxic, phytotoxic, and mutagenic potential of PM from gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas-powered four-stroke auto-rickshaws (FSA). Based on the increased amount of aluminum quantified during proton-induced X-ray emission analysis of PM from TSA and FSA, different concentrations of aluminum sulfate were also tested to determine its eco-toxicological potential. The MTT assay demonstrated significant (p < 0.001) dose-dependent cytotoxic effects of different concentrations of TSA, FSA, and aluminum sulfate on BHK-21 cell line. LC50 of TSA, FSA, and aluminum sulfate was quantified at 16, 11, and 23.8 μg/ml, respectively, establishing PM from FSA, a highly cytotoxic material. In case of phytotoxicity screening using Zea mays, the results demonstrated that all three tested materials were equally phytotoxic at higher concentrations producing significant reduction (p < 0.001) in seed germination. Aluminum sulfate proved to be a highly phytotoxic agent even at its lowest concentration. Mutagenicity was assessed by fluctuation Salmonella reverse mutation assay adopting TA100 and TA98 mutant strains with (+S9) and without (-S9) metabolic activation. Despite the fact that different concentrations of PM from both sources, i.e., TSA and FSA were highly mutagenic (p < 0.001) even at lower concentrations, the mutagenic index was higher in TSA. Data advocate that all tested materials are equally ecotoxic, and if the existing trend of atmospheric pollution by auto-rickshaws is continued, airborne heavy metals will seriously affect the normal growth of local inhabitants and increased contamination of agricultural products, which will amplify the dietary intake of the toxic elements and could result in genetic mutation or long-term health implications.

Nicotine Concentrations in Electronic Cigarette Refill and Do-It-Yourself Fluids

PubMed Central

Davis, Barbara; Dang, Michael; Kim, Jisoo

2015-01-01

Introduction: We evaluated the accuracy of nicotine concentration labeling on electronic cigarette refill products. Methods: The nicotine concentration of 71 electronic cigarette refill fluid products and 1 related do-it-yourself (DIY) product was quantified using high-performance liquid chromatography. Quantified data were compared with manufacturers labeled concentrations. Duplicate refill fluid products purchased at different times were evaluated by visual comparison of fluid coloration and quantified nicotine concentration. Results: Thirty-five of the 54 nicotine-containing fluids had quantified nicotine concentrations that deviated by more than ±10% from the manufacturer labels, with 46 of 50 being in excess of labeled values. Refill fluids labeled as 0 nicotine had no detectable nicotine. Of the 5 products that were unlabeled for nicotine concentration, 3 contained no detectable nicotine, whereas the remaining 2 contained nicotine in excess of 100mg/ml and may have been intended for DIY use. Sixteen of the 18 duplicate bottles of refill fluid varied greatly in their nicotine concentrations. One of the 5 companies showed significant improvement in labeling accuracy among the most recently purchased products. Of the 23 total duplicate pairs, 15 of 23 varied in coloration from their mates. Conclusions: Nicotine concentration labeling on electronic cigarette refill products was often inaccurate but showed improvement recently in products from 1 company. To ensure the safety of refill fluids and DIY products, it is necessary to establish quality control guidelines for the manufacturing and labeling and to monitor products longitudinally. PMID:24862971

Levels of major and trace elements, including rare earth elements, and ²³⁸U in Croatian tap waters.

PubMed

Fiket, Željka; Rožmarić, Martina; Krmpotić, Matea; Benedik, Ljudmila

2015-05-01

Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.

Air quality in the German-Czech border region: A focus on harmful fractions of PM and ultrafine particles

NASA Astrophysics Data System (ADS)

Schladitz, Alexander; Leníček, Jan; Beneš, Ivan; Kováč, Martin; Skorkovský, Jiří; Soukup, Aleš; Jandlová, Jana; Poulain, Laurent; Plachá, Helena; Löschau, Gunter; Wiedensohler, Alfred

2015-12-01

A comprehensive air quality study has been carried out at two urban background sites in Annaberg-Buchholz (Germany) and Ústí nad Labem (Czech Republic) in the German-Czech border region between January 2012 and June 2014. Special attention was paid to quantify harmful fractions of particulate matter (PM) and ultrafine particle number concentration (UFP) from solid fuel combustion and vehicular traffic. Source type contributions of UFP were quantified by using the daily concentration courses of UFP and nitrogen oxide. Two different source apportionment techniques were used to quantify relative and absolute mass contributions: positive matrix factorization for total PM2.5 and elemental carbon in PM2.5 and chemical mass balance for total PM1 and organic carbon in PM1. Contributions from solid fuel combustion strongly differed between the non-heating period (April-September) and the heating period (October-March). Major sources of solid fuel combustion in this study were wood and domestic coal combustion, while the proportion of industrial coal combustion was low (<3%). In Ústí nad Labem combustion of domestic brown coal was the most important source of organic carbon ranging from 34% to 43%. Wood combustion was an important source of organic carbon in Annaberg-Buchholz throughout the year. Heavy metals and less volatile polycyclic aromatic hydrocarbons (PAH) in the accumulation mode were related to solid fuel combustion with enhanced concentrations during the heating period. In contrast, vehicular PAH emissions were allocated to the Aitken mode. Only in Ústí nad Labem a significant contribution of photochemical new particle formation (e.g. from sulfur dioxide) to UFP of almost 50% was observed during noontime. UFPs from traffic emissions (nucleation particles) and primary emitted soot particles dominated at both sites during the rest of the day. The methodology of a combined source apportionment of UFP and PM can be adapted to other regions of the world with similar problems of atmospheric pollution to calculate the relative risk in epidemiological health studies for different sub-fractions of PM and UFP. This will enhance the meaningfulness of published relative risks in health studies based on total PM and UFP number concentrations.

Summary geochemical maps for samples of rock, stream sediment, and nonmagnetic heavy-mineral concentrate, Sweetwater Roadless Area, Mono County, California and Lyon and Douglas Counties, Nevada

USGS Publications Warehouse

Chaffee, Maurice A.

1986-01-01

Map A shows the locations of all sites where rock samples were collected for this report and the distributions of anomalous concentrations for 12 elements in the 127 rock samples collected. In a similar manner, map B shows the collection sites for 59 samples of minus-60-mesh stream sediment, and 59 samples of nonmagnetic heavy-mineral concentrate derived from stream sediment and also shows the distributions of anomalous concentrations for 13 elements in the stream-sediment samples and 17 elements in the concentrate samples. Map C shows outlines of those drainage basins containing samples of stream sediment and concentrate with anomalous element concentrations and also shows weighted values for each outlined basin based on the number of elements with anomalous concentrations in each stream-sediment and concentrate sample and on the degree to which these concentrations are anomalous in each sample.

A systematic review of methods for quantifying serum testosterone in patients with prostate cancer who underwent castration.

PubMed

Comas, I; Ferrer, R; Planas, J; Celma, A; Regis, L; Morote, J

2018-03-01

The clinical practice guidelines recommend measuring serum testosterone in patients with prostate cancer (PC) who undergo castration. The serum testosterone concentration should be <50ng/dL, a level established by using a radioimmunoassay method. The use of chemiluminescent immunoassays (IA) has become widespread, although their metrological characteristics do not seem appropriate for quantifying low testosterone concentrations. The objective of this review is to analyse the methods for quantifying testosterone and to establish whether there is scientific evidence that justifies measuring it in patients with PC who undergo castration, through liquid chromatography attached to a mass spectrometry in tandem (LC-MSMS). We performed a search in PubMed with the following MeSH terms: measurement, testosterone, androgen suppression and prostate cancer. We selected 12 studies that compared the metrological characteristics of various methods for quantifying serum testosterone compared with MS detection methods. IAs are standard tools for measuring testosterone levels; however, there is evidence that IAs lack accuracy and precision for quantifying low concentrations. Most chemiluminescent IAs overestimate their concentration, especially below 100ng/dL. The procedures that use LC-MSMS have an adequate lower quantification limit and proper accuracy and precision. We found no specific evidence in patients with PC who underwent castration. LC-MSMS is the appropriate method for quantifying low serum testosterone concentrations. We need to define the level of castration with this method and the optimal level related to better progression of the disease. Copyright © 2017 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

Sources of inorganic and monomethyl mercury to high and sub Arctic marine ecosystems

NASA Astrophysics Data System (ADS)

Kirk, Jane Liza

Monomethyl mercury (MMHg), a toxic and bioaccumulative form of Hg, is present in some Canadian high and sub Arctic marine mammals at concentrations high enough to pose health risks to Northern peoples using these animals as food. To quantify potentially large sources of Hg to Arctic marine ecosystems, we examined several aspects of Hg cycling in the Canadian Arctic Archipelago (CAA) and Hudson Bay. Firstly, we quantified net Hg inputs to Hudson Bay from atmospheric Hg depletion events (AMDEs). During AMDEs, gaseous elemental Hg(0) (GEM), which is present in the Arctic atmosphere at global background concentrations, is oxidized to inorganic Hg(II) species that deposit to snowpacks. By simultaneously monitoring Hg in the atmosphere and in snowpacks of western Hudson Bay, we demonstrated that most of the Hg(II) deposited during AMDEs is rapidly (photo)reduced and emitted to the atmosphere. Secondly, we examined Hg speciation in marine waters of the CAA and Hudson Bay. We found high concentrations of MMHg and dimethyl Hg (DMHg; a toxic, gaseous form of Hg) in deep marine waters, where they are likely produced from Hg(II). Arctic marine waters were also found to be a substantial source of DMHg and GEM to the atmosphere. Thirdly, we quantified Hg exports to Hudson Bay from two major rivers, the Nelson and the Churchill, which have been altered for hydroelectric power production. When landscapes are inundated during river diversion or reservoir creation, microbial production of MMHg is stimulated in flooded soils. Newly produced MMHg can then be exported to downstream waterbodies. We found that annual inputs of total Hg (THg; includes both Hg(II) and MMHg) to Hudson Bay from combined Nelson and Churchill River discharge were comparable to inputs from AMDEs. MMHg inputs from river discharge are, however, ˜13 times greater than those from annual snowmelt of Hudson Bay snowpacks. Finally, although combined river and AMDE Hg inputs may account for a large portion of the THg pool in Hudson Bay, these inputs account for a lesser portion of the MMHg pool, thus highlighting the importance of water column Hg(II) methylation as a source of MMHg to Arctic marine foodwebs.

The Overshoot Phenomenon in Geodynamics Codes

NASA Astrophysics Data System (ADS)

Kommu, R. K.; Heien, E. M.; Kellogg, L. H.; Bangerth, W.; Heister, T.; Studley, E. H.

2013-12-01

The overshoot phenomenon is a common occurrence in numerical software when a continuous function on a finite dimensional discretized space is used to approximate a discontinuous jump, in temperature and material concentration, for example. The resulting solution overshoots, and undershoots, the discontinuous jump. Numerical simulations play an extremely important role in mantle convection research. This is both due to the strong temperature and stress dependence of viscosity and also due to the inaccessibility of deep earth. Under these circumstances, it is essential that mantle convection simulations be extremely accurate and reliable. CitcomS and ASPECT are two finite element based mantle convection simulations developed and maintained by the Computational Infrastructure for Geodynamics. CitcomS is a finite element based mantle convection code that is designed to run on multiple high-performance computing platforms. ASPECT, an adaptive mesh refinement (AMR) code built on the Deal.II library, is also a finite element based mantle convection code that scales well on various HPC platforms. CitcomS and ASPECT both exhibit the overshoot phenomenon. One attempt at controlling the overshoot uses the Entropy Viscosity method, which introduces an artificial diffusion term in the energy equation of mantle convection. This artificial diffusion term is small where the temperature field is smooth. We present results from CitcomS and ASPECT that quantify the effect of the Entropy Viscosity method in reducing the overshoot phenomenon. In the discontinuous Galerkin (DG) finite element method, the test functions used in the method are continuous within each element but are discontinuous across inter-element boundaries. The solution space in the DG method is discontinuous. FEniCS is a collection of free software tools that automate the solution of differential equations using finite element methods. In this work we also present results from a finite element mantle convection simulation implemented in FEniCS that investigates the effect of using DG elements in reducing the overshoot problem.

Leaf-age and soil-plant relationships: key factors for reporting trace-elements hyperaccumulation by plants and design applications.

PubMed

Losfeld, Guillaume; L'Huillier, Laurent; Fogliani, Bruno; Mc Coy, Stéphane; Grison, Claude; Jaffré, Tanguy

2015-04-01

Relationships between the trace-elements (TE) content of plants and associated soil have been widely investigated especially to understand the ecology of TE hyperaccumulating species to develop applications using TE phytoextraction. Many studies have focused on the possibility of quantifying the soil TE fraction available to plants, and used bioconcentration (BC) as a measure of the plants ability to absorb TE. However, BC only offers a static view of the dynamic phenomenon of TE accumulation. Accumulation kinetics are required to fully account for TE distributions in plants. They are also crucial to design applications where maximum TE concentrations in plant leaves are needed. This paper provides a review of studies of BC (i.e. soil-plant relationships) and leaf-age in relation to TE hyperaccumulation. The paper focuses of Ni and Mn accumulators and hyperaccumulators from New Caledonia who were previously overlooked until recent Ecocatalysis applications emerged for such species. Updated data on Mn hyperaccumulators and accumulators from New Caledonia are also presented and advocate further investigation of the hyperaccumulation of this element. Results show that leaf-age should be considered in the design of sample collection and allowed the reclassification of Grevillea meisneri known previously as a Mn accumulator to a Mn hyperaccumulator.

Technical note: Aerosol light absorption measurements with a carbon analyser - Calibration and precision estimates

NASA Astrophysics Data System (ADS)

Ammerlaan, B. A. J.; Holzinger, R.; Jedynska, A. D.; Henzing, J. S.

2017-09-01

Equivalent Black Carbon (EBC) and Elemental Carbon (EC) are different mass metrics to quantify the amount of combustion aerosol. Both metrics have their own measurement technique. In state-of-the-art carbon analysers, optical measurements are used to correct for organic carbon that is not evolving because of pyrolysis. These optical measurements are sometimes used to apply the technique of absorption photometers. Here, we use the transmission measurements of our carbon analyser for simultaneous determination of the elemental carbon concentration and the absorption coefficient. We use MAAP data from the CESAR observatory, the Netherlands, to correct for aerosol-filter interactions by linking the attenuation coefficient from the carbon analyser to the absorption coefficient measured by the MAAP. Application of the calibration to an independent data set of MAAP and OC/EC observations for the same location shows that the calibration is applicable to other observation periods. Because of simultaneous measurements of light absorption properties of the aerosol and elemental carbon, variation in the mass absorption efficiency (MAE) can be studied. We further show that the absorption coefficients and MAE in this set-up are determined within a precision of 10% and 12%, respectively. The precisions could be improved to 4% and 8% when the light transmission signal in the carbon analyser is very stable.

Geochemistry of aerosols from an urban site, Varanasi, in the Eastern Indo-Gangetic Plain

NASA Astrophysics Data System (ADS)

Ram, Kirpa; Norra, Stefan; Zirzov, Felix; Singh, Sunita; Mehra, Manisha; Nanad Tripathi, Sachichida

2016-04-01

PM2.5 aerosol samples were collected from an urban site, Varanasi, in the eastern Indo-Gangetic Plain on weekly basis during 19 March to 29 May 2015 (n=12), along with daily samples (n=8) during 11 to 18 March 2015 to study the geochemical and morphological features of aerosols. Samples were collected with a low volume sampler (Leckel GmbH, Germany) on the terrace of the Institute of Environment and Sustainable Development building, located in the Banaras Hindu University campus in the southern part of the city. Samples were analyzed for element concentration by Inductively Coupled Plasma Mass Spectrometry and particle morphology by Scanning Electron Microscope. PM2.5 concentration ranged between 22.3 and 70.5 μgm-3 in daily samples, whereas those varied between 52.0 and 106 μgm-3 in weekly samples. Lead, potassium, aluminum, zinc and iron have conspicuously higher concentrations with Pb concentration exceeding above the annual limit of 50 ngm-3 in four samples. First results show a trend of corresponding concentrations of chemical elements originated from anthropogenic and geogenic sources. The biogenic particles are a minor fraction of the total particulate aerosols. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back trajectory analysis of air parcels indicate that the air mass for the low loaded days originate from eastern directions including the region of the gulf of Bengal, where as high aerosols concentrations in cases of air masses arriving from north-western direction transporting the air pollutants from the Gangetic Plain towards Varanasi. Black carbon (BC) concentration, measured using an microaethalometer (AE-51), exhibit a strong variability (4.4 to 8.4 μg m-3) in the University campus which are ˜20-40% lower than those measured in the Varanasi city. The carbon content was found to be high with soot particles constituting the largest part in these samples and exist as single particle as well as attachment to other particles. The Cluster analysis shows a mixture of geogenic and anthropogenic emission sources, though their contribution could not be quantified in the present study. Thus further investigations are started with continuous aerosol sampling in Varanasi.

Risk Management for Weapon Systems Acquisition: A Decision Support System

DTIC Science & Technology

1985-02-28

includes the program evaluation and review technique (PERT) for network analysis, the PMRM for quantifying risk , an optimization package for generating...Despite the inclusion of uncertainty in time, PERT can at best be considered as a tool for quantifying risk with regard to the time element only. Moreover

Trace element distribution in waters of the northern catchment area of Lake Linneret, northern Israel

NASA Astrophysics Data System (ADS)

Sandler, A.; Brenner, I. B.; Halicz, L.

1988-02-01

Waters of the northern watershed of Lake Kineret, sampled during the period 1978 1983, were analyzed for their major and trace element contents. The trace element concentrations of the major water sources of the watershed (the Dan and Banias springs) represent background values. After emergence, the waters are subjected to human activity. In crossing the populated and cultivated Hula Basin in man-made canals, the major and trace element contents increase. In comparison to the trace element concentrations, those of the major elements have narrow ranges and small temporal fluctuations. Trace element concentrations varied by 3 orders of magnitude, and temporal variations were large but not neccessarily seasonal. Point sources of trace elements were urban effluents, fish pond wastes, and peat soil drainage. The trace element concentrations decrease in the waters of the last segment of the Jordan River. All measured trace elements were below the criteria levels established by regulatory agencies. Several, however, were of the same order of magnitude. Addition of wastes from enhanced recycling, and morphologic modification of the final course of the Jordan River could result in increase in the trace element concentrations in the water.

Whole body-element composition of Atlantic salmon Salmo salar influenced by migration direction and life stage in three distinct populations.

PubMed

Ebel, J D; Leroux, S J; Robertson, M J; Dempson, J B

2016-11-01

Body-element content was measured for three life stages of wild Atlantic salmon Salmo salar from three distinct Newfoundland populations as individuals crossed between freshwater and marine ecosystems. Life stage explained most of the variation in observed body-element concentration whereas river of capture explained very little variation. Element composition of downstream migrating post-spawn adults (i.e. kelts) and juvenile smolts were similar and the composition of these two life stages strongly differed from adults migrating upstream to spawn. Low variation within life stages and across populations suggests that S. salar may exert rheostatic control of their body-element composition. Additionally, observed differences in trace element concentration between adults and other life stages were probably driven by the high carbon concentration in adults because abundant elements, such as carbon, can strongly influence the observed concentrations of less abundant elements. Thus, understanding variation among individuals in trace elements composition requires the measurement of more abundant elements. Changes in element concentration with ontogeny have important consequences the role of fishes in ecosystem nutrient cycling and should receive further attention. © 2016 The Fisheries Society of the British Isles.

Nuclear Security: Quantifying Late Detection in MC&A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Surinder Paul; Gibbs, Philip W.; Bultz, Garl A.

2014-03-01

The objectives of this presentation are to understand the concept of late detection; review the statistics used in MC&A; specify the Pd and timelines for Pd for MC&A elements for item inventories; review elements of process control as they relate to bulk processes; and specify the timelines and detection thresholds for Pd for MC&A elements for bulk or Processing Operations.

Exposure assessment models for elemental components of particulate matter in an urban environment: A comparison of regression and random forest approaches

NASA Astrophysics Data System (ADS)

Brokamp, Cole; Jandarov, Roman; Rao, M. B.; LeMasters, Grace; Ryan, Patrick

2017-02-01

Exposure assessment for elemental components of particulate matter (PM) using land use modeling is a complex problem due to the high spatial and temporal variations in pollutant concentrations at the local scale. Land use regression (LUR) models may fail to capture complex interactions and non-linear relationships between pollutant concentrations and land use variables. The increasing availability of big spatial data and machine learning methods present an opportunity for improvement in PM exposure assessment models. In this manuscript, our objective was to develop a novel land use random forest (LURF) model and compare its accuracy and precision to a LUR model for elemental components of PM in the urban city of Cincinnati, Ohio. PM smaller than 2.5 μm (PM2.5) and eleven elemental components were measured at 24 sampling stations from the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). Over 50 different predictors associated with transportation, physical features, community socioeconomic characteristics, greenspace, land cover, and emission point sources were used to construct LUR and LURF models. Cross validation was used to quantify and compare model performance. LURF and LUR models were created for aluminum (Al), copper (Cu), iron (Fe), potassium (K), manganese (Mn), nickel (Ni), lead (Pb), sulfur (S), silicon (Si), vanadium (V), zinc (Zn), and total PM2.5 in the CCAAPS study area. LURF utilized a more diverse and greater number of predictors than LUR and LURF models for Al, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all showed a decrease in fractional predictive error of at least 5% compared to their LUR models. LURF models for Al, Cu, Fe, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all had a cross validated fractional predictive error less than 30%. Furthermore, LUR models showed a differential exposure assessment bias and had a higher prediction error variance. Random forest and other machine learning methods may provide more accurate exposure assessment.

Exposure assessment models for elemental components of particulate matter in an urban environment: A comparison of regression and random forest approaches.

PubMed

Brokamp, Cole; Jandarov, Roman; Rao, M B; LeMasters, Grace; Ryan, Patrick

2017-02-01

Exposure assessment for elemental components of particulate matter (PM) using land use modeling is a complex problem due to the high spatial and temporal variations in pollutant concentrations at the local scale. Land use regression (LUR) models may fail to capture complex interactions and non-linear relationships between pollutant concentrations and land use variables. The increasing availability of big spatial data and machine learning methods present an opportunity for improvement in PM exposure assessment models. In this manuscript, our objective was to develop a novel land use random forest (LURF) model and compare its accuracy and precision to a LUR model for elemental components of PM in the urban city of Cincinnati, Ohio. PM smaller than 2.5 μm (PM2.5) and eleven elemental components were measured at 24 sampling stations from the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). Over 50 different predictors associated with transportation, physical features, community socioeconomic characteristics, greenspace, land cover, and emission point sources were used to construct LUR and LURF models. Cross validation was used to quantify and compare model performance. LURF and LUR models were created for aluminum (Al), copper (Cu), iron (Fe), potassium (K), manganese (Mn), nickel (Ni), lead (Pb), sulfur (S), silicon (Si), vanadium (V), zinc (Zn), and total PM2.5 in the CCAAPS study area. LURF utilized a more diverse and greater number of predictors than LUR and LURF models for Al, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all showed a decrease in fractional predictive error of at least 5% compared to their LUR models. LURF models for Al, Cu, Fe, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all had a cross validated fractional predictive error less than 30%. Furthermore, LUR models showed a differential exposure assessment bias and had a higher prediction error variance. Random forest and other machine learning methods may provide more accurate exposure assessment.

Exposure assessment models for elemental components of particulate matter in an urban environment: A comparison of regression and random forest approaches

PubMed Central

Brokamp, Cole; Jandarov, Roman; Rao, M.B.; LeMasters, Grace; Ryan, Patrick

2017-01-01

Exposure assessment for elemental components of particulate matter (PM) using land use modeling is a complex problem due to the high spatial and temporal variations in pollutant concentrations at the local scale. Land use regression (LUR) models may fail to capture complex interactions and non-linear relationships between pollutant concentrations and land use variables. The increasing availability of big spatial data and machine learning methods present an opportunity for improvement in PM exposure assessment models. In this manuscript, our objective was to develop a novel land use random forest (LURF) model and compare its accuracy and precision to a LUR model for elemental components of PM in the urban city of Cincinnati, Ohio. PM smaller than 2.5 μm (PM2.5) and eleven elemental components were measured at 24 sampling stations from the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). Over 50 different predictors associated with transportation, physical features, community socioeconomic characteristics, greenspace, land cover, and emission point sources were used to construct LUR and LURF models. Cross validation was used to quantify and compare model performance. LURF and LUR models were created for aluminum (Al), copper (Cu), iron (Fe), potassium (K), manganese (Mn), nickel (Ni), lead (Pb), sulfur (S), silicon (Si), vanadium (V), zinc (Zn), and total PM2.5 in the CCAAPS study area. LURF utilized a more diverse and greater number of predictors than LUR and LURF models for Al, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all showed a decrease in fractional predictive error of at least 5% compared to their LUR models. LURF models for Al, Cu, Fe, K, Mn, Pb, Si, Zn, TRAP, and PM2.5 all had a cross validated fractional predictive error less than 30%. Furthermore, LUR models showed a differential exposure assessment bias and had a higher prediction error variance. Random forest and other machine learning methods may provide more accurate exposure assessment. PMID:28959135

How Deep and Hot was Earth's Magma Ocean? Combined Experimental Datasets for the Metal-silicate Partitioning of 11 Siderophile Elements - Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd

NASA Technical Reports Server (NTRS)

Righter, Kevin

2008-01-01

Since approximately 1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients (D) for siderophile (iron-loving) elements are much different than those measured at low PT conditions. The high PT data have been used to argue for a magma ocean during growth of the early Earth. Initial conclusions were based on experiments and calculations for a small number of elements such as Ni and Co. However, for many elements only a limited number of experimental data were available then, and they only hinted at values of metal-silicate D's at high PT conditions. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements. At the same time several different models have been advanced to explain the siderophile elements in the earth's mantle: a) intermediate depth magma ocean; 25-30 GPa, b) deep magma ocean; up to 50 GPa, and c) early reduced and later oxidized magma ocean. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to update the predictive expressions outlined by Righter et al. (1997) with new experimental data from the last decade, test the predictive ability of these expressions against independent datasets (there are more data now to do this properly), and to apply the resulting expressions to the siderophile element patterns in Earth's upper mantle. The predictive expressions have the form: lnD = alnfO2 + b/T + cP/T + d(1Xs) + e(1Xc) + SigmafiXi + g These expressions are guided by the thermodynamics of simple metal-oxide equilibria that control each element, include terms that mimic the activity coefficients of each element in the metal and silicate, and quantify the effect of variable oxygen fugacity. Preliminary results confirm that D(Ni) and D(Co) converge at pressures near 25-30 GPa and approximately 2200 K, and show that D(Pd) and D(Cu) become too low at the PT conditions of the deepest models. Furthermore, models which force fit V and Cr mantle concentrations by metal-silicate equilibrium overlook the fact that at early Earth mantle fO2, these elements will be more compatible in Mg-perovskite and (Fe,Mg)O than in metal. Thus an intermediate depth magma ocean, at 25-30 GPa, 2200 K, and at IW-2, can explain more mantle siderophile element concentrations than other models.

Quantification of diagenesis in Cenozoic sharks: Elemental and mineralogical changes

NASA Astrophysics Data System (ADS)

Labs-Hochstein, Joann; MacFadden, Bruce J.

2006-10-01

Diagenesis of bone during fossilization is pervasive, however, the extent of this process varies with depositional environment. This study quantifies diagenesis of shark vertebral centra through analysis of a suite of physical and chemical characters including crystallinty index (CI), carbonate content, and elemental concentrations. Although shark skeletons are initially cartilaginous, the soft cartilage of the vertebral centra is replaced with carbonate hydroxyapatite during growth. Nine vertebral centra are analyzed from lamnoid (Lamnoidea) sharks ranging in age from the cretaceous to recent using Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma mass spectrometry (ICPMS). The variables CI, carbonate content, rare earth element (REE) concentrations, Ca/P, Ba/Ca, Sr/Ba, (La/Yb) N, (La/Y) N, (La/Yb) N vs. (La/Sm) N, La/Yb, and Ce anomalies elucidate the diagenetic and depositional environments of the seven fossil vertebral centra. The two extant centra demonstrate the initial, unaltered end-member conditions for these variables. Two fossil vertebral centra ( Carcharodon megalodon and Isurus hastalis) demonstrate a strong terrestrial influence during diagenesis (distinctive flattening of shale-normalized REE patterns) that masked the seawater signal. Three centra ( Carcharodon auriculatus, Carcharodon angustidens, and Creotxyrhina mantelli) have indications of some terrestrial influx evident by some flattening of the REE patterns relative to seawater. The terrestrial influence in these five shark centra ( C. megalodon, I. hastalis, C. auriculatus, C. angustidens and C. mantelli) are interpreted to represent a primarily nearshore habitat for these species. In contrast, the two Otodus obliquus centra have REE patterns that represent the original seawater signal and have no indications of terrigenous input. These results indicate that fossil shark vertebral centra have the potential to understand diagenesis and reconstruct paleooceanographic environments.

Refinement of elastic, poroelastic, and osmotic tissue properties of intervertebral disks to analyze behavior in compression.

PubMed

Stokes, Ian A F; Laible, Jeffrey P; Gardner-Morse, Mack G; Costi, John J; Iatridis, James C

2011-01-01

Intervertebral disks support compressive forces because of their elastic stiffness as well as the fluid pressures resulting from poroelasticity and the osmotic (swelling) effects. Analytical methods can quantify the relative contributions, but only if correct material properties are used. To identify appropriate tissue properties, an experimental study and finite element analytical simulation of poroelastic and osmotic behavior of intervertebral disks were combined to refine published values of disk and endplate properties to optimize model fit to experimental data. Experimentally, nine human intervertebral disks with adjacent hemi-vertebrae were immersed sequentially in saline baths having concentrations of 0.015, 0.15, and 1.5 M and the loss of compressive force at constant height (force relaxation) was recorded over several hours after equilibration to a 300-N compressive force. Amplitude and time constant terms in exponential force-time curve-fits for experimental and finite element analytical simulations were compared. These experiments and finite element analyses provided data dependent on poroelastic and osmotic properties of the disk tissues. The sensitivities of the model to alterations in tissue material properties were used to obtain refined values of five key material parameters. The relaxation of the force in the three bath concentrations was exponential in form, expressed as mean compressive force loss of 48.7, 55.0, and 140 N, respectively, with time constants of 1.73, 2.78, and 3.40 h. This behavior was analytically well represented by a model having poroelastic and osmotic tissue properties with published tissue properties adjusted by multiplying factors between 0.55 and 2.6. Force relaxation and time constants from the analytical simulations were most sensitive to values of fixed charge density and endplate porosity.

Refinement of Elastic, Poroelastic, and Osmotic Tissue Properties of Intervertebral Disks to Analyze Behavior in Compression

PubMed Central

Stokes, Ian A. F.; Laible, Jeffrey P.; Gardner-Morse, Mack G.; Costi, John J.; Iatridis, James C.

2011-01-01

Intervertebral disks support compressive forces because of their elastic stiffness as well as the fluid pressures resulting from poroelasticity and the osmotic (swelling) effects. Analytical methods can quantify the relative contributions, but only if correct material properties are used. To identify appropriate tissue properties, an experimental study and finite element analytical simulation of poroelastic and osmotic behavior of intervertebral disks were combined to refine published values of disk and endplate properties to optimize model fit to experimental data. Experimentally, nine human intervertebral disks with adjacent hemi-vertebrae were immersed sequentially in saline baths having concentrations of 0.015, 0.15, and 1.5 M and the loss of compressive force at constant height (force relaxation) was recorded over several hours after equilibration to a 300-N compressive force. Amplitude and time constant terms in exponential force–time curve-fits for experimental and finite element analytical simulations were compared. These experiments and finite element analyses provided data dependent on poroelastic and osmotic properties of the disk tissues. The sensitivities of the model to alterations in tissue material properties were used to obtain refined values of five key material parameters. The relaxation of the force in the three bath concentrations was exponential in form, expressed as mean compressive force loss of 48.7, 55.0, and 140 N, respectively, with time constants of 1.73, 2.78, and 3.40 h. This behavior was analytically well represented by a model having poroelastic and osmotic tissue properties with published tissue properties adjusted by multiplying factors between 0.55 and 2.6. Force relaxation and time constants from the analytical simulations were most sensitive to values of fixed charge density and endplate porosity. PMID:20711754

Size distribution of chemical elements and their source apportionment in ambient coarse, fine, and ultrafine particles in Shanghai urban summer atmosphere.

PubMed

Lü, Senlin; Zhang, Rui; Yao, Zhenkun; Yi, Fei; Ren, Jingjing; Wu, Minghong; Feng, Man; Wang, Qingyue

2012-01-01

Ambient coarse particles (diameter 1.8-10 microm), fine particles (diameter 0.1-1.8 microm), and ultrafine particles (diameter < 0.1 microm) in the atmosphere of the city of Shanghai were sampled during the summer of 2008 (from Aug 27 to Sep 08). Microscopic characterization of the particles was investigated by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX). Mass concentrations of Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, and Pb in the size-resolved particles were quantified by using synchrotron radiation X-ray fluorescence (SRXRF). Source apportionment of the chemical elements was analyzed by means of an enrichment factor method. Our results showed that the average mass concentrations of coarse particles, fine particles and ultrafine particles in the summer air were 9.38 +/- 2.18, 8.82 +/- 3.52, and 2.02 +/- 0.41 microg/m3, respectively. The mass percentage of the fine particles accounted for 51.47% in the total mass of PM10, indicating that fine particles are the major component in the Shanghai ambient particles. SEM/EDX results showed that the coarse particles were dominated by minerals, fine particles by soot aggregates and fly ashes, and ultrafine particles by soot particles and unidentified particles. SRXRF results demonstrated that crustal elements were mainly distributed in the coarse particles, while heavy metals were in higher proportions in the fine particles. Source apportionment revealed that Si, K, Ca, Fe, Mn, Rb, and Sr were from crustal sources, and S, Cl, Cu, Zn, As, Se, Br, and Pb from anthropogenic sources. Levels of P, V, Cr, and Ni in particles might be contributed from multi-sources, and need further investigation.

Characterization and risk of exposure to elements from artisanal gold mining operations in the Bolivian Andes.

PubMed

Pavilonis, Brian; Grassman, Jean; Johnson, Glen; Diaz, Yilmael; Caravanos, Jack

2017-04-01

Artisanal and small-scale gold mining (ASGM) offers low-skilled workers an opportunity to elevate themselves out of poverty. However, this industry operates with little to no pollution controls and the cost to the environment and human health can be large. The objectives of this study were to measure levels of arsenic (As), manganese (Mn), cobalt (Co), lead (Pb), and mercury (Hg) in the environment and characterize health risks to miners and residents in an area with active ASGM operations. An exposure assessment was conducted at two different mining sites and a nearby village in the Bolivian Anders. The resulting measurements were then used to quantify cancerous and noncancerous health risks to children and adults working at and living near ASGM areas. Soil concentrations of As were well above background levels and showed great variations between the village and mining area. Mercury vapor levels at the two mining sites were approximately 30 times larger than the EPA reference concentration. The risk of developing non-cancerous health effects were primarily due to exposure to As and Hg. The probability of individuals developing cancer was considerably increased with adult miners having a probability of 1.3 out of 100. Cancer potential was driven by exposure to As, with de minimus cancer risk from all other elements. Based on the environmental characterization of elements in soils and Hg vapors, the risk of developing cancerous and non-cancerous health outcomes were above a level of concern based on EPA risk assessment guidance. Personal protective equipment was not worn by workers and Hg amalgam is commonly heated in workers' homes. Better education of the risks of ASGM is needed as well as simple controls to reduce exposure. Published by Elsevier Inc.

Single-transducer dual-frequency ultrasound generation to enhance acoustic cavitation.

PubMed

Liu, Hao-Li; Hsieh, Chao-Ming

2009-03-01

Dual- or multiple-frequency ultrasound stimulation is capable of effectively enhancing the acoustic cavitation effect over single-frequency ultrasound. Potential application of this sonoreactor design has been widely proposed such as on sonoluminescence, sonochemistry enhancement, and transdermal drug release enhancement. All currently available sonoreactor designs employed multiple piezoelectric transducers for generating single-frequency ultrasonic waves separately and then these waves were mixed and interfered in solutions. The purpose of this research is to propose a novel design of generating dual-frequency ultrasonic waves with single piezoelectric elements, thereby enhancing acoustic cavitation. Macroscopic bubbles were detected optically, and they were quantified at either a single-frequency or for different frequency combinations for determining their efficiency for enhancing acoustic cavitation. Visible bubbles were optically detected and hydrogen peroxide was measured to quantify acoustic cavitation. Test water samples with different gas concentrations and different power levels were used to determine the efficacy of enhancing acoustic cavitation of this design. The spectrum obtained from the backscattered signals was also recorded and examined to confirm the occurrence of stable cavitation. The results confirmed that single-element dual-frequency ultrasound stimulation can enhance acoustic cavitation. Under certain testing conditions, the generation of bubbles can be enhanced up to a level of five times higher than the generation of bubbles in single-frequency stimulation, and can increase the hydrogen peroxide production up to an increase of one fold. This design may serve as a useful alternative for future sonoreactor design owing to its simplicity to produce dual- or multiple-frequency ultrasound.

Signatures of Evolutionary Adaptation in Quantitative Trait Loci Influencing Trace Element Homeostasis in Liver

PubMed Central

Sabidó, Eduard; Bosch, Elena

2016-01-01

Essential trace elements possess vital functions at molecular, cellular, and physiological levels in health and disease, and they are tightly regulated in the human body. In order to assess variability and potential adaptive evolution of trace element homeostasis, we quantified 18 trace elements in 150 liver samples, together with the expression levels of 90 genes and abundances of 40 proteins involved in their homeostasis. Additionally, we genotyped 169 single nucleotide polymorphism (SNPs) in the same sample set. We detected significant associations for 8 protein quantitative trait loci (pQTL), 10 expression quantitative trait loci (eQTLs), and 15 micronutrient quantitative trait loci (nutriQTL). Six of these exceeded the false discovery rate cutoff and were related to essential trace elements: 1) one pQTL for GPX2 (rs10133290); 2) two previously described eQTLs for HFE (rs12346) and SELO (rs4838862) expression; and 3) three nutriQTLs: The pathogenic C282Y mutation at HFE affecting iron (rs1800562), and two SNPs within several clustered metallothionein genes determining selenium concentration (rs1811322 and rs904773). Within the complete set of significant QTLs (which involved 30 SNPs and 20 gene regions), we identified 12 SNPs with extreme patterns of population differentiation (FST values in the top 5% percentile in at least one HapMap population pair) and significant evidence for selective sweeps involving QTLs at GPX1, SELENBP1, GPX3, SLC30A9, and SLC39A8. Overall, this detailed study of various molecular phenotypes illustrates the role of regulatory variants in explaining differences in trace element homeostasis among populations and in the human adaptive response to environmental pressures related to micronutrients. PMID:26582562

Historical trace element distribution in sediments from the Mississippi River delta

USGS Publications Warehouse

Swarzenski, P.W.; Baskaran, M.; Rosenbauer, R.J.; Orem, W.H.

2006-01-01

Five sediment cores were collected on the shelf of the inner Mississippi Bight in June 2003 for a suite of radionuclides to establish geochronologies and trace elements to examine patterns of contaminant deposition and accumulation. Core sites were chosen to reflect a matrix of variable water depths, proximity to the Mississippi River mouth as the primary source for terrigenous particles, and extent and duration of summertime water column hypoxia. The vertical distribution of 239,240Pu and 210Pbxs (= 210Pbtotal - 226Ra) provided reliable geochronological age constraints to develop models for mass accumulation rates and historic trace element inputs and variations. Mass accumulation rates ranged from 0.27 to 0.87 g cm-2 yr-1 and were internally consistent using either 210Pbxs or 239,240Pu. Measured inventories of 137Cs, 239,240Pu, and 210Pbxs were compared to atmospheric deposition rates to quantify potential sediment focusing or winnowing. Observed variability in calculated mass accumulation rates may be attributed foremost to site-specific proximity to the river mouth (i.e., sediment source), variability in water depth, and enhanced sediment focusing at the Mississippi River canyon site. Trace element concentrations were first normalized to Al, and then Al-normalized enrichment factors (ANEF) were calculated based on preanthropogenic and crustal trace element abundances. These ANEFs were typically > 1 for V and Ba, while for most other elements studied, either no enrichment or depletion was observed. The enrichment of Ba may be related, in part, to the seasonal occurrence of oxygen-depleted subsurface waters off the Mississippi River delta, as well as being an ubiquitous by-product of the petroleum industry. ?? 2006 Estuarine Research Federation.

Methylmercury biomagnification in an Arctic pelagic food web.

PubMed

Ruus, Anders; Øverjordet, Ida B; Braaten, Hans Fredrik V; Evenset, Anita; Christensen, Guttorm; Heimstad, Eldbjørg S; Gabrielsen, Geir W; Borgå, Katrine

2015-11-01

Mercury (Hg) is a toxic element that enters the biosphere from natural and anthropogenic sources, and emitted gaseous Hg enters the Arctic from lower latitudes by long-range transport. In aquatic systems, anoxic conditions favor the bacterial transformation of inorganic Hg to methylmercury (MeHg), which has a greater potential for bioaccumulation than inorganic Hg and is the most toxic form of Hg. The main objective of the present study was to quantify the biomagnification of MeHg in a marine pelagic food web, comprising species of zooplankton, fish, and seabirds, from the Kongsfjorden system (Svalbard, Norway), by use of trophic magnification factors. As expected, tissue concentrations of MeHg increased with increasing trophic level in the food web, though at greater rates than observed in several earlier studies, especially at lower latitudes. There was strong correlation between MeHg and total Hg concentrations through the food web as a whole. The concentration of MeHg in kittiwake decreased from May to October, contributing to seasonal differences in trophic magnification factors. The ecology and physiology of the species comprising the food web in question may have a large influence on the magnitude of the biomagnification. A significant linear relationship was also observed between concentrations of selenium and total Hg in birds but not in zooplankton, suggesting the importance of selenium in Hg detoxification for individuals with high Hg concentrations. © 2015 SETAC.

In silico study on the effects of matrix structure in controlled drug release

NASA Astrophysics Data System (ADS)

Villalobos, Rafael; Cordero, Salomón; Maria Vidales, Ana; Domínguez, Armando

2006-07-01

Purpose: To study the effects of drug concentration and spatial distribution of the medicament, in porous solid dosage forms, on the kinetics and total yield of drug release. Methods: Cubic networks are used as models of drug release systems. They were constructed by means of the dual site-bond model framework, which allows a substrate to have adequate geometrical and topological distribution of its pore elements. Drug particles can move inside the networks by following a random walk model with excluded volume interactions between the particles. The drug release time evolution for different drug concentration and different initial drug spatial distribution has been monitored. Results: The numerical results show that in all the studied cases, drug release presents an anomalous behavior, and the consequences of the matrix structural properties, i.e., drug spatial distribution and drug concentration, on the drug release profile have been quantified. Conclusions: The Weibull function provides a simple connection between the model parameters and the microstructure of the drug release device. A critical modeling of drug release from matrix-type delivery systems is important in order to understand the transport mechanisms that are implicated, and to predict the effect of the device design parameters on the release rate.

An innovative method for nondestructive analysis of cast iron artifacts at Hopewell Furnace National Historic Site, Pennsylvania

USGS Publications Warehouse

Sloto, R.A.; Helmke, M.F.

2011-01-01

Iron ore containing elevated concentrations of trace metals was smelted at Hopewell Furnace during its 113 years of operation (1771-1883). For this study, we sampled iron ore, cast iron furnace products, slag, soil, groundwater, streamflow, and streambed sediment to determine the fate of trace metals released into the environment during the iron-smelting process. Standard techniques were used to sample and analyze all media except cast iron. We analyzed the trace-metal content of the cast iron using a portable X-ray fluorescence spectrometer, which provided rapid, on-site, nondestructive analyses for 23 elements. The artifacts analyzed included eight cast iron stoves, a footed pot, and a kettle in the Hopewell Furnace museum. We measured elevated concentrations of arsenic, copper, lead, and zinc in the cast iron. Lead concentrations as great as 3,150 parts per million were measured in the stoves. Cobalt was detectable but not quantifiable because of interference with iron. Our study found that arsenic, cobalt, and lead were not released to soil or slag, which could pose a significant health risk to visitors and employees. Instead, our study demonstrates these heavy metals remained with the cast iron and were removed from the site.

Tracing carbonaceous sources by using particulate carbon and sulfate in precipitation in Calgary, Alberta Canada

NASA Astrophysics Data System (ADS)

Ge, C.; Stenhouse, K. J.; Du, K.; Xing, Z.; Norman, A. L.

2016-12-01

Carbonaceous matter is often the dominant contributor to Particulate Matter (PM) which has a significant influence on climate, air quality and human health. The measurement of particulate carbon in rainfall in Calgary, Alberta has not been studied. This study reports the sulfate and the first concentrations of particulate carbon (PC) in rainfall in Calgary. It traces seasonal carbonaceous sources for the purpose of understanding sources for air quality control. Precipitation samples are collected twice a day at the University of Calgary. Thermo-optical methods are used to analyze concentrations of PC, including elemental carbon (EC), primary organic carbon (POC) and secondary organic carbon (SOC). Sulfate concentrations are measured using ion chromatography. In this study, sources from long range transport and local emissions are examined. We emphasized the apportionment of OC/EC in oil and gas emissions and diurnal variations in transportation emissions. Weekly average data for dry deposition were calculated to estimate the scavenging ratio of EC/POC/SOC and ions in precipitation. The results of this study will be presented with an emphasis on the relationship of carbonaceous material and sulfate. A range of apportionment methods have been applied to examine limitations in quantifying SOC in fall.

Numerical simulation of trace element transport on subsurface environment pollution in coal mine spoil.

PubMed

Qiang, Xue; Bing, Liang; Hui-yun, Wang; Lei, Liu

2006-01-01

An understanding of the dynamic behavior of trace elements leaching from coal mine spoil is important in predicting the groundwater quality. The relationship between trace element concentrations and leaching times, pH values of the media is studied. Column leaching tests conducted in the laboratory showed that there was a close correlation between pH value and trace element concentrations. The longer the leaching time, the higher the trace element concentrations. Different trace elements are differently affected by pH values of leaching media. A numerical model for water flow and trace element transport has been developed based on analyzing the characteristics of migration and transformation of trace elements leached from coal mine spoil. Solutions to the coupled model are accomplished by Eulerian-Lagrangian localized adjoint method. Numerical simulation shows that rainfall intensity determined maximum leaching depth. As rainfall intensity is 3.6ml/s, the outflow concentrations indicate a breakthrough of trace elements beyond the column base, with peak concentration at 90cm depth. And the subsurface pollution range has a trend of increase with time. The model simulations are compared to experimental results of trace element concentrations, with reasonable agreement between them. The analysis and modeling of trace elements suggested that the infiltration of rainwater through the mine spoil might lead to potential groundwater pollution. It provides theoretical evidence for quantitative assessment soil-water quality of trace element transport on environment pollution.

Trace elements in fish from Taihu Lake, China: levels, associated risks, and trophic transfer.

PubMed

Hao, Ying; Chen, Liang; Zhang, Xiaolan; Zhang, Dongping; Zhang, Xinyu; Yu, Yingxin; Fu, Jiamo

2013-04-01

Concentrations of eight trace elements [iron (Fe), manganese (Mn), zinc (Zn), chromium (Cr), mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As)] were measured in a total of 198 samples covering 24 fish species collected from Taihu Lake, China, in September 2009. The trace elements were detected in all samples, and the total mean concentrations ranged from 18.2 to 215.8 μg/g dw (dry weight). The concentrations of the trace elements followed the sequence of Zn>Fe>Mn>Cr>As>Hg>Pb>Cd. The measured trace element concentrations in fish from Taihu Lake were similar to or lower than the reported values in fish around the world. The metal pollution index was used to compare the total trace element accumulation levels among various species. Toxabramis swinhonis (1.606) accumulated the highest level of the total trace elements, and Saurogobio dabryi (0.315) contained the lowest. The concentrations of human non-essential trace elements (Hg, Cd, Pb, and As) were lower than the allowable maximum levels in fish in China and the European Union. The relationships between the trace element concentrations and the δ(15)N values of fish species were used to investigate the trophic transfer potential of the trace elements. Of the trace elements, Hg might be biomagnified through the food chain in Taihu Lake if the significant level of p-value was set at 0.1. No biomagnification and biodilution were observed for other trace elements. Copyright © 2012 Elsevier Inc. All rights reserved.

Menstrual cycle perturbation by organohalogens and elements in the Cree of James Bay, Canada.

PubMed

Wainman, Bruce C; Kesner, James S; Martin, Ian D; Meadows, Juliana W; Krieg, Edward F; Nieboer, Evert; Tsuji, Leonard J

2016-04-01

Persistent organohalogens (POHs) and metals have been linked to alterations in menstrual cycle function and fertility in humans. The Cree First Nations people living near James Bay in Ontario and Quebec, Canada, have elevated levels of POHs, mercury and lead compared to other Canadians. The present study examines the interrelationships between selected POHs and elements on menstrual cycle function in these Cree women. Menstrual cycle characteristics were derived from structured daily diaries and endocrine measurements from daily urine samples collected during one cycle for 42 women age 19-42. We measured 31 POHs in blood plasma and 18 elements in whole blood, for 31 of the participants. POHs and elements detected in ≥ 70% of the participants were transformed by principal component (PC) analysis to reduce the contaminant exposure data to fewer, uncorrelated PCA variables. Multiple regression analysis revealed that, after adjusting for confounders, PC-3 values showed significant negative association with cycle length, after adjusting for confounders (p = 0.002). PC-3 accounted for 9.2% of the variance and shows positive loadings for cadmium, selenium, and PBDE congeners 47 and 153, and a negative loading for copper. Sensitivity analysis of the model to quantify likely effect sizes showed a range of menstrual cycle length from 25.3 to 28.3 days using the lower and upper 95% confidence limits of mean measured contaminant concentrations to predict cycle length. Our observations support the hypothesis that the menstrual cycle function of these women may be altered by exposure to POHs and elements from their environment. Copyright © 2015. Published by Elsevier Ltd.

Development of phase analysis methods of impurity elements in alloys based on iron and nickel

NASA Astrophysics Data System (ADS)

Andreeva, N. A.; Anuchkin, S. N.; Volchenkova, V. A.; Kazenas, E. K.; Penkina, T. N.; Fomina, A. A.

2018-04-01

Using the method of AES with ICP, new methods have been developed for quantifying the content of various forms of existence of impurity elements: Al-Al2O3; Zr-ZrO2 in alloys based on iron (Fe-Sn) and nickel (Ni-Sn). Open systems were used to dissolve Al and Zr. To translate difficult-to-open aluminum oxides (corundum) and zirconium oxide (baddeleyite) into the solution, accelerated techniques were developed using the microwave system Mars 5. To confirm the completeness of the dissolution of oxides, a classical scheme of alloy fusion with alkali metal salts was used. Optimal analytical parameters for determining the elements: Al and Zr were chosen. The influence of matrix elements (iron and nickel) and methods of its elimination were studied. This made it possible to determine the elements in a wide concentration range from 1 • 10-3 to n% Al and from 1 • 10-4 to n% Zr without preliminary separation of the matrix with good metrological characteristics. The relative standard deviation (Sr) does not exceed 0,2. The separate determination of the contents of aluminum and aluminium oxide in the model melt of Fe-Sn-Al2O3 and zirconium and zirconium oxide in the Ni-Sn-ZrO2 model melt allowed us to estimate the number of nanoparticles participating in the heterophase interaction with tin and retired to the interface in the form of ensembles and the number of nanoparticles present in the melt and affecting the crystallization process and the structure of the metal.

Growth and elemental content of two tree species growing on abandoned coal fly ash basins. [Liquidambar styraciflua L. ; Platanus occidentalis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, C.L.; Adriano, D.C.

Differences in aboveground tissue concentrations of trace elements were assessed for sweetgum (Liquidambar styraciflua L.) and sycamore (Plantanus occidentalis L.) growing on two abandoned coal fly ash basins and a control soil. The wet basin (pH = 5.58) had originally received precipitator ash in an ash-water slurry, while the dry basin (pH = 8.26) had received both precipitator and bottom ash in dry form. In general, trees from the wet basin exhibited elevated trace element concentrations in comparison to the controls, while the dry basin trees exhibited reduced concentrations. On eof the most striking differenced in elemental concentrations among themore » ash basin and control trees was observed for Mn, with the control trees exhibiting concentrations orders of magnitude greater than the ash basin trees. Differences in foliar trace element concentrations among the sites can generally be explained by differences in substrate trace element concentrations and/or substrate pH. While trees from the wet ash basin generally had the highest trace element concentrations, these trees also attained the greatest height and diameter growth, suggesting that the elevated trace element concentrations in the wet basin substrate are not limiting the establishment of these two species. The greater height and diameter growth of the wet basin trees is presumably a result of the greater water-holding capacity of the substrate on this site. Differences in growth and tissue concentrations between sweetgum and sycamore highlight the importance of using more than one species when assessing metal toxicity or deficiency on a given substrate.« less

Whole-body concentrations of elements in three fish species from offshore oil platforms and natural areas in the Southern California Bight, USA

USGS Publications Warehouse

Love, Milton S.; Saiki, Michael K.; May, Thomas W.; Yee, Julie L.

2013-01-01

elements. Forty-two elements were excluded from statistical comparisons as they (1) consisted of major cations that were unlikely to accumulate to potentially toxic concentrations; (2) were not detected by the analytical procedures; or (3) were detected at concentrations too low to yield reliable quantitative measurements. The remaining 21 elements consisted of aluminum, arsenic, barium, cadmium, chromium, cobalt, copper, gallium, iron, lead, lithium, manganese, mercury, nickel, rubidium, selenium, strontium, tin, titanium, vanadium, and zinc. Statistical comparisons of these elements indicated that none consistently exhibited higher concentrations at oil platforms than at natural areas. However, the concentrations of copper, selenium, titanium, and vanadium in Pacific sanddab were unusual because small individuals exhibited either no differences between oil platforms and natural areas or significantly lower concentrations at oil platforms than at natural areas, whereas large individuals exhibited significantly higher concentrations at oil platforms than at natural areas.

Concentrations of mercury and other trace elements in walleye, smallmouth bass, and rainbow trout in Franklin D. Roosevelt Lake and the upper Columbia River, Washington, 1994

USGS Publications Warehouse

Munn, M.D.; Cox, S.E.; Dean, C.J.

1995-01-01

Three species of sportfish--walleye, smallmouth bass, and rainbow trout--were collected from Franklin D. Roosevelt Lake and the upstream reach of the Columbia River within the state of Washington, to determine the concentrations of mercury and other selected trace elements in fish tissue. Concentrations of total mercury in walleye fillets ranged from 0.11 to 0.44 milligram per kilogram, with the higher concentrations in the larger fish. Fillets of smallmouth bass and rainbow trout also contained mercury, but generally at lower concentrations. Other selected trace elements were found in fillet samples, but the concentrations were generally low depending on species and the specific trace element. The trace elements cadmium, copper, lead, and zinc were found in liver tissue of these same species with zinc consistently present in the highest concentration.

HABITAT FINGERPRINTS FOR LAKE SUPERIOR COASTAL WETLANDS DERIVED FROM ELEMENTAL ANALYSIS OF YELLOW PERCH OTOLITHS

EPA Science Inventory

Assessing the ecological importance of coastal habitats to Great Lakes ecosystems requires an understanding of the ecological linkages between coastal and offshore waters. . . . Our results suggest that otolith elemental fingerprints may be useful for quantifying the relative con...

Baseline element concentrations in soils and plants, Bull Island, Cape Romain National Wildlife Refuge, South Carolina, U.S.A.

USGS Publications Warehouse

Gough, L.P.; Severson, R.C.; Jackson, L.L.

1994-01-01

Baseline element concentrations are given for Spanish moss (Tillandsia usneoides), loblolly pine (Pinus taeda), and associated soils. Baseline and variability data for ash, Al, Ba, C, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, S, Sc, Sr, Th, Ti, V, Y, and Zn are reported; however, not all variables are reported for all media because, in some media, certain elements were below the analytical detection limit. Spatial variation in element concentration among and within 0.5 km grid cells are given for each of the media. In general, only a few elements in Spanish moss showed statistically significant landscape patterns, whereas several elements in loblolly pine and in soils exhibited differences among sampling grids. Significant differences in the concentration of three elements in Spanish moss and eight elements (including total S) in loblolly pine were observed between two sampling dates (November and June); however, the absolute amount of these differences was small. Except for perhaps Ni and Pb concentrations in Spanish moss, element levels in all sample media exhibited ranges that indicate natural rather than anthropogenic additions of trace elements.

Discrimination of lichen genera and species using element concentrations

USGS Publications Warehouse

Bennett, James P.

2008-01-01

The importance of organic chemistry in the classification of lichens is well established, but inorganic chemistry has been largely overlooked. Six lichen species were studied over a period of 23 years that were growing in 11 protected areas of the northern Great Lakes ecoregion, which were not greatly influenced by anthropogenic particulates or gaseous air pollutants. The elemental data from these studies were aggregated in order to test the hypothesis that differences among species in tissue element concentrations were large enough to discriminate between taxa faithfully. Concentrations of 16 chemical elements that were found in tissue samples from Cladonia rangiferina, Evernia mesomorpha, Flavopunctelia flaventior, Hypogymnia physodes, Parmelia sulcata, and Punctelia rudecta were analyzed statistically using multivariate discriminant functions and CART analyses, as well as t-tests. Genera and species were clearly separated in element space, and elemental discriminant functions were able to classify 91-100 of the samples correctly into species. At the broadest level, a Zn concentration of 51 ppm in tissues of four of the lichen species effectively discriminated foliose from fruticose species. Similarly, a S concentration of 680 ppm discriminated C. rangiferina and E. mesomorpha, and a Ca concentration of 10 436 ppm discriminated H. physodes from P. sulcata. For the three parmelioid species, a Ca concentration >32 837 ppm discriminated Punctelia rudecta from the other two species, while a Zn concentration of 56 ppm discriminated Parmelia sulcata from F. flaventior. Foliose species also had higher concentrations than did fruticose species of all elements except Na. Elemental signatures for each of the six species were developed using standardized means. Twenty-four mechanisms explaining the differences among species are summarized. Finally, the relationships of four species based on element concentrations, using additive-trees clustering of a Euclidean-distance matrix, produced identical relationships as did analyses based on secondary product chemistry that used additive-trees clustering of a Jaccard similarity matrix. At least for these six species, element composition has taxonomic significance, and may be useful for discriminating other taxa.

Trace-element concentrations in streambed sediment across the conterminous United States

USGS Publications Warehouse

Rice, Karen C.

1999-01-01

Trace-element concentrations in 541 streambed-sediment samples collected from 20 study areas across the conterminous United States were examined as part of the National Water-Quality Assessment Program of the U.S. Geological Survey. Sediment samples were sieved and the <63-μm fraction was retained for determination of total concentrations of trace elements. Aluminum, iron, titanium, and organic carbon were weakly or not at all correlated with the nine trace elements examined:  arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc. Four different methods of accounting for background/baseline concentrations were examined; however, normalization was not required because field sieving removed most of the background differences between samples. The sum of concentrations of trace elements characteristic of urban settings - copper, mercury, lead, and zinc - was well correlated with population density, nationwide. Median concentrations of seven trace elements (all nine examined except arsenic and selenium) were enriched in samples collected from urban settings relative to agricultural or forested settings. Forty-nine percent of the sites sampled in urban settings had concentrations of one or more trace elements that exceeded levels at which adverse biological effects could occur in aquatic biota.

Trace element abundances in major minerals of Late Permian coals from southwestern Guizhou province, China

USGS Publications Warehouse

Zhang, Jiahua; Ren, D.; Zheng, C.; Zeng, R.; Chou, C.-L.; Liu, J.

2002-01-01

Fourteen samples of minerals were separated by handpicking from Late Permian coals in southwestern Guizhou province, China. These 14 minerals were nodular pyrite, massive recrystallized pyrite, pyrite deposited from low-temperature hydrothermal fluid and from ground water; clay minerals; and calcite deposited from low-temperature hydrothermal fluid and from ground water. The mineralogy, elemental composition, and distribution of 33 elements in these samples were studied by optical microscopy, scanning electron microscope equipped with energy-dispersive X-ray spectrometer (SEM-EDX), X-ray diffraction (XRD), cold-vapor atomic absorption spectrometry (CV-AAS), atomic fluorescence spectrometry (AFS), inductively coupled-plasma mass spectrometry (ICP-MS), and ion-selective electrode (ISE). The results show that various minerals in coal contain variable amounts of trace elements. Clay minerals have high concentrations of Ba, Be, Cs, F, Ga, Nb, Rb, Th, U, and Zr. Quartz has little contribution to the concentration of trace elements in bulk coal. Arsenic, Mn, and Sr are in high concentrations in calcite. Pyrite has high concentrations of As, Cd, Hg, Mo, Sb, Se, Tl, and Zn. Different genetic types of calcite in coal can accumulate different trace elements; for example Ba, Co, Cr, Hg, Ni, Rb, Sn, Sr, and Zn are in higher concentrations in calcite deposited from low-temperature hydrothermal fluid than in that deposited from ground water. Furthermore, the concentrations of some trace elements are quite variable in pyrite; different genetic types of pyrites (Py-A, B, C, D) have different concentrations of trace elements, and the concentrations of trace elements are also different in pyrite of low-temperature hydrothermal origin collected from different locations. The study shows that elemental concentration is rather uniform in a pyrite vein. There are many micron and submicron mosaic pyrites in a pyrite vein, which is enriched in some trace elements, such as As and Mo. The content of trace element in pyrite vein depends upon the content of mosaic pyrite and of trace elements in it. Many environmentally sensitive trace elements are mainly contained in the minerals in coal, and hence the physical coal cleaning techniques can remove minerals from coal and decrease the emissions of potentially hazardous trace elements. ?? 2002 Elsevier Science B.V. All rights reserved.

Analytical procedures for the determination of selected trace elements in peat and plant samples by inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Krachler, Michael; Mohl, Carola; Emons, Hendrik; Shotyk, William

2002-08-01

A simple, robust and reliable analytical procedure for the determination of 15 elements, namely Ca, V, Cr, Mn, Co, Ni, Cu, Zn, Rb, Ag, Cd, Ba, Tl, Th and U in peat and plant materials by inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) was developed. Powdered sample aliquots of approximately 220 mg were dissolved with various acid mixtures in a microwave heated high-pressure autoclave capable to digest 40 samples simultaneously. The selection of appropriate amounts of digestion acids (nitric acid, hydrofluoric acid or tetrafluoroboric acid) was crucial to obtain accurate results. The optimized acid mixture for digestion of plant and peat samples consisted of 3 ml HNO 3 and 0.1 ml HBF 4. An ultrasonic nebulizer with an additional membrane desolvation unit was found beneficial for the determination of Co, Ni, Ag, Tl, Th and U, allowing to aspirate a dry sample aerosol into the ICP-QMS. A pneumatic cross flow nebulizer served as sample introduction device for the other elements. Internal standardization was achieved with 103Rh for all elements, except for Th whose ICP-QMS signals were corrected by 103Rh and 185Re. Quality control was ascertained by analysis of the certified plant reference material GBW 07602 Bush Branches and Leaves. In almost all cases HNO 3 alone could not fully liberate the analytes of interest from the peat or plant matrix, probably because of the silicates present. After adding small amounts (0.05-0.1 ml) of either HF or HBF 4 to the digestion mixture, concentrations quantified by ICP-QMS generally increased significantly, in the case of Rb up to 80%. Further increasing the volumes of HF or HBF 4 in turn, resulted in a loss of recoveries of almost all elements, some of which amounted to approximately 60%. The successful analytical procedures were applied to the determination of two bulk peat materials. In general, good agreement between the found concentrations and results from an inter-laboratory trial or from instrumental neutron activation data were obtained, underpinning the suitability of the developed analytical approach.

Analysis with electron microscope of multielement samples using pure element standards

DOEpatents

King, Wayne E.

1987-01-01

A method and modified analytical electron microscope for determining the concentration of elements in a multielement sample by exposing samples with differing thicknesses for each element to a beam of electrons, simultaneously measuring the electron dosage and x-ray intensities for each sample of element to determine a "K.sub.AB " value to be used in the equation ##EQU1## where I is intensity and C is concentration for elements A and B, and exposing the multielement sample to determine the concentrations of the elements in the sample.

Space Vehicle Guidance, Navigation, Control, and Estimation Operations Technologies

DTIC Science & Technology

2018-03-29

angular position around the ellipse, and the out-of-place amplitude and angular position. These elements are explicitly relatable to the six rectangular...quasi) second order relative orbital elements are explored. One theory uses the expanded solution form and introduces several instantaneous ellipses...In each case, the theory quantifies distortion of the first order relative orbital elements when including second order effects. The new variables are

A mass-balance model to separate and quantify colloidal and solute redistributions in soil

USGS Publications Warehouse

Bern, C.R.; Chadwick, O.A.; Hartshorn, A.S.; Khomo, L.M.; Chorover, J.

2011-01-01

Studies of weathering and pedogenesis have long used calculations based upon low solubility index elements to determine mass gains and losses in open systems. One of the questions currently unanswered in these settings is the degree to which mass is transferred in solution (solutes) versus suspension (colloids). Here we show that differential mobility of the low solubility, high field strength (HFS) elements Ti and Zr can trace colloidal redistribution, and we present a model for distinguishing between mass transfer in suspension and solution. The model is tested on a well-differentiated granitic catena located in Kruger National Park, South Africa. Ti and Zr ratios from parent material, soil and colloidal material are substituted into a mixing equation to quantify colloidal movement. The results show zones of both colloid removal and augmentation along the catena. Colloidal losses of 110kgm-2 (-5% relative to parent material) are calculated for one eluviated soil profile. A downslope illuviated profile has gained 169kgm-2 (10%) colloidal material. Elemental losses by mobilization in true solution are ubiquitous across the catena, even in zones of colloidal accumulation, and range from 1418kgm-2 (-46%) for an eluviated profile to 195kgm-2 (-23%) at the bottom of the catena. Quantification of simultaneous mass transfers in solution and suspension provide greater specificity on processes within soils and across hillslopes. Additionally, because colloids include both HFS and other elements, the ability to quantify their redistribution has implications for standard calculations of soil mass balances using such index elements. ?? 2011.

Germanium and Rare Earth Element accumulation in woody bioenergy crops

NASA Astrophysics Data System (ADS)

Hentschel, Werner

2016-04-01

Germanium and REEs are strategic elements that are used for high tech devices and engineered systems, however these elements are hardly concentrated into mineable ore deposits. Since these elements occur widely dispersed in the earth crust with concentrations of several mgṡkg-1 (Ge 1.6 mgṡkg-1, Nd 25 mgṡkg-1) a new possibility to gain these elements could be phytomining, a technique that uses plants to extract elements from soils via their roots. Since knowledge about accumulating plant species is quite limited we conducted research on the concentrations of strategic elements in wood and leaves of fast growing tree species (Salix spec., Populus spec., Betula pendula, Alnus glutinosa, Fraxinus excelsior, Acer pseudoplatanus). In total 35 study sites were selected in the mining affected area around Freiberg (Saxony, Germany), differing in their species composition and degree of contamination with toxic trace metals (Pb, As, Cd). On each site plant tissues (wood and leaves, respectively) of different species were sampled. In addition soil samples were taken from a soil depth of 0 - 30 cm and 30 - 60 cm. The aim of our work was to investigate correlations between the concentrations of the target elements in plant tissues and soil characteristics like pH, texture, nutrients and concentrations in six operationally defined soil fractions (mobile, acid soluble, oxidizable, amorphic oxides, crystalline oxides, residual or siliceous). Concentrations of elements in soil extracts and plant tissues were measured with ICP-MS. The element Nd was selected as representative for the group of REEs, since this element showed a high correlation with the concentrations of the other REE We found that the concentration of Nd in the leaves (0.31 mgṡkg-1Nd) were several times higher than in herbaceous species (0.05 mgṡkg-1 Nd). The concentration of Ge in leaves were ten times lower than that of Nd whereas in herbaceous species Nd and Ge were in equal magnitude. Within the tree species Populus spec. (0.77 mgṡkg-1) and Salix spec. (0.36 mgṡkg-1) showed by far the highest concentrations of Nd in leaves. Fraxinus excelsior (0.10 mgṡkg-1) and Betula pendula (0.06 mgṡkg-1) feature the lowest concentrations of Nd in leaves. We found significant correlations between the concentration of the target elements in the plant tissue and the concentration of these elements in the first steps of the sequential extraction of the soil samples. These studies have been carried out in the framework of the PhytoGerm project financed by the Federal Ministry of Education and Research, Germany.

Quantifying uncertainties in the structural response of SSME blades

NASA Technical Reports Server (NTRS)

Nagpal, Vinod K.

1987-01-01

To quantify the uncertainties associated with the geometry and material properties of a Space Shuttle Main Engine (SSME) turbopump blade, a computer code known as STAEBL was used. A finite element model of the blade used 80 triangular shell elements with 55 nodes and five degrees of freedom per node. The whole study was simulated on the computer and no real experiments were conducted. The structural response has been evaluated in terms of three variables which are natural frequencies, root (maximum) stress, and blade tip displacements. The results of the study indicate that only the geometric uncertainties have significant effects on the response. Uncertainties in material properties have insignificant effects.

Trace elements in feed, manure, and manured soils.

PubMed

Sheppard, S C; Sanipelli, B

2012-01-01

Modern animal feeds often include nutritional mineral supplements, especially elements such as Cu, P, Se, and Zn. Other sources of trace elements also occur in livestock systems, such as pharmaceutical use of As and Zn to control gut flora, Bi in dairy for mastitis control, and Cu as hoof dips. Additionally, potential exists for inadvertent inclusion of trace elements in feeds or manures. There is concern about long-term accumulation of trace elements in manured soil that may even exceed guideline "safe" concentrations. This project measured ∼60 elements in 124 manure samples from broiler, layer, turkey, swine grower, swine nursery, sow, dairy, and beef operations. The corresponding feeds were also analyzed. In general, concentrations in manure were two- to fivefold higher than those in feed: the manure/feed concentration ratios were relatively consistent for all the animal-essential elements and were numerically similar for many of the non-nutrient elements. To confirm the potential for accumulation in soil, total trace element concentrations were measured in the profiles of 10 manured and 10 adjacent unmanured soils. Concentrations of several elements were found to be elevated in the manured soils, with Zn (and P) the most common. One soil from a dairy standing yard had concentrations of B that exceeded soil health guideline concentrations. Given that the Cu/P and Zn/P ratios found in manure were greater than typically reported in harvested crop materials, these elements will accumulate in soil even if manure application rates are managed to prevent accumulation of P in soil. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Intra-clutch and inter-colony variability in element concentrations in eggshells of the black-headed gull, Chroicocephalus ridibundus, in northern Poland.

PubMed

Kitowski, Ignacy; Indykiewicz, Piotr; Wiącek, Dariusz; Jakubas, Dariusz

2017-04-01

Eggshells are good bioindicators of environmental contamination, and therefore, the concentrations of 17 trace elements in 87 eggshells of black-headed gulls, Chroicocephalus ridibundus, were determined in five breeding colonies in an area dominated by farmland in northern Poland. The intra-clutch variability in the eggshell concentrations of heavy metals and other elements was also investigated, and the concentrations of the elements showed the following pattern: Ca > Mg > Sr > Fe > Zn > Al > Cr > Se > Mn > Cu > Pb > As > Ni > Mo = V > Sc > Cd. The concentrations of Fe, Al, and Mn decreased with the order in which the eggs were laid, but Sr concentrations increased. In contrast, the concentration of Cu significantly increased with the laying date. The concentrations of all elements significantly differed among the studied colonies; the highest concentration of eight elements was found in the eggshells from the Kusowo colony, which may have resulted from the intensive use of fertilizers, manure, and slurry in the surrounding agricultural region. The concentrations of Mg, Sr, and Zn in the eggshells from Skoki Duże were higher than those of the other studied colonies, which may have occurred because the gulls were nesting in a functioning gravel pit; soil and the parent rock are natural reservoirs of these elements. The observed element levels indicate that the environment where the black-headed gull eggs were formed, i.e., primarily near the breeding colonies, remains in a relatively unpolluted state, which was reflected by the low levels of Cd, Ni, and Pb and the lack of measurable levels of Hg.

Comparison of trace element concentrations in livers of diseased, emaciated and non-diseased southern sea otters from the California coast

USGS Publications Warehouse

Kannan, K.; Agusa, T.; Perrotta, E.; Thomas, N.J.; Tanabe, S.

2006-01-01

Infectious diseases have been implicated as a cause of high rates of adult mortality in southern sea otters. Exposure to environmental contaminants can compromise the immuno-competence of animals, predisposing them to infectious diseases. In addition to organic pollutants, certain trace elements can modulate the immune system in marine mammals. Nevertheless, reports of occurrence of trace elements, including toxic heavy metals, in sea otters are not available. In this study, concentrations of 20 trace elements (V, Cr, Mn, Co, Cu, Zn, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb, and Bi) were measured in livers of southern sea otters found dead along the central California coast (n = 80) from 1992 to 2002. Hepatic concentrations of trace elements were compared among sea otters that died from infectious diseases (n = 27), those that died from non-infectious causes (n = 26), and otters that died in emaciated condition with no evidence of another cause of death (n = 27). Concentrations of essential elements in sea otters varied within an order of magnitude, whereas concentrations of non-essential elements varied by two to five orders of magnitude. Hepatic concentrations of Cu and Cd were 10- to 100-fold higher in the sea otters in this study than concentrations reported for any other marine mammal species. Concentrations of Mn, Co, Zn, and Cd were elevated in the diseased and emaciated sea otters relative to the non-diseased sea otters. Elevated concentrations of essential elements such as Mn, Zn, and Co in the diseased/emaciated sea otters suggest that induction of synthesis of metallothionein and superoxide dismutase (SOD) enzyme is occurring in these animals, as a means of protecting the cells from oxidative stress-related injuries. Trace element profiles in diseased and emaciated sea otters suggest that oxidative stress mediates the perturbation of essential-element concentrations. Elevated concentrations of toxic metals such as Cd, in addition to several other organic pollutants, may contribute to oxidative stress-meditated effects in sea otters.

Taking Yellowstone's Temperature: a New Clinopyroxene Geothermometer to Improve Timescales of Pre-eruptive Events

NASA Astrophysics Data System (ADS)

Brugman, K. K.; Till, C. B.

2017-12-01

The goal of our research is to quantify the time period between events in the magma chamber and eruption for the Scaup Lake rhyolite lava, as it erupted after a period of quiescence similar to what Yellowstone is experiencing today. The overarching goal of studies such as this that focus on past eruptions is to provide context and statistics that will ultimately improve volcano monitoring at different types of active volcanoes. The Scaup Lake flow contains zoned minerals (e.g., feldspar, zircon, clinopyroxene) that record multiple magma injection events shortly before they were erupted. Our previous work using nano-scale elemental concentration profiles from zoned clinopyroxene (cpx) as a diffusion dating tool reinforced our hypothesis that different minerals may not record the same series of pre-eruptive events, and that cpx crystal rims record older events in the Scaup Lake flow (on the order of 100s of years prior to eruption [Brugman et al., AGU OSPA talk, 2016]) than do feldspar rims (< 10 months and 10-40 years prior to eruption [Till et al., Geology, 2015]). In light of new temperature data, we have updated our diffusion dating results to better quantify pre-eruption timescales at Yellowstone.

ENVIRONMENTAL REACTIVITY OF SOLID STATE HYDRIDE MATERIALS: MODELING AND TESTING FOR AIR AND WATER EXPOSURE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anton, D.; James, C.; Cortes-Concepcion, J.

2010-05-18

To make commercially acceptable condensed phase hydrogen storage systems, it is important to understand quantitatively the risks involved in using these materials. A rigorous set of environmental reactivity tests have been developed based on modified testing procedures codified by the United Nations for the transportation of dangerous goods. Potential hydrogen storage material, 2LiBH4{center_dot}MgH2 and NH3BH3, have been tested using these modified procedures to evaluate the relative risks of these materials coming in contact with the environment in hypothetical accident scenarios. It is apparent that an ignition event will only occur if both a flammable concentration of hydrogen and sufficient thermalmore » energy were available to ignite the hydrogen gas mixture. In order to predict hydride behavior for hypothesized accident scenarios, an idealized finite element model was developed for dispersed hydride from a breached system. Empirical thermodynamic calculations based on precise calorimetric experiments were performed in order to quantify the energy and hydrogen release rates and to quantify the reaction products resulting from water and air exposure. Both thermal and compositional predictions were made with identification of potential ignition event scenarios.« less

Composition of milk from llamas in the United States.

PubMed

Morin, D E; Rowan, L L; Hurley, W L; Braselton, W E

1995-08-01

Neonatal llamas must receive supplemental milk when the dam has inadequate milk yield or fails to accept the cria. Data on llama milk composition are limited, and selection of suitable milk supplements has been difficult. Milk from 83 llamas on eight farms in four states (Illinois, Kentucky, Michigan, and Colorado) was collected, and milk composition was analyzed. Llamas had no history or signs of mastitis, and major mastitis pathogens were not isolated from the milk. Total solids were determined gravimetrically. A colorimetric method, a dye-binding assay, and the modified Mojonnier method were used to quantify lactose, protein, and fat, respectively. Concentrations of seven macrominerals and 17 trace elements were obtained by inductively coupled plasma atomic emission spectroscopy, and Cl was quantified by anion chromatography. Llama milk was higher in sugar (6.5%) and lower in fat (2.7%) and energy content (70.0 kcal/100 g) than milks of domestic ruminants. Llama milk also contained more Ca and less Na, K, and Cl. In general, milk composition was not affected by stage of lactation, lactation number, or body condition score of the llama, but several milk constituents varied among farms.

Some aspects of water quality in a polluted lowland river in relation to the intracellular chemical levels in planktonic and epilithic diatoms.

PubMed

Tien, Chien-Jung

2004-04-01

Changes in elemental concentrations of diatoms and river water from the river Erh-Jen were determined using scanning electron microscopy energy-dispersive X-ray microanalysis and inductively coupled plasma mass spectrometry. Relatively large amounts of copper and lead found in both planktonic and epilithic diatoms implied these algae might play an important role in biogeochemical cycles and in the transfer of those elements to higher trophic levels in the aquatic environment. Changes in elemental concentrations within diatom cells were found to vary with other elements within cells and the same or different elements in water. Planktonic and epilithic cells showed different correlation patterns. For epilithic diatoms, negative correlations were found between concentrations of total phosphorus and phosphate in water and those of phosphorus within cells, and between concentrations of lead in water and in cells. Concentrations of chromium and mercury within planktonic cells and those of phosphorus, manganese and lead within epilithic ones were found to be easily influenced by other elements in river water, indicating appearance of the competitive manner on uptake of such elements by algal cells. Relatively high concentration factors (CFs) for cadmium, mercury and lead by diatoms in this study suggested they are good accumulators for these heavy metals. Significant negative corrections were found between the CFs of diatoms and the concentrations of elements in river water.

Skin collagen can be accurately quantified through noninvasive optical method: Validation on a swine study.

PubMed

Tzeng, S-Y; Kuo, T-Y; Hu, S-B; Chen, Y-W; Lin, Y-L; Chu, K-Y; Tseng, S-H

2018-02-01

Diffuse reflectance spectroscopy (DRS) is a noninvasive optical technology characterized by relatively low system cost and high efficiency. In our previous study, we quantified the relative concentration of collagen for the individual keloid patient. However, no actual value of collagen concentration can prove the reliability of collagen detection by our DRS system. Skin-mimicking phantoms were prepared using different collagen and coffee concentrations, and their chromophore concentrations were quantified using the DRS system to analyze the influence of collagen and other chromophores. Moreover, we used the animal study to compare the DRS system with the collagen evaluation of biopsy section by second-harmonic generation (SHG) microscopy at four different skin parts. In the phantom study, the result showed that coffee chromophore did not severely interfere with collagen concentration recovery. In the animal study, a positive correlation (r=.902) between the DRS system and collagen evaluation with SHG microscopy was found. We have demonstrated that the DRS system can quantify the actual values of collagen concentration and excluded the interference of other chromophores in skin-mimicking phantoms. Furthermore, a high positive correlation was found in the animal study with SHG microscopy. We consider that the DRS is a potential technique and can evaluate skin condition objectively. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Elemental composition and sources of fine and ultrafine ambient particles in Erfurt, Germany.

PubMed

Cyrys, J; Stölzel, M; Heinrich, J; Kreyling, W G; Menzel, N; Wittmaack, K; Tuch, T; Wichmann, H-Erich

2003-04-15

We present the first results of a source apportionment for the urban aerosol in Erfurt, Germany, for the period 1995-1998. The analysis is based on data of particle number concentrations (0.01-2.5 microm; mean 1.8 x 10(4) cm(-3), continuous), the concentration of the ambient gases SO(2), NO, NO(2) and CO (continuous), particle mass less than 2.5 microm (PM(2.5)) and less than 10 microm (PM(10)) (Harvard Impactor sampling, mean PM(2.5) 26.3 micro/m(3), mean PM(10) 38.2 microg/m(3)) and the size fractionated concentrations of 19 elements (impactor sampling 0.05-1.62 microm, PIXE analysis). We determined: (a) the correlations between (i) the 1- and 24-h average concentrations of the gaseous pollutants and the particle number as well as the particle mass concentration and (ii) between the 24-h elemental concentrations; (b) Crustal Enrichment Factors for the PIXE elements using Si as reference element; and (c) the diurnal pattern of the measured pollutants on weekdays and on weekends. The highly correlated PIXE elements Si, Al, Ti and Ca having low enrichment factors were identified as soil elements. The strong correlation of particle number concentrations with NO, which is considered to be typically emitted by traffic, and the striking similarity of their diurnal variation suggest that a sizable fraction of the particle number concentration is associated with emission from vehicles. Besides NO and particle number concentrations other pollutants such as NO(2), CO as well as the elements Zn and Cu were strongly correlated and appear to reflect motor vehicle traffic. Sulfur could be a tracer for coal combustion, however, it was not correlated with any of the quoted elements. Highly correlated elements V and Ni have similar enrichment factors and are considered as tracers for oil combustion.

Feasibility of coupling a thermal/optical carbon analyzer to a quadrupole mass spectrometer for enhanced PM2.5 speciation.

PubMed

Riggio, Gustavo M; Chow, Judith C; Cropper, Paul M; Wang, Xiaoliang; Yatavelli, Reddy L N; Yang, Xufei; Watson, John G

2018-05-01

A thermal/optical carbon analyzer (TOA), normally used for quantification of organic carbon (OC) and elemental carbon (EC) in PM 2.5 (fine particulate matter) speciation networks, was adapted to direct thermally evolved gases to an electron impact quadrupole mass spectrometer (QMS), creating a TOA-QMS. This approach produces spectra similar to those obtained by the Aerodyne aerosol mass spectrometer (AMS), but the ratios of the mass to charge (m/z) signals differ and must be remeasured using laboratory-generated standards. Linear relationships are found between TOA-QMS signals and ammonium (NH 4 + ), nitrate (NO 3 - ), and sulfate (SO 4 2- ) standards. For ambient samples, however, positive deviations are found for SO 4 2- , compensated by negative deviations for NO 3 - , at higher concentrations. This indicates the utility of mixed-compound standards for calibration or separate calibration curves for low and high ion concentrations. The sum of the QMS signals across all m/z after removal of the NH 4 + , NO 3 - , and SO 4 2- signals was highly correlated with the carbon content of oxalic acid (C₂H₂O₄) standards. For ambient samples, the OC derived from the TOA-QMS method was the same as the OC derived from the standard IMPROVE_A TOA method. This method has the potential to reduce complexity and costs for speciation networks, especially for highly polluted urban areas such as those in Asia and Africa. Ammonium, nitrate, and sulfate can be quantified by the same thermal evolution analysis applied to organic and elemental carbon. This holds the potential to replace multiple parallel filter samples and separate laboratory analyses with a single filter and a single analysis to account for a large portion of the PM 2.5 mass concentration.

New technique for quantification of elemental hg in mine wastes and its implications for mercury evasion into the atmosphere

USGS Publications Warehouse

Jew, A.D.; Kim, C.S.; Rytuba, J.J.; Gustin, M.S.; Brown, Gordon E.

2011-01-01

Mercury in the environment is of prime concern to both ecosystem and human health. Determination of the molecular-level speciation of Hg in soils and mine wastes is important for understanding its sequestration, mobility, and availability for methylation. Extended X-ray absorption fine structure (EXAFS) spectroscopy carried out under ambient P-T conditions has been used in a number of past studies to determine Hg speciation in complex mine wastes and associated soils. However, this approach cannot detect elemental (liquid) mercury in Hg-polluted soils and sediments due to the significant structural disorder of liquid Hg at ambient-temperature. A new sample preparation protocol involving slow cooling through the crystallization temperature of Hg(0) (234 K) results in its transformation to crystalline ??-Hg(0). The presence and proportion of Hg(0), relative to other crystalline Hg-bearing phases, in samples prepared in this way can be quantified by low-temperature (77 K) EXAFS spectroscopy. Using this approach, we have determined the relative concentrations of liquid Hg(0) in Hg mine wastes from several sites in the California Coast Range and have found that they correlate well with measured fluxes of gaseous Hg released during light and dark exposure of the same samples, with higher evasion ratios from samples containing higher concentrations of liquid Hg(0). Two different linear relationships are observed in plots of the ratio of Hg emission under light and dark conditions vs % Hg(0), corresponding to silica-carbonate- and hot springs-type Hg deposits, with the hot springs-type samples exhibiting higher evasion fluxes than silica-carbonate type samples at similar Hg(0) concentrations. Our findings help explain significant differences in Hg evasion data for different mine sites in the California Coast Range. ?? 2011 American Chemical Society.

Metals geochemistry and mass export from the Mississippi-Atchafalaya River system to the Northern Gulf of Mexico.

PubMed

Reiman, Jeremy H; Xu, Y Jun; He, Songjie; DelDuco, Emily M

2018-08-01

Discharging 680 km 3 of freshwater annually to the Northern Gulf of Mexico (NGOM), the Mississippi-Atchafalaya River System (MARS) plays a significant role in transporting major and trace elements to the ocean. In this study, we analyzed total recoverable concentrations of thirty-one metals from water samples collected at five locations along the MARS during 2013-2016 to quantify their seasonal mass exports. The Atchafalaya River flows through a large swamp floodplain, allowing us to also test the hypothesis that floodplains function as a sink for metals. We found that the seven major elements (Ca, Na, Mg, Si, K, Al, and Fe) constituted 99% of the total annual mass load of metals (7.38 × 10 7 tons) from the MARS. Higher concentrations of Al, Ba, B, Ca, Fe, Mg, Mn, Ag, and Ti were found in the Mississippi River, while significantly higher Si and Na concentrations were found in the Atchafalaya River. Significant relationships were found between daily discharge and daily loads of Ba, Ca, Fe, K, Sr, and Ti in both rivers, while significant relationships were also found for Al, Mg, Mn, V, and Zn in the Atchafalaya River and B in the Mississippi River. Overall, the Mississippi River contributed 64-76% of the total annual loading of metals from the MARS to the NGOM. Daily loads of Al, Ba, B, Fe, Li, Mn, P, K, Si, Ag, Ti, V, and Zn regularly decreased upstream to downstream in the Atchafalaya River, partially accepting the initial hypothesis on metals transport in river floodplains. Copyright © 2018 Elsevier Ltd. All rights reserved.

Major and trace elements in igneous rocks from Apollo 15.

NASA Technical Reports Server (NTRS)

Helmke, P. A.; Blanchard, D. P.; Haskin, L. A.; Telander, K.; Weiss, C.; Jacobs, J. W.

1973-01-01

The concentrations of major and trace elements have been determined in igneous rocks from Apollo 15. All materials analyzed have typical depletions of Eu except for minerals separated from sample 15085. Four samples have concentrations of trace elements that are similar to those of KREEP. The samples of mare basalt from Apollo 15 have higher concentrations of FeO, MgO, Mn, and Cr and lower concentrations of CaO, Na2O, K2O, and rare-earth elements (REE) as compared to the samples of mare basalt from Apollos 11, 12, and 14. The samples can be divided into two groups on the basis of their normative compositions. One group is quartz normative and has low concentrations of FeO while the other is olivine normative and has high concentrations of FeO. The trace element data indicate that the samples of olivine normative basalt could be from different portions of a single lava flow.

Quantifying Gold Nanoparticle Concentration in a Dietary Supplement Using Smartphone Colorimetry and Google Applications

ERIC Educational Resources Information Center

Campos, Antonio R.; Knutson, Cassandra M.; Knutson, Theodore R.; Mozzetti, Abbie R.; Haynes, Christy L.; Penn, R. Lee

2016-01-01

Spectrophotometry and colorimetry experiments are common in high school and college chemistry courses, and nanotechnology is increasingly common in every day products and new devices. Previous work has demonstrated that handheld camera devices can be used to quantify the concentration of a colored analyte in solution in place of traditional…

Chemical element concentrations in four lichens on a transect entering Voyageurs National Park

USGS Publications Warehouse

Bennett, J.; Wetmore, C.M.

1997-01-01

A three factor transect study was conducted to test the hypothesis that chemical elements from air emissions in the vicinity of International Falls, Minnesota could not be detected in lichens along a 24 km transect reaching into Voyageurs National Park. It was hypothesized that element concentrations in lichens would decline exponentially downwind and would reach background values at a distance before the park boundary. Four species (Cladina rangiferina, Evernia mesomorpha, Hypogymnia physodes, and Parmelia sulcata) were sampled at ten sites for 3 years and 17 chemical elements were measured. The most notable result was a curvilinear geographic trend for many elements, which decreased from International Falls and then increased towards the park. This trend was significant for many anthropogenic elements, including S, Hg, Cd, and Cr, and for all four species. This type of distribution pattern has been observed in Hypogymnia physodes in other studies downwind of a steel mill and an oil refinery. Cladina, a ground-dwelling lichen, generally had lower tissue concentrations of the elements than the three epiphytic species. Tissue concentrations over the 3 years of sampling declined an average of 12%. Sufficient evidence exists to conclude that lichen tissue element concentrations in the vicinity of International Falls may be related to local air emissions, and that an exponential decline of element concentrations downwind of the sources does not apply to this situation.

Quantifying transfer after perceptual-motor sequence learning: how inflexible is implicit learning?

PubMed

Sanchez, Daniel J; Yarnik, Eric N; Reber, Paul J

2015-03-01

Studies of implicit perceptual-motor sequence learning have often shown learning to be inflexibly tied to the training conditions during learning. Since sequence learning is seen as a model task of skill acquisition, limits on the ability to transfer knowledge from the training context to a performance context indicates important constraints on skill learning approaches. Lack of transfer across contexts has been demonstrated by showing that when task elements are changed following training, this leads to a disruption in performance. These results have typically been taken as suggesting that the sequence knowledge relies on integrated representations across task elements (Abrahamse, Jiménez, Verwey, & Clegg, Psychon Bull Rev 17:603-623, 2010a). Using a relatively new sequence learning task, serial interception sequence learning, three experiments are reported that quantify this magnitude of performance disruption after selectively manipulating individual aspects of motor performance or perceptual information. In Experiment 1, selective disruption of the timing or order of sequential actions was examined using a novel response manipulandum that allowed for separate analysis of these two motor response components. In Experiments 2 and 3, transfer was examined after selective disruption of perceptual information that left the motor response sequence intact. All three experiments provided quantifiable estimates of partial transfer to novel contexts that suggest some level of information integration across task elements. However, the ability to identify quantifiable levels of successful transfer indicates that integration is not all-or-none and that measurement sensitivity is a key in understanding sequence knowledge representations.

Trace elements in loggerhead turtles (Caretta caretta) stranded in mainland Portugal: Bioaccumulation and tissue distribution.

PubMed

Nicolau, Lídia; Monteiro, Sílvia S; Pereira, Andreia T; Marçalo, Ana; Ferreira, Marisa; Torres, Jordi; Vingada, José; Eira, Catarina

2017-07-01

Pollution is among the most significant threats that endanger sea turtles worldwide. Waters off the Portuguese mainland are acknowledged as important feeding grounds for juvenile loggerheads. However, there is no data on trace element concentrations in marine turtles occurring in these waters. We present the first assessment of trace element concentrations in loggerhead turtles (Caretta caretta) occurring off the coast of mainland Portugal. Also, we compare our results with those from other areas and discuss parameters that may affect element concentrations. Trace element concentrations (As, Cd, Cu, Pb, Mn, Hg, Ni, Se, Zn) were determined in kidney, liver and muscle samples from 38 loggerheads stranded between 2011 and 2013. As was the only element with higher concentrations in muscle (14.78 μg g -1 ww) than in liver or kidney. Considering non-essential elements, Cd presented the highest concentrations in kidney (34.67 μg g -1 ) and liver (5.03 μg g -1 ). Only a weak positive link was found between renal Cd and turtle size. Inter-elemental correlations were observed in both liver and kidney tissues. Hepatic Hg values (0.30 ± 0.03 μg g -1 ) were higher than values reported in loggerheads in the Canary Islands but lower than in Mediterranean loggerheads. Cd concentrations in the present study were only exceeded by values found in turtles from the Pacific. Although many endogenous and exogenous parameters related with complex life cycle changes and wide geographic range may influence trace element accumulation, the concentrations of Cd are probably related to the importance of crustaceans in loggerhead diet in the Portuguese coast. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nicotine concentrations in electronic cigarette refill and do-it-yourself fluids.

PubMed

Davis, Barbara; Dang, Michael; Kim, Jisoo; Talbot, Prue

2015-02-01

We evaluated the accuracy of nicotine concentration labeling on electronic cigarette refill products. The nicotine concentration of 71 electronic cigarette refill fluid products and 1 related do-it-yourself (DIY) product was quantified using high-performance liquid chromatography. Quantified data were compared with manufacturers labeled concentrations. Duplicate refill fluid products purchased at different times were evaluated by visual comparison of fluid coloration and quantified nicotine concentration. Thirty-five of the 54 nicotine-containing fluids had quantified nicotine concentrations that deviated by more than ± 10% from the manufacturer labels, with 46 of 50 being in excess of labeled values. Refill fluids labeled as 0 nicotine had no detectable nicotine. Of the 5 products that were unlabeled for nicotine concentration, 3 contained no detectable nicotine, whereas the remaining 2 contained nicotine in excess of 100mg/ml and may have been intended for DIY use. Sixteen of the 18 duplicate bottles of refill fluid varied greatly in their nicotine concentrations. One of the 5 companies showed significant improvement in labeling accuracy among the most recently purchased products. Of the 23 total duplicate pairs, 15 of 23 varied in coloration from their mates. Nicotine concentration labeling on electronic cigarette refill products was often inaccurate but showed improvement recently in products from 1 company. To ensure the safety of refill fluids and DIY products, it is necessary to establish quality control guidelines for the manufacturing and labeling and to monitor products longitudinally. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Dynamics of PM2.5 and its Chemical Components During 2015 Spring Festival Period in Beijing, China

NASA Astrophysics Data System (ADS)

Zhang, Y.; Wei, J.; Tang, A.; Zheng, A.; Liu, X.

2016-12-01

Air pollution especially PM2.5 (particles with aerodynamic diameter smaller than 2.5 µm) pollution is a serious problem in Beijing, a megacity in China. In order to quantify the status of PM2.5 pollution as affected by holiday pollution events, we collected and analyzed in urban Beijing during the 2015 Spring Festival period (from February 9th to March 6th 2015). We divided the Spring Festival period into three types of pollution days: normal, haze and fireworks days. The air quality in fireworks and haze days were both substantially worse than that in normal days. The average mass concentration of PM2.5 in fireworks days was 248.9 μg m-3, which was followed by haze days (199.9 μg m-3), and normal days (90.8 μg m-3). Secondary inorganic ions (SO42-, NO3- and NH4+) were enriched in haze days, while the ions of PM2.5 in fireworks days showed high Cl- and K+, but low NO3- and NH4+. Ratios of NO3- /SO42-, SO42-/K+ and Cl- /K+ effective distinguish the characteristics of PM2.5 between fireworks events and haze days. Ion balance calculations indicate that the acidity of PM2.5 from fireworks days was higher than those from haze and normal days. Al, Ca, Fe, and S were the dominant elements in normal days. The concentrations of As, Ba, Cd, Cr, Cu, Pb, S, Se and Zn in haze days were 2.1-10.4 times higher than that in normal days. But fireworks days caused increases in the concentrations of typical fireworks elements Al, Mg, S, Ba, Cu, Pb, Sr, and Zn. It is obvious that the levels of these pollution elements during fireworks days were 1.6-18.6 times higher than that in haze days. A method using EF has been found that fireworks elements (EF>10 in fireworks days, significantly higher than haze days) were made up of Ba, Cr, Cu, Mg, Pb, S, Si, Zn, and common anthropogenic pollution elements (EF>10 in all three sections), such as As, Cd, Cu, Pb, S, Sb, Zn, which would be mainly originated from anthropogenic sources. Therefore reducing anthropogenic reactive N and other pollutants emissions is crucial to tackle PM2.5 pollution in Beijing during traditional festival period.

Localisation of flow separation and transition over a pitching NACA0012 airfoil at transitional Reynolds number

NASA Astrophysics Data System (ADS)

Rudmin, Daniel

Ionic polymer-metal composites (IPMCs) are some of the most well-known electro-active polymers. This is due to their large deformation provided a relatively low voltage source. IPMCs have been acknowledged as a potential candidate for biomedical applications such as cardiac catheters and surgical probes; however, there is still no existing mass manufacturing of IPMCs. This study intends to provide a theoretical framework which could be used to design practical purpose IPMCs depending on the end users interest. This study begins by investigating methodologies used to develop quantify the physical actuation of an IPMC in 3-dimensional space. This approach is taken in two separate means; however, both approaches utilize the finite element method. The first approach utilizes the finite element method in order to describe the dynamic response of a segmented IPMC actuator. The first approach manually constructs each element with a local coordinate system. Each system undergoes a rigid body motion along the element and deformation of the element is expressed in the local coordinate frame. The physical phenomenon in this system is simplified by utilizing a lumped RC model in order to simplify the electro-mechanical phenomena in the IPMC dynamics. The second study investigates 3D modeling of a rod shaped IPMC actuator by explicitly coupling electrostatics, transport phenomenon, and solid mechanics. This portion of the research will briefly discuss the mathematical background that more accurately quantifies the physical phenomena. Solving for the 3-dimensional actuation is explicitly carried out again by utilizing the finite element method. The numerical result is conducted in a software package known as COMSOL MULTIPHYSICS. This simulation allows for explicit geometric rendering as well as more explicit quantification of the physical quantities such as concentration, electric field, and deflection. The final study will conduct design optimization on the COMSOL simulation in order to provide conceptual motivation for future designs. Utilizing a multi-physics analysis approach on a three dimensional cylinder and tube type IPMC provides physically accurate results for time dependent end effector displacement given a voltage source. Simulations are conducted with the finite element method and are also validated with empirical evidences. Having an in-depth understanding of the physical coupling provides optimal design parameters that cannot be altered from a standard electro-mechanical coupling. These parameters are altered in order to determine optimal designs for end-effector displacement, maximum force, and improved mobility with limited voltage magnitude. Design alterations are conducted on the electrode patterns in order to provide greater mobility, electrode size for efficient bending, and Nafion diameter for improved force. The results of this study will provide optimal design parameters of the IPMC for different applications.

Concentration of stable elements in food products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montford, M.A.; Shank, K.E.; Hendricks, C.

1980-01-01

Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentrationmore » of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed.« less

Elemental analysis of urinary calculi by laser induced plasma spectroscopy.

PubMed

Fang, Xiao; Ahmad, S Rafi; Mayo, Mike; Iqbal, Syed

2005-12-01

Laser induced plasma spectroscopy (LIPS) has been applied to analyse and identify elemental constituents of urinary calculi. Measurements on seven different urinary stone samples were conducted and the concentrations of some key elemental species were estimated. The elements detected with the present system were: Calcium, Magnesium, Sodium, Samarium, Potassium and Lead. Absolute concentrations of the species were derived from pre-calibration of the system for each element. Their concentrations were found to be widely different in different samples. It was observed that the samples containing a significant amount of lead have large proportion of calcium. It has been established that LIPS would allow real time clinic measurements of elemental contents and the concentrations in the biomaterials without sample preparation. The technique has the potential for routine clinic applications in urological disorder diagnosis.

Vertical distribution of trace-element concentrations and occurrence of metallurgical slag particles in accumulated bed sediments of Lake Roosevelt, Washington, September 2002

USGS Publications Warehouse

Cox, S.E.; Bell, P.R.; Lowther, J.S.; Van Metre, P.C.

2005-01-01

Sediment cores were collected from six locations in Lake Roosevelt to determine the vertical distributions of trace-element concentrations in the accumulated sediments of Lake Roosevelt. Elevated concentrations of arsenic, cadmium, copper, lead, mercury, and zinc occurred throughout much of the accumulated sediments. Concentrations varied greatly within the sediment core profiles, often covering a range of 5 to 10 fold. Trace-element concentrations typically were largest below the surficial sediments in the lower one-half of each profile, with generally decreasing concentrations from the 1964 horizon to the surface of the core. The trace-element profiles reflect changes in historical discharges of trace elements to the Columbia River by an upstream smelter. All samples analyzed exceeded clean-up guidelines adopted by the Confederated Tribes of the Colville Reservation for cadmium, lead, and zinc and more than 70 percent of the samples exceeded cleanup guidelines for mercury, arsenic, and copper. Although 100 percent of the samples exceeded sediment guidelines for cadmium, lead, and zinc, surficial concentrations of arsenic, copper, and mercury in some cores were less than the sediment-quality guidelines. With the exception of copper, the trace-element profiles of the five cores collected along the pre-reservoir Columbia River channel typically showed trends of decreasing concentrations in sediments deposited after the 1964 time horizon. The decreasing concentrations of trace elements in the upper half of cores from along the pre-reservoir Columbia River showed a pattern of decreasing concentrations similar to reductions in trace-element loading in liquid effluent from an upstream smelter. Except for arsenic, trace-element concentrations typically were smaller at downstream reservoir locations along the pre-reservoir Columbia River. Trace-element concentration in sediments from the Spokane Arm of the reservoir showed distinct differences compared to the similarities observed in cores from along the pre-reservoir Columbia River. Particles of slag, which have physical and chemical characteristics of slag discharged to the Columbia River by a lead-zinc smelter upstream of the reservoir at Trail, British Columbia, were found in sediments of Lake Roosevelt. Slag particles are more common in the upstream reaches of the reservoir. The chemical composition of the interior matrix of slag collected from Lake Roosevelt closely approximated the reported elemental concentrations of fresh smelter slag, although evidence of slag weathering was observed. Exfoliation flakes were observed on the surface of weathered slag particles isolated from the core sediments. The concentrations of zinc on the exposed surface of slag grains were smaller than concentrations on interior surfaces. Weathering rinds also were observed in the cross section of weathered slag grains, indicating that the glassy slag material was undergoing hydration and chemical weathering. Trace elements observed in accumulated sediments in the middle and lower reaches of the reservoir are more likely due to the input from liquid effluent discharges compared to slag discharges from the upstream smelter.

Discrimination of lichen genera and species using element concentrations

USGS Publications Warehouse

Bennett, J.P.

2008-01-01

The importance of organic chemistry in the classification of lichens is well established, but inorganic chemistry has been largely overlooked. Six lichen species were studied over a period of 23 years that were growing in 11 protected areas of the northern Great Lakes ecoregion, which were not greatly influenced by anthropogenic particulates or gaseous air pollutants. The elemental data from these studies were aggregated in order to test the hypothesis that differences among species in tissue element concentrations were large enough to discriminate between taxa faithfully. Concentrations of 16 chemical elements that were found in tissue samples from Cladonia rangiferina, Evernia mesomorpha, Flavopunctelia flaventior, Hypogymnia physodes, Parmelia sulcata, and Punctelia rudecta were analyzed statistically using multivariate discriminant functions and CART analyses, as well as t-tests. Genera and species were clearly separated in element space, and elemental discriminant functions were able to classify 91-100 of the samples correctly into species. At the broadest level, a Zn concentration of 51 ppm in tissues of four of the lichen species effectively discriminated foliose from fruticose species. Similarly, a S concentration of 680 ppm discriminated C. rangiferina and E. mesomorpha, and a Ca concentration of 10 436 ppm discriminated H. physodes from P. sulcata. For the three parmelioid species, a Ca concentration >32 837 ppm discriminated Punctelia rudecta from the other two species, while a Zn concentration of 56 ppm discriminated Parmelia sulcata from F. flaventior. Foliose species also had higher concentrations than did fruticose species of all elements except Na. Elemental signatures for each of the six species were developed using standardized means. Twenty-four mechanisms explaining the differences among species are summarized. Finally, the relationships of four species based on element concentrations, using additive-trees clustering of a Euclidean-distance matrix, produced identical relationships as did analyses based on secondary product chemistry that used additive-trees clustering of a Jaccard similarity matrix. At least for these six species, element composition has taxonomic significance, and may be useful for discriminating other taxa. ?? 2008 British Lichen Society.

Characterizing suspended sediments from the Piracicaba River Basin by means of k0-INAA

NASA Astrophysics Data System (ADS)

França, E. J.; Fernandes, E. A. N.; Cavalca, I. P. O.; Fonseca, F. Y.; Camilli, L.; Rodrigues, V. S.; Bardini Junior, C.; Ferreira, J. R.; Bacchi, M. A.

2010-10-01

The inorganic chemical characterization of suspended sediments is of utmost relevance for the knowledge of the dynamics and movement of chemical elements in the aquatic and wet ecosystems. Despite the complexity of the effective design for studying this ecological compartment, this work has tested a procedure for analyzing suspended sediments by instrumental neutron activation analysis, k0 method ( k0-INAA). The chemical elements As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, K, La, Mo, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Yb and Zn were quantified in the suspended sediment compartment by means of k0-INAA. When compared with World Average for rivers, high mass fractions of Fe (222,900 mg/kg), Ba (4990 mg/kg), Zn (1350 mg/kg), Cr (646 mg/kg), Co (74.5 mg/kg), Br (113 mg/kg) and Mo (31.9 mg/kg) were quantified in suspended sediments from the Piracicaba River, the Piracicamirim Stream and the Marins Stream. Results of the principal component analysis for standardized chemical element mass fractions indicated an intricate correlation among chemical elements evaluated, as a response of the contribution of natural and anthropogenic sources of chemical elements for ecosystems.

Quantifying biomineralization of zinc in the Rio Naracauli (Sardinia, Italy), using a tracer injection and synoptic sampling

USGS Publications Warehouse

De Giudici, Giovanni; Wanty, Richard B.; Podda, F.; Kimball, Briant A.; Verplanck, Philip L.; Lattanzi, P.; Cidu, R.; Medas, D.

2014-01-01

Streams draining mined areas throughout the world commonly have high concentrations of Zn. Because Zn is not easily removed from stream water and because it can be toxic to aquatic organisms, its presence is a persistent problem. The discovery of biomineralization of Zn-bearing solids in the mine drainage of Rio Naracauli, in Sardinia, Italy, provides insights into strategies for removing Zn and improving water quality in streams affected by mine drainage. Until now, the transport and attenuation of Zn has not been quantified in this stream setting. A continuous tracer injection experiment was conducted to quantify the biomineralization process and to identify the loading of constituents that causes a change from precipitation of hydrozincite [Zn5(CO3)2(OH)6] in the upstream reach to precipitation of a Zn-silicate phase downstream. Based on the mass-load calculations derived from the tracer experiment, about 1.2 kg/day of Zn is sequestered in hydrozincite. This biomineralization represents nearly 90% removal of Zn. Other elements such as Pb and Cd also are sequestered, either in the hydrozincite, or in a separate phase that forms simultaneously. In the lower 600 m of the stream, where the Zn-silicate forms, as much as 0.7 kg/day Zn are sequestered in this solid, but additions of Zn to the stream from groundwater discharge lead to an overall increase in load in that portion of the Rio Naracauli.

Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

PubMed

Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

2016-11-01

Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

Chemistry and origin of minor and trace elements in vitrinite concentrates from a rank series from the eastern United States, England, and Australia

USGS Publications Warehouse

Lyons, P.C.; Palmer, C.A.; Bostick, N.H.; Fletcher, J.D.; Dulong, F.T.; Brown, F.W.; Brown, Z.A.; Krasnow, M.R.; Romankiw, L.A.

1989-01-01

A rank series consisting of twelve vitrinite concentrates and companion whole-coal samples from mined coal beds in the eastern United States, England, and Australia were analyzed for C, H, N, O, ash, and 47 trace and minor elements by standard elemental, instrumental neutron activation analysis (INAA), and direct-current-arc spectrographic (DCAS) techniques. The reflectance of vitrinite, atomic H:C and O:C, and ash-free carbon data were used to determine ranks that range from high-volatile C bituminous coal to meta-anthracite. A van Krevelen (atomic H:C vs. O:C) diagram of the vitrinite concentrates shows a smooth curve having its lowest point at H:C = 0.18 and O:C = 0.01. This improves the van Krevelen diagram by the addition of our vitrinite concentrate from meta-anthracite from the Narragansett basin of New England. Boron content (400-450 ppm) in two Illinois basin vitrinite concentrates was about an order of magnitude higher than B contents in other concentrates analyzed. We attribute this to marine origin or hydrothermal activity. The alkaline-earth elements Ca, Mg and Ba (DCAS) have higher concentrations in our vitrinite concentrates from bituminous coals of the Appalachian basin, than they do in vitrinite concentrates from the marine-roofed bituminous coals of the Illinois basin; therefore, a nonmarine origin for these alkaline-earth elements is postulated for the Appalachian basin coals. An ion-exchange mechanism due to high concentrations of these elements as ions in diagenetic water, but probably not recent ground water, may be responsible for the relatively high values of these elements in Appalachian concentrates. Higher concentrations of Ni and Cr in one of the English vitrinite concentrates and of Zr in the Australian concentrate probably indicate organic association and detrital influence, respectively. ?? 1989.

Some General Laws of Chemical Elements Composition Dynamics in the Hydrosphere

NASA Astrophysics Data System (ADS)

Korzh, V.

2012-12-01

The biophysical oceanic composition is a result of substance migration and transformation on river-sea and ocean- atmosphere boundaries. Chemical composition of oceanic water is a fundamental multi-dimensional constant for our planet. Detailed studies revealed three types of chemical element distribution in the ocean: 1) Conservative: concentration normalized to salinity is constant in space and time; 2) Nutrient-type: element concentration in the surface waters decreases due to the biosphere consumption; and 3) Litho-generative: complex character of distribution of elements, which enter the ocean with the river runoff and interred almost entirely in sediments (Fig. 1). The correlation between the chemical compositions of the river and oceanic water is high (r = 0.94). We conclude that biogeochemical features of each element are determined by the relationship between its average concentration in the ocean and the intensity of its migration through hydrosphere boundary zones. In Fig.1 we show intensities of global migration and average concentrations in the ocean in the coordinates lgC - lg τ, where C is an average element concentration and τ is its residual time in the ocean. Fig. 1 shows a relationship between three main geochemical parameters of the dissolved forms of chemical elements in the hydrosphere: 1) average concentration in the ocean, 2) average concentration in the river runoff and 3) the type of distribution in oceanic water. Using knowledge of two of these parameters, it allows gaining theoretical knowledge of the third. The System covers all chemical elements for the entire range of observed concentrations. It even allows to predict the values of the annual river transport of dissolved Be, C, N, Ge, Tl, Re, to refine such estimates for P, V, Zn, Br, I, and to determine the character of distribution in the ocean for Au and U. Furthermore, the System allowed to estimate natural (unaffected by anthropogenic influence) mean concentrations of elements in the river runoff and use them as ecological reference data. Finally, due to the long response time of the ocean, the mean concentrations of elements and patterns of their distribution in the ocean can be used to determine pre-technogenic concentrations of elements in the river runoff. An example of such studies for the Northern Eurasia Arctic Rivers will be presented at the conference. References Korzh 1974: J. de Recher. Atmos, 8, 653-660. Korzh 2008: J. Ecol., 15, 13-21. Korzh 2012: Water: Chem. & Ecol., No. 1, 56-62; Fig.1. The System of chemical elements distribution in the hydrosphere. Types of distribution in the ocean: 1) conservative; 2) nutrient-type; 3) litho-generative.

Positive anomalous concentrations of Pb in some gabbroic rocks of Afikpo basin southeastern Nigeria.

PubMed

Onwualu-John, J N

2016-08-01

Gabbroic rocks have intruded the sedimentary sequence at Ameta in Afikpo basin southeastern Nigeria. Petrographic and geochemical features of the rocks were studied in order to evaluate their genetic and geotectonic history. The petrographic results show that the rocks contain plagioclase, olivine, pyroxene, biotite, iron oxide, and traces of quartz in three samples. Major element characteristics show that the rocks are subalkaline. In addition, the rocks have geochemical characteristics similar to basaltic andesites. The trace elements results show inconsistent concentrations of high field strength elements (Zr, Nb, Th, Ta), moderate enrichment of large-ion lithophile elements (Rb, Sr, Ba) and low concentrations of Ni and Cr. Rare earth element results show that the rocks are characterized by enrichment of light rare earth elements, middle rare earth elements enrichment, and depletion of heavy rare earth elements with slight positive europium anomalies. Zinc concentrations are within the normal range in basaltic rocks. There are extremely high concentrations of Pb in three of the rock samples. The high Pb concentrations in some of these rocks could be as a result of last episodes of magmatic crystallization. The rocks intruded the Asu River Group; organic components in the sedimentary sequence probably contain Pb which has been assimilated into the magma at the evolutionary stage of the magma. Weathering of some rocks that contain galena could lead to an increase in the concentration of lead in the gabbroic rocks, especially when the migration and crystallization of magma take place in an aqueous environment. Nevertheless, high concentration of lead is hazardous to health and environment.

Evaluation of trace element status of organic dairy cattle.

PubMed

Orjales, I; Herrero-Latorre, C; Miranda, M; Rey-Crespo, F; Rodríguez-Bermúdez, R; López-Alonso, M

2018-06-01

The present study aimed to evaluate trace mineral status of organic dairy herds in northern Spain and the sources of minerals in different types of feed. Blood samples from organic and conventional dairy cattle and feed samples from the respective farms were analysed by inductively coupled plasma mass spectrometry to determine the concentrations of the essential trace elements (cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), iodine (I), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se) and zinc (Zn)) and toxic trace elements (arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb)). Overall, no differences between organic and conventional farms were detected in serum concentrations of essential and toxic trace elements (except for higher concentrations of Cd on the organic farms), although a high level of inter-farm variation was detected in the organic systems, indicating that organic production greatly depends on the specific local conditions. The dietary concentrations of the essential trace elements I, Cu, Se and Zn were significantly higher in the conventional than in the organic systems, which can be attributed to the high concentration of these minerals in the concentrate feed. No differences in the concentrations of trace minerals were found in the other types of feed. Multivariate chemometric analysis was conducted to determine the contribution of different feed sources to the trace element status of the cattle. Concentrate samples were mainly associated with Co, Cu, I, Se and Zn (i.e. with the elements supplemented in this type of feed). However, pasture and grass silage were associated with soil-derived elements (As, Cr, Fe and Pb) which cattle may thus ingest during grazing.

Trace Element Concentrations in Beef Cattle Related to the Breed Aptitude.

PubMed

Pereira, Victor; Carbajales, Paloma; López-Alonso, Marta; Miranda, Marta

2018-02-24

Animal feed has traditionally been supplemented with trace elements at dietary concentrations well above physiological needs. However, environmental concerns have led to calls for better adjustment of mineral supplementation to actual physiological needs and, in this context, consideration of breed-related differences in trace element requirements. The aim of this study was to analyze trace element concentrations in the main breeds used for intensive beef production in northern Spain (Holstein-Friesian [HF], Galician Blonde [GB], and GB × HF cross). Samples of blood, internal organs, and muscle were obtained at slaughter from 10 HF, GB, and GB × HF cross calves in the same feedlot. Overall, trace element concentrations in serum and internal organs were within adequate ranges and did not differ between those of breeds, suggesting that trace mineral supplementation was adequate in all groups. The only exception to this was copper, and hepatic copper concentrations were above adequate levels in all calves. This was particularly evident in the HF calves, and the maximum recommended level for human consumption was exceeded in 90% of these animals. Copper, iron, manganese, selenium, and zinc concentrations in muscle were significantly higher in the HF than those in the GB calves, with intermediate values for the crosses. These breed-related differences in trace element concentrations in the muscle may be related to lower muscle mass and/or higher hepatic activity in the HF (dairy) calves than in GB (beef) calves. As meat is an essential source of highly available trace elements in human diets, breed-related differences in trace element concentrations in meat deserve further investigation.

Overall elemental dry deposition velocities measured around Lake Michigan

NASA Astrophysics Data System (ADS)

Yi, Seung-Muk; Shahin, Usama; Sivadechathep, Jakkris; Sofuoglu, Sait C.; Holsen, Thomas M.

Overall dry deposition velocities of several elements were determined by dividing measured fluxes by measured airborne concentrations in different particle size ranges. The dry deposition measurements were made with a smooth surrogate surface on an automated dry deposition sampler (Eagle II) and the ambient particle concentrations were measured with a dichotomous sampler. These long-term measurements were made in Chicago, IL, South Haven, MI, and Sleeping Bear Dunes, MI, from December 1993 through October 1995 as part of the Lake Michigan Mass Balance Study. In general, the dry deposition fluxes of elements were highly correlated with coarse particle concentrations, slightly less well correlated with total particle concentrations, and least well correlated with fine particle concentrations. The calculated overall dry deposition velocities obtained using coarse particle concentrations varied from approximately 12 cm s -1 for Mg in Chicago to 0.2 cm s -1 for some primarily anthropogenic metals at the more remote sites. The velocities calculated using total particle concentrations were slightly lower. The crustal elements (Mg, Al, and Mn) had higher deposition velocities than anthropogenic elements (V, Cr, Cu, Zn, Mo, Ba and Pb). For crustal elements, overall dry deposition velocities were higher in Chicago than at the other sites.

Fire effects on temperate forest soil C and N storage.

PubMed

Nave, Lucas E; Vance, Eric D; Swanston, Christopher W; Curtis, Peter S

2011-06-01

Temperate forest soils store globally significant amounts of carbon (C) and nitrogen (N). Understanding how soil pools of these two elements change in response to disturbance and management is critical to maintaining ecosystem services such as forest productivity, greenhouse gas mitigation, and water resource protection. Fire is one of the principal disturbances acting on forest soil C and N storage and is also the subject of enormous management efforts. In the present article, we use meta-analysis to quantify fire effects on temperate forest soil C and N storage. Across a combined total of 468 soil C and N response ratios from 57 publications (concentrations and pool sizes), fire had significant overall effects on soil C (-26%) and soil N (-22%). The impacts of fire on forest floors were significantly different from its effects on mineral soils. Fires reduced forest floor C and N storage (pool sizes only) by an average of 59% and 50%, respectively, but the concentrations of these two elements did not change. Prescribed fires caused smaller reductions in forest floor C and N storage (-46% and -35%) than wildfires (-67% and -69%), and the presence of hardwoods also mitigated fire impacts. Burned forest floors recovered their C and N pools in an average of 128 and 103 years, respectively. Among mineral soils, there were no significant changes in C or N storage, but C and N concentrations declined significantly (-11% and -12%, respectively). Mineral soil C and N concentrations were significantly affected by fire type, with no change following prescribed burns, but significant reductions in response to wildfires. Geographic variation in fire effects on mineral soil C and N storage underscores the need for region-specific fire management plans, and the role of fire type in mediating C and N shifts (especially in the forest floor) indicates that averting wildfires through prescribed burning is desirable from a soils perspective.

Total and extractable elemental composition of the intertidal estuarine biofilm of the Río de la Plata: Disentangling natural and anthropogenic influences

NASA Astrophysics Data System (ADS)

García-Alonso, J.; Lercari, D.; Araujo, B. F.; Almeida, M. G.; Rezende, C. E.

2017-03-01

Estuarine transitional waters constitute regions affected by or at risk of anthropogenic impact due to urbanization and industrial development. The elemental composition of the intertidal biofilm sediment is an excellent marker for the detection of any impact, and may exert a bottom-up influence by natural concatenation to higher organization levels (e.g. molecules, cells, organisms, communities). The distribution pattern of elemental composition (total and bioavailable fraction) along the estuary axes was analyzed, disentangling potential shifts produced by human activities. We predict that most abundant elements in the Rio de la Plata estuary are the natural earth-crust components and that these will not show any evident gradient along the estuarine axis. Elements involved in human related processes will shape concentration gradients from the most probable source (i.e. cities) indicating estuarine pollution. The research strategy involved the sampling of intertidal biofilm along the entire estuary and the registration of environmental variables and the total and bioavailable elemental composition. Sampling sites represent pristine, agricultural, and urbanized areas along a 428-km-long coastline comprising the inner, middle and outer Río de la Plata estuarine zones and a coastal fringe of oceanic beaches of Uruguay (South America). Biofilm sediment samples were collected in Autumn 2011 and digested for total and extractable (bioavailable) elements quantification measured by ICP-OES. Mercury (Hg) sediments were digested with aqua regia and quantified by cold vapor atomic absorption (CVAAS). The most abundant elements measured were Al, Fe, and Ca in all sampling. Anthropogenic marker elements such as Hg, Cr, Pb, Zn, and Cu were found, even at potentially toxic levels, at urban beaches at the city of Montevideo. The ordination of samples highlights the distinctive characteristics of urban beaches, placed in a particular location along the first principal component. This position is mainly driven by human impact marker metals and C/N ratios. The results highlight the value of bioavailable elemental composition analyses of benthic biofilm as a tool for detecting shifts in estuarine systems.

The System of Chemical Elements Distribution in the Hydrosphere

NASA Astrophysics Data System (ADS)

Korzh, Vyacheslav D.

2013-04-01

The chemical composition of the hydrosphere is a result of substance migration and transformation on lithosphere-river, river-sea, and ocean-atmosphere boundaries. The chemical elements composition of oceanic water is a fundamental multi-dimensional constant for our planet. Detailed studies revealed three types of chemical element distribution in the ocean: 1) Conservative: concentration normalized to salinity is the constant in space and time; 2) Nutrient-type: element concentration in the surface waters decreases due to the biosphere consumption; and 3) Litho-generative: complex character of distribution of elements, which enter the ocean with the river runoff and interred almost entirely in sediments. The correlation between the chemical elements compositions of the river and oceanic water is high (r = 0.94). We conclude that biogeochemical features of each chemical element are determined by the relationship between its average concentration in the ocean and the intensity of its migration through hydrosphere boundary zones. In our presentation, we shall show intensities of global migration and average concentrations in the ocean in the co ordinates lgC - lg [tau], where C is an average element concentration and [tau] is its residence time in the ocean. We have derived a relationship between three main geochemical parameters of the dissolved forms of chemical elements in the hydrosphere: 1) average concentration in the ocean, 2) average concentration in the river runoff and 3) the type of distribution in oceanic water. Using knowledge of two of these parameters, it allows gaining theoretical knowledge of the third. The System covers all chemical elements for the entire range of observed concentrations. It even allows to predict the values of the annual river transport of dissolved Be, C, N, Ge, Tl, Re, to refine such estimates for P, V, Zn, Br, I, and to determine the character of distribution in the ocean for Au and U. Furthermore, the System allowed estimating natural (unaffected by anthropogenic influence) mean concentrations of elements in the river runoff and using them as ecological reference data. Finally, due to the long response time of the ocean, the mean concentrations of elements and patterns of their distribution in the ocean can be used to determine pre-techno-generative concentrations of elements in the river runoff. In our presentation, we shall show several examples of implementation of the System for studying the sediments' transport by the rivers of the Arctic slope of Northern Eurasia. References 1. Korzh V.D. 1974: Some general laws governing the turnover of substance within the ocean-atmosphere-continent-ocean cycle. Journal de Recherches Atmospheriques, 8, 653-660. 2. Korzh V.D. 2008: The general laws in the formation of the element composition of the Hydrosphere and Biosphere. J. Ecologica, 15, 13-21. 3. Korzh V.D. 2012: Determination of general laws of the chemical element composition in Hydrosphere. Water: Chemistry & Ecology, Journal of Water Science and its Practical Application. No. 1, 56-62.

Beam-Forming Concentrating Solar Thermal Array Power Systems

NASA Technical Reports Server (NTRS)

Hoppe, Daniel J. (Inventor); Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor)

2016-01-01

The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics.

PubMed

Kissoon, La Toya T; Jacob, Donna L; Hanson, Mark A; Herwig, Brian R; Bowe, Shane E; Otte, Marinus L

2015-06-01

We measured concentrations of multiple elements, including rare earth elements, in waters and sediments of 38 shallow lakes of varying turbidity and macrophyte cover in the Prairie Parkland (PP) and Laurentian Mixed Forest (LMF) provinces of Minnesota. PP shallow lakes had higher element concentrations in waters and sediments compared to LMF sites. Redundancy analysis indicated that a combination of site- and watershed-scale features explained a large proportion of among-lake variability in element concentrations in lake water and sediments. Percent woodland cover in watersheds, turbidity, open water area, and macrophyte cover collectively explained 65.2 % of variation in element concentrations in lake waters. Sediment fraction smaller than 63 µm, percent woodland in watersheds, open water area, and sediment organic matter collectively explained 64.2 % of variation in element concentrations in lake sediments. In contrast to earlier work on shallow lakes, our results showed the extent to which multiple elements in shallow lake waters and sediments were influenced by a combination of variables including sediment characteristics, lake morphology, and percent land cover in watersheds. These results are informative because they help illustrate the extent of functional connectivity between shallow lakes and adjacent lands within these lake watersheds.

Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics

PubMed Central

Jacob, Donna L.; Hanson, Mark A.; Herwig, Brian R.; Bowe, Shane E.; Otte, Marinus L.

2015-01-01

We measured concentrations of multiple elements, including rare earth elements, in waters and sediments of 38 shallow lakes of varying turbidity and macrophyte cover in the Prairie Parkland (PP) and Laurentian Mixed Forest (LMF) provinces of Minnesota. PP shallow lakes had higher element concentrations in waters and sediments compared to LMF sites. Redundancy analysis indicated that a combination of site- and watershed-scale features explained a large proportion of among-lake variability in element concentrations in lake water and sediments. Percent woodland cover in watersheds, turbidity, open water area, and macrophyte cover collectively explained 65.2 % of variation in element concentrations in lake waters. Sediment fraction smaller than 63 µm, percent woodland in watersheds, open water area, and sediment organic matter collectively explained 64.2 % of variation in element concentrations in lake sediments. In contrast to earlier work on shallow lakes, our results showed the extent to which multiple elements in shallow lake waters and sediments were influenced by a combination of variables including sediment characteristics, lake morphology, and percent land cover in watersheds. These results are informative because they help illustrate the extent of functional connectivity between shallow lakes and adjacent lands within these lake watersheds. PMID:26074657

Multimodel inference to quantify the relative importance of abiotic factors in the population dynamics of marine zooplankton

NASA Astrophysics Data System (ADS)

Everaert, Gert; Deschutter, Yana; De Troch, Marleen; Janssen, Colin R.; De Schamphelaere, Karel

2018-05-01

The effect of multiple stressors on marine ecosystems remains poorly understood and most of the knowledge available is related to phytoplankton. To partly address this knowledge gap, we tested if combining multimodel inference with generalized additive modelling could quantify the relative contribution of environmental variables on the population dynamics of a zooplankton species in the Belgian part of the North Sea. Hence, we have quantified the relative contribution of oceanographic variables (e.g. water temperature, salinity, nutrient concentrations, and chlorophyll a concentrations) and anthropogenic chemicals (i.e. polychlorinated biphenyls) to the density of Acartia clausi. We found that models with water temperature and chlorophyll a concentration explained ca. 73% of the population density of the marine copepod. Multimodel inference in combination with regression-based models are a generic way to disentangle and quantify multiple stressor-induced changes in marine ecosystems. Future-oriented simulations of copepod densities suggested increased copepod densities under predicted environmental changes.

Occurrence and distribution of trace elements in snow, streams, and streambed sediments, Cape Krusenstern National Monument, Alaska, 2002-2003

USGS Publications Warehouse

Brabets, Timothy P.

2004-01-01

Cape Krusenstern National Monument is located in Northwest Alaska. In 1985, an exchange of lands and interests in lands between the Northwest Alaska Native Association and the United States resulted in a 100-year transportation system easement for 19,747 acres in the monument. A road was then constructed along the easement from the Red Dog Mine, a large zinc concentrate producer and located northeast of the monument, through the monument to the coast and a port facility. Each year approximately 1.3 million tonnes of zinc and lead concentrate are transported from the Red Dog Mine via this access road. Concern about the possible deposition of cadmium, lead, zinc and other trace elements in the monument was the basis of a cooperative project with the National Park Service. Concentrations of dissolved cadmium, dissolved lead, and dissolved zinc from 28 snow samples from a 28 mile by 16 mile grid were below drinking water standards. In the particulate phase, approximately 25 percent of the samples analyzed for these trace elements were higher than the typical range found in Alaska soils. Boxplots of concentrations of these trace elements, both in the dissolved and particulate phase, indicate higher concentrations north of the access road, most likely due to the prevailing southeast wind. The waters of four streams sampled in Cape Krusenstern National Monument are classified as calcium bicarbonate. Trace-element concentrations from these streams were below drinking water standards. Median concentrations of 39 trace elements from streambed sediments collected from 29 sites are similar to the median concentrations of trace elements from the U.S. Geological Survey?s National Water-Quality Assessment database. Statistical differences were noted between trace-element concentrations of cadmium, lead, and zinc at sites along the access road and sites north and south of the access road; concentrations along the access road being higher than north or south of the road. When normalized to 1 percent organic carbon, the concentrations of these trace elements are not expected to be toxic to aquatic life when compared to criteria established by the Canadian government and other recent research.

Use of an ultra-clean sampling technique with inductively coupled plasma-mass spectrometry to determine trace-element concentrations in water from the Kirkwood-Cohansey Aquifer system, coastal plain, New Jersey

USGS Publications Warehouse

Ivahnenko, Tamara; Szabo, Zoltan; Hall, G.S.

1996-01-01

Water samples were collected during 1993 from 22 public supply wells screened in the Kirkwood-Cohansey aquifer system; concentrations of 18 trace elements were determined primarily by using inductively coupled plasma-mass spectrometry (ICP-MS) techniques, though graphite furnace atomic adsorption, hydride generation, and cold- vapor flameless atomic adsorption techniques were used for thallium, arsenic, and mercury, respectively, at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL). In addition, laboratory measurements of alkalinity and turbidity were made. The ground-water samples were collected by using ultra-clean sampling protocols developed by the USGS for collecting ground-water samples in areas with water containing low concentrations of trace elements. This technique is based on recently gained experience in sampling surface water for these elements. Field parameters (water temperature, specific conductance, pH, and dissolved-oxygen concentration) were monitored prior to sample collection. Three equipment blanks were collected to ensure that low-level trace-element contamination did not occur during sample collection. One split sample and a commercially- prepared reference standard were submitted to the NWQL o evaluate laboratory precision and accuracy, respectively. Trace-element concentrations in 10 sample splits and one equipment blank were also determined at the Rutgers University Chemistry Department laboratory. Results of the ICP-MS analyses and cold vapor flameless atomic absorption indicated that five trace elements-- cobalt, copper, lead, mercury, and nickel--were detectable in low concentrations (<0.1-29 mg/L) in most of the samples from the 22 wells, and four elements--aluminum, barium, manganese and zinc--were detected in higher concentrations than the other elements (30-710 mg/L for aluminum; 4-180 mg/L for barium, manganese, and zinc). The remaining nine trace elements were present in concentrations consistently lower than the minimum reporting limit. Turbidity was low (less than 1 nephelometric turbidity unit (NTU)), indicating that the trace-element concentrations were present in the dissolved phase and ideally would be reproducible in the absence of highly variable concentrations of particulates. The concentration of lead in one sample exceeded the U.S. Environmental Protection Agency (USEPA) action level of 15 mg/L; concentrations ranged from <1 to 16 mg/L. Mercury was frequently detected; concentrations ranged from <0.1 to 1.1 mg/L but did not exceed the USEPA maximum contaminant level. Results of analyses of the equipment blanks indicated that samples collected by using the new ultra-clean sampling protocols were free of low-level (< 1mg/L) trace-element contamination. The analysis of the split sample sent to the NWQL had a difference of 5 percent or less for all constituents except aluminum, for which the analysis had a difference of 10 percent. Results of ICP-MS analyses of split water samples sent to the Rutgers University Chemistry Department laboratory were, in general, in good agreement (within 10 percent) with those of the NWQL. Results of the analysis of the commercial standard agreed (within 5 percent) with the known concentrations of the trace elements. The quality-assurance data (three blanks, one split sample, and one standard), although not statistically evaluated because of the small data set, indicate that the measured trace-element concentrations are precise and accurate and that the samples were free of contamination at the microgram-per-liter level of contamination.

Origin of inorganic and organic components of PM2.5 in subway stations of Barcelona, Spain.

PubMed

Martins, Vânia; Moreno, Teresa; Minguillón, María Cruz; van Drooge, Barend L; Reche, Cristina; Amato, Fulvio; de Miguel, Eladio; Capdevila, Marta; Centelles, Sonia; Querol, Xavier

2016-01-01

The present work assesses indoor air quality in stations of the Barcelona subway system. PM2.5 concentrations on the platforms of 4 subway stations were measured during two different seasons and the chemical composition was determined. A Positive Matrix Factorization analysis was performed to identify and quantify the contributions of major PM2.5 sources in the subway stations. Mean PM2.5 concentrations varied according to the stations design and seasonal periods. PM2.5 was composed of haematite, carbonaceous aerosol, crustal matter, secondary inorganic compounds, trace elements, insoluble sulphate and halite. Organic compounds such as PAHs, nicotine, levoglucosan and aromatic musk compounds were also identified. Subway PM2.5 source comprised emissions from rails, wheels, catenaries, brake pads and pantographs. The subway source showed different chemical profiles for each station, but was always dominated by Fe. Control actions on the source are important for the achievement of better air quality in the subway environment. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Analysis with electron microscope of multielement samples using pure element standards

DOEpatents

King, W.E.

1986-01-06

This disclosure describes a method and modified analytical electron microscope for determining the concentration of elements in a multielement sample by exposing samples with differing thicknesses for each element to a beam of electrons. Simultaneously the electron dosage and x-ray intensities are measured for each sample of element to determine a ''K/sub AB/'' value to be used in the equation (I/sub A/I/sub B/) = K/sub AB/ (C/sub A//C/sub B/), where I is intensity and C is concentration for elements A and B. The multielement sample is exposed to determine the concentrations of the elements in the sample.

Quantifying Protein Concentrations Using Smartphone Colorimetry: A New Method for an Established Test

ERIC Educational Resources Information Center

Gee, Clifford T.; Kehoe, Eric; Pomerantz, William C. K.; Penn, R. Lee

2017-01-01

Proteins are involved in nearly every biological process, which makes them of interest to a range of scientists. Previous work has shown that hand-held cameras can be used to determine the concentration of colored analytes in solution, and this paper extends the approach to reactions involving a color change in order to quantify protein…

Water-quality assessment of part of the Upper Mississippi River Basin, Minnesota and Wisconsin: Trace elements in streambed sediment and fish livers, 1995-96

USGS Publications Warehouse

Kroening, Sharon E.; Fallon, James D.; Lee, Kathy E.

2000-01-01

In fish livers, all of the trace elements analyzed were detected except antimony, beryllium, cobalt, and uranium. Trace element concentrations in fish livers generally did not show any pronounced patterns. Ranges for concentrations of arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, and zinc were similar to those measured in 20 other NAWQA studies across the United States. Cadmium concentrations in fish livers were moderately correlated to fish length and weight. There were no relations between trace element concentrations in fish livers and streambed sediment.

Unravelling intrinsic efficacy and ligand bias at G protein coupled receptors: A practical guide to assessing functional data.

PubMed

Stott, Lisa A; Hall, David A; Holliday, Nicholas D

2016-02-01

Stephenson's empirical definition of an agonist, as a ligand with binding affinity and intrinsic efficacy (the ability to activate the receptor once bound), underpins classical receptor pharmacology. Quantifying intrinsic efficacy using functional concentration response relationships has always presented an experimental challenge. The requirement for realistic determination of efficacy is emphasised by recent developments in our understanding of G protein coupled receptor (GPCR) agonists, with recognition that some ligands stabilise different active conformations of the receptor, leading to pathway-selective, or biased agonism. Biased ligands have potential as therapeutics with improved selectivity and clinical efficacy, but there are also pitfalls to the identification of pathway selective effects. Here we explore the basics of concentration response curve analysis, beginning with the need to distinguish ligand bias from other influences of the functional system under study. We consider the different approaches that have been used to quantify and compare biased ligands, many of which are based on the Black and Leff operational model of agonism. Some of the practical issues that accompany these analyses are highlighted, with opportunities to improve estimates in future, particularly in the separation of true agonist intrinsic efficacy from the contributions of system dependent coupling efficiency. Such methods are by their nature practical approaches, and all rely on Stephenson's separation of affinity and efficacy parameters, which are interdependent at the mechanistic level. Nevertheless, operational analysis methods can be justified by mechanistic models of GPCR activation, and if used wisely are key elements to biased ligand identification. Copyright © 2015 Elsevier Inc. All rights reserved.

Analysis of elemental concentration censored distributions in breast malignant and breast benign neoplasm tissues

NASA Astrophysics Data System (ADS)

Kubala-Kukuś, A.; Banaś, D.; Braziewicz, J.; Góźdź, S.; Majewska, U.; Pajek, M.

2007-07-01

The total reflection X-ray fluorescence method was applied to study the trace element concentrations in human breast malignant and breast benign neoplasm tissues taken from the women who were patients of Holycross Cancer Centre in Kielce (Poland). These investigations were mainly focused on the development of new possibilities of cancer diagnosis and therapy monitoring. This systematic comparative study was based on relatively large (˜ 100) population studied, namely 26 samples of breast malignant and 68 samples of breast benign neoplasm tissues. The concentrations, being in the range from a few ppb to 0.1%, were determined for thirteen elements (from P to Pb). The results were carefully analysed to investigate the concentration distribution of trace elements in the studied samples. The measurements of concentration of trace elements by total reflection X-ray fluorescence were limited, however, by the detection limit of the method. It was observed that for more than 50% of elements determined, the concentrations were not measured in all samples. These incomplete measurements were treated within the statistical concept called left-random censoring and for the estimation of the mean value and median of censored concentration distributions, the Kaplan-Meier estimator was used. For comparison of concentrations in two populations, the log-rank test was applied, which allows to compare the censored total reflection X-ray fluorescence data. Found statistically significant differences are discussed in more details. It is noted that described data analysis procedures should be the standard tool to analyze the censored concentrations of trace elements analysed by X-ray fluorescence methods.

Selected elements in major minerals from bituminous coal as determined by INAA: Implications for removing environmentally sensitive elements from coal

USGS Publications Warehouse

Palmer, C.A.; Lyons, P.C.

1996-01-01

The four most abundant minerals generally found in Euramerican bituminous coals are quartz, kaolinite, illite and pyrite. These four minerals were isolated by density separation and handpicking from bituminous coal samples collected in the Ruhr Basin, Germany and the Appalachian basin, U.S.A. Trace-element concentrations of relatively pure (??? 99+%) separates of major minerals from these coals were determined directly by using instrumental neutron activation analysis (INAA). As expected, quartz contributes little to the trace-element mass balance. Illite generally has higher trace-element concentrations than kaolinite, but, for the concentrates analyzed in this study, Hf, Ta, W, Th and U are in lower concentrations in illite than in kaolinite. Pyrite has higher concentrations of chalcophile elements (e.g., As and Se) and is considerably lower in lithophile elements as compared to kaolinite and illite. Our study provides a direct and sensitive method of determining trace-element relationships with minerals in coal. Mass-balance calculations suggest that the trace-element content of coal can be explained mainly by three major minerals: pyrite, kaolinite and illite. This conclusion indicates that the size and textural relationships of these major coal minerals may be a more important consideration as to whether coal cleaning can effectively remove the most environmentally sensitive trace elements in coal than what trace minerals are present.

Habitat Use and Trophic Structure in a Highly Migratory Predatory Fish Identified with Geochemical Proxies in Scales

NASA Astrophysics Data System (ADS)

Seeley, M.; Walther, B. D.

2016-02-01

Atlantic tarpon, Megalops atlanticus, are highly migratory euryhaline predators that occupy different habitats throughout ontogeny. Specifically, Atlantic tarpon are known to inhabit oligohaline waters, although the frequency and duration of movements across estuarine gradients into these waters are relatively unknown. This species supports over a two billion dollar industry within the Gulf of Mexico and is currently listed as vulnerable under the International Union for the Conservation of Nature (IUCN). A new non-lethal method for reconstructing migrations across estuaries relies on trace element and stable isotope compositions of growth increments in scales. We analyzed Atlantic tarpon scales from the Texas coast to validate this method using inductively coupled plasma mass spectrometry (ICP-MS) for trace elements and isotope ratio mass spectrometry (IR-MS) for stable isotope ratios. Multiple scales were also taken from the same individual to confirm the consistency of elemental uptake within the same individual. Results show that scale Ba:Ca, Sr:Ca and δ13C are effective proxies for salinity, while enrichments in δ15N are consistent with known ontogenetic trophic shifts. In addition, chemical transects across multiple scales from the same individual were highly consistent, suggesting that any non-regenerated scale removed from a fish can provide equivalent time series. Continuous life history profiles of scales were obtained via laser ablation transects of scale cross-sections to quantify trace element concentrations from the core (youngest increments) to the edge (oldest increments). Stable isotope and trace element results together indicate that behavior is highly variable between individuals, with some but not all fish transiting estuarine gradients into oligohaline waters. Our findings will provide novel opportunities to investigate alternative non-lethal methods to monitor fish migrations across chemical gradients.

Principal locations of major-ion, trace-element, nitrate, and Escherichia coli loading to Emigration Creek, Salt Lake County, Utah, October 2005

USGS Publications Warehouse

Kimball, Briant A.; Runkel, Robert L.; Walton-Day, Katherine

2008-01-01

Housing development and recreational activity in Emigration Canyon have increased substantially since 1980, perhaps causing an observed decrease in water quality of this northern Utah stream located near Salt Lake City. To identify reaches of the stream that contribute to water-quality degradation, a tracer-injection and synoptic-sampling study was done to quantify mass loading of major ions, trace elements, nitrate, and Escherichia coli (E. coli) to the stream. The resulting mass-loading profiles for major ions and trace elements indicate both geologic and anthropogenic inputs to the stream, principally from tributary and spring inflows to the stream at Brigham Fork, Burr Fork, Wagner Spring, Emigration Tunnel Spring, Blacksmith Hollow, and Killyon Canyon. The pattern of nitrate loading does not correspond to the major-ion and trace-element loading patterns. Nitrate levels in the stream did not exceed water-quality standards at the time of synoptic sampling. The majority of nitrate mass loading can be considered related to anthropogenic input, based on the field settings and trends in stable isotope ratios of nitrogen. The pattern of E. coli loading does not correspond to the major-ion, trace-element, or nitrate loading patterns. The majority of E. coli loading was related to anthropogenic sources based on field setting, but a considerable part of the loading also comes from possible animal sources in Killyon Canyon, in Perkins Flat, and in Rotary Park. In this late summer sampling, E. coli concentrations only exceeded water-quality standards in limited sections of the study reach. The mass-loading approach used in this study provides a means to design future studies and to evaluate the loading on a catchment scale.

Toxicological study of injuries of rat’s hippocampus after lead poisoning by synchrotron microradiography and elemental mapping

NASA Astrophysics Data System (ADS)

Liang, Feng; Zhang, Guilin; Xiao, Xianghui; Cai, Zhonghou; Lai, Barry; Hwu, Yeukuang; Yan, Chonghuai; Xu, Jian; Li, Yulan; Tan, Mingguang; Zhang, Chuanfu; Li, Yan

2010-09-01

The hippocampus, a major component of the brain, is one of the target nervous organs in lead poisoning. In this work, a rat's hippocampal injury caused by lead was studied. The lead concentrations in blood, bone and hippocampus collected from rats subject to lead poisoning were quantified by Inductively Coupled Plasma Mass Spectrometry while morphological information and elemental distributions in the hippocampus were obtained with synchrotron radiation X-ray phase contrast imaging and synchrotron radiation micro-beam X-ray fluorescence, respectively. For comparison, identical characterization of the specimens from the rats in the control group was done in parallel. Results show that the ratios between the lead content in the treated group and that in the control group of the hippocampus, bone, and blood are about 2.66, 236, and 39.6, respectively. Analysis also revealed that some health elements such as S, K, Cl and P increase in the regions with high lead content in the treated hippocampus. Morphological differences between the normal and lead-exposed hippocampus specimens in some local areas were observed. Explicitly, the structure of the lead-exposed hippocampus was tortuous and irregular, and the density of the neurons in the Dentate Gyrus was significantly lower than that from the control group. The study shows that the synchrotron radiation methods are very powerful for investigating structural injury caused by heavy metals in the nervous system.

Volatile Concentrations and H-Isotope Composition of Unequilibrated Eucrites

NASA Technical Reports Server (NTRS)

Sarafian, Adam R.; Nielsen, Sune G.; Marschall, Horst R.; Gaetani, Glenn A.; Hauri, Erik H.; Righter, Kevin; Berger, Eve L.

2017-01-01

Eucrites are among the oldest and best studied asteroidal basalts (1). They represent magmatism that occurred on their parent asteroid, likely 4-Vesta, starting at 4563 Ma and continuing for approx. 30 Myr. Two hypotheses are debated for the genesis of eucrites, a magma ocean model (2), and a mantle partial melting model. In general, volatiles (H, C, F, Cl) have been ignored for eucrites and 4-Vesta, but solubility of wt% levels of H2O are possible at Vestan interior PT conditions. Targeted measurements on samples could aid our understanding considerably. Recent studies have found evidence of volatile elements in eucrites, but quantifying the abundance of volatiles remains problematic (6). Volatile elements have a disproportionately large effect on melt properties and phase stability, relative to their low abundance. The source of volatile elements can be elucidated by examining the hydrogen isotope ratio (D/H), as different H reservoirs have drastically different H isotope compositions. Recent studies of apatite in eucrites have shown that the D/H of 4-Vesta matches that of Earth and carbonaceous chondrites, however, the D/H of apatites may not represent the D/H of a primitive 4-Vesta melt due to the possibility of degassing prior to the crystallization of apatite. Therefore, the D/H of early crystallizing phases must be measured to determine if the D/H of 4-Vesta is equal to that of the Earth and carbonaceous chondrites.

Period changes of 7 bright RR Lyrae variables included in the BAV standard program.

NASA Astrophysics Data System (ADS)

Wunder, E.

1995-11-01

On the basis of 1578 times of maxima historical and present period changes of the RR Lyrae stars SW And, SW Aqr, AA Aql, X Ari, RS Boo, RR Cet and XZ Cyg are analysed. In tables the period jumps and the quadratic terms of the elements are quantified and timed; elements are given to describe the historical O-C-curves; instant elements are listed to support nowadays observations.

Study on tar generated from downdraft gasification of oil palm fronds.

PubMed

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study.

Study on Tar Generated from Downdraft Gasification of Oil Palm Fronds

PubMed Central

Atnaw, Samson Mekbib; Kueh, Soo Chuan; Sulaiman, Shaharin Anwar

2014-01-01

One of the most challenging issues concerning the gasification of oil palm fronds (OPF) is the presence of tar and particulates formed during the process considering its high volatile matter content. In this study, a tar sampling train custom built based on standard tar sampling protocols was used to quantify the gravimetric concentration of tar (g/Nm3) in syngas produced from downdraft gasification of OPF. The amount of char, ash, and solid tar produced from the gasification process was measured in order to account for the mass and carbon conversion efficiency. Elemental analysis of the char and solid tar samples was done using ultimate analysis machine, while the relative concentration of the different compounds in the liquid tar was determined making use of a liquid gas chromatography (GC) unit. Average tar concentration of 4.928 g/Nm3 and 1.923 g/Nm3 was obtained for raw gas and cleaned gas samples, respectively. Tar concentration in the raw gas sample was found to be higher compared to results for other biomass materials, which could be attributed to the higher volatile matter percentage of OPF. Average cleaning efficiency of 61% which is comparable to that of sand bed filter and venturi scrubber cleaning systems reported in the literature was obtained for the cleaning system proposed in the current study. PMID:24526899

Effect of combustion temperature on the emission of trace elements under O2/CO2 atmosphere during coal combustion

NASA Astrophysics Data System (ADS)

Qu, Chengrui; Zhang, Mo; Mann, Michael. D.

2018-03-01

The effect of combustion temperature on the emission of trace elementswas studied under O2/CO2 atmosphere during coal combustion in a laboratory scale fluidized bed combustor. The elemental composition of fine fly ash particles collected with a low pressure impactor(LPI)was quantified by X-Ray F1uorescence Spectrometer (XRF). The elemental composition of coal and bottom ash was quantified byinductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results indicate that the contents of Mn, Zn, Cd and Cr in the fly ash increase with the rise of combustion temperature. It is found that the enrichment of Zn and Cd is greater in the submicrometer particles than the supermicrometer particles, but Mn and Cr do not enrich in the submicrometer particles. Mn, Zn, Cd and Cr display one peak around 0.1 μm. The relative enrichment factor (Rij) of four elements is in the order of Zn, Cd, Mn and Cr. Zn and Cd are mostly retained in fly ashwhileMn and Cr are retained in both the fly ash and bottom ash.

Baseline element concentrations in soils and plants, Wattenmeer National Park, North and East Frisian Islands, Federal Republic of Germany

USGS Publications Warehouse

Severson, R.C.; Gough, L.P.; van den Boom, G.

1992-01-01

Baseline element concentrations are given for dune grass (Ammophilia arenaria), willow (Salix repens), moss (Hylocomium splendens) and associated surface soils. Baseline and variability data for pH, ash, Al, As, Ba, C, Ca, Cd, Ce, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, S, Sc, Se, Sr, Th, Ti, V, Y, Yb, and Zn are reported; however, not all variables are reported for all media because, in some media, certain elements were below the analytical detection limit. Spatial variation in element concentration between five Frisian Islands are given for each of the sample media. In general, only a few elements in each media showed statistically significant differences between the islands sampled. The measured concentrations in all sample media exhibited ranges that cannot be attributed to anthropogenic additions of trace elements, with the possible exception of Hg and Pb in surface soils.Baseline element concentrations are given for dune grass (Ammophilia arenaria), willow (Salix repens), moss (Hylocomium splendens) and associated surface soils. Baseline and variability data for pH, ash, Al, As, Ba, C, Ca, Cd, Ce, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, S, Sc, Se, Sr, Th, Ti, V, Y, Yb, and Zn are reported; however, not all variables are reported for all media because, in some media, certain elements were below the analytical detection limit. Spatial variation in element concentration between five Frisian Islands are given for each of the sample media. In general, only a few elements in each media showed statistically significant differences between the islands sampled. The measured concentrations in all sample media exhibited ranges that cannot be attributed to anthropogenic additions of trace elements, with the possible exception of Hg and Pb in surface soils.

Concentrations of 17 elements in the zebra mussel (Dreissena polymorpha), in different tissues of perch (Perca fluviatilis), and in perch intestinal parasites (Acanthocephalus lucii) from the subalpine lake Mondsee, Austria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sures, B.; Steiner, W.; Rydlo, M.

1999-11-01

Concentrations of the elements Al, Ag, Ba, ca, Cd, Co, Cr, cu, Fe, Ga, Mg, Mn, Ni, Pb, Sr, Tl, and Zn were analyzed by inductively coupled plasma mass spectrometry in the acanthocephalan Acanthocephalus lucii (Mueller); in its host, Perca fluviatilis (L.), and in the soft tissue of the zebra mussel, Dreissena polymorpha (Pallas). All animals were collected from the same sampling site in a subalpine lake, Mondsee, in Austria. Most of the elements were found at significantly higher concentrations in the acanthocephalan than in different tissues (muscle, liver, and intestinal wall) of its perch host. Only Co was concentratedmore » in the liver of perch to a level that was significantly higher than that found in the parasite. Most of the analyzed elements were also present at significantly higher concentrations in A. lucii than in D. polymorpha. Barium and Cr were the only elements recorded at higher concentrations in the mussel compared with the acanthocephalan. Thus, when comparing the accumulation of elements, the acanthocephalans appear to be even more suitable than the zebra mussels in terms of their use in the detection of metal contamination within aquatic biotopes. Spearman correlation analysis revealed that the concentrations of several elements within the parasites decreased with increasing infrapopulation. Furthermore, the levels of some elements in the perch liver were negatively correlated with the weight of A. lucii in the intestine. Thus, it emerged that not only is there competition for elements between acanthocephalans inside the gut but there is also competition for these elements between the host and the parasites. The elevated element concentrations demonstrated here in the parasitic worm A. lucii provide support for further investigations of these common helminthes and of their accumulation properties.« less

Evaluation of specimen preparation techniques for micro-PIXE localisation of elements in hyperaccumulating plants

NASA Astrophysics Data System (ADS)

Kachenko, Anthony G.; Siegele, Rainer; Bhatia, Naveen P.; Singh, Balwant; Ionescu, Mihail

2008-04-01

Hybanthus floribundus subsp. floribundus, a rare Australian Ni-hyperaccumulating shrub and Pityrogramma calomelanos var. austroamericana, an Australian naturalized As-hyperaccumulating fern are promising species for use in phytoremediation of contaminated sites. Micro-proton-induced X-ray emission (μ-PIXE) spectroscopy was used to map the elemental distribution of the accumulated metal(loid)s, Ca and K in leaf or pinnule tissues of the two plant species. Samples were prepared by two contrasting specimen preparation techniques: freeze-substitution in tetrahydrofuran (THF) and freeze-drying. The specimens were analysed to compare the suitability of each technique in preserving (i) the spatial elemental distribution and (ii) the tissue structure of the specimens. Further, the μ-PIXE results were compared with concentration of elements in the bulk tissue obtained by ICP-AES analysis. In H. floribundus subsp. floribundus, μ-PIXE analysis revealed Ni, Ca and K concentrations in freeze-dried leaf tissues were at par with bulk tissue concentrations. Elemental distribution maps illustrated that Ni was preferentially localised in the adaxial epidermal tissues (1% DW) and least concentration was found in spongy mesophyll tissues (0.53% DW). Conversely, elemental distribution maps of THF freeze-substituted tissues indicated significantly lower Ni, Ca and K concentrations than freeze-dried specimens and bulk tissue concentrations. Moreover, Ni concentrations were uniform across the whole specimen and no localisation was observed. In P. calomelanos var. austroamericana freeze-dried pinnule tissues, μ-PIXE revealed statistically similar As, Ca and K concentrations as compared to bulk tissue concentrations. Elemental distribution maps showed that As localisation was relatively uniform across the whole specimen. Once again, THF freeze-substituted tissues revealed a significant loss of As compared to freeze-dried specimens and the concentrations obtained by bulk tissue analysis. The results demonstrate that freeze-drying is a suitable sample preparation technique to study elemental distribution of ions in H. floribundus and P. calomelanos plant tissues using μ-PIXE spectroscopy. Furthermore, cellular structure was preserved in samples prepared using this technique.

Trace elements in stormflow, ash, and burned soil following the 2009 station fire in southern California

USGS Publications Warehouse

Burton, Carmen; Hoefen, Todd M.; Plumlee, Geoffrey S.; Baumberger, Katherine L.; Backlin, Adam R.; Gallegos, Elizabeth; Fisher, Robert N.

2016-01-01

Most research on the effects of wildfires on stream water quality has focused on suspended sediment and nutrients in streams and water bodies, and relatively little research has examined the effects of wildfires on trace elements. The purpose of this study was two-fold: 1) to determine the effect of the 2009 Station Fire in the Angeles National Forest northeast of Los Angeles, CA on trace element concentrations in streams, and 2) compare trace elements in post-fire stormflow water quality to criteria for aquatic life to determine if trace elements reached concentrations that can harm aquatic life. Pre-storm and stormflow water-quality samples were collected in streams located inside and outside of the burn area of the Station Fire. Ash and burned soil samples were collected from several locations within the perimeter of the Station Fire. Filtered concentrations of Fe, Mn, and Hg and total concentrations of most trace elements in storm samples were elevated as a result of the Station Fire. In contrast, filtered concentrations of Cu, Pb, Ni, and Se and total concentrations of Cu were elevated primarily due to storms and not the Station Fire. Total concentrations of Se and Zn were elevated as a result of both storms and the Station Fire. Suspended sediment in stormflows following the Station Fire was an important transport mechanism for trace elements. Cu, Pb, and Zn primarily originate from ash in the suspended sediment. Fe primarily originates from burned soil in the suspended sediment. As, Mn, and Ni originate from both ash and burned soil. Filtered concentrations of trace elements in stormwater samples affected by the Station Fire did not reach levels that were greater than criteria established for aquatic life. Total concentrations for Fe, Pb, Ni, and Zn were detected at concentrations above criteria established for aquatic life.

Trace Elements in Stormflow, Ash, and Burned Soil following the 2009 Station Fire in Southern California

PubMed Central

Burton, Carmen A.; Hoefen, Todd M.; Plumlee, Geoffrey S.; Baumberger, Katherine L.; Backlin, Adam R.; Gallegos, Elizabeth; Fisher, Robert N.

2016-01-01

Most research on the effects of wildfires on stream water quality has focused on suspended sediment and nutrients in streams and water bodies, and relatively little research has examined the effects of wildfires on trace elements. The purpose of this study was two-fold: 1) to determine the effect of the 2009 Station Fire in the Angeles National Forest northeast of Los Angeles, CA on trace element concentrations in streams, and 2) compare trace elements in post-fire stormflow water quality to criteria for aquatic life to determine if trace elements reached concentrations that can harm aquatic life. Pre-storm and stormflow water-quality samples were collected in streams located inside and outside of the burn area of the Station Fire. Ash and burned soil samples were collected from several locations within the perimeter of the Station Fire. Filtered concentrations of Fe, Mn, and Hg and total concentrations of most trace elements in storm samples were elevated as a result of the Station Fire. In contrast, filtered concentrations of Cu, Pb, Ni, and Se and total concentrations of Cu were elevated primarily due to storms and not the Station Fire. Total concentrations of Se and Zn were elevated as a result of both storms and the Station Fire. Suspended sediment in stormflows following the Station Fire was an important transport mechanism for trace elements. Cu, Pb, and Zn primarily originate from ash in the suspended sediment. Fe primarily originates from burned soil in the suspended sediment. As, Mn, and Ni originate from both ash and burned soil. Filtered concentrations of trace elements in stormwater samples affected by the Station Fire did not reach levels that were greater than criteria established for aquatic life. Total concentrations for Fe, Pb, Ni, and Zn were detected at concentrations above criteria established for aquatic life. PMID:27144270

High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

NASA Astrophysics Data System (ADS)

Hanley, J. J.; Mungall, J. E.

2004-12-01

The role of "deuteric" fluids (exsolved magmatic volatile phases) in the development of Ni-Cu-PGE (platinum group element) deposits in mafic-ultramafic igneous systems is poorly understood. Although considerable field evidence demonstrates unambiguously that fluids modified most large primary Ni-Cu-PGE concentrations, models which hypothesize that fluids alone were largely responsible for the economic concentration of the base and precious metals are not widely accepted. Determination of the trace element composition of magmatic volatile phases in such ore-forming systems can offer considerable insight into the origin of potentially mineralizing fluids in such igneous environments. Laser ablation ICP-MS microanalysis allows researchers to confirm the original metal budget of magmatic volatile phases and quantify the behavior of trace ore metals in the fluid phase in the absence of well-constrained theoretical or experimental predictions of ore metal solubility. In this study, we present new evidence from major deposits (Sudbury, Ontario, Canada; Stillwater Complex, Montana, U.S.A.) that compositionally distinct magmatic brines and halide melt phases were exsolved from crystallizing residual silicate melt and trapped within high-T fluid conduits now comprised of evolved rock compositions (albite-quartz graphic granite, orthoclase-quartz granophyre). Petrographic evidence demonstrates that brines and halide melts coexisted with immiscible carbonic phases at the time of entrapment (light aliphatic hydrocarbons, CO2). Brine and halide melt inclusions are rich in Na, Fe, Mn, K, Pb, Zn, Ba, Sr, Al and Cl, and homogenize by either halite dissolution at high T ( ˜450-700° C) or by melting of the salt phase (700-800° C). LA-ICPMS analyses of single inclusions demonstrate that high salinity volatile phases contained abundant base metals (Cu, Fe, Sn, Bi) and precious metals (Pt, Pd, Au, Ag) at the time of entrapment. Notably, precious metal concentrations in the inclusions are comparable to and often exceed the economic concentrations of the metals within the ores themselves. As a consequence of these results, current genetic models must be revised to consider the role played by hydrous saline melts and magmatic brines in deposit development, and the potential for interaction and competition between sulfide liquids (or PGE-bearing sulfide minerals) and hydrosaline volatiles for available PGE and Au in a crystallizing mafic igneous system must be critically evaluated.

Annual atmospheric mercury species in downtown Toronto, Canada.

PubMed

Song, Xinjie; Cheng, Irene; Lu, Julia

2009-03-01

Real-time concentrations of atmospheric gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and mercury associated with particles having sizes <2.5 microm (P-Hg < 2.5) were simultaneously measured in downtown Toronto from December 2003 to November 2004. The annual mean concentrations of GEM, P-Hg < 2.5 and RGM were 4.5 +/- 3.1 ng m(-3) (99.2%), 21.5 +/- 16.4 pg m(-3) (0.5%) and 14.2 +/- 13.2 pg m(-3) (0.3%), respectively. The concentrations for all the measured Hg species were highly variable throughout the year and were lower in winter than in the other three seasons. The maximum concentrations of Hg species were observed in June and were a result of the high number of Hg spikes (using [GEM] >10 ng m(-3) as an indicator) that occurred in the month. Nighttime (between 9pm-6am) concentrations of Hg species were higher than those of daytime. The results revealed: (1) an urban area is a continuous source of Hg species that have the potential to pose impacts on local, regional and global scales; (2) local/regional anthropogenic sources contributed significantly to the levels and the distributions of the Hg species in the urban atmosphere. More studies are needed to identify and quantify the anthropogenic sources of Hg and the Hg species emitted from these sources; (3) surface emission and photochemical reactions (including the reactions involving ozone) did not have significant influence on the levels of Hg species and their distribution in the urban atmosphere.

Activity levels of tamoxifen metabolites at the estrogen receptor and the impact of genetic polymorphisms of phase I and II enzymes on their concentration levels in plasma.

PubMed

Mürdter, T E; Schroth, W; Bacchus-Gerybadze, L; Winter, S; Heinkele, G; Simon, W; Fasching, P A; Fehm, T; Eichelbaum, M; Schwab, M; Brauch, H

2011-05-01

The therapeutic effect of tamoxifen depends on active metabolites, e.g., cytochrome P450 2D6 (CYP2D6) mediated formation of endoxifen. To test for additional relationships, 236 breast cancer patients were genotyped for CYP2D6, CYP2C9, CYP2B6, CYP2C19, CYP3A5, UGT1A4, UGT2B7, and UGT2B15; also, plasma concentrations of tamoxifen and 22 of its metabolites, including the (E)-, (Z)-, 3-, and 4'-hydroxymetabolites as well as their glucuronides, were quantified using liquid chromatography-tandem mass spectrometry (MS). The activity levels of the metabolites were measured using an estrogen response element reporter assay; the strongest estrogen receptor inhibition was found for (Z)-endoxifen and (Z)-4-hydroxytamoxifen (inhibitory concentration 50 (IC50) 3 and 7 nmol/l, respectively). CYP2D6 genotypes explained 39 and 9% of the variability of steady-state concentrations of (Z)-endoxifen and (Z)-4-hydroxytamoxifen, respectively. Among the poor metabolizers, 93% had (Z)-endoxifen levels below IC90 values, underscoring the role of CYP2D6 deficiency in compromised tamoxifen bioactivation. For other enzymes tested, carriers of reduced-function CYP2C9 (*2, *3) alleles had lower plasma concentrations of active metabolites (P < 0.004), pointing to the role of additional pathways.

Radiolytic Hydrogen Production in the South Pacific Subseafloor Basaltic Aquifer

NASA Astrophysics Data System (ADS)

Dzaugis, M. E.; Spivack, A. J.; Dunlea, A. G.; Murray, R. W.; D'Hondt, S.

2015-12-01

Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from natural radioactive decay of uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance of radiolytic H2 as an electron donor for microbes within the South Pacific subseafloor basaltic aquifer, we calculate radiolytic H2 production rates in basement fractures utilizing measured radionuclide concentrations in 42 basalt samples from IODP Expedition 329. The samples are from three sites with very different basement ages and a wide range of alteration types. Major and trace element concentrations vary by up to an order of magnitude from sample to sample. Comparison of our samples to each other and to previous studies of fresh East Pacific Rise basalt suggests that between-sample variation in radionuclide concentrations is primarily due to differences in initial (pre-alteration) concentrations (which can vary between eruptive events), rather than to alteration type or extent. Local maxima in radionuclide (U, Th, and K) concentrations produce 'hotspots' of radiolytic H2 production; calculated radiolytic rates differ by up to a factor of 80 from sample to sample. Fracture width also greatly influences H2 production. Due to the low penetration distance of alpha radiation, microfractures are 'hotpots' for radiolytic H2 production. For example, radiolytic H2 production rates normalized to water volume are 170 times higher in 1μm-wide fractures than in 10cm-wide fractures.

Multireaction equilibrium geothermometry: A sensitivity analysis using data from the Lower Geyser Basin, Yellowstone National Park, USA

USGS Publications Warehouse

King, Jonathan M.; Hurwitz, Shaul; Lowenstern, Jacob B.; Nordstrom, D. Kirk; McCleskey, R. Blaine

2016-01-01

A multireaction chemical equilibria geothermometry (MEG) model applicable to high-temperature geothermal systems has been developed over the past three decades. Given sufficient data, this model provides more constraint on calculated reservoir temperatures than classical chemical geothermometers that are based on either the concentration of silica (SiO2), or the ratios of cation concentrations. A set of 23 chemical analyses from Ojo Caliente Spring and 22 analyses from other thermal features in the Lower Geyser Basin of Yellowstone National Park are used to examine the sensitivity of calculated reservoir temperatures using the GeoT MEG code (Spycher et al. 2013, 2014) to quantify the effects of solute concentrations, degassing, and mineral assemblages on calculated reservoir temperatures. Results of our analysis demonstrate that the MEG model can resolve reservoir temperatures within approximately ±15°C, and that natural variation in fluid compositions represents a greater source of variance in calculated reservoir temperatures than variations caused by analytical uncertainty (assuming ~5% for major elements). The analysis also suggests that MEG calculations are particularly sensitive to variations in silica concentration, the concentrations of the redox species Fe(II) and H2S, and that the parameters defining steam separation and CO2 degassing from the liquid may be adequately determined by numerical optimization. Results from this study can provide guidance for future applications of MEG models, and thus provide more reliable information on geothermal energy resources during exploration.

Visualizing trace element distribution in quartz using cathodoluminescence, electron microprobe, and laser ablation-inductively coupled plasma-mass spectrometry

USGS Publications Warehouse

Rusk, Brian; Koenig, Alan; Lowers, Heather

2011-01-01

Cathodoluminescent (CL) textures in quartz reveal successive histories of the physical and chemical fluctuations that accompany crystal growth. Such CL textures reflect trace element concentration variations that can be mapped by electron microprobe or laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Trace element maps in hydrothermal quartz from four different ore deposit types (Carlin-type Au, epithermal Ag, porphyry-Cu, and MVT Pb-Zn) reveal correlations among trace elements and between trace element concentrations and CL textures. The distributions of trace elements reflect variations in the physical and chemical conditions of quartz precipitation. These maps show that Al is the most abundant trace element in hydrothermal quartz. In crystals grown at temperatures below 300 °C, Al concentrations may vary by up to two orders of magnitude between adjacent growth zones, with no evidence for diffusion. The monovalent cations Li, Na, and K, where detectable, always correlate with Al, with Li being the most abundant of the three. In most samples, Al is more abundant than the combined total of the monovalent cations; however, in the MVT sample, molar Al/Li ratios are ~0.8. Antimony is present in concentrations up to ~120 ppm in epithermal quartz (~200–300 °C), but is not detectable in MVT, Carlin, or porphyry-Cu quartz. Concentrations of Sb do not correlate consistently with those of other trace elements or with CL textures. Titanium is only abundant enough to be mapped in quartz from porphyry-type ore deposits that precipitate at temperatures above ~400 °C. In such quartz, Ti concentration correlates positively with CL intensity, suggesting a causative relationship. In contrast, in quartz from other deposit types, there is no consistent correlation between concentrations of any trace element and CL intensity fluctuations.

Particulate matters collected from ceramic factories in Lampang Province affecting rat lungs*

PubMed Central

Fongmoon, Duriya; Pongnikorn, Surathat; Chaisena, Aphiruk; Iamsaard, Sitthichai

2014-01-01

Background: Lung cancer ranks as the fifth largest of all cancer cases in Thailand. However, it is the first leading cancer in the northern part of Thailand (data from 2003–2007). There are several predisposing causes that lead to lung cancer and one important inducement is particulate matters (PMs). Lampang Province in Thailand is famous for the ceramic industry, where there are over 200 ceramic industrial factories. PMs are produced during the ceramic manufacturing process and spread throughout all of the working areas. It is very possible that workers could directly inhale PM-contaminated air during working hours. Objective: This study focuses on the toxic effects of PMs collected from ceramic factories on genes and lungs of rats. Methods: PMs collected from six ceramic factories in Lampang Province were extracted using dimethyl sulfoxide (DMSO). The inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to analyze the chemical elements at lower and higher concentrations, respectively. Then, the toxicity of PMs on the genes was examined by the Ames test, and subsequently, the effect of PMs on DNA was examined by quantifying the amount of 8-hydroxy-2′-deoxyguanosine (8-OHdG). Finally, the toxicity of the PMs on rat’s lungs was examined by histology. Results: As chemical elements of lower concentrations, cadmium, chromium, nickel, copper, and lead were detected by ICP-MS. As chemical elements of higher concentrations, manganese, magnesium, zinc, iron, potassium, calcium, and sodium were detected by ICP-OES. No mutagenicity in Salmonella typhimurium was found in the PM extracts from all six factories by utilizing the Ames test. In the histological study, the reduction in spaces of alveolar ducts and sacs, and terminal bronchioles, the thickening of interstitial connective tissues were noted by PM extracts in high amounts (100 and 350 μg). Female rats were more sensitive to PM extracts than males in terms of their pulmonary damages. Conclusions: PMs were not mutagenic to S. typhimurium but can damage the lung tissue of rats. PMID:24390747

Geothermal Heat Flux and Upper Mantle Viscosity across West Antarctica: Insights from the UKANET and POLENET Seismic Networks

NASA Astrophysics Data System (ADS)

O'Donnell, J. P.; Dunham, C.; Stuart, G. W.; Brisbourne, A.; Nield, G. A.; Whitehouse, P. L.; Hooper, A. J.; Nyblade, A.; Wiens, D.; Aster, R. C.; Anandakrishnan, S.; Huerta, A. D.; Wilson, T. J.; Winberry, J. P.

2017-12-01

Quantifying the geothermal heat flux at the base of ice sheets is necessary to understand their dynamics and evolution. The heat flux is a composite function of concentration of upper crustal radiogenic elements and flow of heat from the mantle into the crust. Radiogenic element concentration varies with tectonothermal age, while heat flow across the crust-mantle boundary depends on crustal and lithospheric thicknesses. Meanwhile, accurately monitoring current ice mass loss via satellite gravimetry or altimetry hinges on knowing the upper mantle viscosity structure needed to account for the superimposed glacial isostatic adjustment (GIA) signal in the satellite data. In early 2016 the UK Antarctic Network (UKANET) of 10 broadband seismometers was deployed for two years across the southern Antarctic Peninsula and Ellsworth Land. Using UKANET data in conjunction with seismic records from our partner US Polar Earth Observing Network (POLENET) and the Antarctic Seismographic Argentinian Italian Network (ASAIN), we have developed a 3D shear wave velocity model of the West Antarctic crust and uppermost mantle based on Rayleigh and Love wave phase velocity dispersion curves extracted from ambient noise cross-correlograms. We combine seismic receiver functions with the shear wave model to help constrain the depth to the crust-mantle boundary across West Antarctica and delineate tectonic domains. The shear wave model is subsequently converted to temperature using a database of densities and elastic properties of minerals common in crustal and mantle rocks, while the various tectonic domains are assigned upper crustal radiogenic element concentrations based on their inferred tectonothermal ages. We combine this information to map the basal geothermal heat flux variation across West Antarctica. Mantle viscosity depends on factors including temperature, grain size, the hydrogen content of olivine and the presence of melt. Using published mantle xenolith and magnetotelluric data to constrain grain size and hydrogen content, respectively, we use the temperature model to estimate the regional upper mantle viscosity structure. The viscosity information will be incorporated in a 3D GIA model that will better constrain estimates of current ice loss from the West Antarctic Ice Sheet.

Composition and Sources of Fine and Coarse Particles Collected during 2002–2010 in Boston, MA

PubMed Central

Masri, Shahir; Kang, Choong-Min; Koutrakis, Petros

2016-01-01

Identifying the sources, composition, and temporal variability of fine (PM2.5) and coarse (PM2.5-10) particles is a crucial component in understanding PM toxicity and establishing proper PM regulations. In this study, a Harvard Impactor was used to collect daily integrated fine and coarse particle samples every third day for nine years at a single site in Boston, MA. A total of 1,960 filters were analyzed for elements, black carbon (BC), and total PM mass. Positive Matrix Factorization (PMF) was used to identify source types and quantify their contributions to ambient PM2.5 and PM2.5-10. BC and 17 elements were identified as the main constituents in our samples. Results showed that BC, S, and Pb were associated exclusively with the fine particle mode, while 84% of V and 79% of Ni were associated with this mode. Elements mostly found in the coarse mode, over 80%, included Ca, Mn (road dust), and Cl (sea salt). PMF identified six source types for PM2.5 and three source types for PM2.5-10. Source types for PM2.5 included regional pollution, motor vehicles, sea salt, crustal/road dust, oil combustion, and wood burning. Regional pollution contributed the most, accounting for 48% of total PM2.5 mass, followed by motor vehicles (21%) and wood burning (19%). Source types for PM2.5-10 included crustal/road dust (62%), motor vehicles (22%), and sea salt (16%). A linear decrease in PM concentrations with time was observed for both fine (−5.2%/yr) and coarse (−3.6%/yr) particles. The fine-mode trend was mostly related to oil combustion and regional pollution contributions. Average PM2.5 concentrations peaked in summer (10.4 μg/m3) while PM2.5-10 concentrations were lower and demonstrated little seasonal variability. The findings of this study show that PM25 is decreasing more sharply than PM2.5-10 over time. This suggests the increasing importance of PM2.5-10 and traffic-related sources for PM exposure and future policies. PMID:25947125

Analysis of major air pollutants and submicron particles in New York City and Long Island

NASA Astrophysics Data System (ADS)

Masiol, M.; Hopke, P. K.; Felton, H. D.; Frank, B. P.; Rattigan, O. V.; Wurth, M. J.; LaDuke, G. H.

2017-01-01

A year-long sampling campaign of major air pollutants and submicron particle number size distributions was conducted at two sites taken as representative of city-wide air quality in New York City and Long Island, respectively. A number of species were quantified with hourly time resolution, including particle number concentrations in 6 size ranges (20-30 nm, 30-50 nm, 50-70 nm, 70-100 nm, 100-200 nm, and >200 nm), nitrogen oxides, sulfur dioxide, ozone, carbon monoxide, methane, non-methane hydrocarbons, PM2.5 mass concentration and some PM major components (sulfate, organic and elemental carbon). Hourly concentrations of primary and secondary organic carbon were estimated using the EC tracer method. Data were matched with weather parameters and air parcel back-trajectories. A series of tools were thus applied to: (i) study the seasonal, weekly, diurnal cycles of pollutants; (ii) investigate the relationships amongst pollutants through correlation and lagged correlation analyses; (iii) depict the role of atmospheric photochemical processes; (iv) examine the location of the potential sources by mean of conditional bivariate probability function analysis and (v) investigate the role of regional transport of air masses to the concentrations of analyzed species. Results indicate that concentrations of NOx, SO2, CO, non-methane hydrocarbons, primary OC and EC are predominantly determined by local sources, but are also affected by regional transports of polluted air masses. On the contrary, the transport of continental polluted air masses has a main effect in raising the concentrations of secondary PM2.5 (sulfate and secondary organic carbon). By providing direct information on the concentrations and trends of key pollutants and submicron particle number concentrations, this study finally enables some general considerations about air quality status and atmospheric processes over the New York City metropolitan area.

Neural basis for generalized quantifier comprehension.

PubMed

McMillan, Corey T; Clark, Robin; Moore, Peachie; Devita, Christian; Grossman, Murray

2005-01-01

Generalized quantifiers like "all cars" are semantically well understood, yet we know little about their neural representation. Our model of quantifier processing includes a numerosity device, operations that combine number elements and working memory. Semantic theory posits two types of quantifiers: first-order quantifiers identify a number state (e.g. "at least 3") and higher-order quantifiers additionally require maintaining a number state actively in working memory for comparison with another state (e.g. "less than half"). We used BOLD fMRI to test the hypothesis that all quantifiers recruit inferior parietal cortex associated with numerosity, while only higher-order quantifiers recruit prefrontal cortex associated with executive resources like working memory. Our findings showed that first-order and higher-order quantifiers both recruit right inferior parietal cortex, suggesting that a numerosity component contributes to quantifier comprehension. Moreover, only probes of higher-order quantifiers recruited right dorsolateral prefrontal cortex, suggesting involvement of executive resources like working memory. We also observed activation of thalamus and anterior cingulate that may be associated with selective attention. Our findings are consistent with a large-scale neural network centered in frontal and parietal cortex that supports comprehension of generalized quantifiers.

Element concentrations in soils and other surficial materials of the conterminous United States

USGS Publications Warehouse

Shacklette, Hansford T.; Boerngen, Josephine G.

1984-01-01

Samples of soils or other regoliths, taken at a depth of approximately 20 cm form locations about 80 km apart, throughout the conterminous United States, were analyzed for their content of elements. In this manner, 1,318 sampling sites were chosen, and the results of the sample analyses for 50 elements were plotted on maps. The arithmetic and geometric mean, the geometric deviation, and a histogram showing frequencies of analytical values are given for 47 elements. The lower concentrations of some elements (notable, aluminum, barium, calcium, magnesium, potassium, sodium, and strontium) in most samples of surficial materials from the Eastern United States, and the greater abundance of heavy metals in the same materials of the Western United States, indicates a regional geochemical pattern of the largest scale. The low concentrations of many elements in soils characterize the Atlantic Coastal Plain. Souls of the Pacific Northwest generally have high concentrations of aluminum, cobalt, iron, scandium, and vanadium, but are low in boron. Soils of the Rocky Mountain region tend to have high concentrations of copper, lead, and zinc. High mercury concentrations in surficial materials are characteristic of Gulf Coast sampling sites and the Atlantic coast sites of Connecticut, Massachusetts, and Maine. At the State level, Florida has the most striking geochemical pattern by having soils that are low in concentrations of most elements considered in this study. Some smaller patterns of element abundance can be noted, but the degree of confidence in the validity of these patterns decreases as the patterns become less extensive.

Quantification of multiple elements in dried blood spot samples.

PubMed

Pedersen, Lise; Andersen-Ranberg, Karen; Hollergaard, Mads; Nybo, Mads

2017-08-01

Dried blood spots (DBS) is a unique matrix that offers advantages compared to conventional blood collection making it increasingly popular in large population studies. We here describe development and validation of a method to determine multiple elements in DBS. Elements were extracted from punches and analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The method was evaluated with quality controls with defined element concentration and blood spiked with elements to assess accuracy and imprecision. DBS element concentrations were compared with concentrations in venous blood. Samples with different hematocrit were spotted onto filter paper to assess hematocrit effect. The established method was precise and accurate for measurement of most elements in DBS. There was a significant but relatively weak correlation between measurement of the elements Mg, K, Fe, Cu, Zn, As and Se in DBS and venous whole blood. Hematocrit influenced the DBS element measurement, especially for K, Fe and Zn. Trace elements can be measured with high accuracy and low imprecision in DBS, but contribution of signal from the filter paper influences measurement of some elements present at low concentrations. Simultaneous measurement of K and Fe in DBS extracts may be used to estimate sample hematocrit. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Transport of trace metals in runoff from soil and pond ash feedlot surfaces

USGS Publications Warehouse

Vogel, J.R.; Gilley, J.E.; Cottrell, G.L.; Woodbury, B.L.; Berry, E.D.; Eigenbert, R.A.

2011-01-01

The use of pond ash (fly ash that has been placed in evaporative ponds for storage and subsequently dewatered) for feedlot surfaces provides a drier environment for livestock and furnishes economic benefits. However, pond ash is known to have high concentrations of trace elements, and the runoff water-quality effects of feedlot surfaces amended with pond ash are not well defined. For this study, two experimental units (plots) were established in eight feedlot pens. Four of the pens contained unamended soil surfaces, and the remaining four pens had pond-ash amended surfaces. Before each test, unconsolidated surface material was removed from four of the plots for each of the amendment treatments, resulting in eight unamended plots and eight pond-ash amended plots. Concentrations for 23 trace elements were measured in cattle feedlot surface material and in the runoff water from three simulated rainfall events. Trace element concentrations in surface material and runoff did not differ between surface consolidation treatments. Amending the feedlot surface material with pond ash resulted in a significant increase in concentration for 14 of the 17 trace elements. Runoff concentrations for 21 trace elements were affected by pond-ash amendment. Sixteen of 21 trace element concentrations that differed significantly were greater in runoff from unamended soil surfaces. Concentrations in runoff were significantly correlated with concentrations in feedlot surface material for boron, manganese, molybdenum, selenium, and uranium.

Rare Earth Element Concentration of Wyoming Thermal Waters Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quillinan, Scott; Nye, Charles; Neupane, Hari

Updated version of data generated from rare earth element investigation of produced waters. These data represent major, minor, trace, isotopes, and rare earth element concentrations in geologic formations and water associated with oil and gas production.

Geochemical surveys in the United States in relation to health.

USGS Publications Warehouse

Tourtelot, H.A.

1979-01-01

Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes. -Author

Seasonal Variations of Quantified Organic Compounds in PM10 over Seoul

NASA Astrophysics Data System (ADS)

Choi, N.; Lee, J.; Kim, Y. P.

2014-12-01

The concentrations of 87 individual organic matters in the PM10 samples, systematically collected on the roof of the School of Public Health building at Seoul National University (mixed commercial and residential area), Seoul, South Korea on a daily basis from April 2010 to April 2011, were quantified by mean of Gas Chromatography/Mass Spectrometry (GC/MS). The daily average concentrations of five organic groups, alkanes, PAHs, fatty acid, DCAs, and sugars were ranged from 498.40 ng m3 to 10.20 μg m3. The seasonal concentrations of the total quantified organic species were 1.73 μg m3 (Spring), 2.04 μg m3 (Summer), 3.11 μg m3 (Fall), and 3.60 μg m3 (Winter), respectively. All the organic groups showed higher average concentration in winter than in summer. However, some organic compounds among fatty acids, DCAs, and sugars showed reverse pattern. The seasonal concentration patterns and episode variation of individual organic compounds were studied to clarify the emission characteristics of organic matters in PM10.

Quantifying transfer after perceptual-motor sequence learning: how inflexible is implicit learning?

PubMed Central

Sanchez, Daniel J.; Yarnik, Eric N.

2015-01-01

Studies of implicit perceptual-motor sequence learning have often shown learning to be inflexibly tied to the training conditions during learning. Since sequence learning is seen as a model task of skill acquisition, limits on the ability to transfer knowledge from the training context to a performance context indicates important constraints on skill learning approaches. Lack of transfer across contexts has been demonstrated by showing that when task elements are changed following training, this leads to a disruption in performance. These results have typically been taken as suggesting that the sequence knowledge relies on integrated representations across task elements (Abrahamse, Jiménez, Verwey, & Clegg, Psychon Bull Rev 17:603–623, 2010a). Using a relatively new sequence learning task, serial interception sequence learning, three experiments are reported that quantify this magnitude of performance disruption after selectively manipulating individual aspects of motor performance or perceptual information. In Experiment 1, selective disruption of the timing or order of sequential actions was examined using a novel response manipulandum that allowed for separate analysis of these two motor response components. In Experiments 2 and 3, transfer was examined after selective disruption of perceptual information that left the motor response sequence intact. All three experiments provided quantifiable estimates of partial transfer to novel contexts that suggest some level of information integration across task elements. However, the ability to identify quantifiable levels of successful transfer indicates that integration is not all-or-none and that measurement sensitivity is a key in understanding sequence knowledge representations. PMID:24668505

Trace elements and organic compounds in bed sediment from selected streams in southern Louisiana, 1998

USGS Publications Warehouse

Skrobialowski, Stanley C.

2002-01-01

Bed-sediment samples from 21 selected streams in southern Louisiana were collected and analyzed for the presence of trace elements and organic compounds during 1998 as part of the U.S. Geological Survey National Water-Quality Assessment Program. Concentrations of selected trace elements and organic compounds were compared on the basis of sediment-quality criteria, land use, and grain size; concentrations of selected trace elements also were compared with concentrations from previous studies. Concentrations of seven selected trace elements and 21 organic compounds were evaluated with sediment-quality criteria established by the Canadian Council of Ministers of the Environment. Concentrations of selected trace elements and organic compounds were highest at sites draining urban and agricultural areas and may result from cumulative effects of relatively high percentages of fine-grained material, iron, and organic material. Concentrations exceeding sediment-quality criteria for the protection of aquatic life occurred most frequently at Bayou Grosse Tete at Rosedale and Bayou Lafourche below weir at Thibodaux. Exceedance of Interim Sediment Quality Guidelines occurred most frequently for arsenic and chromium. Trace-element concentrations in fine-grained samples were compared with concentrations in bulk samples and were determined to be significantly different, and concentrations were generally higher in finegrained sediment. Shapiro-Wilk, paired t-test, and Wilcoxon rank sum statistical procedures, with an alpha of 0.05, were used to compare concentrations of 21 trace elements, total organic carbon, and total carbon in finegrained and bulk sediment samples for 19 sites. Significant differences were determined between fine-grained and bulk sediment samples for aluminum, barium, beryllium, chromium, copper, iron, lithium, nickel, phosphorus, selenium, titanium, and zinc concentrations. Of 133 paired concentrations, 69 percent were greater in fine-grained samples, and 23 percent were greater in bulk samples. Comparisons with data from previous studies indicate increases by more than 20 percent in concentrations of antimony at Bayou Lafourche below weir at Thibodaux, arsenic and chromium at Tickfaw River at Liverpool, lead at Bayou Lafourche below weir at Thibodaux, and zinc at Bayou Lafourche below weir at Thibodaux and Vermilion River at Perry. Historic comparisons also indicate decreases by more than 20 percent in concentrations of chromium at Bayou des Cannes near Eunice and mercury at Mermentau River at Mermentau.

Atmospheric mercury emissions from mine wastes and surrounding geologically enriched terrains

USGS Publications Warehouse

Gustin, M.S.; Coolbaugh, M.F.; Engle, M.A.; Fitzgerald, B.C.; Keislar, R.E.; Lindberg, S.E.; Nacht, D.M.; Quashnick, J.; Rytuba, J.J.; Sladek, C.; Zhang, H.; Zehner, R.E.

2003-01-01

Waste rock and ore associated with Hg, precious and base metal mining, and their surrounding host rocks are typically enriched in mercury relative to natural background concentrations (<0.1 ??g Hg g-1). Mercury fluxes to the atmosphere from mineralized areas can range from background rates (0-15 ng m-2 h-1) to tens of thousands of ng m-2 h-1. Mercury enriched substrate constitutes a long-term source of mercury to the global atmospheric mercury pool. Mercury emissions from substrate are influenced by light, temperature, precipitation, and substrate mercury concentration, and occur during the day and night. Light-enhanced emissions are driven by two processes: desorption of elemental mercury accumulated at the soil:air interface, and photo reduction of mercury containing phases. To determine the need for and effectiveness of regulatory controls on short-lived anthropogenic point sources the contribution of mercury from geologic non-point sources to the atmospheric mercury pool needs to be quantified. The atmospheric mercury contribution from small areas of mining disturbance with relatively high mercury concentrations are, in general, less than that from surrounding large areas of low levels of mercury enrichment. In the arid to semi-arid west-ern United States volatilization is the primary means by which mercury is released from enriched sites.

Apis mellifera ligustica, Spinola 1806 as bioindicator for detecting environmental contamination: a preliminary study of heavy metal pollution in Trieste, Italy.

PubMed

Giglio, Anita; Ammendola, Anna; Battistella, Silvia; Naccarato, Attilio; Pallavicini, Alberto; Simeon, Enrico; Tagarelli, Antonio; Giulianini, Piero Giulio

2017-01-01

Honeybees have become important tools for the ecotoxicological assessment of soil, water and air metal contamination due to their extraordinary capacity to bioaccumulate toxic metals from the environment. The level of heavy metal pollution in the Trieste city was monitored using foraging bees of Apis mellifera ligustica from hives owned by beekeepers in two sites strategically located in the suburban industrial area and urban ones chosen as control. The metal concentration in foraging bees was determined by inductively coupled plasma-mass spectrometry. The chemical analysis has identified and quantified 11 trace elements accumulated in two different rank orders: Zn> Cu > Sr > Bi > Ni > Cr > Pb = Co > V > Cd > As in foraging bees from the suburban site and Zn > Cu > Sr > Cr > Ni > Bi > Co = V > Pb > As > Cd in bees from urban site. Data revealed concentrations of Cr and Cu significantly higher and concentration of Cd significantly lower in bees from urban sites. The spatial difference and magnitude order in heavy metal accumulation along the urban-suburban gradient are mainly related to the different anthropogenic activity within sampled sites and represent a risk for the human health of people living in the city. We discussed and compared results with the range of values reported in literature.

In vitro toxicology of ambient particulate matter: correlation of cellular effects with particle size and components.

PubMed

Kroll, Alexandra; Gietl, Johanna K; Wiesmüller, Gerhard A; Günsel, Andreas; Wohlleben, Wendel; Schnekenburger, Jürgen; Klemm, Otto

2013-02-01

High concentrations of airborne particulate matter (PM) have been associated with increased rates of morbidity and mortality among exposed populations. Although certain components of PM were suggested to influence these effects, no clear-cut correlation was determined thus far. One of the possible modes of action is the induction of oxidative stress by inhaled PM triggering inflammatory responses. Therefore, the in vitro formation of reactive oxygen species (ROS) in three cell lines in the presence of five subfractions of PM(10), collected in Münster, Germany was investigated. The PM components chloride, nitrate, ammonium, sulfate, 68 chemical elements, and endotoxin were quantified. The highest concentration of endotoxin was found in particles of 0.42-1.2 μm aerodynamic diameters, and therefore probably subject to long-range transport. Intracellular ROS formation in three well established mammalian cell lines (CaCo2, human; MDCK, canine; RAW264.7, mouse) only correlated positively with particle size. The two smallest PM size fractions provoked the highest rise in ROS. However, the latter did not correlate with the concentration of any PM components investigated. The smallest PM size fractions significantly dominated the number of particles. Therefore, the particle number may be most effective in inducing oxidative stress in vitro. Copyright © 2011 Wiley Periodicals, Inc.

Quantifying activation of perfluorocarbon-based phase-change contrast agents using simultaneous acoustic and optical observation.

PubMed

Li, Sinan; Lin, Shengtao; Cheng, Yi; Matsunaga, Terry O; Eckersley, Robert J; Tang, Meng-Xing

2015-05-01

Phase-change contrast agents in the form of nanoscale droplets can be activated into microbubbles by ultrasound, extending the contrast beyond the vasculature. This article describes simultaneous optical and acoustical measurements for quantifying the ultrasound activation of phase-change contrast agents over a range of concentrations. In experiments, decafluorobutane-based nanodroplets of different dilutions were sonicated with a high-pressure activation pulse and two low-pressure interrogation pulses immediately before and after the activation pulse. The differences between the pre- and post-interrogation signals were calculated to quantify the acoustic power scattered by the microbubbles activated over a range of droplet concentrations. Optical observation occurred simultaneously with the acoustic measurement, and the pre- and post-microscopy images were processed to generate an independent quantitative indicator of the activated microbubble concentration. Both optical and acoustic measurements revealed linear relationships to the droplet concentration at a low concentration range <10(8)/mL when measured at body temperature. Further increases in droplet concentration resulted in saturation of the acoustic interrogation signal. Compared with body temperature, room temperature was found to produce much fewer and larger bubbles after ultrasound droplet activation. Copyright © 2015. Published by Elsevier Inc.

Concentrations and bioaccessibilities of trace elements in barbecue charcoals.

PubMed

Sharp, Annabel; Turner, Andrew

2013-11-15

Total and bioaccessible concentrations of trace elements (Al, As, Cd, Cu, Fe, Hg, Mn, Ni, Pb and Zn) have been measured in charcoals from 15 barbecue products available from UK retailers. Total concentrations (available to boiling aqua regia) were greater in briquetted products (with mean concentrations ranging from 0.16 μg g(-1) for Cd to 3240 μg g(-1) for Al) than in lumpwoods (0.007 μg g(-1) for Cd to 28 μg g(-1) for Fe), presumably because of the use of additives and secondary constituents (e.g. coal) in the former. On ashing, and with the exception of Hg, elemental concentrations increased by factors ranging from about 1.5 to 50, an effect attributed to the combustion of organic components and offset to varying extents by the different volatilities of the elements. Concentrations in the ashed products that were bioaccessible, or available to a physiologically based extraction test (PBET) that simulates, successively, the chemical conditions in the human stomach and intestine, exhibited considerable variation among the elements studied. Overall, however, bioaccessible concentrations relative to corresponding total concentrations were greatest for As, Cu and Ni (attaining 100% in either or both simulated PBET phases in some cases) and lowest for Pb (generally <1% in both phases). A comparison of bioaccessible concentrations in ashed charcoals with estimates of daily dietary intake suggest that Al and As are the trace elements of greatest concern to human health from barbecuing. Copyright © 2013 Elsevier B.V. All rights reserved.

Concentrations of platinum group elements in 122 U.S. coal samples

USGS Publications Warehouse

Oman, C.L.; Finkelman, R.B.; Tewalt, S.J.

1997-01-01

Analysis of more than 13,000 coal samples by semi-quantitative optical emission spectroscopy (OES) indicates that concentrations of the platinum group elements (iridium, palladium, platinum, osmium, rhodium, and ruthenium) are less than 1 ppm in the ash, the limit of detection for this method of analysis. In order to accurately determine the concentration of the platinum group elements (PGE) in coal, additional data were obtained by inductively coupled plasma mass spectroscopy, an analytical method having part-per-billion (ppb) detection limits for these elements. These data indicate that the PGE in coal occur in concentrations on the order of 1 ppb or less.

Concentrations of trace elements in Great Lakes fishes

USGS Publications Warehouse

Lucas, Henry F.; Edgington, David N.; Colby, Peter J.

1970-01-01

The concentration of 15 trace elements was determined by activation analysis of samples of whole fish and fish livers from three of the Great Lakes: Michigan, Superior, and Erie. The average concentrations of 7 elements in 19 whole fish from 3 species were as follows: uranium, 3 ppb (parts per billion); thorium, 6 ppb; cobalt, 28 ppb; cadmium, 94 ppb; arsenic, 16 ppb; chromium, 1 ppm; and copper, 1.3 ppm. The average concentrations of 8 elements in 40 liver samples from 10 species of fish were as follows: uranium, ~ 2 ppb; thorium, a?? 2 ppb; cobalt, 40 ppb; copper, 9 ppm; zinc, 30 ppm; bromine, 0.4 ppm; arsenic, 30 ppb; and cadmium, 0.4 ppm. Other elements observed in most of the samples were: antimony, 5-100 ppb; gold, 2-5 ppb; lanthanum, 1-20 ppb; rhenium, 0.5-5 ppb; rubidium, 0.06-4 ppm; and selenium, 0.1-2 ppb. Trace element concentrations varied with species and lake. Uranium and thorium varied with species, but not for the same species from different lakes. The levels of copper, cobalt, zinc, and bromine varied little between species and lakes. The concentration of cadmium, arsenic, and chromium varied between species and with species between lakes.

Determination of element levels in human serum: Total reflection X-ray fluorescence applications

NASA Astrophysics Data System (ADS)

Majewska, U.; Łyżwa, P.; Łyżwa, K.; Banaś, D.; Kubala-Kukuś, A.; Wudarczyk-Moćko, J.; Stabrawa, I.; Braziewicz, J.; Pajek, M.; Antczak, G.; Borkowska, B.; Góźdź, S.

2016-08-01

Deficiency or excess of elements could disrupt proper functioning of the human body and could lead to several disorders. Determination of their concentrations in different biological human fluids and tissues should become a routine practice in medical treatment. Therefore the knowledge about appropriate element concentrations in human organism is required. The purpose of this study was to determine the concentration of several elements (P, S, Cl, K, Ca, Cr, Fe, Cu, Zn, Se, Br, Rb, Pb) in human serum and to define the reference values of element concentration. Samples of serum were obtained from 105 normal presumably healthy volunteers (66 women aged between 15 and 78 years old; 39 men aged between 15 and 77 years old). Analysis has been done for the whole studied population and for subgroups by sex and age. It is probably first so a wide study of elemental composition of serum performed in the case of Świętokrzyskie region. Total reflection X-ray fluorescence (TXRF) method was used to perform the elemental analysis. Spectrometer S2 Picofox (Bruker AXS Microanalysis GmbH) was used to identify and measure elemental composition of serum samples. Finally, 1st and 3rd quartiles were accepted as minimum and maximum values of concentration reference range.

Online elemental analysis of process gases with ICP-OES: a case study on waste wood combustion.

PubMed

Wellinger, Marco; Wochele, Joerg; Biollaz, Serge M A; Ludwig, Christian

2012-10-01

A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. The analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparison of PIXE and XRF analysis of airborne particulate matter samples collected on Teflon and quartz fibre filters

NASA Astrophysics Data System (ADS)

Chiari, M.; Yubero, E.; Calzolai, G.; Lucarelli, F.; Crespo, J.; Galindo, N.; Nicolás, J. F.; Giannoni, M.; Nava, S.

2018-02-01

Within the framework of research projects focusing on the sampling and analysis of airborne particulate matter, Particle Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (ED-XRF) techniques are routinely used in many laboratories throughout the world to determine the elemental concentration of the particulate matter samples. In this work an inter-laboratory comparison of the results obtained from analysing several samples (collected on both Teflon and quartz fibre filters) using both techniques is presented. The samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of INFN-LABEC laboratory) and by XRF (in Elche, using the ARL Quant'X EDXRF spectrometer with specific conditions optimized for specific groups of elements). The results from the two sets of measurements are in good agreement for all the analysed samples, thus validating the use of the ARL Quant'X EDXRF spectrometer and the selected measurement protocol for the analysis of aerosol samples. Moreover, thanks to the comparison of PIXE and XRF results on Teflon and quartz fibre filters, possible self-absorption effects due to the penetration of the aerosol particles inside the quartz fibre-filters were quantified.

Quantification of transcription factor-DNA binding affinity in a living cell

PubMed Central

Belikov, Sergey; Berg, Otto G.; Wrange, Örjan

2016-01-01

The apparent dissociation constant (Kd) for specific binding of glucocorticoid receptor (GR) and androgen receptor (AR) to DNA was determined in vivo in Xenopus oocytes. The total nuclear receptor concentration was quantified as specifically retained [3H]-hormone in manually isolated oocyte nuclei. DNA was introduced by nuclear microinjection of single stranded phagemid DNA, chromatin is then formed during second strand synthesis. The fraction of DNA sites occupied by the expressed receptor was determined by dimethylsulphate in vivo footprinting and used for calculation of the receptor-DNA binding affinity. The forkhead transcription factor FoxA1 enhanced the DNA binding by GR with an apparent Kd of ∼1 μM and dramatically stimulated DNA binding by AR with an apparent Kd of ∼0.13 μM at a composite androgen responsive DNA element containing one FoxA1 binding site and one palindromic hormone receptor binding site known to bind one receptor homodimer. FoxA1 exerted a weak constitutive- and strongly cooperative DNA binding together with AR but had a less prominent effect with GR, the difference reflecting the licensing function of FoxA1 at this androgen responsive DNA element. PMID:26657626

Alkaline and ultrasonic dissolution of biological materials for trace silicon determination

PubMed Central

Viveros, Robert D.; Liberman, Alexander; Trogler, William C.; Kummel, Andrew C.

2015-01-01

A simple method for trace elemental determination in biological tissue has been developed. Novel nanomaterials with biomedical applications necessitate the determination of the in vivo fate of the materials to understand their toxicological profile. Hollow iron-doped calcined silica nanoshells have been used as a model to demonstrate that potassium hydroxide and bath sonication at 50 °C can extract elements from alkaline-soluble nanomaterials. After alkali digestion, nitric acid is used to adjust the pH into a suitable range for analysis using techniques such as inductively coupled plasma optical emission spectrometry which require neutral or acidic analytes. In chicken liver phantoms injected with the nanoshells, 96% of the expected silicon concentration was detected. This value was in good agreement with the 94% detection efficiency of nanoshells dissolved in aqueous solution as a control for potential sample matrix interference. Nanoshell detection was further confirmed in a mouse 24 h after intravenous administration; the measured silica above baseline was 35 times greater or more than the standard deviations of the measurements. This method provides a simple and accurate means to quantify alkaline-soluble nanomaterials in biological tissue. PMID:25909037

Laser microprobe analyses of noble gas isotopes and halogens in fluid inclusions: Analyses of microstandards and synthetic inclusions in quartz

USGS Publications Warehouse

Böhlke, J.K.; Irwin, J.J.

1992-01-01

Ar, Kr, Xe, Cl, Br, I, and K abundances and isotopic compositions have been measured in microscopic fluid inclusions in minerals by noble gas mass spectrometry following neutron irradiation and laser extraction. The laser microprobe noble gas mass spectrometric (LMNGMS) technique was quantified by use of microstandards, including air-filled capillary tubes, synthetic basalt glass grains, standard hornblende grains, and synthetic fluid inclusions in quartz. Common natural concentrations of halogens (Cl, Br, and I) and noble gases (Ar and Kr) in trapped groundwaters and hydrothermal fluids can be analyzed simultaneously by LMNGMS in as little as 10−11 L of inclusion fluid, with accuracy and precision to within 5–10% for element and isotope ratios. Multicomponent element and isotope correlations indicate contaminants or persistent reservoirs of excess Xe and/or unfractionated air in some synthetic and natural fluid inclusion samples. LMNGMS analyses of natural fluid inclusions using the methods and calibrations reported here may be used to obtain unique information on sources of fluids, sources of fluid salinity, mixing, boiling (or unmixing), and water-rock interactions in ancient fluid flow systems.

Summertime elemental mercury exchange of temperate grasslands on an ecosystem-scale

PubMed Central

Fritsche, J.; Wohlfahrt, G.; Ammann, C.; Zeeman, M.; Hammerle, A.; Obrist, D.; Alewell, C.

2013-01-01

In order to estimate the air-surface mercury exchange of grasslands in temperate climate regions, fluxes of gaseous elemental mercury (GEM) were measured at two sites in Switzerland and one in Austria during summer 2006. Two classic micrometeorological methods (aerodynamic and modified Bowen ratio) have been applied to estimate net GEM exchange rates and to determine the response of the GEM flux to changes in environmental conditions (e.g. heavy rain, summer ozone) on an ecosystem-scale. Both methods proved to be appropriate to estimate fluxes on time scales of a few hours and longer. Average dry deposition rates up to 4.3 ng m−2 h−1 and mean deposition velocities up to 0.10 cm s−1 were measured, which indicates that during the active vegetation period temperate grasslands are a small net sink for atmospheric mercury. With increasing ozone concentrations depletion of GEM was observed, but could not be quantified from the flux signal. Night-time deposition fluxes of GEM were measured and seem to be the result of mercury co-deposition with condensing water. Effects of grass cuts could also be observed, but were of minor magnitude. PMID:24348525

Relevance of hair and spines of the European hedgehog (Erinaceus europaeus) as biomonitoring tissues for arsenic and metals in relation to blood.

PubMed

Vermeulen, Frouke; D'Havé, Helga; Mubiana, Valentine K; Van den Brink, Nico W; Blust, Ronny; Bervoets, Lieven; De Coen, Wim

2009-02-15

Hair has been proven to be suitable for non-destructive and non-invasive exposure assessments in human and mammal populations. A previous study with European hedgehog (Erinaceus europaeus) showed that, for some metals, hair and spine metal concentrations were positively correlated to levels in liver, kidney and muscle. Although blood has been studied in a wide variety of species, the relationship between hair and blood metal concentrations has yet to be quantified in many mammalian species. Tissue concentrations from hedgehogs residing in a park with known metal pollution were compared with those from a reference park and correlations between contaminant levels in hair and blood, and spines and blood were studied. Moreover, the relative distribution of arsenic and metals in hair, spines and blood was determined. Elevated concentrations were found in hedgehogs residing in the polluted site for As (8.2 microg/g, 6.3 microg/g, 3.6 microg/ml), Cd (0.48 microg/g, 0.17 microg/g, 0.02 microg/ml) and Pb (7.6 microg/g, 7.3 microg/g, 54 microg/ml), in hair, spines and blood respectively. Positive correlations were identified for exposure levels between hair and blood as well as between spines and blood for three elements (As, Cd, and Pb), whereas a negative correlation was found between Cr concentrations in spines and blood. In conclusion, hair and spines can be used to monitor blood concentrations of some metals, although more data are needed on uptake from the food chain and on the incorporation dynamics of these contaminants.

Comprehensive laboratory measurements of biomass-burning emissions: 1. Emissions from Indonesian, African, and other fuels

NASA Astrophysics Data System (ADS)

Christian, T. J.; Kleiss, B.; Yokelson, R. J.; Holzinger, R.; Crutzen, P. J.; Hao, W. M.; Saharjo, B. H.; Ward, D. E.

2003-12-01

Trace gas and particle emissions were measured from 47 laboratory fires burning 16 regionally to globally significant fuel types. Instrumentation included the following: open-path Fourier transform infrared spectroscopy; proton transfer reaction mass spectrometry; filter sampling with subsequent analysis of particles with diameter <2.5 μm for organic and elemental carbon and other elements; and canister sampling with subsequent analysis by gas chromatography (GC)/flame ionization detector, GC/electron capture detector, and GC/mass spectrometry. The emissions of 26 compounds are reported by fuel type. The results include the first detailed measurements of the emissions from Indonesian fuels. Carbon dioxide, CO, CH4, NH3, HCN, methanol, and acetic acid were the seven most abundant emissions (in order) from burning Indonesian peat. Acetol (hydroxyacetone) was a major, previously unobserved emission from burning rice straw (21-34 g/kg). The emission factors for our simulated African fires are consistent with field data for African fires for compounds measured in both the laboratory and the field. However, the higher concentrations and more extensive instrumentation in this work allowed quantification of at least 10 species not previously quantified for African field fires (in order of abundance): acetaldehyde, phenol, acetol, glycolaldehyde, methylvinylether, furan, acetone, acetonitrile, propenenitrile, and propanenitrile. Most of these new compounds are oxygenated organic compounds, which further reinforces the importance of these reactive compounds as initial emissions from global biomass burning. A few high-combustion-efficiency fires emitted very high levels of elemental (black) carbon, suggesting that biomass burning may produce more elemental carbon than previously estimated.

A New Method for Estimation of Emissions and Sources of Measurements Error in the Silicon Refining Process

NASA Astrophysics Data System (ADS)

Næss, Mari k.; Kero, Ida; Tranell, Gabriella

2013-08-01

In the production of metallurgical grade silicon (MG-Si), fugitive emissions are a serious concern due to the health risks associated with the fumes formed in different parts of the production. The fumes are also a potential environmental hazard. Yet, the chemical composition of the fumes from most process steps in the silicon plant, such as oxidative refining ladle, remains unknown. This in turn constitutes a problem with respect to the correct assessment of the environmental impact and working conditions. A comprehensive industrial measurement campaign was performed at the Elkem Salten MG-Si production plant in Norway. Samples of the ingoing and outgoing mass flows were analyzed by high-resolution inductively coupled plasma mass spectrometry, with respect to 62 elements. In every step of the sampling and sample treatment processes, possible sources of error have been identified and quantified, including process variation, mass measurement accuracy, and contamination risk. Total measurement errors for all elements in all phases are established. The method is applied to estimate the order of magnitude of the elemental emissions via the fumes from the tapping and refining processes, with respect to production mass and year. The elements with higher concentrations in the fume than slag and refined silicon include Ag, Bi, Cd, Cu, In, K, Mg, Na, Pb, Rb, Se, Sn, Tl, and Zn: all being present in the ppm range. This work constitutes new and vital information to enable the correct assessment of the environmental impact and working conditions at an MG-Si plant.

Advanced Characterization of Rare Earth Elements in Coal Utilization Byproducts

NASA Astrophysics Data System (ADS)

Verba, C.; Scott, M.; Dieterich, M.; Poston, J.; Collins, K.

2016-12-01

Rare earth elements (REE) in various forms (e.g., crystalline mineral phases; adsorbed/absorbed state on and into organic macerals, neoformed glass from flyash or bottom ash) from domestic feedstocks such as coal deposits to coal utilization byproducts (CUB) have the potential to reduce foreign REE dependence and increase domestic resource security. Characterization is critical for understanding environmental risks related to their fate and transport as well as determining the most practical and economical techniques for concentrating the REE and converting them into chemical stocks for manufacturing. Several complementary electron microscopy (SEM-EDS, EPMA-WDS, FIB-SEM, cathodoluminescence, and XRD) and post image processing techniques were used to understand REE transition from coal to CUB. Sites of interest were identified and imaged and respective elemental x-ray maps acquired and montaged. Pixel classification of SEM imagers was completed using image analysis techniques to quantify the distribution of REE associated features. Quantitative elemental analysis of phases were completed using EMPA-WDS followed by FIB-SEM. The FIB-SEM results were reconstructed into 3D volumes and features of interest (e.g. monazite) were analyzed to determine the structure and volumetric estimation of REEs and thus predict detrital REE phases to ICP-MS results. Trace minerals were identified as pyrite, zircon, REE-phosphates' (monazite, xenotime), and barite within the coal tailings. In CUB, amorphous aluminosilicates, iron oxide cenospheres, and calcium oxides were present; monazite appear to be unaltered and unaffected by the combustion process in these samples. Thermal decomposition may have occurred due to presence of detrital zircon and xenotime and subsequent thin Ca-oxide coating enriched in trace REEs.

Determination of trace elements and their concentrations in clay balls: problem of geophagia practice in Ghana.

PubMed

Arhin, Emmanuel; Zango, Musah S

2017-02-01

Ten samples of 100 g weight were subsampled from 1400 g of the clay balls from which the contained trace element levels were determined by X-ray fluorescence technique. The results of trace elements in the clay balls were calibrated using certified reference materials "MAJMON" and "BH-1." The results showed elevated concentrations but with different concentration levels in the regions, particularly with arsenic, chromium, cobalt, Cs, Zr and La. These trace elements contained in the clay balls are known to be hazardous to human health. Thence the relatively high concentrations of these listed trace elements in clay balls in the three regions, namely Ashanti, Upper East and Volta, which are widely sold in markets in Ghana, could present negative health impact on consumers if consumed at 70 g per day or more and on regular basis. On the basis of these, the study concludes an investigation to establish breakeven range for trace element concentrations in the clay balls as it has been able to demonstrate the uneven and elevated values in them. The standardized safe ranges of trace elements will make the practice safer for the people that ingest clay balls in Ghana.

Analysis of Personal and Home Characteristics Associated with the Elemental Composition of PM2.5 in Indoor, Outdoor, and Personal Air in the RIOPA Study.

PubMed

Ryan, Patrick H; Brokamp, Cole; Fan, Zhi-Hua; Rao, M B

2015-12-01

The complex mixture of chemicals and elements that constitute particulate matter (PM*) varies by season and geographic location because source contributors differ over time and place. The composition of PM having an aerodynamic diameter < 2.5 μm (PM2.5) is hypothesized to be responsible, in part, for its toxicity. Epidemiologic studies have identified specific components and sources of PM2.5 that are associated with adverse health outcomes. The majority of these studies use measures of outdoor concentrations obtained from one or a few central monitoring sites as a surrogate for measures of personal exposure. Personal PM2.5 (and its elemental composition), however, may be different from the PM2.5 measured at stationary outdoor sites. The objectives of this study were (1) to describe the relationships between the concentrations of various elements in indoor, outdoor, and personal PM2.5 samples, (2) to identify groups of individuals with similar exposures to mixtures of elements in personal PM2.5 and to examine personal and home characteristics of these groups, and (3) to evaluate whether concentrations of elements from outdoor PM2.5 samples are appropriate surrogates for personal exposure to PM2.5 and its elements and whether indoor PM2.5 concentrations and information about home characteristics improve the prediction of personal exposure. The objectives of the study were addressed using data collected as part of the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study. The RIOPA study has previously measured the mass concentrations of PM2.5 and its elemental constituents during 48-hour concurrent indoor, outdoor (directly outside the home), and personal samplings in three urban areas (Los Angeles, California; Houston, Texas; and Elizabeth, New Jersey). The resulting data and information about personal and home characteristics (including air-conditioning use, nearby emission sources, time spent indoors, census-tract geography, air-exchange rates, and other information) for each RIOPA participant were downloaded from the RIOPA study database. We performed three sets of analyses to address the study aims. First, we conducted descriptive analyses to describe the relationships between elemental concentrations in the concurrently gathered indoor, outdoor, and personal air samples. We assessed the correlation between personal exposure and indoor concentrations as well as personal exposure and outdoor concentrations of each element and calculated ratios between them. In addition, we performed principal component analysis (PCA) and calculated principal component scores (PCSs) to examine the heterogeneity of the elemental composition and then tested whether the mixture of elements in indoor, outdoor, and personal PM2.5 was significantly different within each study site and across study sites. Secondly, we performed model-based clustering analysis to group RIOPA participants with similar exposures to mixtures of elements in personal PM2.5. We examined the association between cluster membership and the concentrations of elements in indoor and outdoor PM2.5 samples and personal and home characteristics. Finally, we developed a series of linear regression models and random forest models to examine the association between personal exposure to elements in PM2.5 and (1) outdoor measurements, (2) outdoor and indoor measurements, and (3) outdoor and indoor measurements and home characteristics. As we developed each model, the improvement in prediction of personal exposure when including additional information was assessed. Personal exposures to PM2.5 and to most elements were significantly correlated with both indoor and outdoor concentrations, although concentrations in personal samples frequently exceeded those of indoor and outdoor samples. In general, for most PM2.5 elements indoor concentrations were more highly correlated with personal exposure than were outdoor concentrations. PCA showed that the mixture of elements in indoor, outdoor, and personal PM2.5 varied significantly across sample types within each study site and also across study sites within each sample type. Using model-based clustering, we identified seven clusters of RIOPA participants whose personal PM2.5 samples had similar patterns of elemental composition. Using this approach, subsets of RIOPA participants were identified whose personal exposures to PM2.5 (and its elements) were significantly higher than their indoor and outdoor concentrations (and vice versa). The results of linear and random forest regression models were consistent with our correlation analyses and demonstrated that (1) indoor concentrations were more significantly associated with personal exposure than were outdoor concentrations and (2) participant reports of time spent at their home significantly modified many of the associations between indoor and personal concentrations. In linear regression models, the inclusion of indoor concentrations significantly improved the prediction of personal exposures to Ba, Ca, Cl, Cu, K, Sn, Sr, V, and Zn compared with the use of outdoor elemental concentrations alone. Including additional information on personal and home characteristics improved the prediction for only one element, Pb. Our results support the use of outdoor monitoring sites as surrogates of personal exposure for a limited number of individual elements associated with long-range transport and with a few local or indoor sources. Based on our PCA and clustering analyses, we concluded that the overall elemental composition of PM2.5 obtained at outdoor monitoring sites may not accurately represent the elemental composition of personal PM2.5. Although the data used in these analyses compared outdoor PM2.5 composition collected at the home with indoor and personal samples, our results imply that studies examining the complete elemental composition of PM2.5 should be cautious about using data from central outdoor monitoring sites because of the potential for exposure misclassification. The inclusion of personal and home characteristics only marginally improved the prediction of personal exposure for a small number of elements in PM2.5. We concluded that the additional cost and burden of indoor and personal sampling may be justified for studies examining elements because neither outdoor monitoring nor questionnaire data on home and personal characteristics were able to represent adequately the overall elemental composition of personal PM2.5.

Trace elements in soil and biota in confined disposal facilities for dredged material

USGS Publications Warehouse

Beyer, W.N.; Miller, G.; Simmers, J.W.

1990-01-01

We studied the relation of trace element concentrations in soil to those in house mice (Mus musculus), common reed (Phragmites australis) and ladybugs (Coccinella septempunctata) at five disposal facilities for dredged material. The sites had a wide range of soil trace element concentrations, acid soils and a depauperate fauna. They were very poor wildlife habitat because they were dominated by the common reed. Bioassay earthworms exposed to surface soils from three of the five sites died, whereas those exposed to four of five soils collected a meter deep survived, presumably because the deeper, unoxidized soil, was not as acid. Concentrations of Ni and Cr in the biota from each of the sites did not seem to be related to the concentrations of the same elements in soil. Although Pb, Zn and Cu concentrations in biota were correlated with those in soil, the range of concentrations in the biota was quite small compared to that in soil. The concentrations of Pb detected in mice were about as high as the concentrations previously reported in control mice from other studies. Mice from the most contaminated site (530 ppm Pb in soil) contained only slightly more Pb (8 ppm dry wt) than did mice (2-6 ppm dry wt) from sites containing much less Pb (22-92 ppm in soil). Despite the acid soil conditions, very little Cd was incorporated into food chains. Rather, Cd was leaching from the surface soil. We concluded that even the relatively high concentrations of trace elements in the acid dredged material studied did not cause high, concentrations of trace elements in the biota.

Determination of elemental content off rocks by laser ablation inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Lichte, F.E.

1995-01-01

A new method of analysis for rocks and soils is presented using laser ablation inductively coupled plasma mass spectrometry. It is based on a lithium borate fusion and the free-running mode of a Nd/YAG laser. An Ar/N2 sample gas improves sensitivity 7 ?? for most elements. Sixty-three elements are characterized for the fusion, and 49 elements can be quantified. Internal standards and isotopic spikes ensure accurate results. Limits of detection are 0.01 ??g/g for many trace elements. Accuracy approaches 5% for all elements. A new quality assurance procedure is presented that uses fundamental parameters to test relative response factors for the calibration.

Assessing element-specific patterns of bioaccumulation across New England lakes

PubMed Central

Ward, Darren M.; Mayes, Brandon; Sturup, Stefan; Folt, Carol L.; Chen, Celia Y.

2012-01-01

Little is known about differences among trace elements in patterns of bioaccumulation in freshwater food webs. Our goal was to identify patterns in bioaccumulation of different elements that are large and consistent enough to discern despite variation across lakes. We measured methylmercury (MeHg) and trace element (As, Cd, Hg, Pb, and Zn) concentrations in food web components of seven New England lakes on 3–5 dates per lake, and contrasted patterns of bioaccumulation across lakes, metals and seasons. In each lake, trace element concentrations were compared across trophic levels, including three size fractions of zooplankton, planktivorous fish, and piscivorous fish. The trophic position of each food web component was estimated from N isotope analysis. Trace element concentrations varied widely among taxa, lakes and sampling dates. Yet, we identified four consistent patterns of bioaccumulation that were consistent across lakes: (1) MeHg concentration increased (i.e., was biomagnified) and Pb concentration decreased (i.e., was biodiminished) with increased trophic position. (2) Zinc concentration (as with MeHg) was higher in fish than in zooplankton, but overall variation in Zn concentration (unlike MeHg) was low. (3) Arsenic and Cd concentrations (as with Pb) were lower in fish than in zooplankton, but (unlike Pb) were not significantly correlated with trophic position within zooplankton or fish groups. (4) Average summer concentrations of As, Pb, Hg, and MeHg in zooplankton significantly predicted their concentrations in either planktivorous or piscivorous fish. Our secondary goal was to review sampling approaches in forty-five published studies to determine the extent to which current sampling programs facilitate cross-lake and cross-study comparisons of bioaccumulation. We found that studies include different components of the food web and sample too infrequently to enable strong cross-lake and cross-study comparisons. We discuss sampling strategies that would improve our capacity to identify consistent patterns of bioaccumulation and drivers of elevated trace element concentrations under naturally high levels of variability. PMID:22356871

Chemometric evaluation of concentrations of trace elements in intervertebral disc tissue in patient with degenerative disc disease.

PubMed

Kubaszewski, Łukasz; Zioła-Frankowska, Anetta; Gasik, Zuzanna; Frankowski, Marcin; Dąbrowski, Mikołaj; Molisak, Bartłomiej; Kaczmarczyk, Jacek; Gasik, Robert

2017-12-23

The work is designed to uncover the pattern of mutual relation among trace elements and epidemiological data in the degenerated intervertebral disk tissue in humans. Hitherto the reason of the degenerative process is not fully understood. Trace elements are the basic components of the biological compound related both its metabolism as well as environmental exposure. The relation pattern among elements occurs gives new perspective in solving the cause of the disease. We have analysed trace elements content in the 30 intervertebral disc from 22 patients with degenerative disc disease. The concentrations of Al, Cu, Cd, Mo, Ni and Pb were determined with Atomic Absorption Spectrometry. To analyse the multidimentional relation between trace element concentration and epidemiological data the chemometric analysis was applied. The similarity have been shown in occurrence of following pairs: Cd-Mo as well as Mg-Zn. The second pair was correlated with Pb concentration. Pb levels are observed to be competitive to Cu concentration. Cd concentration was related to Zn and Mg deficiency. No single but rather cluster of epidemiological data show observable influence on the TE tissue variance. Zn and Cu was related to the male sex. Operation with orthopedic implants were related to combined Al, Mo and Zn concentration. This is the first chemometric analysis of trace elements in disk tissue. It shows multidimentional relations that are missed by the classical statistic. The analysis shows significant relation. The nature of the relations is the basis for further metabolic and environmental research.

The occurrence and distribution of selected trace elements in the upper Rio Grande and tributaries in Colorado and Northern New Mexico

USGS Publications Warehouse

Taylor, Howard E.; Antweiler, Ronald C.; Roth, D.A.; Brinton, T.I.; Peart, D.B.; Healy, D.F.

2001-01-01

Two sampling trips were undertaken in 1994 to determine the distribution of trace elements in the Upper Rio Grande and several of its tributaries. Water discharges decreased in the main stem of the Rio Grande from June to September, whereas dissolved concentrations of trace elements generally increased. This is attributed to dilution of base flow from snowmelt runoff in the June samples. Of the three major mining districts (Creede, Summitville, and Red River) in the Upper Rio Grande drainage basin, only the Creede District appears to impact the Rio Grande in a significant manner, with both waters and sediments having elevated concentrations of some trace elements considerably downriver. For example, dissolved zinc concentrations upriver of Willow Creek, which primarily drains the Creede District, were about 2-3 μg/L; immediately downstream of the Willow Creek confluence, concentrations were above 20 μg/L; and elevated concentrations occurred in the Rio Grande for the next 100 km. The Red River District does not significantly impact the Upper Rio Grande for most trace elements. Because of current water management practices, it is difficult to assess the impact of the Summitville District on the Upper Rio Grande. There are, however, large increases in many dissolved trace element concentrations as the Rio Grande passes through the San Luis Valley, coincident with elevated concentrations of those same trace elements in tributaries. Among these elements are As, B, Cr, Li, Mn, Mo, Ni, Sr, U, and V. None of the trace elements exceeded U.S. EPA primary drinking water standards in either survey, with the exception of cadmium in Willow Creek. Secondary drinking water standards were frequently violated, especially in tributaries draining areas where mining has occurred. Dissolved zinc (in Willow Creek in both June and September) was the only element that exceeded the EPA Water Quality Criteria for aquatic life of 120 μg/L.

Review of rare earth element concentrations in oil shales of the Eocene Green River Formation

USGS Publications Warehouse

Birdwell, Justin E.

2012-01-01

Concentrations of the lanthanide series or rare earth elements and yttrium were determined for lacustrine oil shale samples from the Eocene Green River Formation in the Piceance Basin of Colorado and the Uinta Basin of Utah. Unprocessed oil shale, post-pyrolysis (spent) shale, and leached shale samples were examined to determine if oil-shale processing to generate oil or the remediation of retorted shale affects rare earth element concentrations. Results for unprocessed Green River oil shale samples were compared to data published in the literature on reference materials, such as chondritic meteorites, the North American shale composite, marine oil shale samples from two sites in northern Tibet, and mined rare earth element ores from the United States and China. The Green River oil shales had lower rare earth element concentrations (66.3 to 141.3 micrograms per gram, μg g-1) than are typical of material in the upper crust (approximately 170 μg g-1) and were also lower in rare earth elements relative to the North American shale composite (approximately 165 μg g-1). Adjusting for dilution of rare earth elements by organic matter does not account for the total difference between the oil shales and other crustal rocks. Europium anomalies for Green River oil shales from the Piceance Basin were slightly lower than those reported for the North American shale composite and upper crust. When compared to ores currently mined for rare earth elements, the concentrations in Green River oil shales are several orders of magnitude lower. Retorting Green River oil shales led to a slight enrichment of rare earth elements due to removal of organic matter. When concentrations in spent and leached samples were normalized to an original rock basis, concentrations were comparable to those of the raw shale, indicating that rare earth elements are conserved in processed oil shales.

RARE EARTH ELEMENTS IN FLY ASHES AS POTENTIAL INDICATORS OF ANTHROPOGENIC SOIL CONTAMINATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mattigod, Shas V.

2003-08-01

Studies of rare earth element (REE) content of disposed fly ashes and their potential mobility were neglected for decades because these elements were believed to be environmentally benign. A number of recent studies have now shown that REE may pose a long-term risk to the biosphere. Therefore, there is a critical need to study the REE concentrations in fly ash and their potential mobilization and dispersal upon disposal in the environment. We analyzed the REE content of bulk, size fractionated, and density separated fractions of three fly ash samples derived from combustion of sub bituminous coals from the western Unitedmore » States and found that the concentrations of these elements in bulk ashes were within the range typical of fly ashes derived from coals from the North American continent. The concentrations of light rare earth elements (LREE) such as La, Ce, and Nd, however, tended towards the higher end of the concentration range whereas, the concentrations of middle rare earth elements (MREE) (Sm and Eu) and heavy rare earth elements (HREE) (Lu) were closer to the lower end of the observed range for North American fly ashes. The concentrations of REE did not show any significant enrichment with decreasing particle size, this is typical of nonvolatile lithophilic element behavior during the combustion process. The lithophilic nature of REE was also confirmed by their concentrations in heavy density fractions of these fly ashes being on average about two times more enriched than the concentrations in the light density fractions. Shale normalized average of REE concentrations of fly ashes and coals revealed significant positive anomalies for Eu and Dy. Because of these distinctive positive anomalies of Eu and Dy, we believe that fly ash contamination of soils can be fingerprinted and distinguished from other sources of anthropogenic REE inputs in to the environment.« less

From soil water to surface water - how the riparian zone controls element transport from a boreal forest to a stream

NASA Astrophysics Data System (ADS)

Lidman, Fredrik; Boily, Åsa; Laudon, Hjalmar; Köhler, Stephan J.

2017-06-01

Boreal headwaters are often lined by strips of highly organic soils, which are the last terrestrial environment to leave an imprint on discharging groundwater before it enters a stream. Because these riparian soils are so different from the Podzol soils that dominate much of the boreal landscape, they are known to have a major impact on the biogeochemistry of important elements such as C, N, P and Fe and the transfer of these elements from terrestrial to aquatic ecosystems. For most elements, however, the role of the riparian zone has remained unclear, although it should be expected that the mobility of many elements is affected by changes in, for example, pH, redox potential and concentration of organic carbon as they are transported through the riparian zone. Therefore, soil water and groundwater was sampled at different depths along a 22 m hillslope transect in the Krycklan catchment in northern Sweden using soil lysimeters and analysed for a large number of major and trace elements (Al, As, B, Ba, Ca, Cd, Cl, Co, Cr, Cs, Cu, Fe, K, La, Li, Mg, Mn, Na, Ni, Pb, Rb, Se, Si, Sr, Th, Ti, U, V, Zn, Zr) and other parameters such as sulfate and total organic carbon (TOC). The results showed that the concentrations of most investigated elements increased substantially (up to 60 times) as the water flowed from the uphill mineral soils and into the riparian zone, largely as a result of higher TOC concentrations. The stream water concentrations of these elements were typically somewhat lower than in the riparian zone, but still considerably higher than in the uphill mineral soils, which suggests that riparian soils have a decisive impact on the water quality of boreal streams. The degree of enrichment in the riparian zone for different elements could be linked to the affinity for organic matter, indicating that the pattern with strongly elevated concentrations in riparian soils is typical for organophilic substances. One likely explanation is that the solubility of many organophilic elements increases as a result of the higher concentrations of TOC in the riparian zone. Elements with low or modest affinity for organic matter (e.g. Na, Cl, K, Mg and Ca) occurred in similar or lower concentrations in the riparian zone. Despite the elevated concentrations of many elements in riparian soil water and groundwater, no increase in the concentrations in biota could be observed (bilberry leaves and spruce shoots).

Elements and elasmobranchs: hypotheses, assumptions and limitations of elemental analysis.

PubMed

McMillan, M N; Izzo, C; Wade, B; Gillanders, B M

2017-02-01

Quantifying the elemental composition of elasmobranch calcified cartilage (hard parts) has the potential to answer a range of ecological and biological questions, at both the individual and population level. Few studies, however, have employed elemental analyses of elasmobranch hard parts. This paper provides an overview of the range of applications of elemental analysis in elasmobranchs, discussing the assumptions and potential limitations in cartilaginous fishes. It also reviews the available information on biotic and abiotic factors influencing patterns of elemental incorporation into hard parts of elasmobranchs and provides some comparative elemental assays and mapping in an attempt to fill knowledge gaps. Directions for future experimental research are highlighted to better understand fundamental elemental dynamics in elasmobranch hard parts. © 2016 The Fisheries Society of the British Isles.

Assessment of trace element impacts on agricultural use of water from the Dan River following the Eden coal ash release.

PubMed

Hesterberg, Dean; Polizzotto, Matthew L; Crozier, Carl; Austin, Robert E

2016-04-01

Catastrophic events require rapid, scientifically sound decision making to mitigate impacts on human welfare and the environment. The objective of this study was to analyze potential impacts of coal ash-derived trace elements on agriculture following a 35,000-tonne release of coal ash into the Dan River at the Duke Energy Steam Station in Eden, North Carolina. We performed scenario calculations to assess the potential for excessive trace element loading to soils via irrigation and flooding with Dan River water, uptake of trace elements by crops, and livestock consumption of trace elements via drinking water. Concentrations of 13 trace elements measured in Dan River water samples within 4 km of the release site declined sharply after the release and were equivalent within 5 d to measurements taken upriver. Mass-balance calculations based on estimates of soil trace-element concentrations and the nominal river water concentrations indicated that irrigation or flooding with 25 cm of Dan River water would increase soil concentrations of all trace elements by less than 0.5%. Calculations of potential increases of trace elements in corn grain and silage, fescue, and tobacco leaves suggested that As, Cr, Se, Sr, and V were elements of most concern. Concentrations of trace elements measured in river water following the ash release never exceeded adopted standards for livestock drinking water. Based on our analyses, we present guidelines for safe usage of Dan River water to diminish negative impacts of trace elements on soils and crop production. In general, the approach we describe here may serve as a basis for rapid assessment of environmental and agricultural risks associated with any similar types of releases that arise in the future. © 2015 SETAC.

Nanoscale measurement of trace element distributions in Spartina alterniflora root tissue during dormancy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Huan; Qian, Yu; Cochran, J. Kirk

Here, this article reports a nanometer-scale investigation of trace element (As, Ca, Cr, Cu, Fe, Mn, Ni, S and Zn) distributions in the root system Spartina alterniflora during dormancy. The sample was collected on a salt marsh island in Jamaica Bay, New York, in April 2015 and the root was cross-sectioned with 10 μm resolution. Synchrotron X-ray nanofluorescence was applied to map the trace element distributions in selected areas of the root epidermis and endodermis. The sampling resolution was 60 nm to increase the measurement accuracy and reduce the uncertainty. The results indicate that the elemental concentrations in the epidermis,more » outer endodermis and inner endodermis are significantly (p < 0.01) different. The root endodermis has relatively higher concentrations of these elements than the root epidermis. Furthermore, this high resolution measurement indicates that the elemental concentrations in the outer endodermis are significantly (p < 0.01) higher than those in the inner endodermis. These results suggest that the Casparian strip may play a role in governing the aplastic transport of these elements. Pearson correlation analysis on the average concentrations of each element in the selected areas shows that most of the elements are significantly (p < 0.05) correlated, which suggests that these elements may share the same transport pathways.« less

Nanoscale measurement of trace element distributions in Spartina alterniflora root tissue during dormancy

DOE PAGES

Feng, Huan; Qian, Yu; Cochran, J. Kirk; ...

2017-01-18

Here, this article reports a nanometer-scale investigation of trace element (As, Ca, Cr, Cu, Fe, Mn, Ni, S and Zn) distributions in the root system Spartina alterniflora during dormancy. The sample was collected on a salt marsh island in Jamaica Bay, New York, in April 2015 and the root was cross-sectioned with 10 μm resolution. Synchrotron X-ray nanofluorescence was applied to map the trace element distributions in selected areas of the root epidermis and endodermis. The sampling resolution was 60 nm to increase the measurement accuracy and reduce the uncertainty. The results indicate that the elemental concentrations in the epidermis,more » outer endodermis and inner endodermis are significantly (p < 0.01) different. The root endodermis has relatively higher concentrations of these elements than the root epidermis. Furthermore, this high resolution measurement indicates that the elemental concentrations in the outer endodermis are significantly (p < 0.01) higher than those in the inner endodermis. These results suggest that the Casparian strip may play a role in governing the aplastic transport of these elements. Pearson correlation analysis on the average concentrations of each element in the selected areas shows that most of the elements are significantly (p < 0.05) correlated, which suggests that these elements may share the same transport pathways.« less

Analysis of 22 Elements in Milk, Feed, and Water of Dairy Cow, Goat, and Buffalo from Different Regions of China.

PubMed

Zhou, Xuewei; Qu, Xueyin; Zhao, Shengguo; Wang, Jiaqi; Li, Songli; Zheng, Nan

2017-03-01

The objectives of this study were to measure the concentrations of elements in raw milk by inductively coupled plasma-mass spectrometry (ICP-MS) and evaluate differences in element concentrations among animal species and regions of China. Furthermore, drinking water and feed samples were analyzed to investigate whether the element concentrations in raw milk are correlated with those in water and feed. All samples were analyzed by ICP-MS following microwave-assisted acid digestion. The mean recovery of the elements was 98.7 % from milk, 103.7 % from water, and 93.3 % from a certified reference material (cabbage). Principal component analysis results revealed that element concentrations differed among animal species and regions. Correlation analysis showed that trace elements Mn, Fe, Ni, Ga, Se, Sr, Cs, U in water and Co, Ni, Cu, Se, U in feed were significantly correlated with those in milk (p < 0.05). Toxic and potential toxic elements Cr, As, Cd, Tl, Pb in water and Al, Cr, As, Hg, Tl in feed were significantly correlated with those in milk (p < 0.05). Results of correlation analysis revealed that elements in water and feed might contribute to the elements in milk.

Developing biogeochemical tracers of apatite weathering by ectomycorrhizal fungi

NASA Astrophysics Data System (ADS)

Vadeboncoeur, M. A.; Bryce, J. G.; Hobbie, E. A.; Meana-Prado, M. F.; Blichert-Toft, J.

2012-12-01

Chronic acid deposition has depleted calcium (Ca) from many New England forest soils, and intensive harvesting may reduce phosphorus (P) available to future rotations. Thin glacial till soils contain trace amounts of apatite, a primary calcium phosphate mineral, which may be an important long-term source of both P and Ca to ecosystems. The extent to which ECM fungi enhance the weathering rate of primary minerals in soil which contain growth-limiting nutrients remains poorly quantified, in part due to biogeochemical tracers which are subsequently masked by within-plant fractionation. Rare earth elements (REEs) and Pb isotope ratios show some potential for revealing differences in soil apatite weathering rates across forest stands and silvicultural treatments. To test the utility of these tracers, we grew birch seedlings semi-hydroponically under controlled P-limited conditions, supplemented with mesh bags containing granite chips. Our experimental design included nonmycorrhizal (NM) as well as ectomycorrhizal cultures (Cortinarius or Leccinum). Resulting mycorrhizal roots and leachates of granite chips were analyzed for these tracers. REE concentrations in roots were greatly elevated in treatments with granite relative to those without granite, demonstrating uptake of apatite weathering products. Roots with different mycorrhizal fungi accumulated similar concentrations of REEs and were generally elevated compared to the NM cultures. Ammonium chloride leaches of granite chips grown in contact with mycorrhizal hyphae show elevated REE concentrations and significantly radiogenic Pb isotope signatures relative to bulk rock, also supporting enhanced apatite dissolution. Our results in culture are consistent with data from field-collected sporocarps from hardwood stands in the Bartlett Experimental Forest in New Hampshire, in which Cortinarius sporocarp Pb isotope ratios were more radiogenic than those of other ectomycorrhizal sporocarps. Taken together, the experimental and field results imply that the coupled approach of REE and Pb isotopic values afford a means to quantify the degree to which primary mineral weathering inputs are contributing to ecosystem nutrient budgets and potentially the role of different types of ECM fungi in the weathering process.

Carbon based secondary compounds do not provide protection against heavy metal road pollutants in epiphytic macrolichens.

PubMed

Gauslaa, Yngvar; Yemets, Olena A; Asplund, Johan; Solhaug, Knut Asbjørn

2016-01-15

Lichens are useful monitoring organisms for heavy metal pollution. They are high in carbon based secondary compounds (CBSCs) among which some may chelate heavy metals and thus increase metal accumulation. This study quantifies CBSCs in four epiphytic lichens transplanted for 6months on stands along transects from a highway in southern Norway to search for relationships between concentrations of heavy metals and CBSCs along a gradient in heavy metal pollutants. Viability parameters and concentrations of 21 elements including nutrients and heavy metals in these lichen samples were reported in a separate paper. Medullary CBSCs in fruticose lichens (Ramalina farinacea, Usnea dasypoga) were reduced in the most polluted sites, but not in foliose ones (Parmelia sulcata, Lobaria pulmonaria), whereas cortical CBSC did not change with distance from the road in any species. Strong positive correlations only occurred between the major medullary compound stictic acid present in L. pulmonaria and most heavy metals, consistent with a chelating role of stictic acid, but not of other studied CBSCs or in other species. However, heavy metal chelating did not protect L. pulmonaria against damage because this species experienced the strongest reduction in viability in the polluted sites. CBSCs with an accumulation potential for heavy metals should be quantified in lichen biomonitoring studies of heavy metals because they, like stictic acid, could overshadow pollutant inputs in some species rendering biomonitoring data less useful. In the two fruticose lichen species, CBSCs decreased with increasing heavy metal concentration, probably because heavy metal exposure impaired secondary metabolism. Thus, we found no support for a heavy metal protection role of any CBSCs in studied epiphytic lichens. No intraspecific relationships occurred between CBSCs versus N or C/N-ratio. Interspecifically, medullary CBSCs decreased and cortical CBSCs increased with increasing C/N-ratio. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantifying restoration success and recovery in a metal-polluted stream: A 17-year assessment of physicochemical and biological responses

USGS Publications Warehouse

Clements, W.H.; Vieira, N.K.M.; Church, S.E.

2010-01-01

Evaluating the effectiveness of stream restoration is often challenging because of the lack of pre-treatment data, narrow focus on physicochemical measures and insufficient post-restoration monitoring. Even when these fundamental elements are present, quantifying restoration success is difficult because of the challenges associated with distinguishing treatment effects from seasonal variation, episodic events and long-term climatic changes.2. We report results of one of the most comprehensive and continuous records of physical, chemical and biological data available to assess restoration success for a stream ecosystem in North America. Over a 17 year period we measured seasonal and annual changes in metal concentrations, physicochemical characteristics, macroinvertebrate communities, and brown trout Salmo trutta populations in the Arkansas River, a metal-contaminated stream in Colorado, USA.3. Although we observed significant improvements in water quality after treatment, the effectiveness of restoration varied temporally, spatially and among biological response variables. The fastest recovery was observed at stations where restoration eliminated point sources of metal contamination. Recovery of macroinvertebrates was significantly delayed at some stations because of residual sediment contamination and because extreme seasonal and episodic variation in metal concentrations prevented recolonization by sensitive species. Synthesis and applications. Because recovery trajectories after the removal of a stressor are often complex or nonlinear, long-term studies are necessary to assess restoration success within the context of episodic events and changes in regional climate. The observed variation in recovery among chemical and biological endpoints highlights the importance of developing objective criteria to assess restoration success. Although the rapid response of macroinvertebrates to reduced metal concentrations is encouraging, we have previously demonstrated that benthic communities from the Arkansas River remained susceptible to other novel anthropogenic stressors. We suggest that the resistance or resilience of benthic macroinvertebrate communities to novel stressors may be effective indicators of restoration success that can account for the non-additive (e.g. synergistic) nature of compound perturbations. ?? 2010 The Authors. Journal compilation ?? 2010 British Ecological Society.

Concentrations and geographical variations of selected toxic elements in meat from semi-domesticated reindeer (Rangifer tarandus tarandus L.) in mid- and northern Norway: evaluation of risk assessment.

PubMed

Hassan, Ammar Ali; Brustad, Magritt; Sandanger, Torkjel M

2012-05-01

Meat samples (n = 100) from semi-domesticated reindeer (Rangifer tarandus tarandus L.) were randomly collected from 10 grazing districts distributed over four Norwegian counties in 2008 and 2009. The main aim was to study concentrations and geographical variations in selected toxic elements; cadmium (Cd), lead (Pb), arsenic (As), copper (Cu), nickel (Ni) and vanadium (V) in order to assess the risk associated with reindeer meat consumption. Sample solutions were analysed using an inductively coupled plasma high resolution mass spectrometer (ICP-HRMS), whereas analysis of variance (ANOVA) was used for statistical analyses. Geographical variations in element concentrations were revealed, with As and Cd demonstrating the largest geographical differences. No clear geographical gradient was observed except for the east-west downward gradient for As. The As concentrations were highest in the vicinity of the Russian border, and only Cd was shown to increase with age (p < 0.05). Sex had no significant effect on the concentration of the studied elements. The concentrations of all the studied elements in reindeer meat were generally low and considerably below the maximum levels (ML) available for toxic elements set by the European Commission (EC). Thus, reindeer meat is not likely to be a significant contributor to the human body burden of toxic elements.

A Priori Method of Using Photon Activation Analysis to Determine Unknown Trace Element Concentrations in NIST Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, Jaromy; Sun Zaijing; Wells, Doug

2009-03-10

Photon activation analysis detected elements in two NIST standards that did not have reported concentration values. A method is currently being developed to infer these concentrations by using scaling parameters and the appropriate known quantities within the NIST standard itself. Scaling parameters include: threshold, peak and endpoint energies; photo-nuclear cross sections for specific isotopes; Bremstrahlung spectrum; target thickness; and photon flux. Photo-nuclear cross sections and energies from the unknown elements must also be known. With these quantities, the same integral was performed for both the known and unknown elements resulting in an inference of the concentration of the un-reported elementmore » based on the reported value. Since Rb and Mn were elements that were reported in the standards, and because they had well-identified peaks, they were used as the standards of inference to determine concentrations of the unreported elements of As, I, Nb, Y, and Zr. This method was tested by choosing other known elements within the standards and inferring a value based on the stated procedure. The reported value of Mn in the first NIST standard was 403{+-}15 ppm and the reported value of Ca in the second NIST standard was 87000 ppm (no reported uncertainty). The inferred concentrations were 370{+-}23 ppm and 80200{+-}8700 ppm respectively.« less

Concentrations and Geographical Variations of Selected Toxic Elements in Meat from Semi-Domesticated Reindeer (Rangifer tarandus tarandus L.) in Mid- and Northern Norway: Evaluation of Risk Assessment

PubMed Central

Hassan, Ammar Ali; Brustad, Magritt; Sandanger, Torkjel M.

2012-01-01

Meat samples (n = 100) from semi-domesticated reindeer (Rangifer tarandus tarandus L.) were randomly collected from 10 grazing districts distributed over four Norwegian counties in 2008 and 2009. The main aim was to study concentrations and geographical variations in selected toxic elements; cadmium (Cd), lead (Pb), arsenic (As), copper (Cu), nickel (Ni) and vanadium (V) in order to assess the risk associated with reindeer meat consumption. Sample solutions were analysed using an inductively coupled plasma high resolution mass spectrometer (ICP-HRMS), whereas analysis of variance (ANOVA) was used for statistical analyses. Geographical variations in element concentrations were revealed, with As and Cd demonstrating the largest geographical differences. No clear geographical gradient was observed except for the east-west downward gradient for As. The As concentrations were highest in the vicinity of the Russian border, and only Cd was shown to increase with age (p < 0.05). Sex had no significant effect on the concentration of the studied elements. The concentrations of all the studied elements in reindeer meat were generally low and considerably below the maximum levels (ML) available for toxic elements set by the European Commission (EC). Thus, reindeer meat is not likely to be a significant contributor to the human body burden of toxic elements. PMID:22754467

Hydrogen sulphide in human nasal air quantified using thermal desorption and selected ion flow tube mass spectrometry.

PubMed

Wondimu, Taddese; Wang, Rui; Ross, Brian

2014-09-01

The discovery that hydrogen sulphide (H2S) acts as a gasotransmitter when present at very low concentrations (sub-parts per billion (ppbv)) has resulted in the need to quickly quantify trace amounts of the gas in complex biological samples. Selected ion flow tube mass spectrometry (SIFT-MS) is capable of real-time quantification of H2S but many SIFT-MS instruments lack sufficient sensitivity for this application. In this study we investigate the utility of combining thermal desorption with SIFT-MS for quantifying H2S in the 0.1-1 ppbv concentration range. Human orally or nasally derived breath, and background ambient air, were collected in sampling bags and dried by passing through CaCl2 and H2S pre-concentrated using a sorbent trap optimised for the capture of this gas. The absorbed H2S was then thermally desorbed and quantified by SIFT-MS. H2S concentrations in ambient air, nasal breath and oral breath collected from 10 healthy volunteers were 0.12  ±  0.02 (mean ± SD), 0.40  ±  0.11 and 3.1  ±  2.5 ppbv respectively, and in the oral cavity H2S, quantified by SIFT-MS without pre-concentration, was present at 13.5  ±  8.6 ppbv. The oral cavity H2S correlates well with oral breath H2S but not with nasal breath H2S, suggesting that oral breath H2S derives mainly from the oral cavity but nasal breath is likely pulmonary in origin. The successful quantification of such low concentrations of H2S in nasal air using a rapid analytical procedure paves the way for the straightforward analysis of H2S in breath and may assist in elucidating the role that H2S plays in biological systems.

Water-quality data (October 1988 through September 1989) and statistical summaries (March 1985 through September 1989) for the Clark Fork and selected tributaries from Galen to Missoula, Montana

USGS Publications Warehouse

Lambing, J.H.

1990-01-01

Water quality sampling was conducted at eight sites on the Clark Fork and selected tributaries from Galen to Missoula, from October 1988 through September 1989. This report presents tabulations and statistical summaries of the water quality data. Included are tabulations of streamflow, onsite water quality, and concentrations of trace elements and suspended sediment for periodic samples. Also included are tables and hydrographs of daily mean values for streamflow, suspended-sediment concentration, and suspended-sediment discharge at three mainstem stations and one tributary. Statistical summaries are presented for periodic water quality data collected from March 1985 through September 1989. Selected data are illustrated by graphs showing median concentrations of trace elements in water, relation of trace-element concentrations to suspended-sediment concentrations, and median concentrations of trace elements in suspended sediment. (USGS)

Water-quality data (October 1987 through September 1988) and statistical summaries (March 1985 through September 1988) for the Clark Fork and selected tributaries from Galen to Missoula, Montana

USGS Publications Warehouse

Lambing, John H.

1989-01-01

Water quality sampling was conducted at eight sites on the Clark Fork and selected tributaries from Galen to Missoula, Mont., from October 1987 through September 1988. This report presents tabulations and statistical summaries of the water quality data. Included in this report are tabulations of streamflow, onsite water quality, and concentrations of trace elements and suspended sediment for periodic samples. Also included are tables and hydrographs of daily mean values for streamflow, suspended-sediment concentration, and suspended-sediment discharge at three mainstream stations and one tributary. Statistical summaries are presented for periodic water quality data collected from March 1985 through September 1988. Selected data are illustrated by graphs showing median concentrations of trace elements in water, relation of trace element concentrations to suspended-sediment concentrations, and median concentrations of trace elements in suspended sediments. (USGS)

Development and Optimization of Voltammetric Methods for Real Time Analysis of Electrorefiner Salt with High Concentrations of Actinides and Fission Products

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, Michael F.; Phongikaroon, Supathorn; Zhang, Jinsuo

This project addresses the problem of achieving accurate material control and accountability (MC&A) around pyroprocessing electrorefiner systems. Spent nuclear fuel pyroprocessing poses a unique challenge with respect to reprocessing technology in that the fuel is never fully dissolved in the process fluid. In this case, the process fluid is molten, anhydrous LiCl-KCl salt. Therefore, there is no traditional input accountability tank. However, electrorefiners (ER) accumulate very large quantities of fissile nuclear material (including plutonium) and should be well safeguarded in a commercial facility. Idaho National Laboratory (INL) currently operates a pyroprocessing facility for treatment of spent fuel from Experimental Breedermore » Reactor-II with two such ER systems. INL implements MC&A via a mass tracking model in combination with periodic sampling of the salt and other materials followed by destructive analysis. This approach is projected to be insufficient to meet international safeguards timeliness requirements. A real time or near real time monitoring method is, thus, direly needed to support commercialization of pyroprocessing. A variety of approaches to achieving real time monitoring for ER salt have been proposed and studied to date—including a potentiometric actinide sensor for concentration measurements, a double bubbler for salt depth and density measurements, and laser induced breakdown spectroscopy (LIBS) for concentration measurements. While each of these methods shows some promise, each also involves substantial technical complexity that may ultimately limit their implementation. Yet another alternative is voltammetry—a very simple method in theory that has previously been tested for this application to a limited extent. The equipment for a voltammetry system consists of off-the-shelf components (three electrodes and a potentiostat), which results in substantial benefits relative to cost and robustness. Based on prior knowledge of electrochemical reduction potentials for each of the species of interest, voltammetry can be used to quantify concentrations of a variety of elemental species—including uranium, plutonium, minor actinides, and rare earths. Various methods have been tested by other researchers to date—including cyclic voltammetry, square wave voltammetry, normal pulse voltammetry, etc. In most cases, it has been observed that there is a very limited concentration range for which the output can be readily correlated with concentration in the salt. Furthermore, testing to date has been limited to simple ternary salts with only a single element being quantified. While incomplete for application to MC&A for pyroprocessing, these results lead us to believe that voltammetry can be optimized based on salt properties and fundamental electrochemical rate processes to yield a highly accurate and robust method. This project is divided into four tasks jointly executed by three university research groups. This includes experimental measurement of key physical data on the systems of interest, development of a predictive voltammetry model, experimental validation of the voltammetry model, and design/verification of an optimized measurement method. This project supports the goals of the US-ROK Joint Fuel Cycle Study in addition to the NA-24 Office of the National Nuclear Security Agency and the International Atomic Energy Agency (IAEA).« less

Diode and method of making the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dickerson, Jeramy Ray; Wierer, Jr., Jonathan; Kaplar, Robert

2018-03-13

A diode includes a second semiconductor layer over a first semiconductor layer. The diode further includes a third semiconductor layer over the second semiconductor layer, where the third semiconductor layer includes a first semiconductor element over the second semiconductor layer. The third semiconductor layer additionally includes a second semiconductor element over the second semiconductor layer, wherein the second semiconductor element surrounds the first semiconductor element. Further, the third semiconductor layer includes a third semiconductor element over the second semiconductor element. Furthermore, a hole concentration of the second semiconductor element is less than a hole concentration of the first semiconductor element.

Macro- and microelements in the rat liver, kidneys, and brain tissues; sex differences and effect of blood removal by perfusion in vivo.

PubMed

Orct, Tatjana; Jurasović, Jasna; Micek, Vedran; Karaica, Dean; Sabolić, Ivan

2017-03-01

Concentrations of macro- and microelements in animal organs indicate the animal health status and represent reference data for animal experiments. Their levels in blood and tissues could be different between sexes, and could be different with and without blood in tissues. To test these hypotheses, in adult female and male rats the concentrations of various elements were measured in whole blood, blood plasma, and tissues from blood-containing (nonperfused) and blood-free liver, kidneys, and brain (perfused in vivo with an elements-free buffer). In these samples, 6 macroelements (Na, Mg, P, S, K, Ca) and 14 microelements (Fe, Mn, Co, Cu, Zn, Se, I, As, Cd, Hg, Pb, Li, B, Sr) were determined by inductively coupled plasma mass spectrometry following nitric acid digestion. In blood and plasma, female- or male-dominant sex differences were observed for 6 and 5 elements, respectively. In nonperfused organs, sex differences were observed for 3 (liver, brain) or 9 (kidneys) elements, whereas in perfused organs, similar differences were detected for 9 elements in the liver, 5 in the kidneys, and none in the brain. In females, perfused organs had significantly lower concentrations of 4, 5, and 2, and higher concentrations of 10, 4, and 7 elements, respectively, in the liver, kidneys, and brain. In males, perfusion caused lower concentrations of 4, 7, and 2, and higher concentrations of 1, 1, and 7 elements, respectively, in the liver, kidneys, and brain. Therefore, the residual blood in organs can significantly influence tissue concentrations of various elements and their sex-dependency. Copyright © 2017 Elsevier GmbH. All rights reserved.

Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters

USGS Publications Warehouse

Nordstrom, D. Kirk

2011-01-01

Mobility of potential or actual contaminants from mining and mineral processing activities depends on (1) occurrence: is the mineral source of the contaminant actually present? (2) abundance: is the mineral present in sufficient quantity to make a difference? (3) reactivity: what are the energetics, rates, and mechanisms of sorption and mineral dissolution and precipitation relative to the flow rate of the water? and (4) hydrology: what are the main flow paths for contaminated water? Estimates of relative proportions of minerals dissolved and precipitated can be made with mass-balance calculations if minerals and water compositions along a flow path are known. Combined with discharge, these mass-balance estimates quantify the actual weathering rate of pyrite mineralization in the environment and compare reasonably well with laboratory rates of pyrite oxidation except when large quantities of soluble salts and evaporated mine waters have accumulated underground. Quantitative mineralogy with trace-element compositions can substantially improve the identification of source minerals for specific trace elements through mass balances. Post-dissolution sorption and precipitation (attenuation) reactions depend on the chemical behavior of each element, solution composition and pH, aqueous speciation, temperature, and contact-time with mineral surfaces. For example, little metal attenuation occurs in waters of low pH (2, and redox-sensitive oxyanions (As, Sb, Se, Mo, Cr, V). Once dissolved, metal and metalloid concentrations are strongly affected by redox conditions and pH. Iron is the most reactive because it is rapidly oxidized by bacteria and archaea and Fe(III) hydrolyzes and precipitates at low pH (1–3) which is related directly to its first hydrolysis constant, pK1 = 2.2. Several insoluble sulfate minerals precipitate at low pH including anglesite, barite, jarosite, alunite and basaluminite. Aluminum hydrolyzes near pH 5 (pK1 = 5.0) and provides buffering and removal of Al by mineral precipitation from pH 4–5.5. Dissolved sulfate behaves conservatively because the amount removed from solution by precipitation is usually too small relative to the high concentrations in the water column and relative to the flow rate of the water.

Preliminary application of tapered glass capillary microbeam in MeV-PIXE mapping of longan leaf for elemental concentration distribution analysis

NASA Astrophysics Data System (ADS)

Natyanun, S.; Unai, S.; Yu, L. D.; Tippawan, U.; Pussadee, N.

2017-09-01

This study was aimed at understanding elemental concentration distribution in local longan leaf for how the plant was affected by the environment or agricultural operation. The analysis applied the MeV-microbeam particle induced X-ray emission (PIXE) mapping technique using a home-developed tapered glass capillary microbeam system at Chiang Mai University. The microbeam was 2-MeV proton beam in 130 µm in diameter. The studying interest was in the difference in the elemental concentrations distributed between the leaf midrib and lamina areas. The micro proton beam analyzed the leaf sample across the leaf midrib edge to the leaf lamina area for total 9 data requisition spots. The resulting data were colored to form a 1D-map of the elemental concentration distribution. Seven dominant elements, Al, S, Cl, K, Ca, Sc and Fe, were identified, the first six of which were found having higher concentrations in the midrib area than in the lamina area, while the Fe concentration was in an opposite trend to that of the others.

Hepatic element concentrations of lesser scaup (Aythya affinis) during spring migration in the upper Midwest

USGS Publications Warehouse

Pillatzki, Angela E.; Neiger, Regg D.; Chipps, Steven R.; Higgins, Kenneth F.; Thiex, Nancy; Afton, Alan D.

2011-01-01

High concentrations of some hepatic elements might be contributing to the decline of the continental lesser scaup (Aythya affinis) population. We evaluated hepatic element concentrations of male and female lesser scaup collected from the upper Midwest (Iowa, Minnesota, North Dakota, and South Dakota) during the 2003 and 2004 spring migrations. We measured concentrations of 24 elements in livers of 117 lesser scaup. We found that only selenium concentrations were at levels (>3.0 μg/g wet weight [ww)]) proposed to adversely affect reproduction. Approximately 49% of females (n = 61) had individual hepatic concentrations >3.0 μg/g ww selenium (Se). Our observed hepatic concentration of Se was similar to that reported in lesser scaup collected from the mid-continental United States but less than Se concentrations reported from the Great Lakes region. We found that the liver cadmium (Cd) concentration for males was significantly higher than that for females. Gender differences in hepatic Cd concentrations have not been previously reported for lesser scaup, but Cd is known to have negative impacts on male reproduction. Our results indicate that lesser scaup migrating through the upper Midwest in spring have elevated Se levels and that males carry a significantly greater Cd burden than females. Moreover, elemental concentrations might be high enough to affect reproduction in both male and female lesser scaup, but controlled laboratory studies are needed to adequately assess the effects of Se and Cd on lesser scaup reproduction.

Hepatic element concentrations of lesser scaup (aythya affinis) during spring migration in the upper midwest

USGS Publications Warehouse

Pillatzki, A.E.; Neiger, R.D.; Chipps, S.R.; Higgins, K.F.; Thiex, N.; Afton, A.D.

2011-01-01

High concentrations of some hepatic elements might be contributing to the decline of the continental lesser scaup (Aythya affinis) population. We evaluated hepatic element concentrations of male and female lesser scaup collected from the upper Midwest (Iowa, Minnesota, North Dakota, and South Dakota) during the 2003 and 2004 spring migrations. We measured concentrations of 24 elements in livers of 117 lesser scaup. We found that only selenium concentrations were at levels (>3.0 ??g/g wet weight [ww)]) proposed to adversely affect reproduction. Approximately 49% of females (n = 61) had individual hepatic concentrations >3.0 ??g/g ww selenium (Se). Our observed hepatic concentration of Se was similar to that reported in lesser scaup collected from the mid-continental United States but less than Se concentrations reported from the Great Lakes region. We found that the liver cadmium (Cd) concentration for males was significantly higher than that for females. Gender differences in hepatic Cd concentrations have not been previously reported for lesser scaup, but Cd is known to have negative impacts on male reproduction. Our results indicate that lesser scaup migrating through the upper Midwest in spring have elevated Se levels and that males carry a significantly greater Cd burden than females. Moreover, elemental concentrations might be high enough to affect reproduction in both male and female lesser scaup, but controlled laboratory studies are needed to adequately assess the effects of Se and Cd on lesser scaup reproduction. ?? 2010 Springer Science+Business Media, LLC.

Neutron activation analysis of thermal power plant ash and surrounding area soils.

PubMed

Al-Masri, M S; Haddad, Kh; Alsomel, N; Sarhil, A

2015-08-01

Elemental concentrations of As, Cd, Co, Cr, Fe, Hg, Mo, Ni, Se, and Zn have been determined in fly and bottom ash collected from Syrian power plants fired by heavy oil and natural gas using instrumental neutron activation analysis. The results showed that all elements were more concentrated in fly ash than in the fly ash; there was a clear increasing trend of the elemental concentrations in the fly ash along the flue gas pathway. The annual emission of elements was estimated. Elemental concentrations were higher inside the campus area than in surrounding areas, and the lowest values were found in natural-gas-fired power plant. In addition, the levels have decreased as the distance from power plant campus increases. However, the levels in the surrounding villages were within the Syrian standard for agriculture soil.

Trace Element Analysis of Biological Samples.

ERIC Educational Resources Information Center

Veillon, Claude

1986-01-01

Reviews background of atomic absorption spectrometry techniques. Discusses problems encountered and precautions to be taken in determining trace elements in the parts-per-billion concentration range and below. Concentrates on determining chromium in biological samples by graphite furnace atomic absorption. Considers other elements, matrices, and…

Online elemental analysis of process gases with ICP-OES: A case study on waste wood combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellinger, Marco, E-mail: marco.wellinger@gmail.com; Ecole Polytechnique Federale de Lausanne; Wochele, Joerg

2012-10-15

Highlights: Black-Right-Pointing-Pointer Simultaneous measurements of 23 elements in process gases of a waste wood combustor. Black-Right-Pointing-Pointer Mobile ICP spectrometer allows measurements of high quality at industrial plants. Black-Right-Pointing-Pointer Continuous online measurements with high temporal resolution. Black-Right-Pointing-Pointer Linear correlations among element concentrations in the raw flue gas were detected. Black-Right-Pointing-Pointer Novel sampling and calibration methods for ICP-OES analysis of process gases. - Abstract: A mobile sampling and measurement system for the analysis of gaseous and liquid samples in the field was developed. An inductively coupled plasma optical emission spectrometer (ICP-OES), which is built into a van, was used as detector. Themore » analytical system was calibrated with liquid and/or gaseous standards. It was shown that identical mass flows of either gaseous or liquid standards resulted in identical ICP-OES signal intensities. In a field measurement campaign trace and minor elements in the raw flue gas of a waste wood combustor were monitored. Sampling was performed with a highly transport efficient liquid quench system, which allowed to observe temporal variations in the elemental process gas composition. After a change in feedstock an immediate change of the element concentrations in the flue gas was detected. A comparison of the average element concentrations during the combustion of the two feedstocks showed a high reproducibility for matrix elements that are expected to be present in similar concentrations. On the other hand elements that showed strong differences in their concentration in the feedstock were also represented by a higher concentration in the flue gas. Following the temporal variations of different elements revealed strong correlations between a number of elements, such as chlorine with sodium, potassium and zinc, as well as arsenic with lead, and calcium with strontium.« less

Geographic patterns of elemental deposition in the Aegean region of Turkey indicated by the lichen, Xanthoria parietina (L.) Th. Fr.

PubMed

Yenisoy-Karakaş, S; Tuncel, S G

2004-08-15

Lichen samples from different parts of the world have been known to accumulate elements to a greater degree than higher plants, if they are exposed to these elements from the atmosphere or from water and sediments. It has been hypothesized that lichens can be used to monitor air pollution around point and area emission sources. Local variation (variation in substrate, age and morphology of lichen samples) of element concentrations would not be large enough to affect the concentration patterns in large areas. We tested this hypothesis in the Aegean region of Turkey, which is very urbanized and industrialized. No such study has been conducted before in this part of the country. A total of 234 samples of the lichen Xanthoria parietina were collected from a 51,800-km2 area. Samples were washed and analyzed by INAA and ICP-AES for 35 elements. The range of the concentrations for most of the elements on a local scale was an order of magnitude lower than for the element concentrations on a regional scale. The mean local coefficient of variance (CV) was found to be 15, providing that the local variation did not affect the concentration of elements in the sampling region. According to cluster analysis, 8 (As, Hg, Pb, Sb, Fe, Mn, Na and K) elements are indicative of important local pollution locations and their zone of impact in the region. By mapping the concentrations of eight indicative elements in lichen Xanthoria parietina of the Aegean region, it was possible to relate deposition to the existence of known sources of pollution in certain areas. Location of pollution sources such as iron-steel plants, and coal burning in the cities, industrial activity and two important coal-fired power plants generally corresponded with locations of highest element accumulations in the lichens.

A Modeling Approach for Burn Scar Assessment Using Natural Features and Elastic Property

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsap, L V; Zhang, Y; Goldgof, D B

2004-04-02

A modeling approach is presented for quantitative burn scar assessment. Emphases are given to: (1) constructing a finite element model from natural image features with an adaptive mesh, and (2) quantifying the Young's modulus of scars using the finite element model and the regularization method. A set of natural point features is extracted from the images of burn patients. A Delaunay triangle mesh is then generated that adapts to the point features. A 3D finite element model is built on top of the mesh with the aid of range images providing the depth information. The Young's modulus of scars ismore » quantified with a simplified regularization functional, assuming that the knowledge of scar's geometry is available. The consistency between the Relative Elasticity Index and the physician's rating based on the Vancouver Scale (a relative scale used to rate burn scars) indicates that the proposed modeling approach has high potentials for image-based quantitative burn scar assessment.« less

Quantitative analysis of trace levels of surface contamination by X-ray photoelectron spectroscopy Part I: statistical uncertainty near the detection limit.

PubMed

Hill, Shannon B; Faradzhev, Nadir S; Powell, Cedric J

2017-12-01

We discuss the problem of quantifying common sources of statistical uncertainties for analyses of trace levels of surface contamination using X-ray photoelectron spectroscopy. We examine the propagation of error for peak-area measurements using common forms of linear and polynomial background subtraction including the correlation of points used to determine both background and peak areas. This correlation has been neglected in previous analyses, but we show that it contributes significantly to the peak-area uncertainty near the detection limit. We introduce the concept of relative background subtraction variance (RBSV) which quantifies the uncertainty introduced by the method of background determination relative to the uncertainty of the background area itself. The uncertainties of the peak area and atomic concentration and of the detection limit are expressed using the RBSV, which separates the contributions from the acquisition parameters, the background-determination method, and the properties of the measured spectrum. These results are then combined to find acquisition strategies that minimize the total measurement time needed to achieve a desired detection limit or atomic-percentage uncertainty for a particular trace element. Minimization of data-acquisition time is important for samples that are sensitive to x-ray dose and also for laboratories that need to optimize throughput.

Quantification of Self Pollution from Two Diesel School Buses using Three Independent Methods.

PubMed

Liu, L-J Sally; Phuleria, Harish C; Webber, Whitney; Davey, Mark; Lawson, Douglas R; Ireson, Robert G; Zielinska, Barbara; Ondov, John M; Weaver, Christopher S; Lapin, Charles A; Easter, Michael; Hesterberg, Thomas W; Larson, Timothy

2010-09-01

We monitored two Seattle school buses to quantify the buses' self pollution using the dual tracers (DT), lead vehicle (LV), and chemical mass balance (CMB) methods. Each bus drove along a residential route simulating stops, with windows closed or open. Particulate matter (PM) and its constituents were monitored in the bus and from a LV. We collected source samples from the tailpipe and crankcase emissions using an on-board dilution tunnel. Concentrations of PM(1), ultrafine particle counts, elemental and organic carbon (EC/OC) were higher on the bus than the LV. The DT method estimated that the tailpipe and the crankcase emissions contributed 1.1 and 6.8 mug/m(3) of PM(2.5) inside the bus, respectively, with significantly higher crankcase self pollution (SP) when windows were closed. Approximately two-thirds of in-cabin PM(2.5) originated from background sources. Using the LV approach, SP estimates from the EC and the active personal DataRAM (pDR) measurements correlated well with the DT estimates for tailpipe and crankcase emissions, respectively, although both measurements need further calibration for accurate quantification. CMB results overestimated SP from the DT method but confirmed crankcase emissions as the major SP source. We confirmed buses' SP using three independent methods and quantified crankcase emissions as the dominant contributor.

Quantification of self pollution from two diesel school buses using three independent methods

NASA Astrophysics Data System (ADS)

Sally Liu, L.-J.; Phuleria, Harish C.; Webber, Whitney; Davey, Mark; Lawson, Douglas R.; Ireson, Robert G.; Zielinska, Barbara; Ondov, John M.; Weaver, Christopher S.; Lapin, Charles A.; Easter, Michael; Hesterberg, Thomas W.; Larson, Timothy

2010-09-01

We monitored two Seattle school buses to quantify the buses' self pollution using the dual tracers (DT), lead vehicle (LV), and chemical mass balance (CMB) methods. Each bus drove along a residential route simulating stops, with windows closed or open. Particulate matter (PM) and its constituents were monitored in the bus and from a LV. We collected source samples from the tailpipe and crankcase emissions using an on-board dilution tunnel. Concentrations of PM 1, ultrafine particle counts, elemental and organic carbon (EC/OC) were higher on the bus than the LV. The DT method estimated that the tailpipe and the crankcase emissions contributed 1.1 and 6.8 μg m -3 of PM 2.5 inside the bus, respectively, with significantly higher crankcase self pollution (SP) when windows were closed. Approximately two-thirds of in-cabin PM 2.5 originated from background sources. Using the LV approach, SP estimates from the EC and the active personal DataRAM (pDR) measurements correlated well with the DT estimates for tailpipe and crankcase emissions, respectively, although both measurements need further calibration for accurate quantification. CMB results overestimated SP from the DT method but confirmed crankcase emissions as the major SP source. We confirmed buses' SP using three independent methods and quantified crankcase emissions as the dominant contributor.

Coal fly ash basins as an attractive nuisance to birds: parental provisioning exposes nestlings to harmful trace elements.

PubMed

Bryan, A L; Hopkins, W A; Parikh, J H; Jackson, B P; Unrine, J M

2012-02-01

Birds attracted to nest around coal ash settling basins may expose their young to contaminants by provisioning them with contaminated food. Diet and tissues of Common Grackle (Quiscalus quiscala) nestlings were analyzed for trace elements to determine if nestlings were accumulating elements via dietary exposure and if feather growth limits elemental accumulation in other tissues. Arsenic, cadmium, and selenium concentrations in ash basin diets were 5× higher than reference diets. Arsenic, cadmium, and selenium concentrations were elevated in feather, liver, and carcass, but only liver Se concentrations approached levels of concern. Approximately 15% of the total body burden of Se, As, and Cd was sequestered in feathers of older (>5 days) nestlings, whereas only 1% of the total body burden of Sr was sequestered in feathers. Feather concentrations of only three elements (As, Se, and Sr) were correlated with liver concentrations, indicating their value as non-lethal indicators of exposure. Copyright © 2011 Elsevier Ltd. All rights reserved.

Determination of Elemental Composition of Malabar spinach, Lettuce, Spinach, Hyacinth Bean, and Cauliflower Vegetables Using Proton Induced X-Ray Emission Technique at Savar Subdistrict in Bangladesh

PubMed Central

Fahad, S. M.; Islam, A. F. M. Mahmudul; Ahmed, Mahiuddin; Alam, Md. Rezaul; Alam, Md. Ferdous; Khalik, Md. Farhan; Hossain, Md. Lokman; Abedin, Md. Joynal

2015-01-01

The concentrations of 18 different elements (K, Ca, Fe, Cl, P, Zn, S, Mn, Ti, Cr, Rb, Co, Br, Sr, Ru, Si, Ni, and Cu) were analyzed in five selected vegetables through Proton Induced X-ray Emission (PIXE) technique. The objective of this study was to provide updated information on concentrations of elements in vegetables available in the local markets at Savar subdistrict in Bangladesh. These elements were found in varying concentrations in the studied vegetables. The results also indicated that P, Cl, K, Ca, Mn, Fe, and Zn were found in all vegetables. Overall, K and Ca exhibited the highest concentrations. Cu and Ni exhibited the lowest concentrations in vegetables. The necessity of these elements was also evaluated, based on the established limits of regulatory standards. The findings of this study suggest that the consumption of these vegetables is not completely free of health risks. PMID:26229953

Possible lunar ores

NASA Technical Reports Server (NTRS)

Gillett, Stephen L.

1991-01-01

Despite the conventional wisdom that there are no lunar ores, geochemical considerations suggest that local concentrations of useful rare elements exist on the Moon in spite of its extreme dryness. The Moon underwent protracted igneous activity in its history, and certain magmatic processes can concentrate incompatible elements even if anhydrous. Such processes include: (1) separation of a magma into immiscible liquid phases (depending on composition, these could be silicate-silicate, silicate-oxide, silicate-sulfide, or silicate-salt); (2) cumulate deposits in layered igneous intrusions; and (3) concentrations of rare, refractory, lithophile elements (e.g., Be, Li, Zr) in highly differentiated, silica-rich magmas, as in the lunar granites. Terrestrial mining experience indicates that the single most important characteristic of a potential ore is its concentration of the desire element. The utility of a planet as a resource base is that the welter of interacting processes over geologic time can concentrate rare element automatically. This advantage is squandered if adequate exploration for ores is not first carried out.

Geochemical stratigraphy of two regolith cores from the Central Highlands of the moon

NASA Technical Reports Server (NTRS)

Korotev, R. L.

1991-01-01

High-resolution concentration profiles are presented for 20-22 chemical elements in the under 1-mm grain-size fractions of 60001-7 and 60009/10. Emphasis is placed on the stratigraphic features of the cores, and the fresh results are compared with those of previous petrographic and geochemical studies. For elements associated with major mineral phases, the variations in concentration in both cores exceed that observed in some 40 samples of surface and trench soils. Most of the variation in lithophile element concentrations at depths of 18 to 21 cm results from the mixing of two components - oil that is relatively mafic and rich in incompatible trace elements (ITEs), and coarse-grained anorthosite. The linearity of mixing lines on two-element concentration plots argues that the relative abundances of these various subcomponents are sufficiently uniform from sample to sample and from region to region in the core that the mixture behaves effectively as a single component. Soils at depths of 52-55 cm exhibit very low concentrations of ITEs.

Quantifying oil filtration effects on bearing life

NASA Technical Reports Server (NTRS)

Needelman, William M.; Zaretsky, Erwin V.

1991-01-01

Rolling-element bearing life is influenced by the number, size, and material properties of particles entering the Hertzian contact of the rolling element and raceway. In general, rolling-element bearing life increases with increasing level of oil filtration. Based upon test results, two equations are presented which allow for the adjustment of bearing L(sub 10) or catalog life based upon oil filter rating. It is recommended that where no oil filtration is used catalog life be reduced by 50 percent.

Trace element exposure of whooper swans (Cygnus cygnus) wintering in a marine lagoon (Swan Lake), northern China.

PubMed

Wang, Feng; Xu, Shaochun; Zhou, Yi; Wang, Pengmei; Zhang, Xiaomei

2017-06-30

Trace element poisoning remains a great threat to various waterfowl and waterbirds throughout the world. In this study, we determined the trace element exposure of herbivorous whooper swans (Cygnus cygnus) wintering in Swan Lake (Rongcheng), an important swan protection area in northern China. A total of 70 samples including abiotic factors (seawater, sediments), food sources (seagrass, macroalgae), feathers and feces of whooper swans were collected from the marine lagoon during the winters of 2014/2015 and 2015/2016. Concentrations of Cu, Zn, Pb, Cr, Cd, Hg and As were determined to investigate the trace element exposure of whooper swans wintering in the area. Results showed that there was an increasing trend in sediment trace element concentrations, compared with historical data. The trace element concentrations in swan feces most closely resembled those of Zostera marina leaves, especially for Cd and Cr. The Zn and Hg concentrations in the swan feces (49.57 and 0.01mg/kg, respectively) were lower than the minimum values reported in the literature for other waterfowls, waterbirds and terrestrial birds. However, the concentrations of the other five trace elements fell within the lower and mediate range of values reported for birds across the world. These results suggest that the whooper swans wintering in Swan Lake, Rongcheng are not suffering severe trace element exposure; however, with the increasing input of trace elements to the lagoon, severe adverse impacts may occur in the future, and we therefore suggest that the input of trace elements to this area should be curbed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study on elemental fingerprint of traditional marine Chinese medicine oysters from Jiaozhou Bay, China

NASA Astrophysics Data System (ADS)

Zheng, Yongjun; Zheng, Kang; Li, Yantuan

2012-09-01

In order to investigate the relationship between the trace elements and the characteristics of the oysters, we analyzed the trace elements present in the germplasm of oysters from different producing areas in the Jiaozhou Bay. The element fingerprints were established to reflect the elemental characteristics of the oysters. Concentration patterns of the elements were deciphered by principle component analysis (PCA) and hierarchical cluster analysis (HCA). The six regions were discriminated with accuracy using HCA and PCA based on the concentration of 16 trace elements. The elements were viewed as characteristic elements of the oysters and the fingerprints of these elements could be used to distinguish the quality of the oysters.

Elements concentration analysis in groundwater from the North Serra Geral aquifer in Santa Helena-Brazil using SR-TXRF spectrometer.

PubMed

Justen, Gisele C; Espinoza-Quiñones, Fernando R; Módenes, Aparecido Nivaldo; Bergamasco, Rosangela

2012-01-01

In this work the analysis of elements concentration in groundwater was performed using the synchrotron radiation total-reflection X-ray fluorescence (SR-TXRF) technique. A set of nine tube-wells with serious risk of contamination was chosen to monitor the mean concentration of elements in groundwater from the North Serra Geral aquifer in Santa Helena, Brazil, during 1 year. Element concentrations were determined applying a SR-TXRF methodology. The accuracy of SR-TXRF technique was validated by analysis of a certified reference material. As the groundwater composition in the North Serra Geral aquifer showed heterogeneity in the spatial distribution of eight major elements, a hierarchical clustering to the data was performed. By a similarity in their compositions, two of the nine wells were grouped in a first cluster, while the other seven were grouped in a second cluster. Calcium was the major element in all wells, with higher Ca concentration in the second cluster than in the first cluster. However, concentrations of Ti, V, Cr in the first cluster are slightly higher than those in the second cluster. The findings of this study within a monitoring program of tube-wells could provide a useful assessment of controls over groundwater composition and support management at regional level.

Trace elements and radon in groundwater across the United States, 1992-2003

USGS Publications Warehouse

Ayotte, Joseph D.; Gronberg, Jo Ann M.; Apodaca, Lori E.

2011-01-01

Trace-element concentrations in groundwater were evaluated for samples collected between 1992 and 2003 from aquifers across the United States as part of the U.S. Geological Survey National Water-Quality Assessment Program. This study describes the first comprehensive analysis of those data by assessing occurrence (concentrations above analytical reporting levels) and by comparing concentrations to human-health benchmarks (HHBs). Data from 5,183 monitoring and drinking-water wells representing more than 40 principal and other aquifers in humid and dry regions and in various land-use settings were used in the analysis. Trace elements measured include aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), beryllium (Be), boron (B), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), lead (Pb), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), silver (Ag), strontium (Sr), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn). Radon (Rn) gas also was measured and is included in the data analysis. Climate influenced the occurrence and distribution of trace elements in groundwater whereby more trace elements occurred and were found at greater concentrations in wells in drier regions of the United States than in humid regions. In particular, the concentrations of As, Ba, B, Cr, Cu, Mo, Ni, Se, Sr, U, V, and Zn were greater in the drier regions, where processes such as chemical evolution, ion complexation, evaporative concentration, and redox (oxidation-reduction) controls act to varying degrees to mobilize these elements. Al, Co, Fe, Pb, and Mn concentrations in groundwater were greater in humid regions of the United States than in dry regions, partly in response to lower groundwater pH and (or) more frequent anoxic conditions. In groundwater from humid regions, concentrations of Cu, Pb, Rn, and Zn were significantly greater in drinking-water wells than in monitoring wells. Samples from drinking-water wells in dry regions had greater concentrations of As, Ba, Pb, Li, Sr, V, and Zn, than samples from monitoring wells. In humid regions, however, concentrations of most trace elements were greater in monitoring wells than in drinking-water wells; the exceptions were Cu, Pb, Zn, and Rn. Cu, Pb, and Zn are common trace elements in pumps and pipes used in the construction of drinking-water wells, and contamination from these sources may have contributed to their concentrations. Al, Sb, Ba, B, Cr, Co, Fe, Mn, Mo, Ni, Se, Sr, and U concentrations were all greater in monitoring wells than in drinking-water wells in humid regions. Groundwater from wells in agricultural settings had greater concentrations of As, Mo, and U than groundwater from wells in urban settings, possibly owing to greater pH in the agricultural wells. Significantly greater concentrations of B, Cr, Se, Ag, Sr, and V also were found in agricultural wells in dry regions. Groundwater from dry-region urban wells had greater concentrations of Co, Fe, Pb, Li, Mn, and specific conductance than groundwater from agricultural wells. The geologic composition of aquifers and aquifer geochemistry are among the major factors affecting trace-element occurrence. Trace-element concentrations in groundwater were characterized in aquifers from eight major groups based on geologic material, including (1) unconsolidated sand and gravel; (2) glacial unconsolidated sand and gravel; (3) semiconsolidated sand; (4) sandstone; (5) sandstone and carbonate rock; (6) carbonate rock; (7) basaltic and other volcanic rock; and (8) crystalline rock. The majority of groundwater samples and the largest percentages of exceedences of HHBs were in the glacial and nonglacial unconsolidated sand and gravel aquifers; in these aquifers, As, Mn, and U are the most common trace elements exceeding HHBs. Overall, 19 percent of wells (962 of 5,097) exceeded an HHB for at least one trace element. The trace elements with HHBs included in this summary were Sb, As, Ba, Be, B, Cd, Cr,

The relationships between mercury and selenium in plankton and fish from a tropical food web.

PubMed

do A Kehrig, Helena; Seixas, Tércia G; Palermo, Elisabete A; Baêta, Aida P; Castelo-Branco, Christina W; Malm, Olaf; Moreira, Isabel

2009-01-01

Selenium (Se) has been shown to reduce mercury (Hg) bioavailability and trophic transfer in aquatic ecosystems. The study of methylmercury (MeHg) and Se bioaccumulation by plankton is therefore of great significance in order to obtain a better understanding of the estuarine processes concerning Hg and Se accumulation and biomagnification throughout the food web. In the western South Atlantic, few studies have documented trace element and MeHg in fish tissues. No previous study about trace elements and MeHg in plankton has been conducted concerning tropical marine food webs. Se, Hg, and MeHg were determined in two size classes of plankton, microplankton (70-290 microm) and mesoplankton (>or=290 microm), and also in muscle tissues and livers of four fish species of different trophic levels (Mugil liza, a planktivorous fish; Bagre spp., an omnivorous fish; Micropogonias furnieri, a benthic carnivorous fish; and Centropomus undecimalis, a pelagic carnivorous fish) from a polluted estuary in the Brazilian Southeast coast, Guanabara Bay. Biological and ecological factors such as body length, feeding habits, and trophic transfer were considered in order to outline the relationships between these two elements. The differences in trace element levels among the different trophic levels were investigated. Fish were collected from July 2004 to August 2005 at Guanabara Bay. Plankton was collected from six locations within the bay in August 2005. Total mercury (THg) was determined by cold vapor atomic absorption spectrometry (CV-AAS) with sodium borohydride as a reducing agent. MeHg analysis was conducted by digesting samples with an alcoholic potassium hydroxide solution followed by dithizone-toluene extraction. MeHg was then identified and quantified in the toluene layer by gas chromatography with an electron capture detector (GC-ECD). Se was determined by AAS using graphite tube with Pin platform and Zeeman background correction. Total mercury, MeHg, and Se increased with plankton size class. THg and Se values were below 2.0 and 4.8 microg g(-1) dry wt in microplankton and mesoplankton, respectively. A large excess of molar concentrations of Se in relation to THg was observed in both plankton size class and both fish tissues. Plankton presented the lowest concentrations of this element. In fish, the liver showed the highest THg and Se concentrations. THg and Se in muscle were higher in Centropomus undecimalis (3.4 and 25.5 nmol g(-1)) than in Micropogonias furnieri (2.9 and 15.3 nmol g(-1)), Bagre spp (1.3 and 3.4 nmol g(-1)) and Mugil liza (0.3 and 5.1 nmol g(-1)), respectively. The trophic transfer of THg and Se was observed between trophic levels from prey (considering microplankton and mesoplankton) to top predator (fish). The top predators in this ecosystem, Centropomus undecimalis and Micropogonias furnieri, presented similar MeHg concentrations in muscles and liver. Microplankton presented lower ratios of methylmercury to total mercury concentration (MeHg/THg) (34%) than those found in mesoplankton (69%) and in the muscle of planktivorous fish, Mugil liza (56%). The other fish species presented similar MeHg/THg in muscle tissue (of around 100%). M. liza showed lower MeHg/THg in the liver than C. undecimalis (35%), M. furnieri (31%) and Bagre spp. (22%). Significant positive linear relationships were observed between the molar concentrations of THg and Se in the muscle tissue of M. furnieri and M. liza. These fish species also showed significant inverse linear relationships between hepatic MeHg and Se, suggesting a strong antagonistic effect of Se on MeHg assimilation and accumulation. Differences found among the concentrations THg, MeHg, and Se in microplankton, mesozooplankton, and fishes were probably related to the preferred prey and bioavailability of these elements in the marine environment. The increasing concentration of MeHg and Se at successively higher trophic levels of the food web of Guanabara Bay corresponds to a transfer between trophic levels from the lower trophic level to the top-level predator, suggesting that MeHg and Se were biomagnified throughout the food web. Hg and Se were positively correlated with the fish standard length, suggesting that larger and older fish bioaccumulated more of these trace elements. THg, MeHg, and Se were a function of the plankton size. There is a need to assess the role of selenium in mercury accumulation in tropical ecosystems. Without further studies of the speciation of selenium in livers of fishes from this region, the precise role of this element, if any, cannot be verified in positively affecting mercury accumulation. Further studies of this element in the study of marine species should include liver samples containing relatively high concentrations of mercury. A basin-wide survey of selenium in fishes is also recommended.

Trace elements in Zn Pb Ag deposits and related stream sediments, Brooks Range Alaska, with implications for Tl as a pathfinder element

USGS Publications Warehouse

Graham, G.E.; Kelley, K.D.; Slack, J.F.; Koenig, A.E.

2009-01-01

The Zn-Pb-Ag metallogenic province of the western and central Brooks Range, Alaska, contains two distinct but mineralogically similar deposit types: shale-hosted massive sulphide (SHMS) and smaller vein-breccia occurrences. Recent investigations of the Red Dog and Anarraaq SHMS deposits demonstrated that these deposits are characterized by high trace-element concentrations of As, Ge, Sb and Tl. This paper examines geochemistry of additional SHMS deposits (Drenchwater and Su-Lik) to determine which trace elements are ubiquitously elevated in all SHMS deposits. Data from several vein-breccia occurrences are also presented to see if trace-element concentrations can distinguish SHMS deposits from vein-breccia occurrences. Whole-rock geochemical data indicate that Tl is the most consistently and highly concentrated characteristic trace element in SHMS deposits relative to regional unmineralized rock samples. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of pyrite and sphalerite indicate that Tl is concentrated in pyrite in SHMS. Stream sediment data from the Drenchwater and Su-Lik SHMS show that high Tl concentrations are more broadly distributed proximal to known or suspected mineralization than As, Sb, Zn and Pb anomalies. This broader distribution of Tl in whole-rock and particularly stream sediment samples increases the footprint of exposed and shallowly buried SHMS mineralization. High Tl concentrations also distinguish SHMS mineralization from the vein-breccia deposits, as the latter lack high concentrations of Tl but can otherwise have similar trace-element signatures to SHMS deposits. ?? 2009 AAG/Geological Society of London.

Bioaccumulation of potentially toxic trace elements in benthic organisms of Admiralty Bay (King George Island, Antarctica).

PubMed

Majer, Alessandra Pereira; Petti, Mônica Angélica Varella; Corbisier, Thais Navajas; Ribeiro, Andreza Portella; Theophilo, Carolina Yume Sawamura; Ferreira, Paulo Alves de Lima; Figueira, Rubens Cesar Lopes

2014-02-15

Data about the concentration, accumulation and transfer of potentially toxic elements in Antarctic marine food webs are essential for understanding the impacts of these elements, and for monitoring the pollution contribution of scientific stations, mainly in Admiralty Bay due to the 2012 fire in the Brazilian scientific station. Accordingly, the concentration of As, Cd, Cu, Ni, Pb and Zn was measured in eight benthic species collected in the 2005/2006 austral summer and the relationship between concentration and trophic position (indicated by δ(15)N values) was tested. A wide variation in metal content was observed depending on the species and the element. In the studied trophic positions, it was observed bioaccumulation for As, Cd and Pb, which are toxic elements with no biological function. In addition, Cd showed a positive relationship between concentration and trophic level suggesting the possible biomagnification of this element. Copyright © 2013 Elsevier Ltd. All rights reserved.

Gaseous Oxidized Mercury Flux from Substrates Associated with Industrial Scale Gold Mining in Nevada, USA

NASA Astrophysics Data System (ADS)

Miller, M. B.

2015-12-01

Gaseous elemental and oxidized mercury (Hg) fluxes were measured in a laboratory setting from substrate materials derived from industrial-scale open pit gold mining operations in Nevada, USA. Mercury is present in these substrates at a range of concentrations (10 - 40000 ng g-1), predominantly of local geogenic origin in association with the mineralized gold ores, but altered and redistributed to a varying degree by subsequent ore extraction and processing operations, including deposition of Hg recently emitted to the atmosphere from large point sources on the mines. Waste rock, heap leach, and tailings material usually comprise the most extensive and Hg emission relevant substrate surfaces. All three of these material types were collected from active Nevada mine sites in 2010 for previous research, and have since been stored undisturbed at the University of Nevada, Reno. Gaseous elemental Hg (GEM) flux was previously measured from these materials under a variety of conditions, and was re-measured in this study, using Teflon® flux chambers and Tekran® 2537A automated ambient air analyzers. GEM flux from dry undisturbed materials was comparable between the two measurement periods. Gaseous oxidized Hg (GOM) flux from these materials was quantified using an active filter sampling method that consisted of polysulfone cation-exchange membranes deployed in conjunction with the GEM flux apparatus. Initial measurements conducted within greenhouse laboratory space indicate that in dry conditions GOM is deposited to relatively low Hg cap and leach materials, but may be emitted from the much higher Hg concentration tailings material.

Fossil and Nonfossil Sources of Organic and Elemental Carbon Aerosols in the Outflow from Northeast China.

PubMed

Zhang, Yan-Lin; Kawamura, Kimitaka; Agrios, Konstantinos; Lee, Meehye; Salazar, Gary; Szidat, Sönke

2016-06-21

Source quantification of carbonaceous aerosols in the Chinese outflow regions still remains uncertain despite their high mass concentrations. Here, we unambiguously quantified fossil and nonfossil contributions to elemental carbon (EC) and organic carbon (OC) of total suspended particles (TSP) from a regional receptor site in the outflow of Northeast China using radiocarbon measurement. OC and EC concentrations were lower in summer, representing mainly marine air, than in other seasons, when air masses mostly traveled over continental regions in Mongolia and northeast China. The annual-mean contribution from fossil-fuel combustion to EC was 76 ± 11% (0.1-1.3 μg m(-3)). The remaining 24 ± 11% (0.03-0.42 μg m(-3)) was attributed to biomass burning, with slightly higher contribution in the cold period (∼31%) compared to the warm period (∼21%) because of enhanced emissions from regional biomass combustion sources in China. OC was generally dominated by nonfossil sources, with an annual average of 66 ± 11% (0.5-2.8 μg m(-3)), approximately half of which was apportioned to primary biomass-burning sources (34 ± 6%). In winter, OC almost equally originated from primary OC (POC) emissions and secondary OC (SOC) formation from fossil fuel and biomass-burning sources. In contrast, summertime OC was dominated by primary biogenic emissions as well as secondary production from biogenic and biomass-burning sources, but fossil-derived SOC was the smallest contributor. Distinction of POC and SOC was performed using primary POC-to-EC emission ratios separated for fossil and nonfossil emissions.

Vertical profile of elemental concentrations in aerosol particles in the Bermuda area during GCE/CASE/WATOX

NASA Astrophysics Data System (ADS)

Ennis, G.; Sievering, H.

1990-06-01

During the 1988 Global Change Expedition/Coordinated Air-Sea Experiment/Western Atlantic Ocean Experiment (GCE/CASE/WATOX) joint effort, research was conducted to determine elemental concentrations in atmospheric aerosol particles near Bermuda, to construct a three-level (15, 150, and 2600 m ASL) vertical profile of these concentrations, and to ascertain the source of the particles. Samples were collected by the NOAA King Air aircraft and NOAA ship Mt. Mitchell on July 24-28, 1988. Concentration determinations were made for 16 elements through the use of an X ray fluorescence instrument designed for analysis of small-mass samples. A layering effect was found; concentrations of several elements at 150 m were more than twice their respective concentrations at 15 m and 2600 m. Enrichment factors, V/Mn ratio, and correlations between concentrations suggest a Saharan mineral source, despite air mass back trajectories that show no direct continental input for up to 10 days prior to sample collection. Estimated total mineral aerosol concentrations at 15 m, 150 m, and 2600 m are 1.5, 4.1, and 2.1 μg m-3.

Reconnaissance for determining effects of land use and surficial geology on concentrations of selected elements on streambed materials from the coal-mining region, southwestern Indiana, October 1979 to March 1980

USGS Publications Warehouse

Wilber, W.G.; Boje, Rita R.

1982-01-01

Streambed materials were collected in October 1979 from 69 watersheds in Southwest Indiana having predominantly forested, agricultural, reclaimed, and unreclaimed mined land use to determine whether concentrations of sorbed and acid-soluble metals and trace elements were affected by land use and surficial geology. Analysis of variance indicated that 10% or more of the total variation in aluminum, arsenic, cobalt, iron, nickel, selenium, and zinc concentrations on streambed materials was accounted for by differences in land use. Concentrations of aluminum, cobalt, iron, nickel, selenium, and zinc on streambed materials smaller than 0.062-millimeter from mined watersheds were significantly greater than the concentrations of these elements on streambed materials from agricultural and forested watersheds. The greater concentrations of these elements on streambed materials are due to (1) their concentrations in mine drainage and their subsequent absorption and (or) copecipitation with the oxides and hydroxides of aluminum and iron and (2) their concentrations in coal and pyritic material in streambed materials. (USGS)

The effect of acidified sample storage time on the determination of trace element concentration in ice cores by ICP-SFMS

NASA Astrophysics Data System (ADS)

Uglietti, C.; Gabrielli, P.; Lutton, A.; Olesik, J.; Thompson, L. G.

2012-12-01

Trace elements in micro-particles entrapped in ice cores are a valuable proxy of past climate and environmental variations. Inductively coupled plasma sector field mass spectrometry (ICP-SFMS) is generally recognized as a sensitive and accurate technique for the quantification of ultra-trace element concentrations in ice cores. Usually, ICP-SFMS analyses of ice core samples are performed by melting and acidifying aliquots. Acidification is important to transfer trace elements from particles into solution by partial and/or complete dissolution. Only elements in solution and in sufficiently small particles will be vaporized and converted to elemental ions in the plasma for detection by ICP-SFMS. However, experimental results indicate that differences in acidified sample storage time at room temperature may lead to the recovery of different trace element fractions. Moreover, different lithologies of the relatively abundant crustal material entrapped in the ice matrix could also influence the fraction of trace elements that are converted into elemental ions in the plasma. These factors might affect the determination of trace elements concentrations in ice core samples and hamper the comparison of results obtained from ice cores from different locations and/or epochs. In order to monitor the transfer of elements from particles into solution in acidified melted ice core samples during storage, a test was performed on sections from nine ice cores retrieved from low latitude drilling sites around the world. When compared to ice cores from polar regions, these samples are characterized by a relative high content of micro-particles that may leach trace elements into solution differently. Of the nine ice cores, five are from the Tibetan Plateau (Dasuopu, Guliya, Naimonanyi, Puruogangri and Dunde), two from the Andes (Quelccaya and Huascaran), one from Africa (Kilimanjaro) and one from the Eastern Alps (Ortles). These samples were decontaminated by triple rinsing, melted and stored in pre-cleaned low-density polyethylene bottles, and kept frozen until acidification (2% v/v ultra-pure HNO3). Determination of twenty trace elements (Ag, Al, As, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Rb, Sb, Sn, Ti, Tl, U, V, and Zn) was repeated at different times after acidification using the same aliquot. Analyses show a mean increase of 40-50% in trace element concentration in all the samples during the first 15 days of storage after acidification, except Al, Fe, V and Cr, which show a larger increase (90-100%). After 15 days the trace element concentrations reach generally stable values (with small increases within measurement uncertainty), except for the Naimonanyi and Kilimanjaro samples which continue to increase. In contrast, Ag concentration decreases after one week, likely due to its low stability in the acidified solution that may depend on the Cl- concentration. We froze the samples 43 days after the acidification. After two weeks the samples were melted and re-analyzed by ICP-SFMS in two different laboratories as an inter-calibration exercise. The results show a good correspondence between the measured concentrations determined by the two instruments and a consistent additional increase of 20-30% of measured trace element concentrations in almost all samples.

Concentrations of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio, from August 1971 to August 1972 and their dependence on wind direction: Complete data listing and concentration roses

NASA Technical Reports Server (NTRS)

King, R. B.; Neustadter, H. E.

1976-01-01

Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio during 1971 and 1972. Daily values, maxima, geometric means and their standard deviations covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented on microfiche for 60 elements, and for a lesser number of days for 10 polycyclic aromatic hydrocarbon compounds (PAH), the aliphatic hydrocarbon compounds (AH) as a group and carbon. In addition, concentration roses showing directional properties are presented for 39 elements, 10 PAH and the AH as a group. The elements (except carbon) are shown both in terms of concentration and percentage of the suspended particulate matter.

Preeclampsia and toxic metals: a case-control study in Kinshasa, DR Congo.

PubMed

Elongi Moyene, Jean-Pierre; Scheers, Hans; Tandu-Umba, Barthélémy; Haufroid, Vincent; Buassa-Bu-Tsumbu, Baudouin; Verdonck, Fons; Spitz, Bernard; Nemery, Benoit

2016-04-05

Preeclampsia is frequent in Kinshasa (Democratic Republic of Congo), especially during the dry season. We tested whether preeclampsia was associated with exposure to environmental metals. Using a case-control design, 88 women hospitalized with preeclampsia (cases) and 88 healthy pregnant women from the antenatal clinic (controls) were included in the study; 67 and 109 women were enrolled during the rainy and dry season, respectively. The concentrations of 24 elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) in 24-h urine collections. Differences in the urinary excretion of metals were investigated between cases and controls, and the interaction with season was assessed. Cases and controls were well matched regarding age, parity and duration of pregnancy. In controls, the urinary concentrations of most elements were substantially higher than reference values for adults from industrially developed countries, e.g. for lead: geometric mean (GM) 8.0 μg/L [25(th)-75(th) percentile 3.1-13.8]. The daily urinary excretions of 14 metals were significantly higher in women with preeclampsia than in control women, e.g. for lead: GM 61 μg/day (25(th)-75(th) percentile 8-345) in women with preeclampsia vs 9 μg/day (25(th)-75(th) percentile 3-21) in controls (p < 0.001). A significant interaction was found between season and preeclampsia for several elements, with higher urinary excretions in preeclamptic women than controls during the dry season, but not during the rainy season. This study revealed not only that women with preeclampsia excrete higher amounts of several toxic metals, especially lead, than control women, but also that this excretion exhibits seasonal variation, thus possibly explaining the high incidence and seasonal variation of preeclampsia in Kinshasa. Although the exact sources of this exposure are unknown, these findings underscore the need for preventing environmental exposures to lead and other toxic metals.

Tracing Anthropogenic Salinity Inputs to the Semi-arid Rio Grande River: A Multi-isotope Tracer (U, S, B and Sr) Approach

NASA Astrophysics Data System (ADS)

Garcia, S.; Nyachoti, S. K.; Ma, L.; Szynkiewicz, A.; McIntosh, J. C.

2015-12-01

High salinity in the Rio Grande has led to severe reductions in crop productivity and accumulation of salts in soils. These pressing issues exist for other arid rivers worldwide. Salinity contributions to the Rio Grande have not been adequately quantified, especially from agriculture, urban activities, and geological sources. Here, we use major element concentrations and U, S, B, Sr isotopic signatures to fingerprint the salinity sources. Our study area focuses on a 200 km long stretch of the Rio Grande from Elephant Butte Reservoir, NM to El Paso, TX. River samples were collected monthly from 2014 to 2015. Irrigation drains, groundwater wells, city drains and wastewater effluents were sampled as possible anthropogenic salinity end-members. Major element chemistry, U, S and Sr isotope ratios in the Rio Grande waters suggest multiple salinity inputs from geological, agricultural, and urban sources. Natural upwelling of groundwater is significant for the Rio Grande near Elephant Butte, as suggested by high TDS values and high (234U/238U), 87Sr/86Sr, δ34S ratios. Agricultural activities (e.g. flood irrigation, groundwater pumping, fertilizer use) are extensive in the Mesilla Valley. Rio Grande waters from this region have characteristic lower (234U/238U), 87Sr/86Sr, and δ34S ratios, with possible agricultural sources from use of fertilizers and gypsum. Agricultural practices during flood irrigation also intensify evaporation of Rio Grande surface water and considerably increase water salinity. Shallow groundwater signatures were also identified at several river locations, possibly due to the artificial pumping of local groundwater for irrigation. Impacts of urban activities to river chemistry (high NO3 and B concentrations) were evident for locations downstream to Las Cruces and El Paso wastewater treatment plants, supporting the use of the B isotope as an urban salinity tracer. This study improves our understanding of human impacts on water quality and elemental cycles.

High Throughput Determination of Critical Human Dosing ...

EPA Pesticide Factsheets

High throughput toxicokinetics (HTTK) is a rapid approach that uses in vitro data to estimate TK for hundreds of environmental chemicals. Reverse dosimetry (i.e., reverse toxicokinetics or RTK) based on HTTK data converts high throughput in vitro toxicity screening (HTS) data into predicted human equivalent doses that can be linked with biologically relevant exposure scenarios. Thus, HTTK provides essential data for risk prioritization for thousands of chemicals that lack TK data. One critical HTTK parameter that can be measured in vitro is the unbound fraction of a chemical in plasma (Fub). However, for chemicals that bind strongly to plasma, Fub is below the limits of detection (LOD) for high throughput analytical chemistry, and therefore cannot be quantified. A novel method for quantifying Fub was implemented for 85 strategically selected chemicals: measurement of Fub was attempted at 10%, 30%, and 100% of physiological plasma concentrations using rapid equilibrium dialysis assays. Varying plasma concentrations instead of chemical concentrations makes high throughput analytical methodology more likely to be successful. Assays at 100% plasma concentration were unsuccessful for 34 chemicals. For 12 of these 34 chemicals, Fub could be quantified at 10% and/or 30% plasma concentrations; these results imply that the assay failure at 100% plasma concentration was caused by plasma protein binding for these chemicals. Assay failure for the remaining 22 chemicals may

Single photon counting fluorescence lifetime detection of pericellular oxygen concentrations

NASA Astrophysics Data System (ADS)

Hosny, Neveen A.; Lee, David A.; Knight, Martin M.

2012-01-01

Fluorescence lifetime imaging microscopy offers a non-invasive method for quantifying local oxygen concentrations. However, existing methods are either invasive, require custom-made systems, or show limited spatial resolution. Therefore, these methods are unsuitable for investigation of pericellular oxygen concentrations. This study describes an adaptation of commercially available equipment which has been optimized for quantitative extracellular oxygen detection with high lifetime accuracy and spatial resolution while avoiding systematic photon pile-up. The oxygen sensitive fluorescent dye, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate [Ru(bipy)3]2+, was excited using a two-photon excitation laser. Lifetime was measured using a Becker & Hickl time-correlated single photon counting, which will be referred to as a TCSPC card. [Ru(bipy)3]2+ characterization studies quantified the influences of temperature, pH, cellular culture media and oxygen on the fluorescence lifetime measurements. This provided a precisely calibrated and accurate system for quantification of pericellular oxygen concentration based on measured lifetimes. Using this technique, quantification of oxygen concentrations around isolated viable chondrocytes, seeded in three-dimensional agarose gel, revealed a subpopulation of cells that exhibited significant spatial oxygen gradients such that oxygen concentration reduced with increasing proximity to the cell. This technique provides a powerful tool for quantifying spatial oxygen gradients within three-dimensional cellular models.

Single photon counting fluorescence lifetime detection of pericellular oxygen concentrations.

PubMed

Hosny, Neveen A; Lee, David A; Knight, Martin M

2012-01-01

Fluorescence lifetime imaging microscopy offers a non-invasive method for quantifying local oxygen concentrations. However, existing methods are either invasive, require custom-made systems, or show limited spatial resolution. Therefore, these methods are unsuitable for investigation of pericellular oxygen concentrations. This study describes an adaptation of commercially available equipment which has been optimized for quantitative extracellular oxygen detection with high lifetime accuracy and spatial resolution while avoiding systematic photon pile-up. The oxygen sensitive fluorescent dye, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate [Ru(bipy)(3)](2+), was excited using a two-photon excitation laser. Lifetime was measured using a Becker & Hickl time-correlated single photon counting, which will be referred to as a TCSPC card. [Ru(bipy)(3)](2+) characterization studies quantified the influences of temperature, pH, cellular culture media and oxygen on the fluorescence lifetime measurements. This provided a precisely calibrated and accurate system for quantification of pericellular oxygen concentration based on measured lifetimes. Using this technique, quantification of oxygen concentrations around isolated viable chondrocytes, seeded in three-dimensional agarose gel, revealed a subpopulation of cells that exhibited significant spatial oxygen gradients such that oxygen concentration reduced with increasing proximity to the cell. This technique provides a powerful tool for quantifying spatial oxygen gradients within three-dimensional cellular models.

Essential and non-essential elements in natural vegetation in southern Norway: contribution from different sources.

PubMed

Nordløkken, Marit; Berg, Torunn; Flaten, Trond Peder; Steinnes, Eiliv

2015-01-01

Concentrations of essential and non-essential elements in five widespread species of natural boreal vegetation were studied with respect to seasonal variation and contribution from different sources. The plant species included in the study were Betula pubescens, Sorbus aucuparia, Vaccinium myrtillus, Vaccinium uliginosum, Calluna vulgaris and Deschampsia flexuosa. Concentrations of elements essential to plants remained essentially constant or decreased slightly throughout the growing season. Concentrations of most non-essential elements increased or tended to increase on a dry mass basis from June to July as well as from July to September. The increasing trend for these elements was observed for all species except C. vulgaris. Principal component analysis (PCA) of the material indicated a common source for many of the non-essential elements; Sc, Ti, V, Ga, As, Y, Sb, lanthanides, Pb, Bi, and U, i.e. both elements presumably of geogenic origin and elements associated with trans-boundary air pollution. Uptake by plant roots appeared to be the main source of nutrient elements as well as some non-essential elements. Copyright © 2014 Elsevier B.V. All rights reserved.

Filter Media Tests Under Simulated Martian Atmospheric Conditions

NASA Technical Reports Server (NTRS)

Agui, Juan H.

2016-01-01

Human exploration of Mars will require the optimal utilization of planetary resources. One of its abundant resources is the Martian atmosphere that can be harvested through filtration and chemical processes that purify and separate it into its gaseous and elemental constituents. Effective filtration needs to be part of the suite of resource utilization technologies. A unique testing platform is being used which provides the relevant operational and instrumental capabilities to test articles under the proper simulated Martian conditions. A series of tests were conducted to assess the performance of filter media. Light sheet imaging of the particle flow provided a means of detecting and quantifying particle concentrations to determine capturing efficiencies. The media's efficiency was also evaluated by gravimetric means through a by-layer filter media configuration. These tests will help to establish techniques and methods for measuring capturing efficiency and arrestance of conventional fibrous filter media. This paper will describe initial test results on different filter media.

Isotope analysis in the transmission electron microscope.

PubMed

Susi, Toma; Hofer, Christoph; Argentero, Giacomo; Leuthner, Gregor T; Pennycook, Timothy J; Mangler, Clemens; Meyer, Jannik C; Kotakoski, Jani

2016-10-10

The Ångström-sized probe of the scanning transmission electron microscope can visualize and collect spectra from single atoms. This can unambiguously resolve the chemical structure of materials, but not their isotopic composition. Here we differentiate between two isotopes of the same element by quantifying how likely the energetic imaging electrons are to eject atoms. First, we measure the displacement probability in graphene grown from either 12 C or 13 C and describe the process using a quantum mechanical model of lattice vibrations coupled with density functional theory simulations. We then test our spatial resolution in a mixed sample by ejecting individual atoms from nanoscale areas spanning an interface region that is far from atomically sharp, mapping the isotope concentration with a precision better than 20%. Although we use a scanning instrument, our method may be applicable to any atomic resolution transmission electron microscope and to other low-dimensional materials.

Analyte-Triggered DNA-Probe Release from a Triplex Molecular Beacon for Nanopore Sensing.

PubMed

Guo, Bingyuan; Sheng, Yingying; Zhou, Ke; Liu, Quansheng; Liu, Lei; Wu, Hai-Chen

2018-03-26

A new nanopore sensing strategy based on triplex molecular beacon was developed for the detection of specific DNA or multivalent proteins. The sensor is composed of a triplex-forming molecular beacon and a stem-forming DNA component that is modified with a host-guest complex. Upon target DNA hybridizing with the molecular beacon loop or multivalent proteins binding to the recognition elements on the stem, the DNA probe is released and produces highly characteristic current signals when translocated through α-hemolysin. The frequency of current signatures can be used to quantify the concentrations of the target molecules. This sensing approach provides a simple, quick, and modular tool for the detection of specific macromolecules with high sensitivity and excellent selectivity. It may find useful applications in point-of-care diagnostics with a portable nanopore kit in the future. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cary, Robert

The purpose of this study was to measure the organic carbon (OC) and elemental carbon (EC) fractions of PM2.5 particulate matter at the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) sampling site for a 6-month period during the summer of 2013. The site is in a rural location remote from any populated areas, so it would be expected to reflect carbon concentration over long-distance transport patterns. During the same period in 2012, a number of prairie fires in Oklahoma and Texas had produced large plumes of smoke particles, but OC andmore » EC particles had not been quantified. In addition, during the summer months, other wild fires, such as forest fires in the Rocky Mountain states and other areas, can produce carbon aerosols that are transported over long distances. Both of these source types would be expected to contain mixtures of both OC and EC.« less

Chemiluminescence imaging ELISA using an imprinted polymer as the recognition element instead of an antibody.

PubMed

Surugiu, I; Danielsson, B; Ye, L; Mosbach, K; Haupt, K

2001-02-01

An imaging assay analogous to competitive enzyme immunoassays has been developed using a molecularly imprinted polymer instead of an antibody. The antigen 2,4-dichlorophenoxyacetic acid (2,4-D) was labeled with tobacco peroxidase, and the chemiluminescence reaction of luminol was used for detection. Microtiter plates (96 or 384 wells) were coated with polymer microspheres imprinted with 2,4-D, which were fixed in place by using poly(vinyl alcohol) as glue. In a competitive mode, the analyte-peroxidase conjugate was incubated with the free analyte in the microtiter plate, after which the bound fraction of the conjugate was quantified. After addition of the chemiluminescent substrates, light emission was measured in a high-throughput imaging format with a CCD camera. Calibration curves corresponding to analyte concentrations ranging from 0.01 to 100 microg/mL were obtained.

Application of lag-k autocorrelation coefficient and the TGA signals approach to detecting and quantifying adulterations of extra virgin olive oil with inferior edible oils.

PubMed

Torrecilla, José S; García, Julián; García, Silvia; Rodríguez, Francisco

2011-03-04

The combination of lag-k autocorrelation coefficients (LCCs) and thermogravimetric analyzer (TGA) equipment is defined here as a tool to detect and quantify adulterations of extra virgin olive oil (EVOO) with refined olive (ROO), refined olive pomace (ROPO), sunflower (SO) or corn (CO) oils, when the adulterating agents concentration are less than 14%. The LCC is calculated from TGA scans of adulterated EVOO samples. Then, the standardized skewness of this coefficient has been applied to classify pure and adulterated samples of EVOO. In addition, this chaotic parameter has also been used to quantify the concentration of adulterant agents, by using successful linear correlation of LCCs and ROO, ROPO, SO or CO in 462 EVOO adulterated samples. In the case of detection, more than 82% of adulterated samples have been correctly classified. In the case of quantification of adulterant concentration, by an external validation process, the LCC/TGA approach estimates the adulterant agents concentration with a mean correlation coefficient (estimated versus real adulterant agent concentration) greater than 0.90 and a mean square error less than 4.9%. Copyright © 2011 Elsevier B.V. All rights reserved.

Dissolved oxygen transfer to sediments by sweep and eject motions in aquatic environments

USGS Publications Warehouse

O'Connor, B.L.; Hondzo, Miki

2008-01-01

Dissolved oxygen (DO) concentrations were quantified near the sediment-water interface to evaluate DO transfer to sediments in a laboratory recirculating flume and open channel under varying fluid-flow conditions. DO concentration fluctuations were observed within the diffusive sublayer, as defined by the time-averaged DO concentration gradient near the sediment-water interface. Evaluation of the DO concentration fluctuations along with detailed fluid-flow characterizations were used to quantify quasi-periodic sweep and eject motions (bursting events) near the sediments. Bursting events dominated the Reynolds shear stresses responsible for momentum and mass fluctuations near the sediment bed. Two independent methods for detecting bursting events using DO concentration and velocity data produced consistent results. The average time between bursting events was scaled with wall variables and was incorporated into a similarity model to describe the dimensionless mass transfer coefficient (Sherwood number, Sh) in terms of the Reynolds number, Re, and Schmidt number, Sc, which described transport in the flow. The scaling of bursting events was employed with the similarity model to quantify DO transfer to sediments and results showed a high degree of agreement with experimental data. ?? 2008, by the American Society of Limnology and Oceanography, Inc.

Characterizing the concentration of Cryptosporidium in Australian surface waters for setting health-based targets for drinking water treatment.

PubMed

Petterson, S; Roser, D; Deere, D

2015-09-01

It is proposed that the next revision of the Australian Drinking Water Guidelines will include 'health-based targets', where the required level of potable water treatment quantitatively relates to the magnitude of source water pathogen concentrations. To quantify likely Cryptosporidium concentrations in southern Australian surface source waters, the databases for 25 metropolitan water supplies with good historical records, representing a range of catchment sizes, land use and climatic regions were mined. The distributions and uncertainty intervals for Cryptosporidium concentrations were characterized for each site. Then, treatment targets were quantified applying the framework recommended in the World Health Organization Guidelines for Drinking-Water Quality 2011. Based on total oocyst concentrations, and not factoring in genotype or physiological state information as it relates to infectivity for humans, the best estimates of the required level of treatment, expressed as log10 reduction values, ranged among the study sites from 1.4 to 6.1 log10. Challenges associated with relying on historical monitoring data for defining drinking water treatment requirements were identified. In addition, the importance of quantitative microbial risk assessment input assumptions on the quantified treatment targets was investigated, highlighting the need for selection of locally appropriate values.

Colorimetric Analysis of Ochratoxin A in Beverage Samples

PubMed Central

Bueno, Diana; Valdez, Luis F.; Gutiérrez Salgado, Juan Manuel; Marty, Jean Louis; Muñoz, Roberto

2016-01-01

This manuscript describes the use of a portable and low cost fluorescence setup to quantify the concentration of ochratoxin A (OTA) in beverage samples using an in-house developed system and different color models. It is reported that OTA is naturally fluorescent, for that reason an ultraviolet light at 365 nm was used to excite the samples and a Complementary Metal Oxide Semiconductor (CMOS) sensor was used to get a photograph of the OTA under excitation conditions, which is controlled by an executable interface designed in MATLAB. For each concentration of OTA, the coordinates with respect to each model color were obtained and plotted to quantify the mycotoxin present in the sample. It was possible to observe that despite the fact no extraction column was employed, the Red, Green, Blue (RGB) model shows a proportional relation to the evaluated concentrations. Despite the fact more analysis and other methods are required to quantify the OTA concentration, the brightness and a,b for the color-opponent dimensions (L*a*b) and Hue, Saturation, Value (HSV) tests provide results whereby it is possible to identify the concentration of OTA in beverage samples such as beer and wine. PMID:27834900

Trace element contamination in feather and tissue samples from Anna’s hummingbirds

USGS Publications Warehouse

Mikoni, Nicole A.; Poppenga, Robert H.; Ackerman, Joshua T.; Foley, Janet E.; Hazlehurst, Jenny; Purdin, Güthrum; Aston, Linda; Hargrave, Sabine; Jelks, Karen; Tell, Lisa A.

2017-01-01

Trace element contamination (17 elements; Be, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Hg, Tl, and Pb) of live (feather samples only) and deceased (feather and tissue samples) Anna's hummingbirds (Calypte anna) was evaluated. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS; 17 elements) and atomic absorption spectrophotometry (Hg only). Mean plus one standard deviation (SD) was considered the benchmark, and concentrations above the mean + 1 SD were considered elevated above normal. Contour feathers were sampled from live birds of varying age, sex, and California locations. In order to reduce thermal impacts, minimal feathers were taken from live birds, therefore a novel method was developed for preparation of low mass feather samples for ICP-MS analysis. The study found that the novel feather preparation method enabled small mass feather samples to be analyzed for trace elements using ICP-MS. For feather samples from live birds, all trace elements, with the exception of beryllium, had concentrations above the mean + 1 SD. Important risk factors for elevated trace element concentrations in feathers of live birds were age for iron, zinc, and arsenic, and location for iron, manganese, zinc, and selenium. For samples from deceased birds, ICP-MS results from body and tail feathers were correlated for Fe, Zn, and Pb, and feather concentrations were correlated with renal (Fe, Zn, Pb) or hepatic (Hg) tissue concentrations. Results for AA spectrophotometry analyzed samples from deceased birds further supported the ICP-MS findings where a strong correlation between mercury concentrations in feather and tissue (pectoral muscle) samples was found. These study results support that sampling feathers from live free-ranging hummingbirds might be a useful, non-lethal sampling method for evaluating trace element exposure and provides a sampling alternative since their small body size limits traditional sampling of blood and tissues. The results from this study provide a benchmark for the distribution of trace element concentrations in feather and tissue samples from hummingbirds and suggests a reference mark for exceeding normal. Lastly, pollinating avian species are minimally represented in the literature as bioindicators for environmental trace element contamination. Given that trace elements can move through food chains by a variety of routes, our study indicates that hummingbirds are possible bioindicators of environmental trace element contamination.

Concentrations and health risk assessment of trace elements in animal-derived food in southern China.

PubMed

Wu, Yaketon; Zhang, Huimin; Liu, Guihua; Zhang, Jianqing; Wang, Jizhong; Yu, Yingxin; Lu, Shaoyou

2016-02-01

This study aimed to investigate the levels of trace elements in animal-derived food in Shenzhen, Southern China. The concentrations of 14 trace elements (Cd, Hg, Pb, As, Cr, Cu, Fe, Zn, Mn, Mo, Ni, Co, Se and Ti) in a total of 220 meat samples, collected from the local markets of Shenzhen were determined. Cu, Fe and Zn were the major elements, with concentrations approximately 2-3 orders of magnitude higher than those of other elements. However, the daily intakes of Cu, Fe and Zn merely via the consumption of the meat products were lower than the recommended nutrient intake values provided by the 2013 Chinese Dietary Guide. Among the non-essential trace elements, Cd was accumulated in animal viscera, and the concentration ratios of chicken gizzard/chicken, chicken liver/chicken, pig kidney/pork and pig liver/pork were 41.6, 55.2, 863 and 177, respectively. In addition, high concentrations of As were found in aquatic products, especially in marine fish. The concentration of As in marine fish was slightly higher than the limits recommended by China, USA and Croatia. The health risk assessment of trace elements through the consumption of meat products by adult residents in Shenzhen was evaluated by using the target hazard quotient (THQ) method. The total THQ was greater than 1, implying a potential health risk. Approximately 66% of total THQ values, mainly from As, were from the consumption of aquatic products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Determining baseline element composition of lichens. I. Parmelia sulcata at Theodore Roosevelt national park, North Dakota

USGS Publications Warehouse

Gough, L.P.; Severson, R.C.; Jackson, L.L.

1988-01-01

Element-concentration baselines are given for Parmelia sulcata and associated soils. Parmelia chlorochroa was found sporadically and therefore only representative concentration ranges are reported for this species. Element data include (1) for lichens; Al, As, Ba, B, Ca, Cr, Cu, Fe, Hg, Mn, Ni, P, Sr, S, Ti, V, Y, and Zn; and (2) for soils: Al, Ba, Be, Ca, Cs, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Nb, P, Pb, Sr, S, Ti, V, Y, and Zn. Very little (usually 7.2 km); thus, P sulcata is, in general, chemically similar throughout the park. This same uniformity was found for soil geochemistry. Numerous samples collected at close intervals would be required, therefore, to produce detailed element-concentration maps for P. sulcata and soils. No instances of elemental phytotoxic conditions were found; however, P. sulcata apparently possesses large concentrations of Ba, Cu, Fe, Pb, S, V, and possibly Zn.

Gases and trace elements in soils at the North Silver Bell deposit, Pima County, Arizona

USGS Publications Warehouse

Hinkle, M.E.; Dilbert, C.A.

1984-01-01

Soil samples were collected over the North Silver Bell porphyry copper deposit near Tucson, Arizona. Volatile elements and compounds in gases derived from the soils and metallic elements in the soils were analyzed in order: (1) to see which volatile constituents of the soils might be indicative of the ore body or the alteration zones; and (2) to distinguish the ore and alteration zones by comparison of trace elements in the soil. Plots of analytical data on trace elements in soils indicated a typical distribution pattern for metals around a porphyry copper deposit, with copper, molybdenum, and arsenic concentrations higher over the ore body, and zinc, lead, and silver concentrations higher over the alteration zones. Higher than average concentrations of helium, carbon disulfide, and sulfur dioxide adsorbed on soils were found over the ore body, whereas higher concentrations of carbon dioxide and carbonyl sulfide were found over the alteration zones. ?? 1984.

A novel membrane inlet mass spectrometer method to measure ¹⁵NH4₄⁺ for isotope-enrichment experiments in aquatic ecosystems.

PubMed

Yin, Guoyu; Hou, Lijun; Liu, Min; Liu, Zhanfei; Gardner, Wayne S

2014-08-19

Nitrogen (N) pollution in aquatic ecosystems has attracted much attention over the past decades, but the dynamics of this bioreactive element are difficult to measure in aquatic oxygen-transition environments. Nitrogen-transformation experiments often require measurement of (15)N-ammonium ((15)NH4(+)) ratios in small-volume (15)N-enriched samples. Published methods to determine N isotope ratios of dissolved ammonium require large samples and/or costly equipment and effort. We present a novel ("OX/MIMS") method to determine N isotope ratios for (15)NH4(+) in experimental waters previously enriched with (15)N compounds. Dissolved reduced (15)N (dominated by (15)NH4(+)) is oxidized with hypobromite iodine to nitrogen gas ((29)N2 and/or (30)N2) and analyzed by membrane inlet mass spectrometry (MIMS) to quantify (15)NH4(+) concentrations. The N isotope ratios, obtained by comparing the (15)NH4(+) to total ammonium (via autoanalyzer) concentrations, are compared to the ratios of prepared standards. The OX/MIMS method requires only small sample volumes of water (ca. 12 mL) or sediment slurries and is rapid, convenient, accurate, and precise (R(2) = 0.9994, p < 0.0001) over a range of salinities and (15)N/(14)N ratios. It can provide data needed to quantify rates of ammonium regeneration, potential ammonium uptake, and dissimilatory nitrate reduction to ammonium (DNRA). Isotope ratio results agreed closely (R = 0.998, P = 0.001) with those determined independently by isotope ratio mass spectrometry for DNRA measurements or by ammonium isotope retention time shift liquid chromatography for water-column N-cycling experiments. Application of OX/MIMS should simplify experimental approaches and improve understanding of N-cycling rates and fate in a variety of freshwater and marine environments.

Rare Earth Element Concentrations in Submarine Hydrothermal Fluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, Andrew; Zierenberg, Robert

Rare earth element concentrations in submarine hydrothermal fluids from Alarcon Rise, East Pacific Rise, REE concentrations in submarine hydrothermal fluids from Pescadero Basin, Gulf of California, and the Cleft vent field, southern Juan de Fuca Ridge. Data are not corrected to zero Mg.

Chemical variations in the Cerro de Mercado (Durango, Mexico) fluorapatite: Assessing the effect of heterogeneity on a geochronologic standard.

NASA Astrophysics Data System (ADS)

Boyce, J. W.; Hodges, K. V.

2001-12-01

Despite the lack of an official pronouncement, the fluorapatite of Cerro de Mercado, Durango, Mexico has become the de facto standard for (U-Th)/He geochronology. In addition to being relatively inclusion-free and easily obtained, these crystals are commonly in excess of 5mm in diameter, permitting the removal of the outer skin of the crystal, theoretically eliminating the alpha-ejection correction. However, bulk analyses of the Durango fluorapatite indicate a substantial variation in U and Th concentrations from aliquot to aliquot (167-238 ppm Th; 9.7-12.3 ppm U, [1]). If similar variations were to occur on the sub-grain scale, small fragments of single crystals could contain helium excesses or deficiencies due to alpha-ejection exchange between zones with varying parent element content. We have performed a series of experiments to quantify the intra-grain variation in U and Th, in order to model the effect of this variation on ages determined on Durango fluorapatite. X-ray maps show concentric zonation in U and Th, with similar, but more apparently pronounced zonation in Si and Cl. Preliminary laser-ablation ICPMS data indicate, not surprisingly, that intra-grain variations in U and Th concentrations obtained by analysis of ~35 μ m spots are larger than that which had been previously obtained by bulk analytical techniques (with overall concentrations greater than for bulk analyses). Thus far, analyses yield U concentrations varying from 11 to 16 ppm, and Th concentrations ranging from 220 to 340 ppm. Modeling underway suggests that parent element variations on the order of 50%, such as those observed, and the resulting differential alpha-exchange could lead to several percent error in age, for ~100 μ m fragments. The effect scales inversely with fragment size, with 300 μ m fragments (roughly the size of a large, single grain analysis) having only ~1% error. This may offer an explanation for the previously observed inability to reproduce ages for the Durango fluorapatite within theoretical uncertainty [2]. [1] Young, E.J. et al., 1969. Mineralogy and geochemistry of fluorapatite from Cerro de Mercado, Durango, Mexico. USGS Professional Paper 650-D, pp D84-D93. [2] House, M.A. et al, 2000. Helium chronometry of apatite and titanite using Nd-YAG laser heating. Earth and Planetary Science Letters, v. 183, pp 365-368.

Concentrations of macro- and micro-elements in the milk of pasture-fed thoroughbred mares.

PubMed

Grace, N D; Pearce, S G; Firth, E C; Fennessy, P F

1999-03-01

To determine the changes in Ca, P, Mg, Na, K, S, Cu, Fe and Zn concentrations of milk during the lactation in pasture-fed Thoroughbred mares and then calculate the dietary mineral requirements of the sucking foal and the lactating mare. Milk was sampled on days 1, 3, 7, 14, 21, 28 and at various times between 55 to 65, 85 to 95 and 135 to 150 days after parturition from 21 pasture-fed mares. The concentrations of macro- and micro-elements in the milk were determined by inductively coupled plasma emission spectrometry. Concentrations (mg/L) of these elements were highest in colostrum (Mg 302, Na 561, K 955, S 1035, Cu 0.76, Fe 0.79 and Zn 5.5) except for Ca (1245) and P (895), which where highest on day 7. The mean milk mineral element concentrations (mg/L) over days 55 to 150 were Ca 843, P 543, Mg 47, Na 120, K 590, S 219, Cu 0.19, Fe 0.34 and Zn 2.1. The mean plasma element concentrations (mg/L) over the same period were Ca 120, P 77.1, Mg 17.0, Na 3110, K 168, S 983, Cu 1.1, Fe 1.5 and Zn 0.49. Concentration gradients between plasma and milk were observed and, in the case of Ca, P, Mg, K and Zn, their concentrations in milk were greater than those in plasma, while a reverse situation was observed for Na, S, Cu and Fe. With the exception of Ca and P, the highest concentrations of mineral elements were observed in the colostrum. The nursing foal should have access to good pasture or creep feed, because the intakes of Ca, P and Cu from milk may be less than optimum to meet the daily mineral element requirements.

Distribution and grain-size partitioning of metals in bovfom sediments of an experimentally acidified Wisconsin lake

USGS Publications Warehouse

Elder, John F.

2007-01-01

A study of concentrations and distribution of major and trace elements in surficial bottom sediments of Little Rock Lake in northern Wisconsin included examination of spatial variation and grain-size effects. No significant differences with respect to metal distribution in sediments were observed between the two basins of the lake, despite the experimental acidification of one of the basins from pH 6.1 to 4.6. The concentrations of most elements in the lake sediments were generally similar to soil concentrations in the area and were well below sediment quality criteria. Two exceptions were lead and zinc, whose concentrations in July 1990 exceeded the criteria of 50 μg/g and 100 μg/g, respectively, in both littoral and pelagic sediments. Concentrations of some elements, particularly Cu, Pb, and Zn, increased along transects from nearshore to midlake, following a similar gradient of sedimentary organic carbon. In contrast, Mn, Fe, and alkali/alkaline-earth elements were at maximum concentrations in nearshore sediments. These elements are less likely to partition to organic particles, and their distribution is more dependent on mineralogical composition, grain size, and other factors. Element concentrations varied among different sediment grain-size fractions, although a simple inverse relation to grain size was not observed. Fe, Mn, Pb, and Zn were more concentrated in a grain-size range 20–60 tm than in either the very fine or the coarse fractions, possibly because of the aggregation of smaller particles cemented together by organic and Fe/Mn hydrous-oxide coatings.

Hg Storage and Mobility in Tundra Soils of Northern Alaska

NASA Astrophysics Data System (ADS)

Olson, C.; Obrist, D.

2017-12-01

Atmospheric mercury (Hg) can be transported over long distances to remote regions such as the Arctic where it can then deposit and temporarily be stored in soils. This research aims to improve the understanding of terrestrial Hg storage and mobility in the arctic tundra, a large receptor area for atmospheric deposition and a major source of Hg to the Arctic Ocean. We aim to characterize spatial Hg pool sizes across various tundra sites and to quantify the mobility of Hg from thawing tundra soils using laboratory mobility experiments. Active layer and permafrost soil samples were collected in the summer of 2014 and 2015 at the Toolik Field Station in northern Alaska (68° 38' N) and along a 200 km transect extending from Toolik to the Arctic Ocean. Soil samples were analyzed for total Hg concentration, bulk density, and major and trace elements. Hg pool sizes were estimated by scaling up Hg soil concentrations using soil bulk density measurements. Mobility of Hg in tundra soils was quantified by shaking soil samples with ultrapure Milli-Q® water as an extracting solution for 24 and 72 hours. Additionally, meltwater samples were collected for analysis when present. The extracted supernatant was analyzed for total Hg, dissolved organic carbon, cations and anions, redox, and ph. Mobility of Hg from soil was calculated using Hg concentrations determined in solid soil samples and in supernatant of soil solution samples. Results of this study show Hg levels in tundra mineral soils that are 2-5 times higher than those observed at temperate sites closer to pollution sources. Most of the soil Hg was located in mineral horizons where Hg mass accounted for 72% of the total soil pool. Soil Hg pool sizes across the tundra sites were highly variable (166 - 1,365 g ha-1; avg. 419 g ha-1) due to the heterogeneity in soil type, bulk density, depth to frozen layer, and soil Hg concentration. Preliminary results from the laboratory experiment show higher mobility of Hg in mineral soils of active layer samples (0.062%) than in permafrost soils (0.026%) where soil Hg concentrations were lower. Mobilization of Hg stored in thawing permafrost soils could lead to accelerated export of Hg to aquatic systems, with major implications to Arctic wildlife and human health.

Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory

USGS Publications Warehouse

Iavorivska , Lidiia; Boyer, Elizabeth W.; Grimm, Jeffrey W.; Miller, Matthew P.; DeWalle, David R.; Davis, Kenneth J.; Kaye, Margot W.

2017-01-01

Organic compounds are removed from the atmosphere and deposited to the earth's surface via precipitation. In this study, we quantified variations of dissolved organic carbon (DOC) in precipitation during storm events at the Shale Hills Critical Zone Observatory, a forested watershed in central Pennsylvania (USA). Precipitation samples were collected consecutively throughout the storm during 13 events, which spanned a range of seasons and synoptic meteorological conditions, including a hurricane. Further, we explored factors that affect the temporal variability by considering relationships of DOC in precipitation with atmospheric and storm characteristics. Concentrations and chemical composition of DOC changed considerably during storms, with the magnitude of change within individual events being comparable or higher than the range of variation in average event composition among events. While some previous studies observed that concentrations of other elements in precipitation typically decrease over the course of individual storm events, results of this study show that DOC concentrations in precipitation are highly variable. During most storm events concentrations decreased over time, possibly as a result of washing out of the below-cloud atmosphere. However, increasing concentrations that were observed in the later stages of some storm events highlight that DOC removal with precipitation is not merely a dilution response. Increases in DOC during events could result from advection of air masses, local emissions during breaks in precipitation, or chemical transformations in the atmosphere that enhance solubility of organic carbon compounds. This work advances understanding of processes occurring during storms that are relevant to studies of atmospheric chemistry, carbon cycling, and ecosystem responses.

A comparison of speciated atmospheric mercury at an urban center and an upwind rural location

USGS Publications Warehouse

Rutter, A.P.; Schauer, J.J.; Lough, G.C.; Snyder, D.C.; Kolb, C.J.; Von Klooster, S.; Rudolf, T.; Manolopoulos, H.; Olson, M.L.

2008-01-01

Gaseous elemental mercury (GEM), particulate mercury (PHg) and reactive gaseous mercury (RGM) were measured every other hour at a rural location in south central Wisconsin (Devil's Lake State Park, WI, USA) between April 2003 and March 2004, and at a predominantly downwind urban site in southeastern Wisconsin (Milwaukee, WI, USA) between June 2004 and May 2005. Annual averages of GEM, PHg, and RGM at the urban site were statistically higher than those measured at the rural site. Pollution roses of GEM and reactive mercury (RM; sum of PHg and RGM) at the rural and urban sites revealed the influences of point source emissions in surrounding counties that were consistent with the US EPA 1999 National Emission Inventory and the 2003-2005 US EPA Toxics Release Inventory. Source-receptor relationships at both sites were studied by quantifying the impacts of point sources on mercury concentrations. Time series of GEM, PHg, and RGM concentrations were sorted into two categories; time periods dominated by impacts from point sources, and time periods dominated by mercury from non-point sources. The analysis revealed average point source contributions to GEM, PHg, and RGM concentration measurements to be significant over the year long studies. At the rural site, contributions to annual average concentrations were: GEM (2%; 0.04 ng m-3); and, RM (48%; 5.7 pg m-3). At the urban site, contributions to annual average concentrations were: GEM (33%; 0.81 ng m-3); and, RM (64%; 13.8 pg m-3). ?? The Royal Society of Chemistry.

Estimated sediment thickness, quality, and toxicity to benthic organisms in selected impoundments in Massachusetts

USGS Publications Warehouse

Breault, Robert F.; Sorenson, Jason R.; Weiskel, Peter K.

2013-01-01

The U.S. Geological Survey and the Massachusetts Department of Fish and Game, Division of Ecological Restoration, collaborated to collect baseline information on the quantity and quality of sediment impounded behind selected dams in Massachusetts, including sediment thickness and the occurrence of contaminants potentially toxic to benthic organisms. The thicknesses of impounded sediments were measured, and cores of sediment were collected from 32 impoundments in 2004 and 2005. Cores were chemically analyzed, and concentrations of 32 inorganic elements and 108 organic compounds were quantified. Sediment thicknesses varied considerably among the 32 impoundments, with an average thickness of 3.7 feet. Estimated volumes also varied greatly, ranging from 100,000 cubic feet to 81 million cubic feet. Concentrations of toxic contaminants as well as the number of contaminants detected above analytical quantification levels (also known as laboratory reporting levels) varied greatly among sampling locations. Based on measured contaminant concentrations and comparison to published screening thresholds, bottom sediments were predicted to be toxic to bottom-dwelling (benthic) organisms in slightly under 30 percent of the impoundments sampled. Statistically significant relations were found between several of the contaminants and individual indicators of urban land use and industrial activity in the upstream drainage areas of the impoundments. However, models developed to estimate contaminant concentrations at unsampled sites from upstream landscape characteristics had low predictive power, consistent with the long and complex land-use history that is typical of many drainage areas in Massachusetts.

Determination of lead content in drilling fueled soil using laser induced spectral analysis and its cross validation using ICP/OES method.

PubMed

Rehan, I; Gondal, M A; Rehan, K

2018-05-15

A detection system based on Laser Induced Breakdown Spectroscopy (LIBS) was designed, optimized, and successfully employed for the estimation of lead (Pb) content in drilling fueled soil (DFS) collected from oil field drilling areas in Pakistan. The concentration of Pb was evaluated by the standard calibration curve method as well as by using an approach based on the integrated intensity of strongest emission of an element of interest. Remarkably, our investigation clearly demonstrated that the concentration of Pb in drilling fueled soil collected at the exact drilling site was greater than the safe permissible limits. Furthermore, the Pb concentration was observed to decline with increasing distance away from the specific drilling point. Analytical determinations were carried out under the assumptions that laser generated plasma was optically thin and in local thermodynamic equilibrium (LTE). In order to improve the sensitivity of our LIBS detection system, various parametric dependence studies were performed. To further validate the precision of our LIBS results, the concentration of Pb present in the acquired samples were also quantified via a standard analytical tool like inductively coupled plasma/optical emission spectroscopy (ICP/OES). Both results were in excellent agreement, implying remarkable reliability for the LIBS data. Furthermore, the Limit of detection (LOD) of our LIBS system for Pb was estimated to be 125.14 mg L -1 . Copyright © 2018 Elsevier B.V. All rights reserved.

Metal exposure influences the melanin and carotenoid-based colorations in great tits.

PubMed

Giraudeau, M; Mateos-Gonzalez, F; Cotín, J; Pagani-Nuñez, E; Torné-Noguera, A; Senar, J C

2015-11-01

Metals are naturally found in the environment but are also emitted through anthropogenic activities, raising some concerns about the potential deleterious effects of these elements on wildlife. The potential effects of metals on bird coloration have been the focus of several recent studies since animal colored-signals often reflect the physiology of their bearers and are thus used by animals to assess the quality of another individual as a mate or competitor. These studies have shown that the melanin pigmentation seems to be positively associated and the carotenoid-based coloration negatively associated with metal exposure in wild birds. Although these studies have been very useful to show the associations between metal exposure and coloration, only few of them have actually quantified the levels of metal exposure at the individual level; always focusing on one or two of them. Here, we measured the concentrations of eight metals in great tits' feathers and then assessed how these levels of metals were associated with the carotenoid and melanin-based colorations. We found that the melanin pigmentation was positively associated with the copper concentration and negatively correlated with the chromium concentration in feathers. In addition, we have shown that the carotenoid-based coloration was negatively associated with the feather's mercury concentration. This study is the first one to identify some metals that might affect positively and negatively the deposition of melanin and carotenoid into the plumage of wild birds. Copyright © 2015 Elsevier B.V. All rights reserved.

New approach to the determination phosphorothioate oligonucleotides by ultra high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry.

PubMed

Studzińska, Sylwia; Mounicou, Sandra; Szpunar, Joanna; Łobiński, Ryszard; Buszewski, Bogusław

2015-01-15

This text presents a novel method for the separation and detection of phosphorothioate oligonucleotides with the use of ion pair ultra high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry The research showed that hexafluoroisopropanol/triethylamine based mobile phases may be successfully used when liquid chromatography is coupled with such elemental detection. However, the concentration of both HFIP and TEA influences the final result. The lower concentration of HFIP, the lower the background in ICP-MS and the greater the sensitivity. The method applied for the analysis of serum samples was based on high resolution inductively coupled plasma mass spectrometry. Utilization of this method allows determination of fifty times lower quantity of phosphorothioate oligonucleotides than in the case of quadrupole mass analyzer. Monitoring of (31)P may be used to quantify these compounds at the level of 80 μg L(-1), while simultaneous determination of sulfur is very useful for qualitative analysis. Moreover, the results presented in this paper demonstrate the practical applicability of coupling LC with ICP-MS in determining phosphorothioate oligonucleotides and their metabolites in serum within 7 min with a very good sensitivity. The method was linear in the concentration range between 0.2 and 3 mg L(-1). The limit of detection was in the range of 0.07 and 0.13 mg L(-1). Accuracy varied with concentration, but was in the range of 3%. Copyright © 2014 Elsevier B.V. All rights reserved.

Seasonal differences in trace element concentrations and distribution in Spartina alterniflora root tissue

DOE PAGES

Feng, Huan; Qian, Yu; Cochran, J. Kirk; ...

2018-04-13

This study uses nanometer-scale synchrotron X-ray nanofluorescence to investigate season differences in concentrations and distributions of major (Ca, K, S and P) and trace elements (As, Cr, Cu, Fe and Zn) in the root system of Spartina alterniflora collected from Jamaica Bay, New York, in April and September 2015. The root samples were cross-sectioned at a thickness of 10 μm. Selected areas in the root epidermis and endodermis were mapped with a sampling resolution of 100 and 200 nm, varying with the mapping areas. The results indicate that trace element concentrations in the epidermis and endodermis vary among the elementsmore » measured, possibly because of their different chemical properties or their ability to act as micronutrients for the plants. Elemental concentrations (As, Ca, Cr, Cu, Fe, K, P, S and Zn) within each individual root sample and between the root samples collected during two different seasons are both significantly different (p < 0.01). Furthermore, this study indicates that the nonessential elements (As and Cr) are significantly correlated (p < 0.01) with Fe, with high concentrations in the root epidermis, while others are not, implying that Fe may be a barrier to nonessential element transport in the root system. Hierarchy cluster analysis shows two distinct groups, one including As, Cr and Fe and the other the rest of the elements measured. Factor analysis also indicates that the processes and mechanisms controlling element transport in the root system can be different between the nutrient and nonessential elements.« less

Essential and toxic elements in seaweeds for human consumption.

PubMed

Desideri, D; Cantaluppi, C; Ceccotto, F; Meli, M A; Roselli, C; Feduzi, L

2016-01-01

Essential elements (K, Ca, P, S, Cl, Mn, Fe, Cu, Zn, Ni, Br, and I) and nonessential or toxic elements (Al, Ti, Si, Rb, Sr, As, Cd, Sn, and Pb) were determined by energy-dispersive polarized x-ray fluorescence spectrometry in 14 seaweeds purchased in local specialty stores in Italy and consumed by humans. The differences in elements between the algae species reached up to 2-4 orders of magnitude. Lithothamnium calcareum showed the highest levels of Ca, Al, Si, Fe, and Ti. Palmaria palmata showed the highest concentrations of K, Rb, and Cl. The highest content of S was in Chondrus crispus. Laminaria digitata contained the highest concentrations of total As, Cd, Sn, Br, and I. The highest concentration of Zn was in Chlorella pyrenoidosa. Ulva lactuca displayed the highest levels of Cu, Ni, Mn, and Pb. Iodine levels ranged from 3.4 in Chlorella pyrenoidosa to 7316 mg/kg(dry) in Laminaria digitata. The nutrimental importance of essential elements was assessed using nutritional requirements. The results showed that the consumption of algae might serve as an important source of the essential elements. Health risk due to the toxic elements present in seaweed was estimated using risk estimators. Total As, Cd, and Pb concentrations ranged from <1 to 67.6, to 7.2 and to 6.7 mg/kg(dry) respectively; therefore, their contribution to total elemental intake does not appear to pose any threat to the consumers, but the concentrations of these elements should be controlled to protect the consumer against potential adverse health risks.

Seasonal differences in trace element concentrations and distribution in Spartina alterniflora root tissue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Huan; Qian, Yu; Cochran, J. Kirk

This study uses nanometer-scale synchrotron X-ray nanofluorescence to investigate season differences in concentrations and distributions of major (Ca, K, S and P) and trace elements (As, Cr, Cu, Fe and Zn) in the root system of Spartina alterniflora collected from Jamaica Bay, New York, in April and September 2015. The root samples were cross-sectioned at a thickness of 10 μm. Selected areas in the root epidermis and endodermis were mapped with a sampling resolution of 100 and 200 nm, varying with the mapping areas. The results indicate that trace element concentrations in the epidermis and endodermis vary among the elementsmore » measured, possibly because of their different chemical properties or their ability to act as micronutrients for the plants. Elemental concentrations (As, Ca, Cr, Cu, Fe, K, P, S and Zn) within each individual root sample and between the root samples collected during two different seasons are both significantly different (p < 0.01). Furthermore, this study indicates that the nonessential elements (As and Cr) are significantly correlated (p < 0.01) with Fe, with high concentrations in the root epidermis, while others are not, implying that Fe may be a barrier to nonessential element transport in the root system. Hierarchy cluster analysis shows two distinct groups, one including As, Cr and Fe and the other the rest of the elements measured. Factor analysis also indicates that the processes and mechanisms controlling element transport in the root system can be different between the nutrient and nonessential elements.« less

Trace elemental correlation study in malignant and normal breast tissue by PIXE technique

NASA Astrophysics Data System (ADS)

Raju, G. J. Naga; Sarita, P.; Kumar, M. Ravi; Murty, G. A. V. Ramana; Reddy, B. Seetharami; Lakshminarayana, S.; Vijayan, V.; Lakshmi, P. V. B. Rama; Gavarasana, Satyanarayana; Reddy, S. Bhuloka

2006-06-01

Particle induced X-ray emission technique was used to study the variations in trace elemental concentrations between normal and malignant human breast tissue specimens and to understand the effects of altered homeostasis of these elements in the etiology of breast cancer. A 3 MeV proton beam was used to excite the biological samples of normal and malignant breast tissues. The elements Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb and Sr were identified and their relative concentrations were estimated. Almost all the elements were found to be elevated (p < 0.05, Wilcoxon signed-ranks test) in the cancerous tissues when compared with normal tissues. The excess levels of trace elements observed in the cancerous breast tissues could either be a cause or a consequence of breast cancer. Regarding their role in the initiation or promotion of breast cancer, one possible interpretation is that the elevated levels of Cu, Fe and Cr could have led to the formation of free radicals or other reactive oxygen species (ROS) that adversely affect DNA thereby causing breast cancer, which is mainly attributed to genetic abnormalities. Moreover, since Cu and Fe are required for angiogenesis, elevated concentrations of these elements are likely to promote breast cancer by increasing the blood supply for tumor growth. On the other hand elevated concentrations of elements in breast cancer tissues might also be a consequence of the cancer. This can be understood in terms of the biochemical and histological differences between normal and cancerous breast tissues. Tumors, characterized by unregulated multiplication of cells, need an ever-increasing supply of essential nutrients including trace elements. This probably results in an increased vascularity of malignant tissues, which in turn leads to enhancement of elemental concentrations in tumors.

Linking trace element variations with macronutrients and major cations in marine mussels Mytilus edulis and Perna viridis.

PubMed

Liu, Fengjie; Wang, Wen-Xiong

2015-09-01

Marine mussels have long been used as biomonitors of contamination of trace elements, but little is known about whether variation in tissue trace elements is significantly associated with those of macronutrients and major cations. The authors examined the variability of macronutrients and major cations and their potential relationships with bioaccumulation of trace elements. The authors analyzed the concentrations of macronutrients (C, N, P, S), major cations (Na, Mg, K, Ca), and trace elements (Al, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Pb) in the whole soft tissues of marine mussels Mytilus edulis and Perna viridis collected globally from 21 sites. The results showed that 12% to 84% of the variances in the trace elements was associated with major cations, and the tissue concentration of major cations such as Na and Mg in mussels was a good proxy for ambient seawater concentrations of the major cations. Specifically, bioaccumulation of most of the trace elements was significantly associated with major cations, and the relationships of major cations with trace cations and trace oxyanions were totally opposite. Furthermore, 14% to 69% of the variances in the trace elements were significantly associated with macronutrients. Notably, more than half of the variance in the tissue concentrations of As, Cd, V, Ba, and Pb was explained by the variance in macronutrients in one or both species. Because the tissue macronutrient concentrations were strongly associated with animal growth and reproduction, the observed coupling relationships indicated that these biological processes strongly influenced the bioaccumulation of some trace elements. The present study indicated that simultaneous quantification of macronutrients and major cations with trace elements can improve the interpretation of biomonitoring data. © 2015 SETAC.

Elemental distribution patterns in the skins of false killer whales (Pseudorca crassidens) from a mass stranding in South Africa, analysed using micro-PIXE

NASA Astrophysics Data System (ADS)

Mouton, M.; Botha, A.; Thornton, M.; Mesjasz-Przybyłowicz, J.; Przybyłowicz, W. J.

2015-11-01

Several studies revealed that anthropogenic activities often cause toxic concentrations of some elements, such as mercury, which bio-accumulate through the marine food chain, impacting negatively on the health of animals in the top trophic levels, such as a variety of marine mammals. Moreover, analysis of cetacean skin has been reported to be a reliable, long-term and mostly non-invasive method to monitor bio-accumulation of chemicals in cetacean populations. Several elements, including trace elements, occur naturally in cetacean skin, although nothing is known about their distribution patterns and little about safe base line concentrations. In May 2009, 42 false killer whales (FKWs) beached and died at Kommetjie in the Western Cape of South Africa. Skin samples of these FKWs were collected and analysed to determine elemental distribution patterns. The concentrations and distribution patterns of the major, as well as detectable trace elements were determined in skin samples from ten randomly selected FKW individuals, using micro-PIXE (particle-induced X-ray emission) analysis. Results revealed differences between the distribution patterns of elements in the skin sections. Fe, for example, was found to be concentrated in the dermal papillae, whereas the highest Zn concentrations occurred in the epidermis and particularly in the epidermal papillae. Since these essential elements mediate factors such as host immunity, from skin integrity to humoral immunity, knowledge of their typical distribution patterns can be of great value in studies of bio-accumulation. This is the first report of micro-PIXE being employed to study elemental distribution in cetacean skin and the resulting elemental distribution maps can serve as reference in future environmental pollution studies.

Comparison of humus and till as prospecting material in areas of thick overburden and multiple ice-flow events: An example from northeastern New Brunswick

USGS Publications Warehouse

Broster, Bruce E.; Dickson, M.L.; Parkhill, M.A.

2009-01-01

Thirty-nine elements in humus and till matrix were compared at 109 sites overlying Ag-As-Cu-Mo-Pb-Zn mineralized occurrences in northeastern New Brunswick to assess humus for anomaly identification. Humus element concentrations were not consistently correlative with maximum or minimum concentrations found in the underlying till or bedrock. The humus demonstrated significantly higher mean elemental concentrations than the till for six specific elements: 9 times greater for Mn, 6 times greater for Cd, 5 times greater for Ag and Pb, 3 times greater for Hg, and double the concentration of Zn. Spatial dispersal patterns for these elements were much larger for humus content than that exhibited by the till matrix analysis, but did not delineate a point source. For elements in till, the highest concentrations were commonly found directly overlying the underlying mineralized bedrock source or within one km down-glacier of the source. The complexity of the humus geochemical patterns is attributed to the effects of post-glacial biogenic, down-slope hydrodynamic and solifluction modification of dispersed mineralization in the underlying till, and the greater capacity of humus to adsorb cations and form complexes with some elements, relative to the till matrix. Humus sampling in areas of glaciated terrain is considered to be mostly valuable for reconnaissance exploration as elements can be spatially dispersed over a much larger area than that found in the till or underlying bedrock. ?? 2009 Elsevier B.V. All rights reserved.

Elemental composition of native wetland plants in constructed mesocosm treatment wetlands.

PubMed

Collins, Beverly S; Sharitz, Rebecca R; Coughlin, Daniel P

2005-05-01

Plants that accumulate a small percentage of metals in constructed treatment wetlands can contribute to remediation of acidic, metal contaminated runoff waters from coal mines or processing areas. We examined root and shoot concentrations of elements in four perennial wetland species over two seasons in mesocosm wetland systems designed to remediate water from a coal pile runoff basin. Deep wetlands in each system contained Myriophyllum aquaticum and Nymphaea odorata; shallow wetlands contained Juncus effusus and Pontederia cordata. Shoot elemental concentrations differed between plants of deep and shallow wetlands, with higher Zn, Al, and Fe concentrations in plants in shallow wetlands and higher Na, Mn, and P concentrations in plants in deep wetlands. Root and shoot concentrations of most elements differed between species in each wetland type. Over two seasons, these four common wetland plants did help remediate acidic, metal-contaminated runoff from a coal storage pile.

Micro-PIXE analysis of trace element concentrations of natural rubies from different locations in Myanmar

NASA Astrophysics Data System (ADS)

Sanchez, J. L.; Osipowicz, T.; Tang, S. M.; Tay, T. S.; Win, T. T.

1997-07-01

The trace element concentrations found in geological samples can shed light on the formation process. In the case of gemstones, which might be of artificial or natural origin, there is also considerable interest in the development of methods that provide identification of the origin of a sample. For rubies, trace element concentrations present in natural samples were shown previously to be significant indicators of the region of origin [S.M. Tang et al., Appl. Spectr. 42 (1988) 44, and 43 (1989) 219]. Here we report the results of micro-PIXE analyses of trace element (Ti, V, Cr, Fe, Cu and Ga) concentrations of a large set ( n = 130) of natural rough rubies from nine locations in Myanmar (Burma). The resulting concentrations are subjected to statistical analysis. Six of the nine groups form clusters when the data base is evaluated using tree clustering and principal component analysis.

Bioacumulation of trace elements in the crab Ucides cordatus (Linnaeus, 1763) from the macrotidal mangrove coast region of the Brazilian Amazon.

PubMed

Silva, Bruna Mariáh da S E; Morales, Gundisalvo P; Gutjahr, Ana Lúcia N; Freitas Faial, Kelson do C; Carneiro, Bruno S

2018-03-14

In this study, trace element concentrations were measured in chelipod and gill samples of the crab U. cordatus by induced coupled plasma optical emission spectrometry (ICP OES). The element average concentrations between the structures were statistically compared. Gill concentrations of Cu and Zn were higher in female crabs, while in chelipods, Pb concentrations were higher in males. The concentration of Zn in crabs from Curuçá City were higher than the recommended by health agencies, but the provisional tolerable daily intake value (PTDI), for Zn and Cu, showed only 10 and 23% contribution, respectively. The bioaccumulation factor was higher than 1 for Cu (gills and chelipods) and Zn (only for chelipods), which suggests bioaccumulation for these elements. Further metallomic and oxidative stress analyses are suggested, in order to evaluate possible protein and/or enzymatic biomarkers of toxicity.

Quantifiable Lateral Flow Assay Test Strips

NASA Technical Reports Server (NTRS)

2003-01-01

As easy to read as a home pregnancy test, three Quantifiable Lateral Flow Assay (QLFA) strips used to test water for E. coli show different results. The brightly glowing control line on the far right of each strip indicates that all three tests ran successfully. But the glowing test line on the middle left and bottom strips reveal their samples were contaminated with E. coli bacteria at two different concentrations. The color intensity correlates with concentration of contamination.

Mafic intrusion remobilising silicic magma under El Hierro, Canary Islands

NASA Astrophysics Data System (ADS)

Sigmarsson, O.; Laporte, D.; Marti, J.; Devouard, B.; Cluzel, N.

2012-04-01

The 2011 submarine eruption at El Hierro, Canary Islands, has produced volcanic bombs that degas at sea surface, boil seawater and sink when cooled and degassed. At the beginning of the eruption white coloured pumices enveloped in darker coloured spatters floated on land. These composite pumices show evidence of magma mingling with folds and undulations of the darker coloured magma within the white pumice suggesting magma mingling in a viscous regime. The white pumice is highly vesicular and resembles foam. Most of the vesicular structure is made of tightly packed, polygonal bubbles of uniform size (˜ 100 μm), suggesting a single event of homogeneous bubble nucleation. An earlier event of heterogeneous bubble nucleation is indicated by the presence of a few large bubbles developed around tiny quartz crystals. Both the darker and lighter coloured pumices are almost aphyric. A few olivine crystals with perfect euhedral morphology occur within the darker part. Rare olivines of same composition are also found in the white pumice glass but then display somewhat rounded outlines and hopper-type structure. Melt inclusions in olivines of the darker pumice are of the same composition as the enveloping mafic glass, whereas olivines in the mixing boundary layer have melt inclusions of less mafic composition. The whole-rock composition and slightly more evolved glass composition are of basanitc and alkali rhyolitic composition (at the limit of the trachyte field) according to the TAS classification. Such rhyolitic compositions are rare in the Canaries. Analyses of residual volatile concentration in the glasses show that the silicic glass is highly degassed (F: 511 ±222; Cl: 202 ±58; S: below detection limit; values in ppm,1SD, n=10), whereas the basanitic glass still has very high halogene concentrations (F: 1354 ±151; Cl: 1026 ±47; S: 362 ±29; 1SD, n=10). In-situ analysis of trace element compositions of the dark glasses reveal typical basanitic compositions with elevated incompatible element concentrations and primitive mantle normalised spectra characteristic for the Canary Island basanites (e.g. La is of 100 times higher concentration than primitive mantle with important LREE enrichments). In contrast, the trace element composition of the alkali rhyolite shows surprisingly low concentrations for all elements except the most incompatible ones (such as Rb, Ba, K and Th). All other measured incompatible LILE, HFSE and REE have significantly lower concentration than the basanitic counterpart. This differences increase with the atomic number of the REE reaching maximum for the MREE and thus forming an intriguing U-shaped rhyolite spectra. Furthermore, unusual U-depletion is observed in the rhyolite. Other negative spikes, such as those for Sr and P, are readily accounted for by the removal of plagioclase and apatite during magma evolution from a basanite to a more evolved melt. The results obtained so far suggest an intrusion of gas-rich basanitic melt at the base of an evolved intrusion remobilising a stagnant phonolitic melt present as late differentiate in the crust. Interaction with old oceanic crust and the volcanic edifice can be quantified and shown to have modified the phonolite melt composition and produced the alkali rhyolitic composition of the white floating pumice. Extensive gas exsolution shortly before the melt-glass transition explains the foam texture and the low volatile concentrations in the quenched alkali rhyolite.