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Concentrating Solar Power | NREL Gemasolar Thermosolar Plant This page provides information on Gemasolar Thermosolar Plant, a concentrating solar power (CSP) project, with data organized by background , participants, and power plant configuration. Gemasolar is the first high-temperature solar receiver with molten

Understanding how roadside concentrations of NOx are influenced by the background levels, traffic density, and meteorological conditions using Boosted Regression Trees

NASA Astrophysics Data System (ADS)

Sayegh, Arwa; Tate, James E.; Ropkins, Karl

2016-02-01

Oxides of Nitrogen (NOx) is a major component of photochemical smog and its constituents are considered principal traffic-related pollutants affecting human health. This study investigates the influence of background concentrations of NOx, traffic density, and prevailing meteorological conditions on roadside concentrations of NOx at UK urban, open motorway, and motorway tunnel sites using the statistical approach Boosted Regression Trees (BRT). BRT models have been fitted using hourly concentration, traffic, and meteorological data for each site. The models predict, rank, and visualise the relationship between model variables and roadside NOx concentrations. A strong relationship between roadside NOx and monitored local background concentrations is demonstrated. Relationships between roadside NOx and other model variables have been shown to be strongly influenced by the quality and resolution of background concentrations of NOx, i.e. if it were based on monitored data or modelled prediction. The paper proposes a direct method of using site-specific fundamental diagrams for splitting traffic data into four traffic states: free-flow, busy-flow, congested, and severely congested. Using BRT models, the density of traffic (vehicles per kilometre) was observed to have a proportional influence on the concentrations of roadside NOx, with different fitted regression line slopes for the different traffic states. When other influences are conditioned out, the relationship between roadside concentrations and ambient air temperature suggests NOx concentrations reach a minimum at around 22 °C with high concentrations at low ambient air temperatures which could be associated to restricted atmospheric dispersion and/or to changes in road traffic exhaust emission characteristics at low ambient air temperatures. This paper uses BRT models to study how different critical factors, and their relative importance, influence the variation of roadside NOx concentrations. The paper highlights the importance of either setting up local background continuous monitors or improving the quality and resolution of modelled UK background maps and the need to further investigate the influence of ambient air temperature on NOx emissions and roadside NOx concentrations.

Soil contamination in the impact zone of mining enterprises in the Bashkir Transural region

NASA Astrophysics Data System (ADS)

Opekunova, M. G.; Somov, V. V.; Papyan, E. E.

2017-06-01

The results of long-term studies of the contents of bulk forms of metals (Cu, Zn, Fe, Ni, Pb, Mn, Co, and Cd) and their mobile compounds in soils of background and human-disturbed areas within the Krasnoural'sk-Sibai-Gai copper-zinc and Baimak-Buribai mixed copper mineralization zones in the Bashkir Transural region are discussed. It is shown that soils of the region are characterized by abnormally high natural total contents of heavy metals (HMs) typomorphic for ore mineralization: Cu, Zn, and Fe for the Sibai province and Cu, Zn, and Ni for the Baimak province. In the case of a shallow depth of the ores, the concentrations of HMs in the soils are close to or higher than the tentative permissible concentration values. The concentrations of mobile HM compounds in soils of background areas and their percentage in the total HM content strongly vary from year to year in dependence on weather conditions, position in the soil catenas, species composition of vegetation, and distance from the source of technogenic contamination. The high natural variability in the content of mobile HM compounds in soils complicates the reliable determination of the regional geochemical background and necessitates annual estimation of background parameters for the purposes of the ecological monitoring of soils. The bulk content of Cu and Zn content in soils near mining enterprises exceeds the regional geochemical background values by 2-12 times and the tentative permissible concentrations of these metals by 2-4 times. Anthropogenic contamination results in a sharp rise in the content of mobile HM compounds in soils. Their highest concentrations exceed the maximum permissible concentrations by 26 times for Cu, 18 times for Zn, and 2 times for Pb. Soil contamination in the impact zone of mining enterprises is extremely dangerous or dangerous. However, because of the high temporal variability in the migration and accumulation of HMs in the soils, the recent decline in the ore mining activities, and the construction of purification facilities, no definite temporal trends in the contents of HMs in the soils have been found in the studied region for the period from 1998 to 2015.

Trends of NOx, NO2 and O3 concentrations at three different types of air quality monitoring stations in Athens, Greece

NASA Astrophysics Data System (ADS)

Mavroidis, I.; Ilia, M.

2012-12-01

This work presents a systematic analysis and evaluation of the historic and current levels of atmospheric pollution in the Athens metropolitan region, regarding nitrogen oxides (NOx = NO + NO2), ozone (O3) and the NO2/NOx and NO/NO2 concentration ratios. Hourly, daily, monthly, seasonal and annual pollutant variations are examined and compared, using the results of concentration time series from three different stations of the national network for air pollution monitoring, one urban-traffic, one urban-background and one suburban-background. Concentration data are also related to meteorological parameters. The results show that the traffic affected station of Patission Street presents the higher NOx values and the lower concentrations of O3, while it is the station with the highest number of NO2 limit exceedances. The monitoring data suggest, inter alia, that there is a change in the behaviour of the suburban-background station of Liossia at about year 2000, indicating that the exact location of this station may need to be reconsidered. Comparison of NOx concentrations in Athens with concentrations in urban areas of other countries reveal that the Patission urban-traffic station records very high NOx concentrations, while remarkably high is the ratio of NO2 concentrations recorded at the urban-traffic vs. the urban-background station in Athens, indicating the overarching role of vehicles and traffic congestion on NO2 formation. The NO2/NOx ratio in the urban-traffic station appears to be almost constant with time, while it has been increasing in other urban areas, such as London and Seoul, suggesting an increased effect of primary NO2 in these areas. Diesel passenger cars were only recently allowed in Athens and, therefore, NO2 trends should be carefully monitored since a possible increase in primary NO2 may affect compliance with NO2 air quality standards.

Multisite study of particle number concentrations in urban air.

PubMed

Harrison, Roy M; Jones, Alan M

2005-08-15

Particle number concentration data are reported from a total of eight urban site locations in the United Kingdom. Of these, six are central urban background sites, while one is an urban street canyon (Marylebone Road) and another is influenced by both a motorway and a steelworks (Port Talbot). The concentrations are generally of a similar order to those reported in the literature, although higher than those in some of the other studies. Highest concentrations are at the Marylebone Road site and lowest are at the Port Talbot site. The central urban background locations lie somewhere between with concentrations typically around 20 000 cm(-3). A seasonal pattern affects all sites, with highest concentrations in the winter months and lowest concentrations in the summer. Data from all sites show a diurnal variation with a morning rush hour peak typical of an anthropogenic pollutant. When the dilution effects of windspeed are accounted for, the data show little directionality at the central urban background sites indicating the influence of sources from all directions as might be expected if the major source were road traffic. At the London Marylebone Road site there is high directionality driven by the air circulation in the street canyon, and at the Port Talbot site different diurnal patterns are seen for particle number count and PM10 influenced by emissions from road traffic (particle number count) and the steelworks (PM10) and local meteorological factors. Hourly particle number concentrations are generally only weakly correlated to NO(x) and PM10, with the former showing a slightly closer relationship. Correlations between daily average particle number count and PM10 were also weak. Episodes of high PM10 concentration in summer typically show low particle number concentrations consistent with transport of accumulation mode secondary aerosol, while winter episodes are frequently associated with high PM10 and particle number count arising from poor dispersion of local primary emissions.

Recovery of intrinsic fluorescence from single-point interstitial measurements for quantification of doxorubicin concentration.

PubMed

Baran, Timothy M; Foster, Thomas H

2013-10-01

We developed a method for the recovery of intrinsic fluorescence from single-point measurements in highly scattering and absorbing samples without a priori knowledge of the sample optical properties. The goal of the study was to demonstrate accurate recovery of fluorophore concentration in samples with widely varying background optical properties, while simultaneously recovering the optical properties. Tissue-simulating phantoms containing doxorubicin, MnTPPS, and Intralipid-20% were created, and fluorescence measurements were performed using a single isotropic probe. The resulting spectra were analyzed using a forward-adjoint fluorescence model in order to recover the fluorophore concentration and background optical properties. We demonstrated recovery of doxorubicin concentration with a mean error of 11.8%. The concentration of the background absorber was recovered with an average error of 23.2% and the scattering spectrum was recovered with a mean error of 19.8%. This method will allow for the determination of local concentrations of fluorescent drugs, such as doxorubicin, from minimally invasive fluorescence measurements. This is particularly interesting in the context of transarterial chemoembolization (TACE) treatment of liver cancer. © 2013 Wiley Periodicals, Inc.

Selenium metabolites in urine of cancer patients receiving L-selenomethionine at high doses

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

Kuehnelt, Doris; Juresa, Dijana; Francesconi, Kevin A.

2007-04-15

We investigated, with quantitative HPLC/mass spectrometry, the selenium metabolites in urine from five cancer patients receiving high doses of L-selenomethionine over an extended period (2 x 4000 {mu}g Se/day for 7 days, then 4000 {mu}g Se/day for 21 days) as an adjunct to their normal cancer chemotherapy. Urine samples were collected at day 0 (all 5 patients), and at 2-3 additional collection times ranging from 1 to 33 days. The background selenium concentrations ranged from 12 to 55 {mu}g Se/L and increased to 870 to 4420 {mu}g Se/L for the five patients during the study. All five patients had appreciablemore » levels of selenosugars in their background urine sample, and the concentrations increased dramatically after selenium intake. Trimethylselenonium ion (TMSe), on the other hand, was generally present as only a trace metabolite in background urine, and, although the concentration of TMSe increased following selenium exposure, it became a less significant proportion relative to selenosugars. These data refute the currently accepted role of TMSe as the preferred excretion metabolite when selenium exposure is high.« less

Mapping the Life Satisfaction of Adolescents in Hong Kong Secondary Schools with High Ethnic Concentration

ERIC Educational Resources Information Center

Yuen, Yuet Mui Celeste; Lee, Moosung

2016-01-01

The present study aims to map the life satisfaction of adolescents from ethnic minority/immigrant backgrounds in schools with high concentrations of co-ethnic peers by comparing them with their mainstream counterparts in Hong Kong. The life satisfaction of 1,522 students was measured by the validated Multidimensional Students' Life Satisfaction…

Background contamination by coplanar polychlorinated biphenyls (PCBs) in trace level high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) analytical procedures.

PubMed

Ferrario, J; Byrne, C; Dupuy, A E

1997-06-01

The addition of the "dioxin-like" polychlorinated biphenyl (PCB) congeners to the assessment of risk associated with the 2,3,7,8-chlorine substituted dioxins and furans has dramatically increased the number of laboratories worldwide that are developing analytical procedures for their detection and quantitation. Most of these procedures are based on established sample preparation and analytical techniques employing high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS), which are used for the analyses of dioxin/furans at low parts-per-trillion (ppt) levels. A significant and widespread problem that arises when using these sample preparation procedures for the analysis of coplanar PCBs is the presence of background levels of these congeners. Industrial processes, urban incineration, leaking electrical transformers, hazardous waste accidents, and improper waste disposal practices have released appreciable quantities of PCBs into the environment. This contamination has resulted in the global distribution of these compounds via the atmosphere and their ubiquitous presence in ambient air. The background presence of these compounds in method blanks must be addressed when determining the exact concentrations of these and other congeners in environmental samples. In this study reliable procedures were developed to accurately define these background levels and assess their variability over the course of the study. The background subtraction procedures developed and employed increase the probability that the values reported accurately represent the concentrations found in the samples and were not biased due to this background contamination.

Background contamination by coplanar polychlorinated biphenyls (PCBs) in trace level high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) analytical procedures

NASA Technical Reports Server (NTRS)

Ferrario, J.; Byrne, C.; Dupuy, A. E. Jr

1997-01-01

The addition of the "dioxin-like" polychlorinated biphenyl (PCB) congeners to the assessment of risk associated with the 2,3,7,8-chlorine substituted dioxins and furans has dramatically increased the number of laboratories worldwide that are developing analytical procedures for their detection and quantitation. Most of these procedures are based on established sample preparation and analytical techniques employing high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS), which are used for the analyses of dioxin/furans at low parts-per-trillion (ppt) levels. A significant and widespread problem that arises when using these sample preparation procedures for the analysis of coplanar PCBs is the presence of background levels of these congeners. Industrial processes, urban incineration, leaking electrical transformers, hazardous waste accidents, and improper waste disposal practices have released appreciable quantities of PCBs into the environment. This contamination has resulted in the global distribution of these compounds via the atmosphere and their ubiquitous presence in ambient air. The background presence of these compounds in method blanks must be addressed when determining the exact concentrations of these and other congeners in environmental samples. In this study reliable procedures were developed to accurately define these background levels and assess their variability over the course of the study. The background subtraction procedures developed and employed increase the probability that the values reported accurately represent the concentrations found in the samples and were not biased due to this background contamination.

Long term assessment of air quality from a background station on the Malaysian Peninsula.

PubMed

Latif, Mohd Talib; Dominick, Doreena; Ahamad, Fatimah; Khan, Md Firoz; Juneng, Liew; Hamzah, Firdaus Mohamad; Nadzir, Mohd Shahrul Mohd

2014-06-01

Rural background stations provide insight into seasonal variations in pollutant concentrations and allow for comparisons to be made with stations closer to anthropogenic emissions. In Malaysia, the designated background station is located in Jerantut, Pahang. A fifteen-year data set focusing on ten major air pollutants and four meteorological variables from this station were analysed. Diurnal, monthly and yearly pollutant concentrations were derived from hourly continuous monitoring data. Statistical methods employed included principal component regression (PCR) and sensitivity analysis. Although only one of the yearly concentrations of the pollutants studied exceeded national and World Health Organisation (WHO) guideline standards, namely PM10, seven of the pollutants (NO, NO2, NOx, O3, PM10, THC and CH4) showed a positive upward trend over the 15-year period. High concentrations of PM10 were recorded during severe haze episodes in this region. Whilst, monthly concentrations of most air pollutants, such as: PM10, O3, NOx, NO2, CO and NmHC were recorded at higher concentrations between June and September, during the southwest monsoon. Such results correspond with the mid-range transport of pollutants from more urbanised and industrial areas. Diurnal patterns, rationed between major air pollutants and sensitivity analysis, indicate the influence of local traffic emissions on air quality at the Jerantut background station. Although the pollutant concentrations have not shown a rapid increase, an alternative background station will need to be assigned within the next decade if development projects in the surrounding area are not halted. Copyright © 2014 Elsevier B.V. All rights reserved.

Correlations of particle number concentrations and metals with nitrogen oxides and other traffic-related air pollutants in Glasgow and London

NASA Astrophysics Data System (ADS)

Sánchez Jiménez, Araceli; Heal, Mathew R.; Beverland, Iain J.

2012-07-01

Particle number concentration (PNC) and transition metal content are implicated in the health effects of airborne particulate matter (PM) but they are difficult to measure so consequently their temporal and spatial variations are not well characterized. Daily concentrations of PNC and particle-bound water-soluble metals (V, Cr, Mn, Fe, Ni, Cu, As, Cd and Pb) were measured at background and kerbside sites in Glasgow and London to examine if other metrics of air pollution such as optical darkness (absorbance) of collected filter samples of PM, gravimetric PM, and NO, NO2 and CO gas concentrations, can be used as surrogates for the temporal and spatial variations of the former. NO2 and NOx exhibited a high degree of within-site correlation and with PNC and water-soluble metals (Fe, Cu, As, Cd, Pb) at background sites in both cities. There is therefore potential to use NO2 and NOx as surrogates for PNC and water-soluble metal at background sites. However, correlation was weaker in complex street canyon environments where pollutant concentrations are strongly affected by local sources and the small-scale variations in pollutant dispersion induced by the wind regimes within street canyons. The corollary of the high correlation between NO2 and PNC and water-soluble metals at the background sites is that the latter pollutants may act as confounders for health effects attributed to NO2 from such sites. Concentrations of CO cannot be used as a surrogate for PNC. Increments in daily NOx and NO2 concentrations between trafficked and background sites were shown to be a simple and novel surrogate for daily spatial variation of PNC; for example, increments in NOx explained 78-79% of the variance in PNC at the paired sites in both Glasgow and London, but relationships were city specific. The increments in NOx also explained 70% of the spatial variation in Cu and Ni in Glasgow but not in London. Weekly NO2 measurements derived from passive diffusion tubes were also shown to correlate well with increments in PNC. A high temporal correlation between PNC and 1,3-butadiene and benzene (which can also be measured by passive sampler) implies that passive sampler measurements may be a straightforward tool for deriving long-term spatial patterns in PNC.

[Effect of a high fat or high carbohydrate breakfast on postprandial lipid profile in healthy subjects with or without family history of type 2 diabetes mellitus].

PubMed

González-Ortiz, Manuel; Balcázar-Muñoz, Blanca R; Mora-Martínez, José M; Martínez-Abundis, Esperanza

2004-09-01

The objective of this study was to evaluate the effect of a high fat or high carbohydrate breakfast on postprandial lipid profile in healthy subjects with or without family history of type 2 diabetes mellitus. A single blind, controlled clinical trial with parallel groups was performed in 20 healthy subjects; 10 subjects with family history of type 2 diabetes mellitus and 10 individuals without that background. Each group was randomized to receive a high fat or high carbohidrate breakfast. A metabolic profile that included fasting and postprandial lipids, as well as, the assessment of insulin sensitivity were performed. Lower high-lipoprotein cholesterol (p < 0.02) and apolipoprotein A1 (p < 0.03) concentrations were found in subjects with family history of type 2 diabetes mellitus than those without that background. In this same above mentioned group with the high carbohydrate breakfast, there were significant increments in apoliprotein B at minute 300 (p < 0.03) and in triglycerides at minute 360 (p < 0.03). In the group without family history of diabetes that received the high fat breakfast, there were increments in triglycerides (p < 0.03) and very-low density lipoprotein concentrations at minute 180 (p < 0.03). In conclusion, healthy subjects with family history of type 2 diabetes showed some atherogenic characteristics in their metabolic profile, and the high carbohydrate breakfast produced in them increments in apolipoprotein B and in triglycerides, meanwhile that, in those subjects without such background the high fast breakfast produced unfavorable effects on their lipid concentrations.

The impact of background organic matter and alkalinity on the degradation of the pesticide metaldehyde by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂.

PubMed

Autin, Olivier; Hart, Julie; Jarvis, Peter; MacAdam, Jitka; Parsons, Simon A; Jefferson, Bruce

2013-04-15

The impact of background constituents on the degradation of trace levels of micropollutants by two advanced oxidation processes: UV/H₂O₂ and UV/TiO₂ was studied. Experimental results demonstrated that the background scavenging rate rather than the concentration of micropollutant controls the required UV irradiation dose. The character of the natural organic matter had a limited impact on scavenging when the water source remains unchanged, however, a periodic bleed of hydrophobic material may substantially increase the minimum UV dose required to reach the desired micropollutant concentration. Moreover, in the case of UV/TiO₂, high concentrations of background organic matter do not only act as scavengers but also saturate the TiO₂ surface. Alkalinity inhibits the efficacy of UV/TiO₂ photocatalysis due to the formation of large TiO₂ aggregates. The study also demonstrated that the use of synthetic waters for treatability test purposes was an acceptable approach as long as both the background organic matter and the alkalinity were matched to that of the projected application. Finally spiking micropollutants at higher concentrations does not alter the significance of the findings as long as the background constituents represent more than 85% of the total scavenging rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Thyroid nodularity and chromosome aberrations among women in areas of high background radiation in China

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

Wang, Z.Y.; Boice, J.D. Jr.; Wei, L.X.

1990-03-21

Thyroid nodularity following continuous low-dose radiation exposure in China was determined in 1,001 women aged 50-65 years who resided in areas of high background radiation (330 mR/yr) their entire lives, and in 1,005 comparison subjects exposed to normal levels of radiation (114 mR/yr). Cumulative doses to the thyroid were estimated to be of the order of 14 cGy and 5 cGy, respectively. Personal interviews and physical examinations were conducted, and measurements were made of serum thyroid hormone levels, urinary iodine concentrations, and chromosome aberrations in circulating lymphocytes. For all nodular disease, the prevalences in the high background and control areasmore » were 9.5% and 9.3%, respectively. For single nodules, the prevalences were 7.4% in the high background area and 6.6% in the control area (prevalence ratio = 1.13; 95% confidence interval = 0.82-1.55). There were no differences found in serum levels of thyroid hormones. Women in the high background region, however, had significantly lower concentrations of urinary iodine and significantly higher frequencies of stable and unstable chromosome aberrations. Increased intake of allium vegetables such as garlic and onions was associated with a decreased risk of nodular disease, which seems consistent with experimental studies suggesting that allium compounds can inhibit tumor growth and proliferation. The prevalence of mild diffuse goiter was higher in the high background radiation region, perhaps related to a low dietary intake of iodine. These data suggest that continuous exposure to low-level radiation throughout life is unlikely to appreciably increase the risk of thyroid cancer. However, such exposure may cause chromosomal damage.« less

Watershed-scale assessment of background concentrations and guidance values for heavy metals in soils from a semiarid and coastal zone of Brazil.

PubMed

da Silva, Yuri Jacques Agra Bezerra; do Nascimento, Clístenes Williams Araújo; Cantalice, José Ramon Barros; da Silva, Ygor Jacques Agra Bezerra; Cruz, Cinthia Maria Cordeiro Atanázio

2015-09-01

Determining heavy metal background concentrations in soils is fundamental in order to support the monitoring of potentially contaminated areas. This is particularly important to areas submitted to high environmental impact where an intensive and local monitoring is required. To this end, the aim of this study was to establish background concentrations and quality reference values (QRVs) for the heavy metals Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, As, and Hg in an environmentally impacted watershed from Brazil. Geochemical associations among Fe, Mn, and trace elements were also assessed to provide an alternative tool for establishing background concentrations. A total of one hundred and four samples comprised twenty-six composite soil samples from areas of native forest or minimal anthropic influence. Samples were digested (USEPA method 3051A), and the metals were determined by ICP-OES, except for As and Hg measured by atomic absorption spectrophotometer. Background concentrations of heavy metals in soils had the following decreasing order: Fe > Mn > Zn > Cr > Pb > Ni > Cu > As > Cd > Hg. These values were usually lower than those observed in the international and national literature. The QRVs for Ipojuca watershed followed the order (mg kg(-1)) Fe (13,020.40) > Mn (91.80) > Zn (30.12) > Cr (15.00) > Pb (13.12) > Cu (3.53) > Ni (3.30) > As (0.51) > Cd (0.08) > Hg (0.04). Significant correlation among Fe, Mn, and heavy metals shows that solubilization by the method 3051A provides a reasonable estimate for predicting background concentrations for Cd, Cr, and Cu as well as Zn, Cr, Cu, and Ni.

Using exterior building surface films to assess human exposure and health risks from PCDD/Fs in New York City, USA, after the World Trade Center attacks.

PubMed

Rayne, Sierra

2005-12-09

Concentrations of tetra- through octa-chlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in exterior window films from Manhattan and Brooklyn in New York City (NYC), USA, 6 weeks after the World Trade Center (WTC) attacks of 11 September 2001. High concentrations of the 2,3,7,8-substituted congeners (P(2378)CDD/Fs) were observed, at levels up to 6600 pg-TEQ g(-1) nearest the WTC site. An equilibrium partitioning model was developed to reconstruct total gas + particle-phase atmospheric concentrations of P(2378)CDD/Fs at each site. The reconstructed atmospheric and window film concentrations were subsequently used in a preliminary human health risk assessment to estimate the potential cancer and non-cancer risks posed to residents of lower Manhattan from these contaminants over the 6 week exposure period between the WTC attacks and sampling dates. Residents of lower Manhattan appear to have a slightly elevated cancer risk (up to 1.6% increase over background) and increased P(2378)CDD/F body burden (up to 8.0% increase over background) because of above-background exposure to high concentrations of P(2378)CDD/Fs produced from the WTC attacks during the short period between 11 September 2001, and window film sampling 6 weeks later.

Long open-path TDL based system for monitoring the background concentration for deployment at Jungfraujoch High Altitude Research Station- Switzerland

NASA Astrophysics Data System (ADS)

Simeonov, V.; van den Bergh, H.; Parlange, M. B.

2009-12-01

A new long-open-path instrument developed at EPFL for methane and water vapor observation will be presented. The instrument is developed and will be used within the GAW+ CH program and aims at long-term monitoring of background methane concentration at the High Altitude Research Station Jungfraujoch (3580 mASL). The instrument is built on the monostatic scheme (transceiver -distant retroreflector) using a 1.65 nm tunable diode laser (TDL) and a retroreflector at 1200 m from the transceiver. The data will be compared with in-situ measurements to evaluate the effect of the station on the in-situ data.

Investigating high concentrations of three greenhouse gases in the Los Angeles Basin and San Bernardino Valley

NASA Astrophysics Data System (ADS)

Kirpes, R.; Blake, D. R.; Marrero, J.

2013-12-01

Following the Montreal Protocol of 1987 calling for the phase-out of CFCs and other ozone depleting substances, HCFCs and HFCs were introduced as alternatives despite still being greenhouse gases with high global warming potentials. In this study, whole air samples were collected during four research flights over Southern California aboard the NASA DC-8 Airborne Science Laboratory as part of the NASA Student Airborne Science Program. These samples were then analyzed by gas chromatography using a suite of detectors for many compounds, including HFC-134a, HCFC-22, and HFC-152a. HCFC-22 is primarily used as a refrigerant, while HFC-134a and HFC-152a are also used as aerosol propellants and foam blowing agents. High concentrations of these three compounds were observed for samples taken at low altitudes over urban areas around Los Angeles and San Bernardino. Exceptionally high concentrations were seen for all three compounds in samples taken near the Ontario and San Bernardino airports. Concentrations of HFC-134a, HCFC-22, and HFC-152a were enhanced above background levels near other airports sampled in the Los Angeles Basin and San Bernardino Valley. It is clear that concentrations of these three gases are higher in the San Bernardino Valley than in the Los Angeles Basin, and locations with exceptionally high concentrations were investigated to identify potential point sources. Concentrations of these three compounds were also compared to data from past SARP missions and data collected at Trinidad Head, California since 2005 as part of the AGAGE network. Comparison of the average values for each of these campaigns reveal that the background concentrations of HFC-134a, HCFC-22, and HFC-152a are all increasing with a strong linear trend in Southern California.

[Characteristics of atmospheric NO2 in the Beijing-Tianjin-Hebei region and the Yangtze River Delta analyzed by satellite and ground observations].

PubMed

Wang, Ying; Li, Ling-Jun; Liu, Yang

2012-11-01

The interannual variability of NO2 levels in two major Chinese economic regions, the Beijing-Tianjin-Hebei (BTH) economic circle and the Yangtze River Delta (YRD), were studied using multiple years of OMI-retrieved NO2 columns and ground measurements. The NO2 columns were comparable in the two regions, which were - 50% higher than the BTH and YRD regional background and two times higher than the Asia-Europe continental background. Satellite data showed that the high NO2 regions scattered around Beijing and Shanghai in summer, and the coverage of high NO2 regions increased in spring and merged in winter, affecting the entire eastern China. Ground level NO2 concentrations in the urban centers of Beijing and Shanghai were also comparable, which were - 10 times greater than the regional background and 1 000 times higher than the Asia-Europe continental background. As industries gradually migrated out of the urban centers, the NO2 concentrations in Beijing and Shanghai decreased, but the regional background NO2 concentration in BTH and YRD increased. It reflected in part the impact of NO2 emission reductions related to fossil fuel combustion as a result of air quality control measures in BTH and YRD. NO2 levels during the Beijing 2008 Olympic Games and the Shanghai World Expo 2010 decreased temporarily, but bounced back quickly afterwards, indicating that sustainable air quality improvement can only be achieved through long-term regional efforts.

Factors influencing the spatial extent of mobile source air pollution impacts: a meta-analysis

PubMed Central

Zhou, Ying; Levy, Jonathan I

2007-01-01

Background There has been growing interest among exposure assessors, epidemiologists, and policymakers in the concept of "hot spots", or more broadly, the "spatial extent" of impacts from traffic-related air pollutants. This review attempts to quantitatively synthesize findings about the spatial extent under various circumstances. Methods We include both the peer-reviewed literature and government reports, and focus on four significant air pollutants: carbon monoxide, benzene, nitrogen oxides, and particulate matter (including both ultrafine particle counts and fine particle mass). From the identified studies, we extracted information about significant factors that would be hypothesized to influence the spatial extent within the study, such as the study type (e.g., monitoring, air dispersion modeling, GIS-based epidemiological studies), focus on concentrations or health risks, pollutant under study, background concentration, emission rate, and meteorological factors, as well as the study's implicit or explicit definition of spatial extent. We supplement this meta-analysis with results from some illustrative atmospheric dispersion modeling. Results We found that pollutant characteristics and background concentrations best explained variability in previously published spatial extent estimates, with a modifying influence of local meteorology, once some extreme values based on health risk estimates were removed from the analysis. As hypothesized, inert pollutants with high background concentrations had the largest spatial extent (often demonstrating no significant gradient), and pollutants formed in near-source chemical reactions (e.g., nitrogen dioxide) had a larger spatial extent than pollutants depleted in near-source chemical reactions or removed through coagulation processes (e.g., nitrogen oxide and ultrafine particles). Our illustrative dispersion model illustrated the complex interplay of spatial extent definitions, emission rates, background concentrations, and meteorological conditions on spatial extent estimates even for non-reactive pollutants. Our findings indicate that, provided that a health risk threshold is not imposed, the spatial extent of impact for mobile sources reviewed in this study is on the order of 100–400 m for elemental carbon or particulate matter mass concentration (excluding background concentration), 200–500 m for nitrogen dioxide and 100–300 m for ultrafine particle counts. Conclusion First, to allow for meaningful comparisons across studies, it is important to state the definition of spatial extent explicitly, including the comparison method, threshold values, and whether background concentration is included. Second, the observation that the spatial extent is generally within a few hundred meters for highway or city roads demonstrates the need for high resolution modeling near the source. Finally, our findings emphasize that policymakers should be able to develop reasonable estimates of the "zone of influence" of mobile sources, provided that they can clarify the pollutant of concern, the general site characteristics, and the underlying definition of spatial extent that they wish to utilize. PMID:17519039

Multiple factors impact the contents of heavy metals in vegetables in high natural background area of China.

PubMed

Gan, Yandong; Wang, Lihong; Yang, Guiqiang; Dai, Jiulan; Wang, Renqing; Wang, Wenxing

2017-10-01

A field survey was conducted to investigate the concentrations of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in vegetables, corresponding cultivated soils and irrigation waters from 36 open sites in high natural background area of Wuzhou, South China. Redundancy analysis, Spearman's rho correlation analysis and multiple regression analysis were adopted to evaluate the contributions of impacting factors on metal contents in the edible parts of vegetables. This study concluded that leafy and root vegetables had relatively higher metal concentrations and adjusted transfer factor values compared to fruiting vegetables according to nonparametric tests. Plant species, total soil metal content and soil pH value were affirmed as three critical factors with the highest contribution rate among all the influencing factors. The bivariate curve equation models for heavy metals in the edible vegetable tissues were well fitted to predict the metal concentrations in vegetables. The results from this case study also suggested that it could be one of efficient strategies for clean agricultural production and food safety in high natural background area to breed vegetable varieties with low heavy metal accumulation and to enlarge planting scale of these varieties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemical characteristics of urban stormwater sediments and implications for environmental management, Maricopa County, Arizona

USGS Publications Warehouse

Parker, J.T.C.; Fossum, K.D.; Ingersoll, T.L.

2000-01-01

Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.Investigations of the chemical characteristics of urban stormwater sediments in the rapidly growing Phoenix metropolitan area of Maricopa County, Arizona, showed that the inorganic component of these sediments generally reflects geologic background values. Some concentrations of metals were above background values, especially cadmium, copper, lead, and zinc, indicating an anthropogenic contribution of these elements to the sediment chemistry. Concentrations, however, were not at levels that would require soil remediation according to guidelines of the U.S. Environmental Protection Agency. Arsenic concentrations generally were above recommended values for remediation at a few sites, but these concentrations seem to reflect geologic rather than anthropogenic factors. Several organochlorine compounds no longer in use were ubiquitous in the Phoenix area, although concentrations generally were low. Chlordane, DDT and its decay products DDE and DDD, dieldrin, toxaphene, and PCBs were found at almost all sites sampled, although some of the pesticides in which these compounds are found have been banned for almost 30 years. A few sites showed exceptionally high concentrations of organochlorine compounds. On the basis of published guidelines, urban stormwater sediments do not appear to constitute a major regional environmental problem with respect to the chemical characteristics investigated here. At individual sites, high concentrations of organic compounds - chlordane, dieldrin, PCBs, and toxaphene - may require some attention. The possible environmental hazard presented by low-level organochlorine contamination is not addressed in this paper; however, high levels of toxicity in urban sediments are difficult to explain. Sediment toxicity varied significantly with time, which indicates that these tests should be evaluated carefully before they are used for management decisions.

Fluorescence lifetime correlation spectroscopy for precise concentration detection in vivo by background subtraction

NASA Astrophysics Data System (ADS)

Gärtner, Maria; Mütze, Jörg; Ohrt, Thomas; Schwille, Petra

2009-07-01

In vivo studies of single molecule dynamics by means of Fluorescence correlation spectroscopy can suffer from high background. Fluorescence lifetime correlation spectroscopy provides a tool to distinguish between signal and unwanted contributions via lifetime separation. By studying the motion of the RNA-induced silencing complex (RISC) within two compartments of a human cell, the nucleus and the cytoplasm, we observed clear differences in concentration as well as mobility of the protein complex between those two locations. Especially in the nucleus, where the fluorescence signal is very weak, a correction for background is crucial to provide reliable results of the particle number. Utilizing the fluorescent lifetime of the different contributions, we show that it is possible to distinguish between the fluorescent signal and the autofluorescent background in vivo in a single measurement.

Monitoring In Vivo Changes in Tonic Extracellular Dopamine Level by Charge-Balancing Multiple Waveform Fast-Scan Cyclic Voltammetry.

PubMed

Oh, Yoonbae; Park, Cheonho; Kim, Do Hyoung; Shin, Hojin; Kang, Yu Min; DeWaele, Mark; Lee, Jeyeon; Min, Hoon-Ki; Blaha, Charles D; Bennet, Kevin E; Kim, In Young; Lee, Kendall H; Jang, Dong Pyo

2016-11-15

Dopamine (DA) modulates central neuronal activity through both phasic (second to second) and tonic (minutes to hours) terminal release. Conventional fast-scan cyclic voltammetry (FSCV), in combination with carbon fiber microelectrodes, has been used to measure phasic DA release in vivo by adopting a background subtraction procedure to remove background capacitive currents. However, measuring tonic changes in DA concentrations using conventional FSCV has been difficult because background capacitive currents are inherently unstable over long recording periods. To measure tonic changes in DA concentrations over several hours, we applied a novel charge-balancing multiple waveform FSCV (CBM-FSCV), combined with a dual background subtraction technique, to minimize temporal variations in background capacitive currents. Using this method, in vitro, charge variations from a reference time point were nearly zero for 48 h, whereas with conventional background subtraction, charge variations progressively increased. CBM-FSCV also demonstrated a high selectivity against 3,4-dihydroxyphenylacetic acid and ascorbic acid, two major chemical interferents in the brain, yielding a sensitivity of 85.40 ± 14.30 nA/μM and limit of detection of 5.8 ± 0.9 nM for DA while maintaining selectivity. Recorded in vivo by CBM-FSCV, pharmacological inhibition of DA reuptake (nomifensine) resulted in a 235 ± 60 nM increase in tonic extracellular DA concentrations, while inhibition of DA synthesis (α-methyl-dl-tyrosine) resulted in a 72.5 ± 4.8 nM decrease in DA concentrations over a 2 h period. This study showed that CBM-FSCV may serve as a unique voltammetric technique to monitor relatively slow changes in tonic extracellular DA concentrations in vivo over a prolonged time period.

Heavy Metals in Surface Soils in the Upper Reaches of the Heihe River, Northeastern Tibetan Plateau, China

PubMed Central

Bu, Jianwei; Sun, Ziyong; Zhou, Aiguo; Xu, Youning; Ma, Rui; Wei, Wenhao; Liu, Meng

2016-01-01

The upper reaches of the Heihe River have been regarded as a hotspot for phytoecology, climate change, water resources and hydrology studies. Due to the cold-arid climate, high elevation, remote location and poor traffic conditions, few studies focused on heavy metal contamination of soils have been conducted or reported in this region. In the present study, an investigation was performed to provide information regarding the concentration levels, sources, spatial distributions, and environmental risks of heavy metals in this area for the first time. Fifty-six surface soil samples collected from the study area were analyzed for Cr, Mn, Ni, Cu, Zn, As, Cd and Pb concentrations, as well as TOC levels. Basic statistics, concentration comparisons, correlation coefficient analysis and multivariate analyses coupled with spatial distributions were utilized to delineate the features and the sources of different heavy metals. Risk assessments, including geoaccumulation index, enrichment factor and potential ecological risk index, were also performed. The results indicate that the concentrations of heavy metals have been increasing since the 1990s. The mean values of each metal are all above the average background values in the Qinghai Province, Tibet, China and the world, except for that of Cr. Of special note is the concentration of Cd, which is extremely elevated compared with all background values. The distinguished ore-forming conditions and well-preserved, widely distributed limestones likely contribute to the high Cd concentration. Heavy metals in surface soils in the study area are primarily inherited from parent materials. Nonetheless, anthropogenic activities may have accelerated the process of weathering. Cd presents a high background concentration level and poses a severe environmental risk throughout the whole region. Soils in Yinda, Reshui daban, Kekeli and Zamasheng in particular pose threats to the health of the local population, as well as that of livestock and wildlife. PMID:26907322

Longitudinal study of alcohol consumption and high-density lipoprotein concentrations: A community-based study

USDA-ARS?s Scientific Manuscript database

Background: In cross-sectional studies and short-term clinical trials, it has been suggested that there is a positive dose-response relation between alcohol consumption and HDL concentrations. However, prospective data have been limited. Objective: We sought to determine the association between tota...

Serum selenium concentrations and diabetes in U.S. adults: National Health and Nutrition Examination Survey (NHANES) 2003-2004

USDA-ARS?s Scientific Manuscript database

BACKGROUND: Increasing evidence suggests that high selenium levels are associated with diabetes and other cardiometabolic risk factors. OBJECTIVES: We evaluated the association of serum selenium concentrations with fasting plasma glucose, glycosylated hemoglobin levels, and diabetes in the most rec...

Late-pregnancy salivary cortisol concentrations of Ghanaian women participating in a randomized controlled trial of prenatal lipid-based nutrient supplements

USDA-ARS?s Scientific Manuscript database

Background: High maternal circulating cortisol in pregnancy is associated with miscarriage, preterm birth, and low birth weight. Research in non-pregnant individuals suggests that reducing nutritional deficiencies may lower cortisol concentrations. It is unknown whether nutritional supplementation d...

[PM₂.₅ Background Concentration at Different Directions in Beijing in 2013].

PubMed

Li, Yun-ting; Cheng, Niam-liang; Zhang, Da-wei; Sun, Rui-wen; Dong, Xin; Sun, Nai-di; Chen, Chen

2015-12-01

PM₂.₅, background concentration at different directions in 2013 in Beijing was analyzed combining the techniques of mathematical statistics, physical identification and numerical simulation (CMAQ4.7.1) as well as using monitoring data of six PM₂.₅ auto-monitoring sites and five meteorological sites in 2013. Results showed that background concentrations of PM₂.₅ at northwest, northeast, eastern, southeast, southern and southwest boundary sites were between 40.3 and 85.3 µg · m⁻³ in Beijing. From the lowest to the highest, PMPM₂.₅ background concentrations at different sites were: Miyun reservoir, Badaling, Donggaocun, Yufa, Yongledian and Liulihe. Background concentration of PM₂.₅ was the lowest under north wind, then under west wind, and significantly higher under south and east wind. Calculated PM₂.₅ background average concentrations were 6.5-27.9, 22.4-73.4, 67.2-91.7, 40.7-116.1 µg · m⁻³ respectively in different wind directions. Simulated PM₂.₅ background concentration showed a clear north-south gradient distribution and the surrounding area had a notable effect on the spatial distribution of PM₂.₅ background concentration in 2013 in Beijing.

Characterizing the vertical presence of atmospheric black carbon in the in the high Arctic region from airborne measurements

NASA Astrophysics Data System (ADS)

Schulz, H.; Zanatta, M.; Stefanie, W.; Herber, A. B.

2016-12-01

Black carbon (BC) is an important contributor to climate change in the Arctic region. Due to its light absorption behavior, BC leads to a direct warming of the corresponding aerosol layer. Nevertheless, the net Arctic warming induced by BC strongly depends on its vertical distribution. At present, the low level of knowledge in BC vertical variability in the Arctic region may introduce a strong source of uncertainty in radiative forcing estimations. Vertical distribution of refractory black carbon (rBC) was investigated in spring 2015 during an aircraft campaign, as part of the NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) project. A single particle soot photometer was deployed on the research aircraft POLAR-6 during nine flights over the European and Canadian high Arctic. In the European Arctic, a decreasing vertical trend of rBC mass concentration was observed, with an average of 40 ng m-3 below 1000 m asl, and less than 10 ng m-3 above 3000 m asl. Combining potential temperature trends and number fraction of rBC particles, plume events were isolated from background conditions. At the Canadian site of Alert, low and high altitude background conditions were characterized by an average rBC number fraction below 10%, while higher values (17%) were observed during plume events. rBC mass concentration was found to decrease by a factor of five from low altitude background (27 ng m-3) to high altitude background (5.4 ng m-3). The plume event, located between 2500 and 3000 m asl, represented a discontinuity point in the decreasing vertical trend showing a rBC concentration of 25 ng m-3. Moreover, background conditions were characterized by a rBC mass mean diameter of 230 nm, while during plume events the observed mean size distribution was peaking at 180 nm only. Our work provides new insights on vertical variability of rBC properties and plume outbreaks in the high Arctic. This information is of actual interest for decreasing the high uncertainty of radiative forcing and atmospheric warming estimations in the Arctic region.

Effects of the Bermuda High and the Great Plains low-level jet upon background and peak ozone concentrations in Texas urban areas

NASA Astrophysics Data System (ADS)

Estes, M. J.; Wang, Y.; Lei, R.; Wang, S. C.; Jia, B.

2017-12-01

Previous studies have established that the westward extent of the Bermuda High is strongly linked to the ozone concentrations in Houston. This study examines the linkages between the Bermuda High, the Great Plains low-level jet, background ozone in the eastern half of Texas, and local contributions to peak ozone in Texas urban areas. Analysis of North American Regional Reanalysis (NARR) wind and pressure fields will be used to establish the presence and strength of synoptic-scale weather features, and this information will be used with ozone data from air quality networks to determine the effects upon the seasonal and interannual variations of ozone. Quantification of the effects of large-scale meteorological factors will improve understanding of the causes of ozone variations, including decadal trends in Texas cities.

Single-molecule imaging at high fluorophore concentrations by local activation of dye

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

Geertsema, Hylkje J.; Mangel, Walter F.; Schulte, Aartje C.

Single-molecule fluorescence microscopy is a powerful approach to observe biomolecular interactions with high spatial and temporal resolution. Detecting fluorescent signals from individual, labeled proteins above high levels of background fluorescence remains challenging, however. For this reason, the concentrations of labeled proteins in in vitro assays are often kept low compared to their in vivo concentrations. Here, we present a new fluorescence imaging technique by which single fluorescent molecules can be observed in real time at high, physiologically relevant concentrations. The technique requires a protein and its macromolecular substrate to be labeled each with a different fluorophore. Then, making use ofmore » short-distance energy-transfer mechanisms, the fluorescence from only those proteins bound to their substrate are selectively activated. This approach is demonstrated by labeling a DNA substrate with an intercalating stain, exciting the stain, and using energy transfer from the stain to activate the fluorescence of only those labeled DNA-binding proteins bound to the DNA. Such an experimental design allowed us to observe the sequence-independent interaction of Cy5-labeled interferon-inducible protein 16 (IFI16) with DNA and the sliding via one-dimensional diffusion of Cy5-labeled adenovirus protease (pVIc-AVP) on DNA in the presence of a background of hundreds of nM Cy5 fluorophore.« less

Single-molecule imaging at high fluorophore concentrations by local activation of dye

DOE PAGES

Geertsema, Hylkje J.; Mangel, Walter F.; Schulte, Aartje C.; ...

2015-02-17

Single-molecule fluorescence microscopy is a powerful approach to observe biomolecular interactions with high spatial and temporal resolution. Detecting fluorescent signals from individual, labeled proteins above high levels of background fluorescence remains challenging, however. For this reason, the concentrations of labeled proteins in in vitro assays are often kept low compared to their in vivo concentrations. Here, we present a new fluorescence imaging technique by which single fluorescent molecules can be observed in real time at high, physiologically relevant concentrations. The technique requires a protein and its macromolecular substrate to be labeled each with a different fluorophore. Then, making use ofmore » short-distance energy-transfer mechanisms, the fluorescence from only those proteins bound to their substrate are selectively activated. This approach is demonstrated by labeling a DNA substrate with an intercalating stain, exciting the stain, and using energy transfer from the stain to activate the fluorescence of only those labeled DNA-binding proteins bound to the DNA. Such an experimental design allowed us to observe the sequence-independent interaction of Cy5-labeled interferon-inducible protein 16 (IFI16) with DNA and the sliding via one-dimensional diffusion of Cy5-labeled adenovirus protease (pVIc-AVP) on DNA in the presence of a background of hundreds of nM Cy5 fluorophore.« less

Biomedical aspects of natural and manufactured environmental radioactivity

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

Hodge, V.

1996-12-31

While weapons testing has altered natural radioactivity background, manufactured radioactivity in most parts of the world constitutes but a very small fraction of the total alpha, beta, and gamma radioactivity in soil, air, water, and the biota. For example, in the early 1970s, we found what appeared to be the highest natural concentration of radioactivity ever reported in fish while attempting to measure the manufactured plutonium ({sup 239}Pu and {sup 240}Pu) in organs of oceanic tuna. The natural alpha emitter polonium ({sup 210}Po) was discovered in the same organs at orders of magnitude higher concentrations. In particular, the caecum, whichmore » is a digestive organ composed of many small closed-ended sacs, contained concentrations of polonium as high as 79 pCi/g of wet tissue and lesser amounts of two manufactured isotopes: 0.0001 pCi/g of plutonium and 0.01 pCi/g of radiocesium ({sup 137}Cs). This equates to {approximately}80 rem/yr of radiation dose to this organ, overwhelmingly from the natural polonium, or {approximately}5000 times higher than is found in the human liver, the highest polonium concentration in man. The average background radiation for humans, for comparison, is {approximately}0.2 rem/yr, but the dose for Japanese, whose diet is high in seafood, is {approximately}15 rem/yr. The question arose: {open_quotes}Are these high concentrations of natural polonium limited to oceanic fish?{close_quotes} To answer this question, polonium was determined in the organs of striped bass and catfish from Lake Mead. In a related study, the plutonium and radiocesium ({sup 137}Cs) distributions in soils were determined to ascertain the impact of weapons testing on the natural background radioactivity of soils.« less

Serum PCBs and organochlorine pesticides in Slovakia: age, gender, and residence as determinants of organochlorine concentrations.

PubMed

Petrik, Jan; Drobna, Beata; Pavuk, Marian; Jursa, Stanislav; Wimmerova, Sona; Chovancova, Jana

2006-10-01

We measured organochlorine concentrations of 15 polychlorinated biphenyl congeners and six organochlorine pesticides (PCB28, 52, 101, 123(+149), 118, 114, 153, 105, 138(+163), 167, 156(+171), 157, 180, 170, 189, alpha-, beta-, gamma-HCH, HCB, p,p'-DDT and p,p'-DDE) in 2047 subjects from contaminated and background areas of eastern Slovakia. Data were collected in 2001 and analyzed by high-resolution gas chromatography with electron capture detection in 2002-2003. Elevated levels persist in subjects from Michalovce district, site of former production facility, after almost 20-years since the end of the PCB manufacturing. Sum of 15 PCB congeners was 3105 ng/g of lipid in the Michalovce district versus 871 ng/g of lipid for subjects from the background districts of Svidnik and Stropkov. Relatively high concentration in children from the Michalovce district, sum PCB = 766 ng/g of lipid versus 372 ng/g of lipid in children from background area suggest ongoing exposure from environmental reservoirs and contaminated food. Consistent differences between genders in both contaminated and background areas are reported here. Levels in males are about 20% higher in both districts. Levels of organochlorine pesticides, particularly of DDT metabolite DDE and hexachlorobenzene are also elevated in the Michalovce district, reflecting intensive use of pesticides in agriculture in the past. About 30% decrease in serum organochlorine levels was observed in comparison with our earlier samples collected in 1998. These results suggest that contamination with PCBs still remains a source of relatively high environmental exposure for subjects in the Michalovce district.

Uranium hydrogeochemical and stream sediment reconnaissance of the Cortez NTMS Quadrangle, Colorado/Utah, including concentrations of forty-three additional elements

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

Warren, R.G.

1979-05-01

During the summers of 1976, 1977, and 1978, 598 water and 1657 sediment samples were collected from 1775 locations within the 19,600-km/sup 2/ area of the Cortez Quadrangle, Colorado and Utah. Water samples were collected from streams, springs, and wells; sediment samples were collected from stream channels (wet and dry) and from springs. Each water sample was analyzed for 13 elements, and each sediment sample was analyzed for 43 elements. Uranium concentrations in water samples range from below the detection limit of 0.02 to 241.47 ppB and have a median of 0.87 ppB and a mean of 3.80 ppB. Backgroundmore » uranium concentrations are 2 to 5 ppB in several nonmountainous regions but are much lower in mountainous areas, particularly in the northeastern portion of the quadrangle. Water samples containing high uranium concentrations (>20 ppB) generally are associated with high conductivities, high concentrations of other metallic elements, and geologic units, such as the Mancos shale, that are unfavorable for uranium mineralization. However, four ground-water samples exhibit high uranium concentrations without concomitant high conductivities or high concentrations of other metallic elements. Two of these samples were collected from sites in the Slick Rock U--V district, and two were collected in the Morrison formation in the southern portion of the quadrangle where large uranium deposits are not known. Water samples collected from the northwestern corner of the quadrangle uniformly exhibit background uranium values but generally contain high nickel concentrations. In this area, U--Cu (White Canyon-type) deposits are hosted primarily by the Shinarump member of the Chinle formation. Uranium concentrations in sediment samples range from 0.51 to 76.41 ppM and have a median of 2.76 ppM and a mean of 3.08 ppM. Background uranium and metallic element concentrations decrease to the southwest from the highest values in the northeastern portion of the quadrangle.« less

Local cartography of persistent organic pollutants (PCDD/F, PCB) concentrations in soils of three French departments. How to define background concentrations?

NASA Astrophysics Data System (ADS)

Clozel, Blandine

2017-04-01

As part of the Regional Health Plan for the Rhône-Alpes area (France), a cartography of soil contamination by persistent organic pollutants (dioxins/furans (PCDD/PCDF) and polychlorinated biphenyls (PCB)) was undertaken in order to define the background concentrations of soils located away from point source pollution. In the natural environment, PCDD/PCDF and PCB comes from air pollution and accumulate in the upper part of the soils. To define the background concentration of persistent organic pollutants from diffuse atmospheric origin in soils, sampling was carried out within the first 5 centimeters of soils that have been very little anthropized and untilled for more than 15 years. In such soils mixing and dilution of the pollutants is very limited. 170 samples were collected following a systematic plan of grid type (mesh of 8 x 8 km) in an area of 14 000km2, avoiding soil of high altitude and from urban area. Beyond their total concentration, the ratio of the congeners of PCBs (7 indicators and 12 dioxin-like) and of the 17 dioxins/furans was also used for interpretation. As expected, the concentrations in pollutants are globally lower in the rural zones than in the more industrialized ones. However, the pollutants are relatively enriched in valleys, confirming that the meteorological conditions and the local topography play a significant role in the repartition of the diffuse atmospheric pollution. For the vast majority of samples, even some of those presenting the highest total concentration, the ratio of the various congeners argues for an ancient origin of the contamination. All studies at the French or European level of the atmospheric concentration of organic pollutants indicate a progressive decrease in emissions of these contaminants for about 20 years. However, the soils have been receptors since a long time and such pollutants have accumulated. The congeners ratio give evolved signature of pollution indicating, on one hand, it is mainly due to past activities but, on the other hand, indicate that it will persist because of its high stability. These results show the importance of knowing the spatial distribution of the concentrations of PCDD/PCDF and PCB and taking into account the signature of their congeners when defining the reference value of background concentration which are applied to distinguish a recent point source pollution

Use of in Vitro HTS-Derived Concentration-Response Data as Biological Descriptors Improves the Accuracy of QSAR Models of in Vivo Toxicity

EPA Science Inventory

Background: Quantitative high-throughput screening (qHTS) assays are increasingly being employed to inform chemical hazard identification. Hundreds of chemicals have been tested in dozens of cell lines across extensive concentration ranges by the National Toxicology Program in co...

Seasonal variation of organic aerosol in PM2.5 at Anmyeondo, a background site in Korea

NASA Astrophysics Data System (ADS)

Lee, J.; Kim, E. S.; Kim, Y. P.; Jung, C. H.; Lee, J.

2016-12-01

Routine measurements of PM2.5 and chemical speciation for 100 individual organic compounds were carried out to understand seasonal variation of organic compounds at a background area in Korea between 2015 and 2016. Organic compounds analyzed in this study were classified into five groups, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), fatty acids (FA), dicarboxylic acids (DCAs), and sugar. Further, organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and Humic Like Substance-Carbon (HULIS-C) in PM2.5 were simultaneously analyzed to make mass balance of carbonaceous aerosol in PM2.5 at a background site in Korea. PAHs concentrations at this site was lower than that at Seoul, a representative urban site in Korea. PAHs and n-Alkanes concentrations showed clear seasonal variation with summer minimum and winter maximum, while, seasonal variation of DCAs and Sugars were different with PAHs and n-Alkanes.WSOC concentrations were highly correlated with SOC (Secondary Organic Carbon) concentrations which were estimated by the EC tracer method. The results indicate the formation of secondary organic aerosol (SOA) is major factor for the determination of WSOC concentrations in this region. HULIS-C as known one of brown carbon was major component of WSOC which accounts for 39 to 99% in WSOC. The average concentrations of HULIS-C was 2.02±1.42 and the highest concentration was observed in fall.

Hybridization parameters revisited: solutions containing SDS.

PubMed

Rose, Ken; Mason, John O; Lathe, Richard

2002-07-01

Salt concentration governs nucleic acid hybridization according to the Schildkraut-Lifson equation. High concentrations of SDS are used in some common protocols, but the effects of SDS on hybridization stringency have not been reported. We investigated hybridization parameters in solutions containing SDS. With targets immobilized on nylon membranes and PCR- or transcription-generated probes, we report that the 50% dissociation temperature (Tm*) in the absence of SDS was 15 degrees C-17degrees C lower than the calculated Tm. SDS had only modest effects on Tm* [1% (w/v) equating to 8 mM NaCl]. RNA/DNA hybrids were approximately 11 degrees C more stable than DNA/DNA hybrids. Incomplete homology (69%) significantly reduced the Tm* for DNA/DNA hybrids (approximately /4degrees C; 0.45 degrees C/% nonhomology) but far less so for RNA/DNA hybrids (approximately 2.3 degrees C; approximately 0.07 degrees C/% non-homology); incomplete homology also markedly reduced the extent of hybridization. On these nylonfilters, SDS had a major effect on nonspecific binding. Buffers lacking SDS, or with low salt concentration, gave high hybridization backgrounds; buffers containing SDS, or high-salt buffers, gave reproducibly low backgrounds.

High School Students' Implicit Theories of What Facilitates Science Learning

ERIC Educational Resources Information Center

Parsons, Eileen Carlton; Miles, Rhea; Petersen, Michael

2011-01-01

Background: Research has primarily concentrated on adults' implicit theories about high quality science education for all students. Little work has considered the students' perspective. This study investigated high school students' implicit theories about what helped them learn science. Purpose: This study addressed (1) What characterizes high…

Physical inactivity interacts with an endothelial lipase polymorphism to modulate high density lipoprotein cholesterol in the GOLDN study

USDA-ARS?s Scientific Manuscript database

BACKGROUND: Plasma high density lipoprotein (HDL) cholesterol (HDL-C) concentration is highly heritable but is also modifiable by environmental factors including physical activity. HDL-C response to exercise varies among individuals, and this variability may be associated with genetic polymorphism...

Environmental 238U and 232Th concentration measurements in an area of high level natural background radiation at Palong, Johor, Malaysia.

PubMed

Ramli, A Termizi; Hussein, A Wahab M A; Wood, A Khalik

2005-01-01

Concentrations of uranium-238 and thorium-232 in soil, water, grass, moss and oil-palm fruit samples collected from an area of high background radiation were determined using neutron activation analysis (NAA). U-238 concentration in soil ranged from 4.9 mg kg(-1) (58.8 Bq kg(-1)) to 40.4 mg kg(-1) (484.8 Bq kg(-1)), Th-232 concentration ranged from 14.9 mg kg(-1) (59.6 Bq kg(-1)) to 301.0 mg kg(-1) (1204 Bq kg(-1)). The concentration of U-238 in grass samples ranged from below the detection limit to 0.076 mg kg(-1) (912 mBq kg(-1)), and Th-232 ranged from 0.008 mg kg(-1) (32 mBq kg(-1)) to 0.343 mg kg(-1) (1.372 Bq kg(-1)). U-238 content in water samples ranged from 0.33 mg kg(-1) (4.0 Bq L(-1)) to 1.40 mg kg(-1) (16.8 Bq L(-1)), and Th-232 ranged from 0.19 mg kg(-1) (0.76 Bq L(-1)) to 0.66 mg kg(-1) (2.64 Bq L(-1)). It can be said that the concentrations of environmental U-238 and Th-232 in grass and water samples in the study area are insignificant. Mosses were found to be possible bio-radiological indicators due to their high absorption of the heavy radioelements from the environment.

Regional distribution of mercury in sediments of the main rivers of French Guiana (Amazonian basin).

PubMed

Laperche, Valérie; Hellal, Jennifer; Maury-Brachet, Régine; Joseph, Bernard; Laporte, Pierre; Breeze, Dominique; Blanchard, François

2014-01-01

Use of mercury (Hg) for gold-mining in French Guiana (up until 2006) as well as the presence of naturally high background levels in soils, has led to locally high concentrations in soils and sediments. The present study maps the levels of Hg concentrations in river sediments from five main rivers of French Guiana (Approuague River, Comté River, Mana River, Maroni River and Oyapock River) and their tributaries, covering more than 5 450 km of river with 1 211 sampling points. The maximum geological background Hg concentration, estimated from 241 non-gold-mined streams across French Guiana was 150 ng g(-1). Significant differences were measured between the five main rivers as well as between all gold-mining and pristine areas, giving representative data of the Hg increase due to past gold-mining activities. These results give a unique large scale vision of Hg contamination in river sediments of French Guiana and provide fundamental data on Hg distribution in pristine and gold-mined areas.

Cleaning and passivation of copper surfaces to remove surface radioactivity and prevent oxide formation

NASA Astrophysics Data System (ADS)

Hoppe, E. W.; Seifert, A.; Aalseth, C. E.; Bachelor, P. P.; Day, A. R.; Edwards, D. J.; Hossbach, T. W.; Litke, K. E.; McIntyre, J. I.; Miley, H. S.; Schulte, S. M.; Smart, J. E.; Warren, G. A.

2007-08-01

High-purity copper is an attractive material for constructing ultra-low-background radiation measurement devices. Many low-background experiments using high-purity copper have indicated surface contamination emerges as the dominant background. Radon daughters plate out on exposed surfaces, leaving a residual 210Pb background that is difficult to avoid. Dust is also a problem; even under cleanroom conditions, the amount of U and Th deposited on surfaces can represent the largest remaining background. To control these backgrounds, a copper cleaning chemistry has been developed. Designed to replace an effective, but overly aggressive concentrated nitric acid etch, this peroxide-based solution allows for a more controlled cleaning of surfaces. The acidified hydrogen peroxide solution will generally target the Cu +/Cu 2+ species which are the predominant surface participants, leaving the bulk of copper metal intact. This preserves the critical tolerances of parts and eliminates significant waste disposal issues. Accompanying passivation chemistry has also been developed that protects copper surfaces from oxidation. Using a high-activity polonium surface spike, the most difficult-to-remove daughter isotope of radon, the performance of these methods are quantified.

Utilizing Diffuse Reflection to Increase the Efficiency of Luminescent Solar Concentrators

NASA Astrophysics Data System (ADS)

Bowser, Seth; Weible, Seth; Solomon, Joel; Schrecengost, Jonathan; Wittmershaus, Bruce

A luminescent solar concentrator (LSC) consists of a high index solid plate containing a fluorescent material that converts sunlight into fluorescence. Utilizing total internal reflection, the LSC collects and concentrates the fluorescence at the plate's edges where it is converted into electricity via photovoltaic solar cells. The lower production costs of LSCs make them an attractive alternative to photovoltaic solar cells. To optimize an LSC's efficiency, a white diffusive surface (background) is positioned behind it. The background allows sunlight transmitted in the first pass to be reflected back through the LSC providing a second chance for absorption. Our research examines how the LSC's performance is affected by changing the distance between the white background and the LSC. An automated linear motion apparatus was engineered to precisely measure this distance and the LSC's electrical current, simultaneously. LSC plates, with and without the presence of fluorescent material and in an isolated environment, showed a maximum current at a distance greater than zero. Further experimentation has proved that the optimal distance results from the background's optical properties and how the reflected light enters the LSC. This material is based upon work supported by the National Science Foundation under Grant Number NSF-ECCS-1306157.

The effects of ABCG5/G8 polymorphisms on plasma HDL cholesterol concentrations depend on smoking habit in the Boston Puerto Rican Health Study

USDA-ARS?s Scientific Manuscript database

Background-Low high-density lipoprotein cholesterol (HDL-C) is associated with an increased risk for atherosclerosis and concentrations are modulated by genetic and environmental factors such as smoking. Objective- To assess whether the association of common single nucleotide polymorphisms (SNPs...

Spatial variations of tritium concentrations in groundwater collected in the southern coastal region of Fukushima, Japan, after the nuclear accident.

PubMed

Kashiwaya, Koki; Muto, Yuta; Kubo, Taiki; Ikawa, Reo; Nakaya, Shinji; Koike, Katsuaki; Marui, Atsunao

2017-10-03

Spatial variations in tritium concentrations in groundwater were identified in the southern part of the coastal region in Fukushima Prefecture, Japan. Higher tritium concentrations were measured at wells near the Fukushima Daiichi Nuclear Power Station (F1NPS). Mean tritium concentrations in precipitation in the 5 weeks after the F1NPS accident were estimated to be 433 and 139 TU at a distance of 25 and 50 km, respectively, from the F1NPS. The elevations of tritium concentrations in groundwater were calculated using a simple mixing model of the precipitation and groundwater. By assuming that these precipitation was mixed into groundwater with a background tritium concentration in a hypothetical well, concentrations of 13 and 7 TU at distances of 25 and 50 km from the F1NPS, respectively, were obtained. The calculated concentrations are consistent with those measured at the studied wells. Therefore, the spatial variation in tritium concentrations in groundwater was probably caused by precipitation with high tritium concentrations as a result of the F1NPS accident. However, the highest estimated tritium concentrations in precipitation for the study site were much lower than the WHO limits for drinking water, and the concentrations decreased to almost background level at the wells by mixing with groundwater.

Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port.

PubMed

Cutroneo, L; Castellano, M; Carbone, C; Consani, S; Gaino, F; Tucci, S; Magrì, S; Povero, P; Bertolotto, R M; Canepa, G; Capello, M

2015-12-30

The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs.

Quantifying the contribution of individual vehicles to NO2 pollution in an urban area

NASA Astrophysics Data System (ADS)

Pöhler, Denis; Kanatschnig, Florian; Horbanski, Martin; Friedrich, Axel; Lampel, Johannes; Platt, Ulrich

2015-04-01

Nitrogen Dioxide (NOx) emissions by road vehicles are the mayor contributor for poor air quality in urban areas. High NOx concentrations, and especially NO2, are typically the most problematic pollutant in mega and other cities. However emissions vary significantly depending on the type of vehicle and its engine, the age and condition of the vehicle, driving properties and many more. Even if data of the manufacturer exists how much NOx different vehicle types emit, reliable data under real driving conditions are rare and often missing. Especially data showing the degree to which different cars contribute to observed NOx levels are missing. Significant reduction of NOx concentrations can be achieved by identifying the strong emitting vehicles and excluding / replacing these. As this is only a small amount of vehicles (typically less than 10% of the vehicles make 90% of the emissions), such a small investment can significantly improve air quality. In order to perform measurements of NOx we applied a high speed NO2 CE-DOAS (Cavity-Enhanced DOAS) instrument in a car which was modified for this application. It measured directly the NO2 concentration behind followed vehicles while driving, with a time resolution of 2 s and an accuracy of ~1ppb. Even if such observations depend on many parameters like mixing-in of ambient air, distance, solar radiation, ozone concentration, background concentration etc., it delivers valuable data under real driving conditions. The instrument was applied in the city of Mainz, Germany to investigate within 7 days (March / April 2014) the NOx emission of 728 vehicles and to quantify the main emitters. Therefore the measured NO2 concentration in comparison to the background concentrations was quantified. Observed vehicles were separated in 4 categories: cars, busses, trucks, and motorcycles. We observed NO2 levels from a few ppb (within the background variation) up to 7000ppb NO2 above the background level. Strong variations within the same vehicle category could be observed. NO2 levels above 500ppb are found only for 2,2% of all measured vehicles and these are mainly busses (especially older models) but also few cars and motorcycles. On average NO2 concentrations behind the vehicles were 222ppb above background level. This could be reduced by 45% by just excluding the strongest emitters (2,2% of all vehicles). Our study clearly shows which vehicles exhibit the strongest NO2 emissions under real driving conditions and which vehicles contribute most to urban NOx pollution. It demonstrates how such measurements at high temporal resolution on a mobile platform can give recommendations to policy makers to significantly improve air quality in mega and other cities at moderate cost. In the future our system will be expanded with a NO and O3 measurement system to quantify all relevant species.

Modelling of the urban concentrations of PM2.5 on a high resolution for a period of 35 years, for the assessment of lifetime exposure and health effects

NASA Astrophysics Data System (ADS)

Kukkonen, Jaakko; Kangas, Leena; Kauhaniemi, Mari; Sofiev, Mikhail; Aarnio, Mia; Jaakkola, Jouni J. K.; Kousa, Anu; Karppinen, Ari

2018-06-01

Reliable and self-consistent data on air quality are needed for an extensive period of time for conducting long-term, or even lifetime health impact assessments. We have modelled the urban-scale concentrations of fine particulate matter (PM2.5) in the Helsinki Metropolitan Area for a period of 35 years, from 1980 to 2014. The regional background concentrations were evaluated based on reanalyses of the atmospheric composition on global and European scales, using the SILAM model. The high-resolution urban computations included both the emissions originated from vehicular traffic (separately exhaust and suspension emissions) and those from small-scale combustion, and were conducted using the road network dispersion model CAR-FMI and the multiple-source Gaussian dispersion model UDM-FMI. The modelled concentrations of PM2.5 agreed fairly well with the measured data at a regional background station and at four urban measurement stations, during 1999-2014. The modelled concentration trends were also evaluated for earlier years, until 1988, using proxy analyses. There was no systematic deterioration of the agreement of predictions and data for earlier years (the 1980s and 1990s), compared with the results for more recent years (2000s and early 2010s). The local vehicular emissions were about 5 times higher in the 1980s, compared with the emissions during the latest considered years. The local small-scale combustion emissions increased slightly over time. The highest urban concentrations of PM2.5 occurred in the 1980s; these have since decreased to about to a half of the highest values. In general, regional background was the largest contribution in this area. Vehicular exhaust has been the most important local source, but the relative shares of both small-scale combustion and vehicular non-exhaust emissions have increased in time. The study has provided long-term, high-resolution concentration databases on regional and urban scales that can be used for the assessment of health effects associated with air pollution.

Temperature effect on triacylglycerol species in seed oil from high stearic sunflower lines with different genetic backgrounds.

PubMed

Izquierdo, Natalia G; Martínez-Force, Enrique; Garcés, Rafael; Aguirrezábal, Luis An; Zambelli, Andrés; Reid, Roberto

2016-10-01

This study characterized the influence of temperature during grain filling on the saturated fatty acid distribution in triacylglycerol molecules from high stearic sunflower lines with different genetic backgrounds. Two growth chamber experiments were conducted with day/night temperatures of 16/16, 26/16, 26/26 and 32/26 °C. In all genotypes, independently of the genetic background, higher temperatures increased palmitic and oleic acid and reduced linoleic acid concentrations. Increasing night temperature produced an increase in saturated-unsaturated-saturated species, indicating a more symmetrical distribution of saturated fatty acids. The solid fat index was more affected by temperature during grain filling in lines with high linoleic than high oleic background. Higher variations in symmetry among night temperatures were observed in lines with high oleic background, which are more stable in fatty acid composition. The effect of temperature on triacylglycerol composition is not completely explained by its effect on fatty acid composition. Thus night temperature affects oil properties via its effects on fatty acid synthesis and on the distribution of fatty acids in the triacylglycerol molecules. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

A Model and Satellite-Based Analysis of the Tropospheric Ozone Distribution in Clear Versus Convectively Cloudy Conditions

NASA Technical Reports Server (NTRS)

Strode, Sarah A.; Douglass, Anne R.; Ziemke, Jerald R.; Manyin, Michael; Nielsen, J. Eric; Oman, Luke D.

2017-01-01

Satellite observations of in-cloud ozone concentrations from the Ozone Monitoring Instrument and Microwave Limb Sounder instruments show substantial differences from background ozone concentrations. We develop a method for comparing a free-running chemistry-climate model (CCM) to in-cloud and background ozone observations using a simple criterion based on cloud fraction to separate cloudy and clear-sky days. We demonstrate that the CCM simulates key features of the in-cloud versus background ozone differences and of the geographic distribution of in-cloud ozone. Since the agreement is not dependent on matching the meteorological conditions of a specific day, this is a promising method for diagnosing how accurately CCMs represent the relationships between ozone and clouds, including the lower ozone concentrations shown by in-cloud satellite observations. Since clouds are associated with convection as well as changes in chemistry, we diagnose the tendency of tropical ozone at 400 hPa due to chemistry, convection and turbulence, and large-scale dynamics. While convection acts to reduce ozone concentrations at 400 hPa throughout much of the tropics, it has the opposite effect over highly polluted regions of South and East Asia.

On the spatial distribution and evolution of ultrafine particles in Barcelona

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

2013-01-01

Sources and evolution of ultrafine particles were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 m a.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5 nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under cleaner atmospheric conditions (low condensation sink, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5 nm) allow us to identify three types of nucleation and growth events: (1) a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding urban background area; (2) a regional type event impacting only the regional background area but not the urban agglomerate; (3) an urban type event which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the optimal combination between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre of Barcelona is a source of non-volatile traffic primary particles (29-39% of N>5 nm), but other sources, including secondary freshly nucleated particles contribute up to 61-71% of particle number (N>5 nm) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

On the spatial distribution and evolution of ultrafine aerosols in urban air

NASA Astrophysics Data System (ADS)

Dall'Osto, M.; Querol, X.; Alastuey, A.; O'Dowd, C.; Harrison, R. M.; Wenger, J.; Gómez-Moreno, F. J.

2012-07-01

Sources and evolution of ultrafine particles (<0.1 μ m diameter) were investigated both horizontally and vertically in the large urban agglomerate of Barcelona, Spain. Within the SAPUSS project (Solving Aerosol Problems by Using Synergistic Strategies), a large number of instruments was deployed simultaneously at different monitoring sites (road, two urban background, regional background, urban tower 150 μa.s.l., urban background tower site 80 m a.s.l.) during a 4 week period in September-October 2010. Particle number concentrations (N>5nm) are highly correlated with black carbon (BC) at all sites only under strong vehicular traffic influences. By contrast, under clean atmospheric conditions (low condensation sinks, CS) such correlation diverges towards much higher N/BC ratios at all sites, indicating additional sources of particles including secondary production of freshly nucleated particles. This is also evident in the urban background annual mean diurnal trend of N/BC, showing a midday peak in all seasons. Size-resolved aerosol distributions (N10-500) as well as particle number concentrations (N>5nm) allow us to identify two types of nucleation and growth events: a regional type event originating in the whole study region and impacting almost simultaneously the urban city of Barcelona and the surrounding background area; and an urban type which originates only within the city centre but whose growth continues while transported away from the city to the regional background. Furthermore, during these clean air days, higher N are found at tower level than at ground level only in the city centre whereas such a difference is not so pronounced at the remote urban background tower. In other words, this study suggests that the column of air above the city ground level possesses the best compromise between low CS and high vapour source, hence enhancing the concentrations of freshly nucleated particles. By contrast, within stagnant polluted atmospheric conditions, higher N and BC concentrations are always measured at ground level relative to tower level at all sites. Our study suggests that the city centre is a source of both non-volatile traffic primary (29-39%) and secondary freshly nucleated particles (up to 61-71%) at all sites. We suggest that organic compounds evaporating from freshly emitted traffic particles are a possible candidate for new particle formation within the city and urban plume.

Spectrophotometric Analysis of Pigments: A Critical Assessment of a High-Throughput Method for Analysis of Algal Pigment Mixtures by Spectral Deconvolution

PubMed Central

Thrane, Jan-Erik; Kyle, Marcia; Striebel, Maren; Haande, Sigrid; Grung, Merete; Rohrlack, Thomas; Andersen, Tom

2015-01-01

The Gauss-peak spectra (GPS) method represents individual pigment spectra as weighted sums of Gaussian functions, and uses these to model absorbance spectra of phytoplankton pigment mixtures. We here present several improvements for this type of methodology, including adaptation to plate reader technology and efficient model fitting by open source software. We use a one-step modeling of both pigment absorption and background attenuation with non-negative least squares, following a one-time instrument-specific calibration. The fitted background is shown to be higher than a solvent blank, with features reflecting contributions from both scatter and non-pigment absorption. We assessed pigment aliasing due to absorption spectra similarity by Monte Carlo simulation, and used this information to select a robust set of identifiable pigments that are also expected to be common in natural samples. To test the method’s performance, we analyzed absorbance spectra of pigment extracts from sediment cores, 75 natural lake samples, and four phytoplankton cultures, and compared the estimated pigment concentrations with concentrations obtained using high performance liquid chromatography (HPLC). The deviance between observed and fitted spectra was generally very low, indicating that measured spectra could successfully be reconstructed as weighted sums of pigment and background components. Concentrations of total chlorophylls and total carotenoids could accurately be estimated for both sediment and lake samples, but individual pigment concentrations (especially carotenoids) proved difficult to resolve due to similarity between their absorbance spectra. In general, our modified-GPS method provides an improvement of the GPS method that is a fast, inexpensive, and high-throughput alternative for screening of pigment composition in samples of phytoplankton material. PMID:26359659

Perfluorocarbon background concentrations in Europe

NASA Astrophysics Data System (ADS)

Straume, Anne Grete; Dietz, Russel N.; Koffı̀, Ernest N.'dri; Nodop, Katrin

Five studies of the background level of several perfluorocarbon compounds in Europe are here presented together with measurements from the European Tracer Experiment (ETEX). The tracers used during the two ETEX tracer releases were the perfluorocarbons (PFCs); perfluoromethylcyclohexane (C 7F 14, PMCH) and perfluoromethylcyclopentane (C 6F 12, PMCP). Their background concentrations were detected by using both passive and active sampling techniques, to define the spatial and temporal variation of the PFCs over Europe. Also the background variations of four isomers of the PFC compound perfluorodimethylcyclohexane (C 8F 16, PDCH) were studied. The results were compared to other PFC tracer studies in the U.S.A. and Europe. The mean and median values of the measured PFCs were found to vary slightly and randomly in space and time. They were found to be higher and to have a larger standard deviation than the measurements from the American studies. The background concentrations were still found to be low and stable enough for PFCs to be highly suitable for use in tracer studies. The following concentrations were found: PMCP; 4.6±0.3 fl ℓ -1, PMCH: 4.6±0.8 fl ℓ -1, ocPDCH: 0.96±0.33 fl ℓ -1, mtPDCH: 9.3±0.8 fl ℓ -1, mcPDCH: 8.8±0.8 fl ℓ -1, ptPDCH: 6.1±0.8 fl ℓ -1. A study of the correlation between the measured PFC compounds showed a significant correlation between most of the compounds, which indicate that there are no major PFC sources in Europe.

Reprint of Mechanisms of maintaining high suspended sediment concentration over tide-dominated offshore shoals in the southern Yellow Sea

NASA Astrophysics Data System (ADS)

Xiong, Jilian; Wang, Xiao Hua; Wang, Ya Ping; Chen, Jingdong; Shi, Benwei; Gao, Jianhua; Yang, Yang; Yu, Qian; Li, Mingliang; Yang, Lei; Gong, Xulong

2018-06-01

An understanding of the dynamics and behaviors of suspended sediments is vital in analysis of morphological, environmental, and ecological processes occurring in coastal marine environments. To study the mechanisms of maintaining high suspended sediment concentrations (SSCs) on a tide-dominated offshore shoal, we measured water depths, current velocities, SSCs, wave parameters and bottom sediment compositions in the southern Yellow Sea. These data were then used to calculate bottom shear stresses generated by currents (τc), waves (τw), and wave-current interactions (τcw). SSCs time series exhibited strong quarter-diurnal peaks during spring tides, in contrast to the semidiurnal signal during neap tides. A Fourier analysis showed that suspended sediment variations within tidal cycles was mainly controlled by resuspension in most stations. There existed relatively stable background SSCs (maintaining high SSCs among tidal cycles) values at all four stations during both windy (wind speed > 9.0 m/s) and normal weather conditions (wind speed < 3.0 m/s). The background SSCs had strong relationship with spring/neap-averaged τcw, indicating background SSCs were mainly controlled by mean bottom shear stress, with a minimum value of 0.21 N/m2. On account of the strong tidal currents, background SSCs of spring tides were greater than that of neap tides. In addition, on the base of wavelet, statistics analyses and turbulence dissipation parameter, background SSCs during slack tide in the study area may be maintained by intermittent turbulence events induced by a combined tidal current and wave action.

Mechanisms of maintaining high suspended sediment concentration over tide-dominated offshore shoals in the southern Yellow Sea

NASA Astrophysics Data System (ADS)

Xiong, Jilian; Wang, Xiao Hua; Wang, Ya Ping; Chen, Jingdong; Shi, Benwei; Gao, Jianhua; Yang, Yang; Yu, Qian; Li, Mingliang; Yang, Lei; Gong, Xulong

2017-05-01

An understanding of the dynamics and behaviors of suspended sediments is vital in analysis of morphological, environmental, and ecological processes occurring in coastal marine environments. To study the mechanisms of maintaining high suspended sediment concentrations (SSCs) on a tide-dominated offshore shoal, we measured water depths, current velocities, SSCs, wave parameters and bottom sediment compositions in the southern Yellow Sea. These data were then used to calculate bottom shear stresses generated by currents (τc), waves (τw), and wave-current interactions (τcw). SSCs time series exhibited strong quarter-diurnal peaks during spring tides, in contrast to the semidiurnal signal during neap tides. A Fourier analysis showed that suspended sediment variations within tidal cycles was mainly controlled by resuspension in most stations. There existed relatively stable background SSCs (maintaining high SSCs among tidal cycles) values at all four stations during both windy (wind speed > 9.0 m/s) and normal weather conditions (wind speed < 3.0 m/s). The background SSCs had strong relationship with spring/neap-averaged τcw, indicating background SSCs were mainly controlled by mean bottom shear stress, with a minimum value of 0.21 N/m2. On account of the strong tidal currents, background SSCs of spring tides were greater than that of neap tides. In addition, on the base of wavelet, statistics analyses and turbulence dissipation parameter, background SSCs during slack tide in the study area may be maintained by intermittent turbulence events induced by a combined tidal current and wave action.

Neural network model for the prediction of PM10 daily concentrations in two sites in the Western Mediterranean.

PubMed

de Gennaro, Gianluigi; Trizio, Livia; Di Gilio, Alessia; Pey, Jorge; Pérez, Noemi; Cusack, Michael; Alastuey, Andrés; Querol, Xavier

2013-10-01

An artificial neural network (ANN) was developed and tested to forecast PM10 daily concentration in two contrasted environments in NE Spain, a regional background site (Montseny), and an urban background site (Barcelona-CSIC), which was highly influenced by vehicular emissions. In order to predict 24-h average PM10 concentrations, the artificial neural network previously developed by Caselli et al. (2009) was improved by using hourly PM concentrations and deterministic factors such as a Saharan dust alert. In particular, the model input data for prediction were the hourly PM10 concentrations 1-day in advance, local meteorological data and information about air masses origin. The forecasted performance indexes for both sites were calculated and they showed better results for the regional background site in Montseny (R(2)=0.86, SI=0.75) than for urban site in Barcelona (R(2)=0.73, SI=0.58), influenced by local and sometimes unexpected sources. Moreover, a sensitivity analysis conducted to understand the importance of the different variables included among the input data, showed that local meteorology and air masses origin are key factors in the model forecasts. This result explains the reason for the improvement of ANN's forecasting performance at the Montseny site with respect to the Barcelona site. Moreover, the artificial neural network developed in this work could prove useful to predict PM10 concentrations, especially, at regional background sites such as those on the Mediterranean Basin which are primarily affected by long-range transports. Hence, the artificial neural network presented here could be a powerful tool for obtaining real time information on air quality status and could aid stakeholders in their development of cost-effective control strategies. © 2013 Elsevier B.V. All rights reserved.

Contrast in air pollution components between major streets and background locations: Particulate matter mass, black carbon, elemental composition, nitrogen oxide and ultrafine particle number

NASA Astrophysics Data System (ADS)

Boogaard, Hanna; Kos, Gerard P. A.; Weijers, Ernie P.; Janssen, Nicole A. H.; Fischer, Paul H.; van der Zee, Saskia C.; de Hartog, Jeroen J.; Hoek, Gerard

2011-01-01

Policies to reduce outdoor air pollution concentrations are often assessed on the basis of the regulated pollutants. Whether these are the most appropriate components to assess the potential health benefits is questionable, as other health-relevant pollutants may be more strongly related to traffic. The aim of this study is to compare the contrast in concentration between major roads and (sub)urban background for a large range of pollutants and to analyze the magnitude of the measured difference in the street - background for major streets with different street configurations. Measurements of PM 10, PM 2.5, particle number concentrations (PNC), black carbon (BC), elemental composition of PM 10 and PM 2.5 and NO x were conducted simultaneously in eight major streets and nine (sub)urban background locations in the Netherlands. Measurements were done six times for a week during a six month period in 2008. High contrasts between busy streets and background locations in the same city were found for chromium, copper and iron (factor 2-3). These elements were especially present in the coarse fraction of PM. In addition, high contrasts were found for BC and NO x (factor 1.8), typically indicators of direct combustion emissions. The contrast for PNC was similar to BC. NO 2 contrast was lower (factor 1.5). The largest contrast was found for two street canyons and two streets with buildings at one side of the street only. The contrast between busy streets and urban background in NO 2 was less than the contrast found for BC, PNC and elements indicative of non-exhaust emissions, adding evidence that NO 2 is not representing (current) traffic well. The study supports a substantial role for non-exhaust emissions including brake- and tyre wear and road dust in addition to direct combustion emissions. Significant underestimation of disease burden may occur when relying too much on the regulated components.

Measurement of suspended solids in lakes and oceans using satellite remote sensing data

NASA Technical Reports Server (NTRS)

Sydor, M. (Principal Investigator)

1980-01-01

Using satellite remote sensing data to measure low concentrations of suspended solids in lakes and oceans requires careful evaluation of background signals from the atmosphere and the water surface. Typical background corrections for Lake Superior are presented and the spectral distribution of the residual radiance from three major categories of turbidity in the lake are determined. The results indicate that for large bodies of water, some general information on atmospheric scattering, water clarity, and the optical properties of suspended solids allows estimates of concentrations of suspended solids to within + or - 0.5 mg/L without using real time ground truth data. Under calibrated conditions the threshold detection level is 0.3 mg/L for the fine particulates dispersed throughout the lake and 1 mg/L for the highly light absorbing effluent from rivers. Comparisons of the minimum reflectance over the open lake areas with reflection from the highly absorbing tannin water from rivers provides a check on the clarity of the atmosphere and the excessive background scatter from the water surface.

Variability of aerosols and chemical composition of PM10, PM2.5 and PM1 on a platform of the Prague underground metro

NASA Astrophysics Data System (ADS)

Cusack, M.; Talbot, N.; Ondráček, J.; Minguillón, M. C.; Martins, V.; Klouda, K.; Schwarz, J.; Ždímal, V.

2015-10-01

Measurements of PM10, PM2.5 and PM1 and particle number concentration and size distribution were measured for 24 h on a platform of the Prague underground metro in October 2013. The three PM fractions were analysed for major and minor elements, secondary inorganic aerosols (SIA) and total carbon (TC). Measurements were performed both when the metro was inoperative and closed to the public (referred to as background), and when the metro was in operation and open to passengers. PM concentrations were elevated during both periods, but were substantially increased in the coarse fraction during hours when the metro was in operation. Average PM concentrations were 214.8, 93.9 and 44.8 μg m-3 for PM10, PM2.5 and PM1, respectively (determined gravimetrically). Average particle number concentrations were 8.5 × 103 cm-3 for background hours and 11.5 × 103 cm-3 during operational hours. Particle number concentrations were found to not vary as significantly as PM concentrations throughout the day. Variations in PM were strongly governed by passing trains, with highest concentrations recorded during rush hour. When trains were less frequent, PM concentrations were shown to fluctuate in unison with the entrance and exit of trains (as shown by wind velocity measured on the platform). PM was found to be highly enriched with iron, especially in the coarse fraction, comprising 46% of PM10 (98.9 μg m-3). This reduces to 6.7 μg m-3 during background hours, proving that the trains themselves were the main source of iron, most probably from wheel-rail mechanical abrasion. Other enriched elements relative to background hours included Ba, Cu, Mn, Cr, Mo, Ni and Co, among others. Many of these elements exhibited a similar size distribution, further indicating their sources were common and were attributed to train operations.

40 CFR 1065.650 - Emission calculations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... following sequence of preliminary calculations on recorded concentrations: (i) Correct all THC and CH4.... (iii) Calculate all THC and NMHC concentrations, including dilution air background concentrations, as... NMHC to background corrected mass of THC. If the background corrected mass of NMHC is greater than 0.98...

Hole traps associated with high-concentration residual carriers in p-type GaAsN grown by chemical beam epitaxy

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

Elleuch, Omar, E-mail: mr.omar.elleuch@gmail.com; Wang, Li; Lee, Kan-Hua

2015-01-28

The hole traps associated with high background doping in p-type GaAsN grown by chemical beam epitaxy are studied based on the changes of carrier concentration, junction capacitance, and hole traps properties due to the annealing. The carrier concentration was increased dramatically with annealing time, based on capacitance–voltage (C–V) measurement. In addition, the temperature dependence of the junction capacitance (C–T) was increased rapidly two times. Such behavior is explained by the thermal ionization of two acceptor states. These acceptors are the main cause of high background doping in the film, since the estimated carrier concentration from C–T results explains the measuredmore » carrier concentration at room temperature using C–V method. The acceptor states became shallower after annealing, and hence their structures are thermally unstable. Deep level transient spectroscopy (DLTS) showed that the HC2 hole trap was composed of two signals, labeled HC21 and HC22. These defects correspond to the acceptor levels, as their energy levels obtained from DLTS are similar to those deduced from C–T. The capture cross sections of HC21 and HC22 are larger than those of single acceptors. In addition, their energy levels and capture cross sections change in the same way due to the annealing. This tendency suggests that HC21 and HC22 signals originate from the same defect which acts as a double acceptor.« less

Environmental risk assessment of cobalt and manganese from industrial sources in an estuarine system.

PubMed

Barrio-Parra, F; Elío, J; De Miguel, E; García-González, J E; Izquierdo, M; Álvarez, R

2018-04-01

A total of 74 samples of soil, sediment, industrial sludge, and surface water were collected in a Mediterranean estuarine system in order to assess the potential ecological impact of elevated concentrations of Co and Mn associated with a Terephthalic (PTA) and Isophthalic (PIPA) acids production plant. Samples were analyzed for elemental composition (37 elements), pH, redox potential, organic carbon, and CaCO 3 content, and a group of 16 selected samples were additionally subjected to a Tessier sequential extraction. Co and Mn soil concentrations were significantly higher inside the industrial facility and around its perimeter than in background samples, and maximum dissolved Co and Mn concentrations were found in a creek near the plant's discharge point, reaching values 17,700 and 156 times higher than their respective background concentrations. The ecological risk was evaluated as a function of Co and Mn fractionation and bioavailability which were controlled by the environmental conditions generated by the advance of seawater into the estuarine system during high tide. Co appeared to precipitate near the river mouth due to the pH increase produced by the influence of seawater intrusion, reaching hazardous concentrations in sediments. In terms of their bioavailability and the corresponding risk assessment code, both Co and Mn present sediment concentrations that result in medium to high ecological risk whereas water concentrations of both elements reach values that more than double their corresponding Secondary Acute Values.

Determination of perchlorate in drinking water by ion chromatography using macrocycle-based concentration and separation methods.

PubMed

Lamb, John D; Simpson, David; Jensen, Bryce D; Gardner, Joseph S; Peterson, Quinn P

2006-06-16

Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.

Influence of impurities on the high temperature conductivity of SrTiO3

NASA Astrophysics Data System (ADS)

Bowes, Preston C.; Baker, Jonathon N.; Harris, Joshua S.; Behrhorst, Brian D.; Irving, Douglas L.

2018-01-01

In studies of high temperature electrical conductivity (HiTEC) of dielectrics, the impurity in the highest concentration is assumed to form a single defect that controls HiTEC. However, carrier concentrations are typically at or below the level of background impurities, and all impurities may complex with native defects. Canonical defect models ignore complex formation and lump defects from multiple impurities into a single effective defect to reduce the number of associated reactions. To evaluate the importance of background impurities and defect complexes on HiTEC, a grand canonical defect model was developed with input from density functional theory calculations using hybrid exchange correlation functionals. The influence of common background impurities and first nearest neighbor complexes with oxygen vacancies (vO) was studied for three doping cases: nominally undoped, donor doped, and acceptor doped SrTiO3. In each case, conductivity depended on the ensemble of impurity defects simulated with the extent of the dependence governed by the character of the dominant impurity and its tendency to complex with vO. Agreement between simulated and measured conductivity profiles as a function of temperature and oxygen partial pressure improved significantly when background impurities were included in the nominally undoped case. Effects of the impurities simulated were reduced in the Nb and Al doped cases as both elements did not form complexes and were present in concentrations well exceeding all other active impurities. The influence of individual impurities on HiTEC in SrTiO3 was isolated and discussed and motivates further experiments on singly doped SrTiO3.

Radon progeny in hydrometeors at the earth's surface.

PubMed

Voltaggio, M

2012-07-01

During atmospheric thermal inversions, dew and hoarfrost concentrate gamma emitting radionuclides of the short-lived (222)Rn progeny ((214)Pb and (214)Bi), causing an increase in the total natural gamma background from the ground. To highlight this phenomenon, a volcanic zone of high (222)Rn flux was studied during the winter season 2010-11. High-specific short-lived radon progeny activities up to 122 Bq g(-1) were detected in hydrometeors forming at the earth's surface (ESHs), corresponding to a mean increase of up to 17 % of the normal gamma background value. A theoretical model, depending on radon flux from soil and predicting the radon progeny concentrations in hydrometeors forming at the ESHs is presented. The comparison between model and field data shows a good correspondence. Around nuclear power plants or in nuclear facilities that use automatic NaI or CsI total gamma spectroscopy systems for monitoring radioactive contamination, hydrometeors forming at the ESHs in sites with a high radon flux could represent a relevant source of false alarms of radioactive contamination.

Macrofaunal recolonization of copper-contaminated sediments in San Diego Bay.

PubMed

Neira, Carlos; Mendoza, Guillermo; Porrachia, Magali; Stransky, Chris; Levin, Lisa A

2015-12-30

Effects of Cu-loading on macrofaunal recolonization were examined in Shelter Island Yacht Basin (San Diego Bay, California). Sediments with high and low Cu levels were defaunated and Cu-spiked, translocated, and then placed back into the environment. These demonstrated that the alteration observed in benthic communities associated with Cu contamination occurs during initial recolonization. After a 3-month exposure to sediments with varying Cu levels, two primary colonizing communities were identified: (1) a "mouth assemblage" resembling adjacent background fauna associated with low-Cu levels that was more diverse and predominantly dominated by surface- and subsurface-deposit feeders, burrowers, and tube builders, and (2) a "head assemblage" resembling adjacent background fauna associated with high-Cu concentrations, with few dominant species and an increasing importance of carnivores and mobile epifauna. Cu loading can cause reduced biodiversity and lower structural complexity that may last several months if high concentrations persist, with a direct effect on community functioning. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cleaning and passivation of copper surfaces to remove surface radioactivity and prevent oxide formation

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

Hoppe, Eric W.; Seifert, Allen; Aalseth, Craig E.

High-purity copper is an attractive material for constructing ultra-low-background radiation measurement devices. Many low-background experiments using high-purity copper have indicated surface contamination emerges as the dominant background. Radon daughters plate out on exposed surfaces, leaving a residual 210Pb background that is difficult to avoid. Dust is also a problem; even under cleanroom conditions, the amount of U and Th deposited on surfaces can represent the largest remaining background. To control these backgrounds, a copper cleaning chemistry has been developed. Designed to replace an effective, but overly aggressive concentrated nitric acid etch, this peroxide-based solution allows for a more controlled cleaningmore » of surfaces. The acidified hydrogen peroxide solution will generally target the Cu+/Cu2+ species which are the predominant surface participants, leaving the bulk of copper metal intact. This preserves the critical tolerances of parts and eliminates significant waste disposal issues. Accompanying passivation chemistry has also been developed that protects copper surfaces from oxidation. Using a high-activity polonium surface spike, the most difficult-to-remove daughter isotope of radon, the performance of these methods are quantified. © 2001 Elsevier Science. All rights reserved« less

Atmospheric CO2 at Waliguan station in China: Transport climatology, temporal patterns and source-sink region representativeness

NASA Astrophysics Data System (ADS)

Cheng, Siyang; An, Xingqin; Zhou, Lingxi; Tans, Pieter P.; Jacobson, Andy

2017-06-01

In order to explore where the source and sink have the greatest impact on CO2 background concentration at Waliguan (WLG) station, a statistical method is here proposed to calculate the representative source-sink region. The key to this method is to find the best footprint threshold, and the study is carried out in four parts. Firstly, transport climatology, expressed by total monthly footprint, was simulated by FLEXPART on a 7-day time scale. Surface CO2 emissions in Eurasia frequently transported to WLG station. WLG station was mainly influenced by the westerlies in winter and partly controlled by the Southeast Asian monsoon in summer. Secondly, CO2 concentrations, simulated by CT2015, were processed and analyzed through data quality control, screening, fitting and comparing. CO2 concentrations displayed obvious seasonal variation, with the maximum and minimum concentration appearing in April and August, respectively. The correlation of CO2 fitting background concentrations was R2 = 0.91 between simulation and observation. The temporal patterns were mainly correlated with CO2 exchange of biosphere-atmosphere, human activities and air transport. Thirdly, for the monthly CO2 fitting background concentrations from CT2015, a best footprint threshold was found based on correlation analysis and numerical iteration using the data of footprints and emissions. The grid cells where monthly footprints were greater than the best footprint threshold were the best threshold area corresponding to representative source-sink region. The representative source-sink region of maximum CO2 concentration in April was primarily located in Qinghai province, but the minimum CO2 concentration in August was mainly influenced by emissions in a wider region. Finally, we briefly presented the CO2 source-sink characteristics in the best threshold area. Generally, the best threshold area was a carbon sink. The major source and sink were relatively weak owing to less human activities and vegetation types in this high altitude area. CO2 concentrations were more influenced by human activities when air mass passed through many urban areas in summer. Therefore, the combination of footprints and emissions is an effective approach for assessing the source-sink region representativeness of CO2 background concentration.

Impacts of Central American Fires on Ozone Air Quality in Texas

NASA Astrophysics Data System (ADS)

Wang, S. C.; Wang, Y.; Lei, R.; Talbot, R. W.

2016-12-01

Background ozone represents the portion of ozone level in one day that cannot be reduced by local emission controls. One of the important factors causing high background ozone events is wildfires. Satellite observations have documented frequent transport of wildfire smoke from Mexico and Central America to the southern US, particularly Texas, causing haze and exceedance of fine particle matters. However, the impact of those fires on background ozone in Texas is poorly understood. In this study, the effects of the Central America fire emissions in spring (Apr-May) from 2000 to 2013 on high background ozone events in Texas are investigated and quantified. We first examine through back trajectory analysis if any high background ozone days in cities of Texas such as Houston can be traced back to fire events in Central America. The GEOS-Chem global chemical transport model and its nested-grid version over North America are used to simulate the periods of the selected cases studies of Central American fires. Long-large transport of gaseous emissions (NOx, VOCs, and CO) from Central American fires are simulated and background ozone concentrations variations in Texas region due to those fire events are also quantified through the difference in model results with and without fire emissions in Central America. Finally, this study connects those fires and high background ozone events, and also quantifies the contribution of fire emissions from Central America on Texas ozone air quality.

Vapor concentration monitor

DOEpatents

Bayly, John G.; Booth, Ronald J.

1977-01-01

An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

Glucose concentration measured by the hybrid coherent anti-Stokes Raman-scattering technique

NASA Astrophysics Data System (ADS)

Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei V.; Welch, George R.

2010-01-01

We investigate the possibility of using a hybrid coherent anti-Stokes Raman scattering technique for noninvasive monitoring of blood glucose levels. Our technique combines instantaneous coherent excitation of several characteristic molecular vibrations with subsequent probing of these vibrations by an optimally shaped, time-delayed, narrowband laser pulse. This pulse configuration mitigates the nonresonant four-wave mixing background while maximizing the Raman-resonant signal and allows rapid and highly specific detection even in the presence of multiple scattering. Under certain conditions we find that the measured signal is linearly proportional to the glucose concentration due to optical interference with the residual background light, which allows reliable detection of spectral signatures down to medically relevant glucose levels.

Intrinsic backgrounds from Rn and Kr in the XENON100 experiment

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Di Gangi, P.; Di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morå, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Ramírez García, D.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rupp, N.; dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Silva, M.; Simgen, H.; Sivers, M. Von; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Wang, H.; Wang, Z.; Weber, M.; Wei, Y.; Weinheimer, C.; Wittweg, C.; Wulf, J.; Ye, J.; Zhang, Y.

2018-02-01

In this paper, we describe the XENON100 data analyses used to assess the target-intrinsic background sources radon (?), thoron (?) and krypton (?). We detail the event selections of high-energy alpha particles and decay-specific delayed coincidences. We derive distributions of the individual radionuclides inside the detector and quantify their abundances during the main three science runs of the experiment over a period of ˜ 4 years, from January 2010 to January 2014. We compare our results to external measurements of radon emanation and krypton concentrations where we find good agreement. We report an observed reduction in concentrations of radon daughters that we attribute to the plating-out of charged ions on the negatively biased cathode.

Evaluation of methods to reduce background using the Python-based ELISA_QC program.

PubMed

Webster, Rose P; Cohen, Cinder F; Saeed, Fatima O; Wetzel, Hanna N; Ball, William J; Kirley, Terence L; Norman, Andrew B

2018-05-01

Almost all immunological approaches [immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), Western blot], that are used to quantitate specific proteins have had to address high backgrounds due to non-specific reactivity. We report here for the first time a quantitative comparison of methods for reduction of the background of commercial biotinylated antibodies using the Python-based ELISA_QC program. This is demonstrated using a recombinant humanized anti-cocaine monoclonal antibody. Several approaches, such as adjustment of the incubation time and the concentration of blocking agent, as well as the dilution of secondary antibodies, have been explored to address this issue. In this report, systematic comparisons of two different methods, contrasted with other more traditional methods to address this problem are provided. Addition of heparin (HP) at 1 μg/ml to the wash buffer prior to addition of the secondary biotinylated antibody reduced the elevated background absorbance values (from a mean of 0.313 ± 0.015 to 0.137 ± 0.002). A novel immunodepletion (ID) method also reduced the background (from a mean of 0.331 ± 0.010 to 0.146 ± 0.013). Overall, the ID method generated more similar results at each concentration of the ELISA standard curve to that using the standard lot 1 than the HP method, as analyzed by the Python-based ELISA_QC program. We conclude that the ID method, while more laborious, provides the best solution to resolve the high background seen with specific lots of biotinylated secondary antibody. Copyright © 2018. Published by Elsevier B.V.

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

Phelan, J.M.

A high volume sampling system was developed for the collection of volcanic plume aerosols from an aircraft sampling platform. Concentrations of up to 30 elements on particles were determined simultaneously with gas-phase concentrations of S, Cl, and Br in the quiescent plumes of five active volcanoes: Mount St. Helens, US; Arenal and Poas, Costa Rica; Colima and El Chichon, Mexico. Volatile and chalcophilic elements were found to be highly enriched, relative to average crustal and bulk pyroclastic material, in the quiescent plumes of all volcanoes studied. Enriched volatile elements were found to be primarily associated with fine (less than ormore » equal to 3-..mu..m diam) particles, those expected to have the longest residence times in the atmosphere. Samples were also collected using the aircraft sampling system in background, mid-tropospheric air. Analysis of these samples revealed that many of the same elements that are enriched in volcanic plumes are also enriched in clean, relatively remote aerosols collected in the free troposphere (5-7 km). Concentrations of sulfates made in the North American free troposphere (280 ng/m/sup 3/) approach those measured at remote background sites.« less

Workshop Background and Summary of Webinars (IVIVE workshop)

EPA Science Inventory

Toxicokinetics (TK) provides a bridge between hazard and exposure by predicting tissue concentrations due to exposure. Higher throughput toxicokinetics (HTTK) appears to provide essential data to established context for in vitro bioactivity data obtained through high throughput ...

Radiation dose due to radon and thoron progeny inhalation in high-level natural radiation areas of Kerala, India.

PubMed

Omori, Yasutaka; Tokonami, Shinji; Sahoo, Sarata Kumar; Ishikawa, Tetsuo; Sorimachi, Atsuyuki; Hosoda, Masahiro; Kudo, Hiromi; Pornnumpa, Chanis; Nair, Raghu Ram K; Jayalekshmi, Padmavaty Amma; Sebastian, Paul; Akiba, Suminori

2017-03-20

In order to evaluate internal exposure to radon and thoron, concentrations for radon, thoron, and thoron progeny were measured for 259 dwellings located in high background radiation areas (HBRAs, outdoor external dose: 3-5 mGy y -1 ) and low background radiation areas (control areas, outdoor external dose: 1 mGy y -1 ) in Karunagappally Taluk, Kerala, India. The measurements were conducted using passive-type radon-thoron detectors and thoron progeny detectors over two six-month measurement periods from June 2010 to June 2011. The results showed no major differences in radon and thoron progeny concentrations between the HBRAs and the control areas. The geometric mean of the annual effective dose due to radon and thoron was calculated as 0.10 and 0.44 mSv, respectively. The doses were small, but not negligible compared with the external dose in the two areas.

Workplace exposure to nanoparticles from gas metal arc welding process

NASA Astrophysics Data System (ADS)

Zhang, Meibian; Jian, Le; Bin, Pingfan; Xing, Mingluan; Lou, Jianlin; Cong, Liming; Zou, Hua

2013-11-01

Workplace exposure to nanoparticles from gas metal arc welding (GMAW) process in an automobile manufacturing factory was investigated using a combination of multiple metrics and a comparison with background particles. The number concentration (NC), lung-deposited surface area concentration (SAC), estimated SAC and mass concentration (MC) of nanoparticles produced from the GMAW process were significantly higher than those of background particles before welding ( P < 0.01). A bimodal size distribution by mass for welding particles with two peak values (i.e., 10,000-18,000 and 560-320 nm) and a unimodal size distribution by number with 190.7-nm mode size or 154.9-nm geometric size were observed. Nanoparticles by number comprised 60.7 % of particles, whereas nanoparticles by mass only accounted for 18.2 % of the total particles. The morphology of welding particles was dominated by the formation of chain-like agglomerates of primary particles. The metal composition of these welding particles consisted primarily of Fe, Mn, and Zn. The size distribution, morphology, and elemental compositions of welding particles were significantly different from background particles. Working activities, sampling distances from the source, air velocity, engineering control measures, and background particles in working places had significant influences on concentrations of airborne nanoparticle. In addition, SAC showed a high correlation with NC and a relatively low correlation with MC. These findings indicate that the GMAW process is able to generate significant levels of nanoparticles. It is recommended that a combination of multiple metrics is measured as part of a well-designed sampling strategy for airborne nanoparticles. Key exposure factors, such as particle agglomeration/aggregation, background particles, working activities, temporal and spatial distributions of the particles, air velocity, engineering control measures, should be investigated when measuring workplace exposure to nanoparticles.

Radon exhalation rate and natural radionuclide content in building materials of high background areas of Ramsar, Iran.

PubMed

Bavarnegin, E; Fathabadi, N; Vahabi Moghaddam, M; Vasheghani Farahani, M; Moradi, M; Babakhni, A

2013-03-01

Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m(-2) h(-1). The (226)Ra, (232)Th and (40)K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of (226)Ra, (232)Th and (40)K content varied from below the minimum detection limit up to 86,400 Bq kg(-1), 187 Bq kg(-1) and 1350 Bq kg(-1), respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modeled summer background concentration nutrients and ...

EPA Pesticide Factsheets

We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. From best-model linear regressions of water quality indicators with land use and other stressor variables, we determined the concentration of the indicators when the land use and stressor variables were all set to zero the y-intercept. Except for total P on the Upper Mississippi River and chloride on the Ohio River, we were able to predict background concentration from significant regression models. In every model with more than one predictor variable, the model included at least one variable representing agricultural land use and one variable representing development. Predicted background concentration of total N was the same on the Upper Mississippi and Lower Missouri rivers (350 ug l-1), which was much lower than a published eutrophication threshold and percentile-based thresholds (25th percentile of concentration at all sites in the population) but was similar to a threshold derived from the response of sestonic chlorophyll a to great river total N concentration. Background concentration of total P on the Lower Missouri (53 ug l-1) was also lower than published and percentile-based thresholds. Background TSS concentration was higher on the Lower Missouri (30 mg l-1) than the other ri

Biosorption and Biomineralization of U(VI) by the Marine Bacterium Idiomarina loihiensis MAH1: Effect of Background Electrolyte and pH

PubMed Central

Morcillo, Fernando; González-Muñoz, María T.; Reitz, Thomas; Romero-González, María E.; Arias, José M.; Merroun, Mohamed L.

2014-01-01

The main goal of this study is to compare the effects of pH, uranium concentration, and background electrolyte (seawater and NaClO4 solution) on the speciation of uranium(VI) associated with the marine bacterium Idiomarina loihiensis MAH1. This was done at the molecular level using a multidisciplinary approach combining X-ray Absorption Spectroscopy (XAS), Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS), and High Resolution Transmission Electron Microscopy (HRTEM). We showed that the U(VI)/bacterium interaction mechanism is highly dependent upon pH but also the nature of the used background electrolyte played a role. At neutral conditions and a U concentration ranging from 5·10−4 to 10−5 M (environmentally relevant concentrations), XAS analysis revealed that uranyl phosphate mineral phases, structurally resembling meta-autunite [Ca(UO2)2(PO4)2 2–6H2O] are precipitated at the cell surfaces of the strain MAH1. The formation of this mineral phase is independent of the background solution but U(VI) luminescence lifetime analyses demonstrated that the U(VI) speciation in seawater samples is more intricate, i.e., different complexes were formed under natural conditions. At acidic conditions, pH 2, 3 and 4.3 ([U] = 5·10−4 M, background electrolyte  = 0.1 M NaClO4), the removal of U from solution was due to biosorption to Extracellular Polysaccharides (EPS) and cell wall components as evident from TEM analysis. The L III-edge XAS and TRLFS studies showed that the biosorption process observed is dependent of pH. The bacterial cell forms a complex with U through organic phosphate groups at pH 2 and via phosphate and carboxyl groups at pH 3 and 4.3, respectively. The differences in the complexes formed between uranium and bacteria on seawater compared to NaClO4 solution demonstrates that the actinide/microbe interactions are influenced by the three studied factors, i.e., the pH, the uranium concentration and the chemical composition of the solution. PMID:24618567

Study of the dislocation contribution to the internal friction background of gold

NASA Astrophysics Data System (ADS)

Baur, J.; Benoit, W.

1987-04-01

The dislocation contribution to the internal friction (IF) background is studied in annealed gold samples containing various dilute concentrations of platinum impurities. The measurements are performed in the kHz frequency range in order to determine the loss mechanism responsible for the high IF background observed at these low frequencies. To this end, the IF background was systematically measured as a function of frequency, vibration amplitude, temperature, and impurity concentration. The experimental results show that the high dislocation contribution observed in annealed samples is strain-amplitude independent for amplitudes in the range 10-7 to 2×10-6, but rapidly decreases for amplitudes smaller than 10-7. In particular, the dislocation contribution tends to zero when the strain amplitude tends to zero. Furthermore, this contribution is frequency independent. These observations demonstrate that the dislocation contribution cannot be explained by relaxations. In particular, this contribution cannot be attributed to a viscous damping of the dislocation motion. On the contrary, the experiments show that the IF background due to dislocations must be explained by hysteretic and athermal motions of dislocations interacting with point defects. However, these hysteretic motions are not due to breakaway of dislocations from pinning points distributed along their length. The experimental results can be explained by the presence of point defects close to the dislocations, but not on them. The mechanical energy loss is attributed to hysteretic motions of dislocations between potential minima created by point defects.

Radionuclide Concentrations in Honey Bees from Area G at TA-54 during 1999

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

T. K. Haarmann; P. R. Fresquez

Honey bees were collected from two colonies located at Los Alamos National Laboratory's Area G, Technical Area 54, and from one control (background) colony located near Jemez Springs, NM. Samples were analyzed for various radionuclides. Area G sample results from both colonies were higher than the upper (95%) level background concentration for {sup 3}H. Sample results from one colony were higher than the upper (95%) level background concentration for total uranium, while sample results from the other colony were higher than the upper (95%) level background concentration for {sup 90}Sr.

Reanalysis of and attribution to near-surface ozone concentrations in Sweden during 1990-2013

NASA Astrophysics Data System (ADS)

Andersson, Camilla; Alpfjord, Heléne; Robertson, Lennart; Karlsson, Per Erik; Engardt, Magnuz

2017-11-01

We have constructed two data sets of hourly resolution reanalyzed near-surface ozone (O3) concentrations for the period 1990-2013 for Sweden. Long-term simulations from a chemistry-transport model (CTM) covering Europe were combined with hourly ozone concentration observations at Swedish and Norwegian background measurement sites using retrospective variational data analysis. The reanalysis data sets show improved performance over the original CTM when compared to independent observations. In one of the reanalyses, we included all available hourly near-surface O3 observations, whilst in the other we carefully selected time-consistent observations. Based on the second reanalysis we investigated statistical aspects of the distribution of the near-surface O3 concentrations, focusing on the linear trend over the 24-year period. We show that high near-surface O3 concentrations are decreasing and low O3 concentrations are increasing, which is reflected in observed improvement of many health and vegetation indices (apart from those with a low threshold). Using the CTM we also conducted sensitivity simulations to quantify the causes of the observed change, focusing on three factors: change in hemispheric background concentrations, meteorology and anthropogenic emissions. The rising low concentrations of near-surface O3 in Sweden are caused by a combination of all three factors, whilst the decrease in the highest O3 concentrations is caused by European O3 precursor emissions reductions. While studying the impact of anthropogenic emissions changes, we identified systematic differences in the modeled trend compared to observations that must be caused by incorrect trends in the utilized emissions inventory or by too high sensitivity of our model to emissions changes.

Source origin of trace elements in PM from regional background, urban and industrial sites of Spain

NASA Astrophysics Data System (ADS)

Querol, X.; Viana, M.; Alastuey, A.; Amato, F.; Moreno, T.; Castillo, S.; Pey, J.; de la Rosa, J.; Sánchez de la Campa, A.; Artíñano, B.; Salvador, P.; García Dos Santos, S.; Fernández-Patier, R.; Moreno-Grau, S.; Negral, L.; Minguillón, M. C.; Monfort, E.; Gil, J. I.; Inza, A.; Ortega, L. A.; Santamaría, J. M.; Zabalza, J.

Despite their significant role in source apportionment analysis, studies dedicated to the identification of tracer elements of emission sources of atmospheric particulate matter based on air quality data are relatively scarce. The studies describing tracer elements of specific sources currently available in the literature mostly focus on emissions from traffic or large-scale combustion processes (e.g. power plants), but not on specific industrial processes. Furthermore, marker elements are not usually determined at receptor sites, but during emission. In our study, trace element concentrations in PM 10 and PM 2.5 were determined at 33 monitoring stations in Spain throughout the period 1995-2006. Industrial emissions from different forms of metallurgy (steel, stainless steel, copper, zinc), ceramic and petrochemical industries were evaluated. Results obtained at sites with no significant industrial development allowed us to define usual concentration ranges for a number of trace elements in rural and urban background environments. At industrial and traffic hotspots, average trace metal concentrations were highest, exceeding rural background levels by even one order of magnitude in the cases of Cr, Mn, Cu, Zn, As, Sn, W, V, Ni, Cs and Pb. Steel production emissions were linked to high levels of Cr, Mn, Ni, Zn, Mo, Cd, Se and Sn (and probably Pb). Copper metallurgy areas showed high levels of As, Bi, Ga and Cu. Zinc metallurgy was characterised by high levels of Zn and Cd. Glazed ceramic production areas were linked to high levels of Zn, As, Se, Zr, Cs, Tl, Li, Co and Pb. High levels of Ni and V (in association) were tracers of petrochemical plants and/or fuel-oil combustion. At one site under the influence of heavy vessel traffic these elements could be considered tracers (although not exclusively) of shipping emissions. Levels of Zn-Ba and Cu-Sb were relatively high in urban areas when compared with industrialised regions due to tyre and brake abrasion, respectively.

The impact of photovoltaic (PV) installations on downwind particulate matter concentrations: Results from field observations at a 550-MWAC utility-scale PV plant.

PubMed

Ravikumar, Dwarakanath; Sinha, Parikhit

2017-10-01

With utility-scale photovoltaic (PV) projects increasingly developed in dry and dust-prone geographies with high solar insolation, there is a critical need to analyze the impacts of PV installations on the resulting particulate matter (PM) concentrations, which have environmental and health impacts. This study is the first to quantify the impact of a utility-scale PV plant on PM concentrations downwind of the project site. Background, construction, and post-construction PM 2.5 and PM 10 (PM with aerodynamic diameters <2.5 and <10 μm, respectively) concentration data were collected from four beta attenuation monitor (BAM) stations over 3 yr. Based on these data, the authors evaluate the hypothesis that PM emissions from land occupied by a utility-scale PV installation are reduced after project construction through a wind-shielding effect. The results show that the (1) confidence intervals of the mean PM concentrations during construction overlap with or are lower than background concentrations for three of the four BAM stations; and (2) post-construction PM 2.5 and PM 10 concentrations downwind of the PV installation are significantly lower than the background concentrations at three of the four BAM stations. At the fourth BAM station, downwind post-construction PM 2.5 and PM 10 concentrations increased marginally by 5.7% and 2.6% of the 24-hr ambient air quality standards defined by the U.S. Environmental Protection Agency, respectively, when compared with background concentrations, with the PM 2.5 increase being statistically insignificant. This increase may be due to vehicular emissions from an access road near the southwest corner of the site or a drainage berm near the south station. The findings demonstrate the overall environmental benefit of downwind PM emission abatement from a utility-scale PV installation in desert conditions due to wind shielding. With PM emission reductions observed within 10 months of completion of construction, post-construction monitoring of downwind PM levels may be reduced to a 1-yr period for other projects with similar soil and weather conditions. This study is the first to analyze impact of a utility photovoltaic (PV) project on downwind particulate matter (PM) concentration in desert conditions. The PM data were collected at four beta attenuation monitor stations over a 3-yr period. The post-construction PM concentrations are lower than background concentrations at three of four stations, therefore supporting the hypothesis of post-construction wind shielding from PV installations. With PM emission reductions observed within 10 months of completion of construction, postconstruction monitoring of downwind PM levels may be reduced to a 1-yr period for other PV projects with similar soil and weather conditions.

Radiological survey of the inactive uranium-mill tailings at Durango, Colorado

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

Haywood, F.F.; Perdue, P.T.; Shinpaugh, W.H.

1980-03-01

Results of a radiological survey of the inactive uranium-mill site at Durango, Colorado, conducted in April 1976, in cooperation with a team from Ford, Bacon and Davis Utah Inc., are presented together with descriptions of the instruments and techniques used to obtain the data. Direct above-ground gamma measurements and analysis of surface soil and sediment samples indicate movement of tailings from the piles toward Lightner Creek on the north and the Animas River on the east side of the piles. The concentration of /sup 226/Ra in the former raffinate pond area is only slightly above the background level. Two structuresmore » in Durango were found to contain high concentrations of airborne radon daughters, where tailings are known to have been utilized in construction. Near-background concentrations of radon daughters were found in a well-ventilated building close to the tailings.« less

PCDD/F measurement at a high-altitude station in Central Taiwan: evaluation of long-range transport of PCDD/Fs during the Southeast Asia biomass burning event.

PubMed

Chi, Kai Hsien; Lin, Chuan-Yao; Yang, Chang-Feng Ou; Wang, Jia-Lin; Lin, Neng-Heui; Sheu, Guey-Rong; Lee, Chung-Te

2010-04-15

Recent biomass burning in Southeast Asia has raised global concerns over its adverse effects on visibility, human health, and global climate. The concentrations of total suspended particles (TSPs) and other vapor-phase pollutants (CO and ozone) were monitored at Lulin, an atmospheric background station in central Taiwan in 2008. To evaluate the long-range transport of persistent organic pollutants (POPs) during the Southeast Asia biomass burning event, the atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were also measured at Lulin station. The atmospheric PCDD/F and TSP concentrations measured at Lulin station ranged from 0.71-3.41 fg I-TEQ/m(3) and 5.32-55.6 microg/m(3), respectively, during the regular sampling periods. However, significantly higher concentrations of PCDD/Fs, TSPs, CO, and ozone were measured during the spring season. These high concentrations could be the result of long-range transport of the products of Southeast Asia biomass burning. During the Southeast Asia biomass burning event (March 18-24, 2008), an intensive observation program was also carried out at the same station. The results of this observation program indicated that the atmospheric PCDD/F concentration increased dramatically from 2.33 to 390 fg I-TEQ/m(3) (March 19, 2008). The trace gas (CO) of biomass burning also significantly increased to 232 ppb during the same period, while the particle-bound PCDD/Fs in the TSP increased from 28.7 to 109 pg I-TEQ/g-TSP at Lulin station during the burning event. We conclude that there was a significant increase in the PCDD/F concentration in ambient air at a high-altitude background station in central Taiwan during the Southeast Asia biomass burning event.

Estimation of background CO2 concentrations at the high alpine station Schneefernerhaus by atmospheric observations and inverse modelling

NASA Astrophysics Data System (ADS)

Giemsa, Esther; Jacobeit, Jucundus; Ries, Ludwig; Frank, Gabriele; Hachinger, Stephan; Meyer-Arnek, Julian

2016-04-01

In order to estimate the influence of Central European CO2 emissions, a new method to retrieve background concentrations based on statistics of radon-222 and backward trajectories is developed and applied to the CO2 observations at the alpine high-altitude research station Schneefernerhaus (2670 m a.s.l.). The reliable identification of baseline conditions is important for perceiving changes in time as well as in the sources and sinks of greenhouse gases and thereby assessing the efficiency of existing mitigation strategies. In the particular case of Central Europe, the analysis of background concentrations could add further insights on the question why background CO2 concentrations increased in the last few decades, despite a significant decrease in the reported emissions. Ongoing effort to define the baseline conditions has led to a variety of data selection techniques. In this diversity of data filtering concepts, a relatively recent data selection method effectively appropriates observations of radon-222 to reliably and unambiguously identify baseline air masses. Owing to its relatively constant emission rate from the ice-free land surface and its half-life of 3.8 days that is solely achieved through radioactive decay, the tropospheric background concentration of the inert radioactive gas is low and temporal variations caused by changes in atmospheric transport are precisely detectable. For defining the baseline air masses reaching the high alpine research station Schneefernerhaus, an objective analysis approach is applied to the two-hourly radon records. The CO2 values of days by the radon method associated with prevailing atmospheric background conditions result in the CO2 concentrations representing the least land influenced air masses. Additionally, three-dimensional back-trajectories were retrieved using the Lagrangian Particle Dispersion Model (LPDM) FLEXPART driven by analysis fields of the Global Forecast System (GFS) produced by the National Centers for Environmental Prediction (NCEP). For the past five years, every two hours a total of 10.000 particles was released and followed backward in time for ten days. The trajectory position was stored with a time step of two hours. Based on the thereby calculated residence time each trajectory spent in the European planetary boundary layer (PBL), a validation of the baseline values derived from the radon statistics is received. Only terms where back trajectories and radon agree in the baseline detection are selected as unpolluted. The ability to eliminate air masses contaminated by European pollution via combining these two filtering techniques permits to analyze the influence of different large-scale source regions to the receptor point Schneefernerhaus. In order to identify the different source regions, cluster analysis with the COST733 classification software is applied to the normalized position coordinates of each selected trajectory. This accounts for the variations in transport speed and direction in both horizontal and vertical directions simultaneously, yielding clusters of trajectories as homogeneous and as distinctly different from each other as possible. This methodology relates the variability in trace gas measurements to variations in synoptic-scale circulation facing a challenging task in the currently changing atmosphere.

Results of a long-term study of vapor intrusion at four large buildings at the NASA Ames Research Center.

PubMed

Brenner, David

2010-06-01

Most of the published empirical data on indoor air concentrations resulting from vapor intrusion of contaminants from underlying groundwater are for residential structures. The National Aeronautics and Space Administration (NASA) Research Park site, located in Moffett Field, CA, and comprised of 213 acres, is being planned for redevelopment as a collaborative research and educational campus with associated facilities. Groundwater contaminated with hydrocarbon and halogenated hydrocarbon volatile organic compounds (VOCs) is the primary environmental medium of concern at the site. Over a 15-month period, approximately 1000 indoor, outdoor ambient, and outdoor ambient background samples were collected from four buildings designated as historical landmarks using Summa canisters and analyzed by the U.S. Environmental Protection Agency TO-15 selective ion mode. Both 24-hr and sequential 8-hr samples were collected. Comparison of daily sampling results relative to daily background results indicates that the measured trichloroethylene (TCE) concentrations were primarily due to the subsurface vapor intrusion pathway, although there is likely some contribution due to infiltration of TCE from the outdoor ambient background concentrations. Analysis of the cis-1,2-dichloroethylene concentrations relative to TCE concentrations with respect to indoor air concentrations and the background air support this hypothesis; however, this indicates that relative contributions of the vapor intrusion and infiltration pathways vary with each building. Indoor TCE concentrations were also compared with indoor benzene and background benzene concentrations. These data indicate significant correlation between background benzene concentrations and the concentration of benzene in the indoor air, indicating benzene was present in the indoor air primarily through infiltration of outdoor air into the indoor space. By comparison, measured TCE indoor air concentrations showed a significantly different relationship to background concentrations. Analysis of the results show that indoor air samples can be used to definitively define the source of the TCE present in the indoor air space of large industrial buildings.

Levels, trends and health concerns of atmospheric PAHs in Europe

NASA Astrophysics Data System (ADS)

Garrido, Adrián; Jiménez-Guerrero, Pedro; Ratola, Nuno

2014-12-01

Changes in climate can affect the concentration patterns of polycyclic aromatic hydrocarbons (PAHs) by altering the dispersion (wind speed, mixing layer height, convective fronts), deposition by precipitation, dry deposition, photochemistry, natural emissions and background concentrations. This means the evolution trends of these pollutants have to be studied under a multi-scale perspective, allowing the establishment of transport patterns and distribution of PAHs. In this sense, this work tries to unveil the atmospheric behaviour of these pollutants using temporal data series collected in different stations from the European Monitoring and Evaluation Programme (EMEP) air sampling network. These sites are thought to avoid the direct influence of emitting areas (background stations), allowing the study of long-range transport effects, intra- and trans-annual variability, relationships between concentrations patterns and meteorological variables and latitudinal gradients of PAH levels in Europe. Overall, a typical high concentration pattern was found for the colder months (and an opposite behaviour is found for summertime). Negative trends were detected over high latitudes, for instance, in Svalbard (Norway), whereas for the United Kingdom the pattern is the inverse. Also, negative latitudinal gradients were observed in 4 of the 15 PAHs studied. Finally, air quality parameters revealed concern over human health issues, given the recent increase of BaP levels in Europe.

Prediction Metrics for Chemical Detection in Long-Wave Infrared Hyperspectral Imagery

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

Chilton, Marie C.; Walsh, Stephen J.; Daly, Don S.

2009-01-29

A natural or anthropogenic process often generates a signature gas plume whose chemical constituents may be identified using hyperspectral imagery. A hyperspectral image is a pixel-indexed set of spectra where each spectrum reflects the chemical constituents of the plume, the atmosphere, the bounding background surface, and instrument noise. This study explored the relationship between gas absorbance and background emissivity across the long-wave infrared (LWIR) spectrum and how they affect relative gas detection sensitivity. The physics-based model for the observed radiance shows that high gas absorbance coupled with low background emissivity at a single wavenumber results in a stronger recorded radiance.more » Two sensitivity measures were developed to predict relative probability of detection using chemical absorbance and background emissivity: one focused on a single wavenumber while another accounted for the entire spectrum. The predictive abilities of these measures were compared to synthetic image analysis. This study simulated images with 499 distinct gases at each of 6 concentrations over 6 different background surfaces with the atmosphere and level of instrument noise held constant. The Whitened Matched Filter was used to define gas detection from an image spectrum. The estimate of a chemical’s probability of detection at a given concentration over a specific background was the proportion of detections in 500 trials. Of the 499 chemicals used in the images, 276 had estimated probabilities of detection below 0.2 across all backgrounds and concentrations; these chemicals were removed from the study. For 92.8 percent of the remaining chemicals, the single channel measure correctly predicted the background over which the chemical had the largest relative probability of detection. Further, the measure which accounted for information across all wavenumbers predicted the background over which the chemical had the largest relative probability of detection for 93.3 percent of the chemicals. These results suggest that the wavenumber with largest gas absorbance has the most influence over gas detection for this data. By furthering the in-silico experimentation with higher concentrations of gases not detectable in this experiment or by standardizing the gas absorbance spectra to unit vectors, these conclusions may be confirmed and generalized to more gases. This will help simplify image acquisition planning and the identification of unknowns in field collected images.« less

Cadmium background concentrations to establish reference quality values for soils of São Paulo State, Brazil.

PubMed

de Oliveira, Vinicius Henrique; de Abreu, Cleide Aparecida; Coelho, Ricardo Marques; Melo, Leônidas Carrijo Azevedo

2014-03-01

Proper assessment of soil cadmium (Cd) concentrations is essential to establish legislative limits. The present study aimed to assess background Cd concentrations in soils from the state of São Paulo, Brazil, and to correlate such concentrations with several soil attributes. The topsoil samples (n = 191) were assessed for total Cd contents and for other metals using the USEPA 3051A method. The background concentration was determined according to the third quartile (75th). Principal component analysis, Spearman correlation, and multiple regressions between Cd contents and other soil attributes (pH, cation exchange capacity (CEC), clay content, sum of bases, organic matter, and total Fe, Al, Zn, and Pb levels) were performed. The mean Cd concentration of all 191 samples was 0.4 mg kg(-1), and the background concentration was 0.5 mg kg(-1). After the samples were grouped by parent material (rock origin) and soil type, the background Cd content varied, i.e., soils from igneous, metamorphic, and sedimentary rocks harbored 1.5, 0.4, and 0.2 mg kg(-1) of Cd, respectively. The background Cd content in Oxisols (0.8 mg kg(-1)) was higher than in Ultisols (0.3 mg kg(-1)). Multiple regression demonstrated that Fe was primarily attributed to the natural Cd contents in the soils (R (2) = 0.79). Instead of a single Cd background concentration value representing all São Paulo soils, we propose that the concentrations should be specific for at least Oxisols and Ultisols, which are the primary soil types.

High purity low dislocation GaAs single crystals

NASA Technical Reports Server (NTRS)

Chen, R. T.; Holmes, D. E.; Kirkpatrick, C. G.

1982-01-01

Recent advances in GaAs bulk crystal growth using the LEC (liquid encapsulated Czochralski) technique are described. The dependence of the background impurity concentration and the dislocation density distribution on the materials synthesis and growth conditions were investigated. Background impurity concentrations as low as 4 x 10 to the 15th power were observed in undoped LEC GaAs. The dislocation density in selected regions of individual ingots was very low, below the 3000 cm .3000/sq cm threshold. The average dislocation density over a large annular ring on the wafers fell below the 10000/sq cm level for 3 inch diameter ingots. The diameter control during the program advanced to a diameter variation along a 3 inch ingot less than 2 mm.

Associations of obesity with triglycerides and C-reactive protein are attenuated in adults with high red blood cell eicosapentaenoic and docosahexaenoic acids

USDA-ARS?s Scientific Manuscript database

Background:N-3 fatty acids are associated with favorable, and obesity with unfavorable, concentrations of chronic disease risk biomarkers.Objective:We examined whether high eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid intakes, measured as percentages of total red blood cell (RBC) fatty acid...

Ecological risk assessment: influence of texture on background concentration of microelements in soils of Russia.

NASA Astrophysics Data System (ADS)

Beketskaya, Olga

2010-05-01

In Russia quality standards of contaminated substances values in environment consist of ecological and sanitary rate-setting. The sanitary risk assessment base on potential risk that contaminants pose to protect human beings. The main purpose of the ecological risk assessment is to protect ecosystem. To determine negative influence on living organisms in the sanitary risk assessment in Russia we use MPC. This value of contaminants show how substances affected on different part of environment, biological activity and soil processes. The ecological risk assessment based on comparison compounds concentration with background concentration for definite territories. Taking into account high interval of microelements value in soils, we suggest using statistic method for determination of concentration levels of chemical elements concentration in soils of Russia. This method is based on determination middle levels of elements content in natural condition. The top limit of middle chemical elements concentration in soils is value, which exceed middle regional background level in three times standard deviation. The top limit of natural concentration excess we can explain as anthropogenic impact. At first we study changing in the middle content value of microelements in soils of geographic regions in European part of Russia on the basis of cartographical analysis. Cartographical analysis showed that the soil of mountainous and mountain surrounding regions is enriched with microelements. On the plain territory of European part of Russia for most of microelements was noticed general direction of increasing their concentration in soils from north to south, also in the same direction soil clay content rise for majority of soils. For all other territories a clear connection has been noticed between the distribution of sand sediment. By our own investigation and data from scientific literature data base was created. This data base consist of following soil properties: texture, organic matter content, concentration of microelements and pH value. On the basis of this data base massive of data for Forest-steppe and Steppe regions was create, which was divided by texture. For all data statistics method was done and was calculated maximum level natural microelements content for soils with different texture (?+3*δ). As a result of our statistic calculation we got middle and the top limit of background concentration of microelements in sandy and clay soils (conditional border - sandy loam) of two regions. We showed, that for all territory of European part of Russia and for Forest-steppe and Steppe regions separately middle content and maximum level natural microelements concentrations (?+3*σ) are higher in clay soils, rather then in sandy soils. Data characterizing soils, in different regions, of similar texture differs less than the data collected for sandy and clay soils of the same region. After all this calculation we can notice, that data of middle and top limit of background microelements concentration in soils, based on statistic method, can be used in the aim of ecological risk assessment. Using offered method allow to calculate top limit of background concentration for sandy and clay soils for large-scale geographic regions, exceeding which will be evidence of anthropogenic contamination of soil.

Monitoring heavy metal concentrations in the sediments of the Moskva and Oka River system- Results of the Volga-Rhine-Project

NASA Astrophysics Data System (ADS)

Andresen, Höpke

2010-05-01

In the course of the Volga-Rhine-Project sediment, water and pore water samples were collected on the Volga as well as the Moskva and Oka river systems. The sampling area discussed here is located south east of the city of Moscow. Sediment samples were taken along the Moskva River between Moscow and the city of Kolomna, which is approximately 100 km to the southeast of Moscow and in the Oka River close to the confluence with the Moskva River (Kolomna). The first sampling campaign in this region took place in 1993, followed by further sampling in 1997 and 2007. For evaluation of sediment quality classification systems are often used. The geo-accumulation index proposed by Mueller (1979) is a classification system which consists of seven classes given by the following expression: I = log2×Cn- geo 1.5×Bn Where Cn = measured concentration; Bn = background value (Turekian & Wedepol 1961) of element n and 1.5 = background matrix correction factor. The geo-accumulation index consists of seven grades (0-6) which indicate the enrichment of an element compared to the background value. These grades range from 'not polluted' to 'very strongly polluted'. Another possibility to express sediment contamination is to evaluate the effects on the ecosystem. The lowest effect level (LEL) gives the concentrations of the heavy metals in sediment below which no effect on the majority of the sediment dwelling organisms is expected. The probable effect level (PEL) represents the concentration of heavy metals above which the organisms frequently will show adverse effects. Both of these approaches were used to evaluate the results of the Volga-Rhine-Project. In the last two decades the concentrations of heavy metals in the sediments decreased by up to 60%. In 1993 sediments revealed high concentrations of several heavy metals such as chromium, cadmium, lead, zinc, arsenic, nickel and cobalt, whereas in 2007 only two sediment samples were classified as 'very strongly polluted' regarding lead and cadmium concentrations. Additionally six other sediment samples were found to be 'strongly polluted' with cadmium, zinc and lead, respectively. Using the ecotoxicological approach on the sediments, chromium, cadmium and zinc are above the PEL, whereas the content of lead exceeds the LEL. Thus, these metals may still cause toxic effects on the fresh water system. Although the input of heavy metals into the river systems has clearly decreased during the last 20 years, there are still some locations where high concentrations of heavy metals are found, suggesting point sources. Especially cadmium still shows significantly higher concentrations than the background value in the entire sampling area. There are even two sampling points where the cadmium concentrations reach approximately 100x the background value. To determine the temporal variation of the heavy metal input, sediment cores were taken. Heavy metal concentrations increase with depth in the cores and show a maximum at a depth of about 35-40 cm. Some part of this increase may be a result of early diagenesis as well as a result of reduced heavy metal input. The nature of the decline of the heavy metal concentrations is still in progress. Despite all the improvements achieved in environmental protection in Russia, still some problems have to be addressed. Especially in urban areas like the Moscow region the number and the size of illegal dump sites is increasing dramatically, leading to strong inputs of heavy metals and other pollutants into the river systems, with consequences for the sensitive eco systems.

Application of nonparametric regression methods to study the relationship between NO2 concentrations and local wind direction and speed at background sites.

PubMed

Donnelly, Aoife; Misstear, Bruce; Broderick, Brian

2011-02-15

Background concentrations of nitrogen dioxide (NO(2)) are not constant but vary temporally and spatially. The current paper presents a powerful tool for the quantification of the effects of wind direction and wind speed on background NO(2) concentrations, particularly in cases where monitoring data are limited. In contrast to previous studies which applied similar methods to sites directly affected by local pollution sources, the current study focuses on background sites with the aim of improving methods for predicting background concentrations adopted in air quality modelling studies. The relationship between measured NO(2) concentration in air at three such sites in Ireland and locally measured wind direction has been quantified using nonparametric regression methods. The major aim was to analyse a method for quantifying the effects of local wind direction on background levels of NO(2) in Ireland. The method was expanded to include wind speed as an added predictor variable. A Gaussian kernel function is used in the analysis and circular statistics employed for the wind direction variable. Wind direction and wind speed were both found to have a statistically significant effect on background levels of NO(2) at all three sites. Frequently environmental impact assessments are based on short term baseline monitoring producing a limited dataset. The presented non-parametric regression methods, in contrast to the frequently used methods such as binning of the data, allow concentrations for missing data pairs to be estimated and distinction between spurious and true peaks in concentrations to be made. The methods were found to provide a realistic estimation of long term concentration variation with wind direction and speed, even for cases where the data set is limited. Accurate identification of the actual variation at each location and causative factors could be made, thus supporting the improved definition of background concentrations for use in air quality modelling studies. Copyright © 2010 Elsevier B.V. All rights reserved.

U. S. EPA’S NA APPROACH FOR PETROLEUM HYDROCARBONS

EPA Science Inventory

Most evaluations of NA of petroleum hydrocarbons use geochemical data to document the NA through biodegradation. The expected trends during biodegradation (plume interior vs. background concentrations) are Dissolved oxygen concentrations below background, Nitrate concentrations ...

Sprayable enzyme-activatable fluorescent probes: kinetic mapping using dynamic fluorescence imaging can help detecting tiny cancer foci (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kobayashi, Hisataka

2017-02-01

Optical fluorescence-guided imaging is increasingly used to guide surgery and endoscopic procedures. Sprayable enzyme-activatable probes are particularly useful because of high target-to-background ratios that increase sensitivity for tiny cancer foci. However, green fluorescent activatable probes suffers from interference from autofluorescence found in biological tissue. Dynamic imaging followed by the kinetic analysis could be detected local enzyme activity and used to differentiate specific fluorescence arising from an activated probe in a tumor from autofluorescence in background tissues especially when low concentrations of the dye are applied to detect tiny cancer foci. Serial fluorescence imaging was performed using various concentrations of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) which was sprayed on the peritoneal surface with tiny implants of SHIN3-dsRed ovarian cancer tumors. Temporal differences in signal between specific green fluorescence in cancer foci and non-specific autofluorescence in background tissue was measured and processed into three kinetic maps reflecting maximum fluorescence signal (MF), wash-in rate (WIR), and area under the curve (AUC), respectively. Especially at lower concentrations, kinetic maps derived from dynamic fluorescence imaging were clearly superior to unprocessed images for detection small cancer foci.

Land cover and air pollution are associated with asthma hospitalisations: A cross-sectional study.

PubMed

Alcock, Ian; White, Mathew; Cherrie, Mark; Wheeler, Benedict; Taylor, Jonathon; McInnes, Rachel; Otte Im Kampe, Eveline; Vardoulakis, Sotiris; Sarran, Christophe; Soyiri, Ireneous; Fleming, Lora

2017-12-01

There is increasing policy interest in the potential for vegetation in urban areas to mitigate harmful effects of air pollution on respiratory health. We aimed to quantify relationships between tree and green space density and asthma-related hospitalisations, and explore how these varied with exposure to background air pollution concentrations. Population standardised asthma hospitalisation rates (1997-2012) for 26,455 urban residential areas of England were merged with area-level data on vegetation and background air pollutant concentrations. We fitted negative binomial regression models using maximum likelihood estimation to obtain estimates of asthma-vegetation relationships at different levels of pollutant exposure. Green space and gardens were associated with reductions in asthma hospitalisation when pollutant exposures were lower but had no significant association when pollutant exposures were higher. In contrast, tree density was associated with reduced asthma hospitalisation when pollutant exposures were higher but had no significant association when pollutant exposures were lower. We found differential effects of natural environments at high and low background pollutant concentrations. These findings can provide evidence for urban planning decisions which aim to leverage health co-benefits from environmental improvements. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of brightness and stoichiometry of bright particles by flow-fluorescence fluctuation spectroscopy.

PubMed

Johnson, Jolene; Chen, Yan; Mueller, Joachim D

2010-11-03

Characterization of bright particles at low concentrations by fluorescence fluctuation spectroscopy (FFS) is challenging, because the event rate of particle detection is low and fluorescence background contributes significantly to the measured signal. It is straightforward to increase the event rate by flow, but the high background continues to be problematic for fluorescence correlation spectroscopy. Here, we characterize the use of photon-counting histogram analysis in the presence of flow. We demonstrate that a photon-counting histogram efficiently separates the particle signal from the background and faithfully determines the brightness and concentration of particles independent of flow speed, as long as undersampling is avoided. Brightness provides a measure of the number of fluorescently labeled proteins within a complex and has been used to determine stoichiometry of protein complexes in vivo and in vitro. We apply flow-FFS to determine the stoichiometry of the group specific antigen protein within viral-like particles of the human immunodeficiency virus type-1 from the brightness. Our results demonstrate that flow-FFS is a sensitive method for the characterization of complex macromolecular particles at low concentrations. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Large inter annual variation in air quality during the annual festival 'Diwali' in an Indian megacity.

PubMed

Parkhi, Neha; Chate, Dilip; Ghude, Sachin D; Peshin, Sunil; Mahajan, Anoop; Srinivas, Reka; Surendran, Divya; Ali, Kaushar; Singh, Siddhartha; Trimbake, Hanumant; Beig, Gufran

2016-05-01

A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research (SAFAR) project in Delhi. We report observations of ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM2.5 and PM10) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM10 and PM2.5 mass concentration is as high as 2070µg/m3 and 1620μg/m(3), respectively (24hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards (NAAQS). For Diwali-2011, the increase in PM10 and PM2.5 mass concentrations was much less with their peaks of 600 and of 390μg/m(3) respectively, as compared to the background concentrations. Contrary to previous reports, firework display was not found to strongly influence the NOx, and O3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters. Copyright © 2015. Published by Elsevier B.V.

Determinants of aerosol lung-deposited surface area variation in an urban environment.

PubMed

Reche, Cristina; Viana, Mar; Brines, Mariola; Pérez, Noemí; Beddows, David; Alastuey, Andrés; Querol, Xavier

2015-06-01

Ultrafine particles are characterized by a high surface area per mass. Particle surface has been reported to play a significant role in determining the toxicological activity of ultrafine particles. In light of this potential role, the time variation of lung deposited surface area (LDSA) concentrations in the alveolar region was studied at the urban background environment of Barcelona (Spain), aiming to asses which processes and sources govern this parameter. Simultaneous data on Black Carbon (BC), total particle number (N) and particle number size distribution were correlated with LDSA. Average LDSA concentrations in Barcelona were 37 ± 26 μm(2)cm(-3), levels which seem to be characteristic for urban environments under traffic influence across Europe. Results confirm the comparability between LDSA data provided by the online monitor and those calculated based on particle size distributions (by SMPS), and reveal that LDSA concentrations are mainly influenced by particles in the size range 50-200 nm. A set of representative daily cycles for LDSA concentrations was obtained by means of a k-means cluster technique. The contribution of traffic emissions to daily patterns was evidenced in all the clusters, but was quantitatively different. Traffic events under stable atmospheric conditions increased mean hourly background LDSA concentrations up to 6 times, attaining levels higher than 200 μm(2)cm(-3). However, under warm and relatively clean atmospheric conditions, the traffic rush hour contribution to the daily LDSA mean appeared to be lower and the contribution of new urban particle formation events (by photochemically induced nucleation) was detected. These nucleation events were calculated to increase average background LDSA concentrations by 15-35% (maximum LDSA levels=45-50 μm(2)cm(-3)). Thereby, it may be concluded that in the urban background of Barcelona road traffic is the main source increasing the aerosol surface area which can deposit on critical regions of the human lung, followed by nucleation episodes. Copyright © 2015 Elsevier B.V. All rights reserved.

Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories

NASA Astrophysics Data System (ADS)

Schmale, Julia; Henning, Silvia; Decesari, Stefano; Henzing, Bas; Keskinen, Helmi; Sellegri, Karine; Ovadnevaite, Jurgita; Pöhlker, Mira L.; Brito, Joel; Bougiatioti, Aikaterini; Kristensson, Adam; Kalivitis, Nikos; Stavroulas, Iasonas; Carbone, Samara; Jefferson, Anne; Park, Minsu; Schlag, Patrick; Iwamoto, Yoko; Aalto, Pasi; Äijälä, Mikko; Bukowiecki, Nicolas; Ehn, Mikael; Frank, Göran; Fröhlich, Roman; Frumau, Arnoud; Herrmann, Erik; Herrmann, Hartmut; Holzinger, Rupert; Kos, Gerard; Kulmala, Markku; Mihalopoulos, Nikolaos; Nenes, Athanasios; O'Dowd, Colin; Petäjä, Tuukka; Picard, David; Pöhlker, Christopher; Pöschl, Ulrich; Poulain, Laurent; Prévôt, André Stephan Henry; Swietlicki, Erik; Andreae, Meinrat O.; Artaxo, Paulo; Wiedensohler, Alfred; Ogren, John; Matsuki, Atsushi; Yum, Seong Soo; Stratmann, Frank; Baltensperger, Urs; Gysel, Martin

2018-02-01

Aerosol-cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN). Here we present a data set - ready to be used for model validation - of long-term observations of CCN number concentrations, particle number size distributions and chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural background, alpine sites, remote forests and an urban surrounding. Expectedly, CCN characteristics are highly variable across site categories. However, they also vary within them, most strongly in the coastal background group, where CCN number concentrations can vary by up to a factor of 30 within one season. In terms of particle activation behaviour, most continental stations exhibit very similar activation ratios (relative to particles > 20 nm) across the range of 0.1 to 1.0 % supersaturation. At the coastal sites the transition from particles being CCN inactive to becoming CCN active occurs over a wider range of the supersaturation spectrum. Several stations show strong seasonal cycles of CCN number concentrations and particle number size distributions, e.g. at Barrow (Arctic haze in spring), at the alpine stations (stronger influence of polluted boundary layer air masses in summer), the rain forest (wet and dry season) or Finokalia (wildfire influence in autumn). The rural background and urban sites exhibit relatively little variability throughout the year, while short-term variability can be high especially at the urban site. The average hygroscopicity parameter, κ, calculated from the chemical composition of submicron particles was highest at the coastal site of Mace Head (0.6) and lowest at the rain forest station ATTO (0.2-0.3). We performed closure studies based on κ-Köhler theory to predict CCN number concentrations. The ratio of predicted to measured CCN concentrations is between 0.87 and 1.4 for five different types of κ. The temporal variability is also well captured, with Pearson correlation coefficients exceeding 0.87. Information on CCN number concentrations at many locations is important to better characterise ACI and their radiative forcing. But long-term comprehensive aerosol particle characterisations are labour intensive and costly. Hence, we recommend operating migrating-CCNCs to conduct collocated CCN number concentration and particle number size distribution measurements at individual locations throughout one year at least to derive a seasonally resolved hygroscopicity parameter. This way, CCN number concentrations can only be calculated based on continued particle number size distribution information and greater spatial coverage of long-term measurements can be achieved.

Comparison of background levels of culturable fungal spore concentrations in indoor and outdoor air in southeastern Austria

NASA Astrophysics Data System (ADS)

Haas, D.; Habib, J.; Luxner, J.; Galler, H.; Zarfel, G.; Schlacher, R.; Friedl, H.; Reinthaler, F. F.

2014-12-01

Background concentrations of airborne fungi are indispensable criteria for an assessment of fungal concentrations indoors and in the ambient air. The goal of this study was to define the natural background values of culturable fungal spore concentrations as reference values for the assessment of moldy buildings. The concentrations of culturable fungi were determined outdoors as well as indoors in 185 dwellings without visible mold, obvious moisture problems or musty odor. Samples were collected using the MAS-100® microbiological air sampler. The study shows a characteristic seasonal influence on the background levels of Cladosporium, Penicillium and Aspergillus. Cladosporium sp. had a strong outdoor presence, whereas Aspergillus sp. and Penicillium sp. were typical indoor fungi. For the region of Styria, the median outdoor concentrations are between 100 and 940 cfu/m³ for culturable xerophilic fungi in the course of the year. Indoors, median background levels are between 180 and 420 cfu/m³ for xerophilic fungi. The I/O ratios of the airborne fungal spore concentrations were between 0.2 and 2.0. For the assessment of indoor and outdoor air samples the dominant genera Cladosporium, Penicillium and Aspergillus should receive special consideration.

Determination of semi-volatile and particle-associated polycyclic aromatic hydrocarbons in Stockholm air with emphasis on the highly carcinogenic dibenzopyrene isomers

NASA Astrophysics Data System (ADS)

Masala, Silvia; Lim, Hwanmi; Bergvall, Christoffer; Johansson, Christer; Westerholm, Roger

2016-09-01

The concentrations of polycyclic aromatic hydrocarbons (PAHs) have been determined in the gaseous phase and in various particulate matter (PM) size fractions at different locations in and outside of Stockholm, Sweden, representative of street level, urban and rural background. The focus has been on the seldom determined but highly carcinogenic dibenzopyrene isomers (DBPs) dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene. PAHs with 3 rings were found to be mainly associated with the vapor phase (>90%) whereas PAHs with 5-6 rings were mostly associated with particulate matter (>92%) and the 4-ringed PAHs partitioned between the two phases. PAH abundance was determined to be in the order street level > urban background > rural background with the PM10 street level 2010 mean of benzo[a]pyrene (B[a]P) reaching 0.24 ng/m3, well below the EU annual limit value of 1 ng/m3. In addition, higher PAH concentrations were found in the sub-micron particle fraction (PM1) as compared to the super-micron fraction (PM1-10) with the abundance in PM1 varying between 57 and 86% of the total PAHs. The B[a]P equivalent concentrations derived for DB[a,l]P and total DBPs exceeded 1-2 and 2-4 times, respectively, that of B[a]P at the four sampling sites; therefore underestimation of the cancer risk posed by PAHs in air could be made if the DBPs were not considered in risk assessment using the toxic equivalency approach, whilst the high correlation (p < 0.001) found in the relative concentrations supports the use of B[a]P as a marker substance for assessment of the carcinogenic risk associated to PAHs. However, the big difference in concentration ratios of B[a]P and the DBPs between the present study and some literature data calls for further research to evaluate the temporal and spatial invariance of the B[a]P/DBP ratios.

Excretion Profiles and Half-Lives of Ten Urinary Polycyclic Aromatic Hydrocarbon Metabolites after Dietary Exposure

PubMed Central

Li, Zheng; Romanoff, Lovisa; Bartell, Scott; Pittman, Erin N.; Trinidad, Debra A.; McClean, Michael; Webster, Thomas F.; Sjödin, Andreas

2015-01-01

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed by biomonitoring of their urinary mono-hydroxylated metabolites (OH-PAHs). Limited information exists on the human pharmacokinetics of OH-PAHs. This study aimed to investigate the excretion half-life of 1-hydroxypyrene (1-PYR), the most used biomarker for PAH exposure, and 9 other OH-PAHs following a dietary exposure in 9 non-smoking volunteers with no occupational exposure to PAHs. Each person avoided food with known high PAH-content during the study period, except for a high PAH-containing lunch (barbecued chicken) on the first day. Individual urine samples (n = 217) were collected from 15 hours before to 60 hours following the dietary exposure. Levels of all OH-PAHs in all subjects increased rapidly by 9–141 fold after the exposure, followed by a decrease consistent with first order kinetics, and returned to background levels 24–48 hours after the exposure. The average time to reach maximal concentration ranged from 3.1 h (1-naphthol) to 5.5 h (1-PYR). Creatinine-adjusted urine concentrations for each metabolite were analyzed using a non-linear mixed effects model including a term to estimate background exposure. The background-adjusted half-life estimate was 3.9 h for 1-PYR and ranged 2.5–6.1 h for the other 9 OH-PAHs, which in general, were shorter than those previously reported. The maximum concentrations after the barbecued chicken consumption were comparable to the levels found in reported occupational settings with known high PAH exposures. It is essential to consider the relatively short half-life, the timing of samples relative to exposures, and the effect of diet when conducting PAH exposure biomonitoring studies. PMID:22663094

Reevalution of background iodine-129 concentrations in water from the Snake River Plain Aquifer, Idaho, 2003

USGS Publications Warehouse

Cecil, L. DeWayne; Hall, L. Flint; Green, Jaromy R.

2003-01-01

Background concentrations of iodine-129 (129I, half-life = 15.7 million years) resulting from natural production in the earth?s atmosphere, in situ production in the earth by spontaneous fission of uranium-238(238U), and fallout from nuclear weapons tests conducted in the 1950s and 1960s were reevaluated on the basis of 52 analyses of ground- and surface-water samples collected from the eastern Snake River Plain in southeastern Idaho. The background concentration estimated using the results of a subset of 30 ground-water samples analyzed in this reevaluation is 5.4 attocuries per liter (aCi/L; 1 aCi = 10-18 curies) and the 95-percent nonparametric confidence interval is 5.2 to 10.0 aCi/L. In a previous study, a background 129I concentration was estimated on the basis of analyses of water samples from 16 sites on or tributary to the eastern Snake River Plain. At the 99-percent confidence level, background concentrations of 129I in that study were less than or equal to 8.2 aCi/L. During 1993?94, 34 water samples from 32 additional sites were analyzed for 129I to better establish the background concentrations in surface and ground water from the eastern Snake River Plain that is presumed to be unaffected by wastedisposal practices at the Idaho National Engineering and Environmental Laboratory (INEEL). Surface water contained larger 129I concentrations than water from springs and wells contained. Because surface water is more likely to be affected by anthropogenic fallout and evapotranspiration, background 129I concentrations were estimated in the current research using the laboratory results of ground-water samples that were assumed to be unaffected by INEEL disposal practices.

RNase-assisted RNA chromatography

PubMed Central

Michlewski, Gracjan; Cáceres, Javier F.

2010-01-01

RNA chromatography combined with mass spectrometry represents a widely used experimental approach to identify RNA-binding proteins that recognize specific RNA targets. An important drawback of most of these protocols is the high background due to direct or indirect nonspecific binding of cellular proteins to the beads. In many cases this can hamper the detection of individual proteins due to their low levels and/or comigration with contaminating proteins. Increasing the salt concentration during washing steps can reduce background, but at the cost of using less physiological salt concentrations and the likely loss of important RNA-binding proteins that are less stringently bound to a given RNA, as well as the disassembly of protein or ribonucleoprotein complexes. Here, we describe an improved RNA chromatography method that relies on the use of a cocktail of RNases in the elution step. This results in the release of proteins specifically associated with the RNA ligand and almost complete elimination of background noise, allowing a more sensitive and thorough detection of RNA-binding proteins recognizing a specific RNA transcript. PMID:20571124

Importance of background values in assessing the impact of heavy metals in river ecosystems: case study of Tisza River, Serbia.

PubMed

Štrbac, Snežana; Kašanin Grubin, Milica; Vasić, Nebojša

2017-11-30

The main objective of this paper is to evaluate how a choice of different background values may affect assessing the anthropogenic heavy metal pollution in sediments from Tisza River (Serbia). The second objective of this paper is to underline significance of using geochemical background values when establishing quality criteria for sediment. Enrichment factor (EF), geoaccumulation index (I geo ), pollution load index (PLI), and potential ecological risk index (PERI) were calculated using different background values. Three geochemical (average metal concentrations in continental crust, average metal concentrations in shale, and average metal concentrations in non-contaminated core sediment samples) and two statistical methods (delineation method and principal component analyses) were used for calculating background values. It can be concluded that obtained information of pollution status can be more dependent on the use of background values than the index/factor chosen. The best option to assess the potential river sediment contamination is to compare obtained concentrations of analyzed elements with concentrations of mineralogically and texturally comparable, uncontaminated core sediment samples. Geochemical background values should be taken into account when establishing quality criteria for soils, sediments, and waters. Due to complexity of the local lithology, it is recommended that environmental monitoring and assessment include selection of an appropriate background values to gain understanding of the geochemistry and potential source of pollution in a given environment.

Differences in relative bioavailability of traditional Bangladeshi meal plans

USDA-ARS?s Scientific Manuscript database

Background: Iron (Fe) deficiency is the most common nutrient deficiency worldwide. Large intakes of micronutrient-poor staple crops, coupled with low intakes of highly bioavailable dietary Fe is a major cause of this deficiency. Objective: This study examined the Fe concentration and relative Fe ...

Management practices affect soil nutrients and bacterial populations in backgrounding beef feedlot

USDA-ARS?s Scientific Manuscript database

Contaminants associated with manure in animal production sites are of significant concern. Unless properly managed, high soil nutrient concentrations in feedlots can deteriorate soil and water quality. This three year study tested a nutrient management strategy with three sequentially imposed manage...

IMPACT OF AN INDOOR COOK STOVE INTERVENTION ON MEASURES OF SYSTEMIC INFLAMMATION

EPA Science Inventory

Background and Aims: Approximately three billion people use inefficient and poorly-vented indoor cook stoves, which can result in high indoor air pollution concentrations. Few studies have evaluated the cardiovascular effects of indoor biomass burning. Methods: In this pilot s...

Concentrations of ultrafine particles at a highway toll collection booth and exposure implications for toll collectors.

PubMed

Cheng, Yu-Hsiang; Huang, Cheng-Hsiung; Huang, Hsiao-Lin; Tsai, Chuen-Jinn

2010-12-15

Research regarding the magnitude of ultrafine particle levels at highway toll stations is limited. This study measured ambient concentrations of ultrafine particles at a highway toll station from October 30 to November 1 and November 5 to November 6, 2008. A scanning mobility particle sizer was used to measure ultrafine particle concentrations at a ticket/cash tollbooth. Levels of hourly average ultrafine particles at the tollbooth were about 3-6 times higher than those in urban backgrounds, indicating that a considerable amount of ultrafine particles are exhausted from passing vehicles. A bi-modal size distribution pattern with a dominant mode at about <6 nm and a minor mode at about 40 nm was observed at the tollbooth. The high amounts of nanoparticles in this study can be attributed to gas-to-particle reactions in fresh fumes emitted directly from vehicles. The influences of traffic volume, wind speed, and relative humidity on ultrafine particle concentrations were also determined. High ambient concentrations of ultrafine particles existed under low wind speed, low relative humidity, and high traffic volume. Although different factors account for high ambient concentrations of ultrafine particles at the tollbooth, measurements indicate that toll collectors who work close to traffic emission sources have a high exposure risk. Copyright © 2010 Elsevier B.V. All rights reserved.

S-phenyl-N-acetylcysteine in urine of rats and workers after exposure to benzene

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

Jongeneelen, F.J.; Dirven, H.A.; Leijdekkers, C.M.

1987-05-01

An HPLC method for the determination of S-phenyl-N-acetylcysteine in urine is described. The sensitivity is 6 mumol/L (CV = 9%) urine. Exposure of rats to six different concentrations of benzene, ranging from 0-30 ppm, was highly associated with urinary excretion of S-phenyl-N-acetylcysteine (r = 0.86) and with total phenol (r = 0.81). A background level of phenol was found in urine of both non-exposed rats and of non-exposed referents. However, no background excretion of S-phenyl-N-acetylcysteine was found, either in rats or in humans. In urine of exposed rats, the level of S-phenyl-N-acetylcysteine was approximately five times lower than the phenolmore » level. Workers occupationally exposed to benzene, showing high levels of urinary phenol, revealed low concentrations of urinary S-phenyl-N-acetylcysteine. The biological monitoring of industrial exposure to benzene by determination of S-phenyl-N-acetylcysteine in urine is not better than the determination of phenol in urine.« less

Contamination of soils with heavy metals and metalloids in the vicinity of the Erdenet copper-molybdenum mining area in Mongolia

NASA Astrophysics Data System (ADS)

Timofeev, Ivan; Kosheleva, Natalia; Gunin, Petr; Bazha, Sergei; Enkh-Amgalan, Sandag

2014-05-01

The present study was conducted to assess soil contamination taking place in Erdenet, the Mongolian city with a gigantic ore-mining and ore-dressing complex that was founded mainly to exploit the area's huge deposits of copper and molybdenum ore. The objectives of the study were: (1) to determine the content of heavy metals and metalloids (HMs) in soils of background and urban landscapes and to evaluate environmental hazard of HMs pollution; (2) to compile geochemical maps and to define zones with anomalously high concentrations of toxic elements in the city, (3) to identify spatial patterns and leading factors of pollutant accumulation. Sampling was performed in 2011 using regular spacing of 500-700m. In total 225 samples were collected from surface soil horizons (0 - 10 cm) in different functional areas of the city and in the background area located 5-6km from the city. The sampling scheme in background area took into account the topography and geological heterogeneity of the study area. The bulk contents of HMs in soil samples were analyzed by mass spectrometry and inductively coupled mass spectrometry (ICP-MS). Background concentrations of HMs were estimated for several soil groups formed on specific parent rocks and were compared with their global abundances in soils. The pollution of urban soils was evaluated using background soils as reference objects. Associations of HMs were identified according to the enrichment factor (EF) values and using cluster analysis with complete linkage algorithm. Visualization of soil-geochemical data was performed by local interpolation or kriging method in MapInfo 11.5 and Surfer 11. Multiple regression analysis (decision trees method) was applied to determine soil properties and landscape factors that may control HMs accumulation in soils. Background soils formed on granite and granodiorite of Permian-Selenga complex occupy the largest area and are characterized by high concentrations of V, Cr, Co, Ni, Zn, Sr, Cu, Zn, Mo and W. The lowest concentrations of the elements are typical of soils formed on triassic volcanic suite and sub-volcanic intrusions. Urban soils are heavily polluted in industrial zone, where accumulation of Mo (EF=10.7) and Cu (10.6) are the highest among other elements (Se, As, Sb, W, EF=2.4-1.5). The mining area and the landscapes in its immediate vicinity are characterized by high and dangerous level of multi-elemental contamination while the most part of the urban territory has low level of contamination. Soils in all functional zones, with the exception of the ger district, have elevated concentrations of Mo, Cu and Se. Three geochemical associations W-Bi-Cd-Sn-Zn-Pb; Cu-As-Sb-Mo and V-Co-Sr-Cr-Ni have been identified in urban soils. The maximum concentrations of the elements in the first two groups are typical of the disturbed soils adjacent to the plant and tailings area (EFs for individual elements range from1.4 to1080). Statistical analysis revealed that such soil characteristics as grain-size distribution, pH, humus content have a direct impact on HMs fixation in urban soils while the influence of landscape factors (topography, lithology, functional assignment) is not so evident.

Deconvolution of trace element (As, Cr, Mo, Th, U) sources and pathways to surface waters of a gold mining-influenced watershed.

PubMed

Grosbois, C; Schäfer, J; Bril, H; Blanc, G; Bossy, A

2009-03-01

The Upper Isle River (SW France) drains the second most productive gold-mining district of France. A high resolution survey during one hydrological year of As, Cl(-), Cr, Fe, Mn, Mo, SO(4)(2-), Th and U dissolved concentrations in surface water aimed to better understand pathways of trace element export to the river system downstream from the mining district. Dissolved concentrations of As (up to 35000 ng/L) and Mo (up to 292 ng/L) were about 3-fold higher than the regional dissolved background and showed a negative logarithmic relation with discharge. Dissolved concentrations of Cr (up to 483 ng/L), Th (up to 48 ng/L) and U (up to 184 ng/L) increased with discharge. Geochemical relationships between molar ratios in surface water, geochemical background as well as rain- and groundwater data were combined. The contrasting behavior of distinct element groups was explained by a scenario involving three seasonal components: (i) The high flow component is poorly concentrated in As and Mo but highly concentrated in Cr, Th, U. This has been attributed to diffuse sources such as water-soil interactions, atmospheric inputs, bedrock and bed sediment weathering. Although this component probably also includes a contribution by weathering of sulfide veins, this signal is masked by dilution. (ii) One low flow component presents high SO(4)(2-), Fe, As and Mo and moderate Cr, Th and U concentrations. This component has been attributed to point sources such as mine gallery effluents, mining waste weathering and groundwater inputs from natural and/or mining-induced sulfide oxidation in the ore deposit. (iii) A second low flow component showing high As plus Mo concentrations associated with very low SO(4)(2-), Fe, Cr, Th and U concentrations, probably reflects trace element scavenging by ferric oxyhydroxide formation in the adjacent aquifer. This is supported by the decrease of Fe, Cr, Th and U in surface waters. Flux estimates suggest contrasting element-specific impacts on annual dissolved fluxes. Runoff may account for the major part of annual dissolved As, Mo, Th and U fluxes in the Upper Isle River. Inputs related to sulfide oxidation respectively contributed approximately 30% and approximately 24% to annual As and Mo fluxes. The formation of ferric oxyhydroxides strongly retained Cr, Th and U during the low flow, limiting their dissolved concentrations in surface waters. If this process may eventually decrease As mobility, its impact on dissolved As concentrations in surface water may be limited or/and counterbalanced by As release during sulfide oxidation.

Trace gas transport out of the Indian Summer Monsoon

NASA Astrophysics Data System (ADS)

Tomsche, Laura; Pozzer, Andrea; Zimmermann, Peter; Parchatka, Uwe; Fischer, Horst

2016-04-01

The trace gas transport out of the Indian summer monsoon was investigated during the aircraft campaign OMO (Oxidation Mechanism Observations) with the German research aircraft HALO (High Altitude and Long Range Research Aircraft) in July/August 2015. HALO was based at Paphos/Cyprus and also on Gan/Maledives. Flights took place over the Mediterranean Sea, the Arabian Peninsula and the Arabian Sea. In this work the focus is on the distribution of carbon monoxide (CO) and methane (CH4) in the upper troposphere. They were measured with the laser absorption spectrometer TRISTAR on board of HALO. During the Indian summer monsoon strong convection takes place over India and the Bay of Bengal. In this area the population is high accompanied by many emission sources e.g. wetlands and cultivation of rice. Consequently the boundary layer is polluted containing high concentrations of trace gases like methane and carbon monoxide. Due to vertical transport these polluted air masses are lifted to the upper troposphere. Here they circulate with the so called Asian monsoon anticyclone. In the upper troposphere polluted air masses lead to a change in the chemical composition thus influence the chemical processes. Furthermore the anticyclone spreads the polluted air masses over a larger area. Thus the outflow of the anticyclone in the upper troposphere leads to higher concentrations of trace gases over the Arabian Sea, the Arabian Peninsula and also over the eastern part of North Africa and the eastern part of the Mediterranean Sea. During OMO higher concentrations of methane and carbon monoxide were detected at altitudes between 11km and 15km. The highest measured concentrations of carbon monoxide and methane were observed over Oman. The CO concentration in the outflow of the monsoon exceeds background levels by 10-15ppb. However the enhancement in the concentration is not obviously connected to the monsoon due to the natural variability in the troposphere. The enhancement in the methane concentration (30-40ppb) is more obviously connected to the monsoon because it is much higher than the natural variability. Consequently methane is a very good tracer for the monsoon influenced air masses. Beside flights into the outflow of the Indian summer monsoon, there were also measurements of background concentrations in the upper troposphere in air not influenced by the monsoon. Profiles have shown that the high concentrations of trace gases are only observed in the upper troposphere. The high concentrations in the upper troposphere cannot be explained by vertical transport form local ground sources.

Propylthiouracil, Perchlorate, and Thyroid-Stimulating Hormone Modulate High Concentrations of Iodide Instigated Mitochondrial Superoxide Production in the Thyroids of Metallothionein I/II Knockout Mice

PubMed Central

Duan, Qi; Wang, Tingting; Zhang, Na; Perera, Vern; Liang, Xue; Abeysekera, Iruni Roshanie

2016-01-01

Background Increased oxidative stress has been suggested as one of the underlying mechanisms in iodide excess-induced thyroid disease. Metallothioneins (MTs) are regarded as scavengers of reactive oxygen species (ROS) in oxidative stress. Our aim is to investigate the effects of propylthiouracil (PTU), a thyroid peroxidase inhibitor, perchlorate (KClO4), a competitive inhibitor of iodide transport, and thyroid stimulating hormone (TSH) on mitochondrial superoxide production instigated by high concentrations of iodide in the thyroids of MT-I/II knockout (MT-I/II KO) mice. Methods Eight-week-old 129S7/SvEvBrd-Mt1tm1Bri Mt2tm1Bri/J (MT-I/II KO) mice and background-matched wild type (WT) mice were used. Results By using a mitochondrial superoxide indicator (MitoSOX Red), lactate dehydrogenase (LDH) release, and methyl thiazolyl tetrazolium (MTT) assay, we demonstrated that the decreased relative viability and increased LDH release and mitochondrial superoxide production induced by potassium iodide (100 µM) can be relieved by 300 µM PTU, 30 µM KClO4, or 10 U/L TSH in the thyroid cell suspensions of both MT-I/II KO and WT mice (P<0.05). Compared to the WT mice, a significant decrease in the relative viability along with a significant increase in LDH release and mitochondrial superoxide production were detected in MT-I/II KO mice(P<0.05). Conclusion We concluded that PTU, KClO4, or TSH relieved the mitochondrial oxidative stress induced by high concentrations of iodide in the thyroids of both MT-I/II KO and WT mice. MT-I/II showed antioxidant effects against high concentrations of iodide-induced mitochondrial superoxide production in the thyroid. PMID:26754589

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.

Fast time resolution measurements of high concentrations of iodine above a Laminaria Digitata seaweed bed

NASA Astrophysics Data System (ADS)

Ball, Stephen; Adams, Thomas; Leblanc, Catherine; Potin, Philippe

2013-04-01

We report observations of extremely large concentrations of molecular iodine (I2) measured in situ above a seaweed bed composed of laminaria digitata (90%) and laminaria hyperborea (10%) growing in its natural habitat. Measurements were made off the coast of Roscoff in Brittany, France, during day-time low tides on several days in September and November 2012 with the greatest tidal amplitudes. Iodine was quantified using a portable, battery-powered broadband cavity enhanced absorption spectrometer (BBCEAS) deployed from the in-shore research vessel "Aurelia" operated by the Station Biologique de Roscoff. For the 5 second integration times used here, the BBCEAS instrument has a detection limit for iodine of 12 pptv (parts per trillion by volume). The boat was anchored above the seaweed bed before it was exposed to air by the ebbing tide; the boat was grounded on the seaweed bed around the tidal minimum, and then refloated as the incoming tide covered the seaweed. I2 concentrations were strongly anti-correlated with water depth. Initially little I2 was seen above background levels whilst the blades of the seaweed plants were floating on the water surface. However several hundred pptv of I2 was observed within a few minutes of the plants' stipes breaking the surface and first blades coming to rest on rocks out of the water. Iodine concentrations increased further as the tide ebbed, typically peaking around 1500 pptv around the tidal minimum (by which time the seaweed had been exposed for 45 minutes). I2 concentrations decreased rapidly back to background levels as the returning tide submerged the seaweeds. The concentration profiles showed a lot of high frequency structure, with I2 concentrations commonly varying by a factor 2 (or more) within 60 seconds. Additionally the profiles of I2 emitted from the seaweeds immediately below the instrument's inlet typically sat on a smoothly-varying background of approximately 100 pptv, which we attribute to I2 from other more-distant seaweeds whose emissions are better-mixed into the atmosphere. The peak I2 concentrations observed here are three to five times greater than the maximum amounts recorded above/closeby laminaria beds in previous studies: 350 pptv max in O Grove, Galicia, Spain (Mahajan et al., ACP, 11, 2545, 2011), and 302 and 547 pptv max at Mweenish Bay, near Mace Head, County Galway, Ireland (Huang et al., GRL, 37, L03803, 2010; ACPD, 12, 25915, 2012). In part, the larger peak concentrations seen here are a consequence of deploying a fast response instrument very close to the source, enabling the emission's high temporal variability to be captured with fewer averaging effects. Nevertheless, the I2 concentrations averaged over the 30 minute period around the tidal minimum were still typically 750 pptv, suggesting laminaria beds are even stronger emitters of I2 into coastal atmospheres than previously thought. Some implications for such high concentrations of iodine for the local atmospheric chemistry are considered. We acknowledge support from the European Community FP7 project "ASSEMBLE", grant 227799.

Assessment of atmospheric metal pollution in the urban area of Mexico City, using Ficus benjamina as biomonitor.

PubMed

Guzmán-Morales, Janin; Morton-Bermea, Ofelia; Hernández-Álvarez, Elizabeth; Rodríguez-Salazar, María Teresa; García-Arreola, María Elena; Tapia-Cruz, Víctor

2011-05-01

Concentrations of vanadium, chromium, cobalt, nickel, copper, zinc, antimony, and lead were measured in Ficus benjamina leaves from the Mexico City urban area in order to assess their enrichment against background values. The instrumental analysis was performed using inductively coupled plasma mass spectrometry and the analytical method was tested using two certified reference materials from the National Institute of Standards and Technology (1547 Peach Leaves and 1573a Tomato Leaves). Enrichment factors were calculated, i.e., total to background concentration ratio, for each metal. Low enrichments of vanadium, cobalt, nickel, and copper (≈2), and mild enrichments of chromium and zinc (4.4, 4.5 respectively) were found in the entire area; oppositely, high enrichments were assessed for antimony (28.6) and lead (17.2). However, results indicate that metal concentrations strongly depend on the specific urban sub-area. Increments of metals were attributed to natural, vehicular, and industrial sources. © Springer Science+Business Media, LLC 2011

Influence of dissolved organic matter concentration and composition on the removal efficiency of perfluoroalkyl substances (PFASs) during drinking water treatment.

PubMed

Kothawala, Dolly N; Köhler, Stephan J; Östlund, Anna; Wiberg, Karin; Ahrens, Lutz

2017-09-15

Drinking water treatment plants (DWTPs) are constantly adapting to a host of emerging threats including the removal of micro-pollutants like perfluoroalkyl substances (PFASs), while concurrently considering how background levels of dissolved organic matter (DOM) influences their removal efficiency. Two adsorbents, namely anion exchange (AE) and granulated active carbon (GAC) have shown particular promise for PFAS removal, yet the influence of background levels of DOM remains poorly explored. Here we considered how the removal efficiency of 13 PFASs are influenced by two contrasting types of DOM at four concentrations, using both AE (Purolite A-600 ® ) and GAC (Filtrasorb 400 ® ). We placed emphasis on the pre-equilibrium conditions to gain better mechanistic insight into the dynamics between DOM, PFASs and adsorbents. We found AE to be very effective at removing both PFASs and DOM, while largely remaining resistant to even high levels of background DOM (8 mg carbon L -1 ) and surprisingly found that smaller PFASs were removed slightly more efficiently than longer chained counterparts, In contrast, PFAS removal efficiency with GAC was highly variable with PFAS chain length, often improving in the presence of DOM, but with variable response based on the type of DOM and PFAS chain length. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improving qPCR methodology for detection of foaming bacteria by analysis of broad-spectrum primers and a highly specific probe for quantification of Nocardia spp. in activated sludge.

PubMed

Asvapathanagul, P; Olson, B H

2017-01-01

To develop qPCR broad-spectrum primers combined with a Nocardia genus-specific probe for the identification of a broad spectrum of Nocardia spp. and to analyse the effects of using this developed primer and probe set on the ability to quantify Nocardia spp. in mixed DNA. The consequences of using a degenerative primer set and species-specific probe for the genus Nocardia on qPCR assays were examined using DNA extracts of pure cultures and activated sludge. The mixed DNA extracts where the target organism Nocardia flavorosea concentration ranged from 5 × 10 2 to 5 × 10 6 copies per reaction, while the background organism's DNA (Mycobacterium bovis) concentration was held at 5 × 10 6 copies per reaction, only produced comparable cycle threshold florescence levels when N. flavorosea concentration was greater than or equal to the background organism concentration. When concentrations of N. flavorosea were lowered in increments of 1 log, while holding M. bovis concentrations constant at 5 × 10 6 copies per reaction, all assays demonstrated delayed cycle threshold values with a maximum 34·6-fold decrease in cycle threshold at a ratio of 10 6 M. bovis: 10 2 N. flavorosea copies per reaction. The data presented in this study indicated that increasing the ability of a primer set to capture a broad group of organisms can affect the accuracy of quantification even when a highly specific probe is used. This study examined several applications of molecular tools in complex communities such as evaluating the effect of mispriming vs interference. It also elucidates the importance of understanding the community genetic make-up on primer design. Degenerative primers are very useful in amplifying bacterial DNA across genera, but reduce the efficiency of qPCR reactions. Therefore, standards that address closely related background species must be used to obtain accurate qPCR results. © 2016 The Society for Applied Microbiology.

Plant/soil concentration ratios of SSWRa for contrasting sites around an active U mine-mill

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

Ibrahim, S.A.; Whicker, F.W.

Concentrations of 226Ra were determined in native vegetation and underlying substrate (soil and tailings) at various sites around a conventional open-pit, acid leach U production operation in Wyoming. Plant/soil concentration ratios (CRs) for 226Ra were estimated for various sites, including weathered tailings; a tailings impoundment shoreline; downwind from exposed tailings; a mine overburden reclamation area; and several background locations. Radium-226 concentrations for vegetation and substrate and CR values from the perturbed sites were elevated above background. The highest vegetation concentration (1.3 Bq g-1) was found in a grass which had invaded exposed, weathered tailings. Levels of 226Ra in soil andmore » vegetation and CR values decreased with distance from the tailings impoundment edge. CR values varied significantly among sites, but few differences were found between plant species groups. The observed CR values ranged from 0.07 at the background and reclamation areas to 0.4 downwind from the tailings area. Average CR values for plants growing on exposed tailings and within one meter from the impoundment edge were 0.15 and 0.3, respectively. CR values of 226Ra for plants on tailings substrates were comparatively low in contrast to other radionuclides in the U chain. We speculate that in the case of sulfuric acid leached tailings-derived material, 226Ra is sequestered as sulfate, which is highly insoluble relative to the sulfates of the other elements (e.g., U and Th) resulting in reduced availability for plant uptake.« less

Ice nucleation and dehydration in the Tropical Tropopause Layer.

PubMed

Jensen, Eric J; Diskin, Glenn; Lawson, R Paul; Lance, Sara; Bui, T Paul; Hlavka, Dennis; McGill, Matthew; Pfister, Leonhard; Toon, Owen B; Gao, Rushan

2013-02-05

Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to ∼70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L(-1) (often less than 20 L(-1)), whereas the high ice concentration layers (with concentrations up to 10,000 L(-1)) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as ∼1.7 times the ice saturation mixing ratio.

Probe diffusion of labeled polymers inside polyacrylic acid solutions: A polyelectrolyte effect

NASA Astrophysics Data System (ADS)

Mishra, Banani; Mithra, K.; Khandai, Santripti; Jena, Sidhartha S.

2018-05-01

Probe diffusion of fluorescently labeled Dextran 40 inside polyelectrolyte solution of polyacrylic acid (PAA) was investigated using Fluorescence Recovery After Photobleaching technique. The crowding and interaction effects on probe diffusion were controlled by tuning background polymer and added external electrolyte concentration. For all the salt concentration, an overall decrease in diffusion coefficient is observed with rise in polymer concentration. The diffusion coefficient decreases with decrease in salt concentration whereas the solution viscosity increases, indicating a competition between viscous drag and electrostatic interaction. A large positive deviation from the ideal Stokes-Einstein relation is observed for high polymer and low salt concentration, which reduces markedly with addition of salt confirming polyelectrolyte effects, plays a major role in deciding the probe diffusion.

Response of Stream Chemistry During Base Flow to Gradients of Urbanization in Selected Locations Across the Conterminous United States, 2002-04

USGS Publications Warehouse

Sprague, Lori A.; Harned, Douglas A.; Hall, David W.; Nowell, Lisa H.; Bauch, Nancy J.; Richards, Kevin D.

2007-01-01

During 2002-2004, the U.S. Geological Survey's National Water-Quality Assessment Program conducted a study to determine the effects of urbanization on stream water quality and aquatic communities in six environmentally heterogeneous areas of the conterminous United States--Atlanta, Georgia; Raleigh-Durham, North Carolina; Milwaukee-Green Bay, Wisconsin; Dallas-Fort Worth, Texas; Denver, Colorado; and Portland, Oregon. This report compares and contrasts the response of stream chemistry during base flow to urbanization in different environmental settings and examines the relation between the exceedance of water-quality benchmarks and the level of urbanization in these areas. Chemical characteristics studied included concentrations of nutrients, dissolved pesticides, suspended sediment, sulfate, and chloride in base flow. In three study areas where the background land cover in minimally urbanized basins was predominantly forested (Atlanta, Raleigh-Durham, and Portland), urban development was associated with increased concentrations of nitrogen and total herbicides in streams. In Portland, there was evidence of mixed agricultural and urban influences at sites with 20 to 50 percent urban land cover. In two study areas where agriculture was the predominant background land cover (Milwaukee-Green Bay and Dallas-Fort Worth), concentrations of nitrogen and herbicides were flat or decreasing as urbanization increased. In Denver, which had predominantly shrub/grass as background land cover, nitrogen concentrations were only weakly related to urbanization, and total herbicide concentrations did not show any clear pattern relative to land cover - perhaps because of extensive water management in the study area. In contrast, total insecticide concentrations increased with increasing urbanization in all six study areas, likely due to high use of insecticides in urban applications and, for some study areas, the proximity of urban land cover to the sampling sites. Phosphorus concentrations increased with urbanization only in Portland; in Atlanta and Raleigh-Durham, leachate from septic tanks may have increased phosphorus concentrations in basins with minimal urban development. Concentrations of suspended sediment were only weakly associated with urbanization, probably because this study analyzed only base-flow samples, and the bulk of sediment loads to streams is transported in storm runoff rather than base flow. Sulfate and chloride concentrations increased with increasing urbanization in four study areas (Atlanta, Raleigh-Durham, Milwaukee-Green Bay, and Portland), likely due to increasing contributions from urban sources of these constituents. The weak relation between sulfate and chloride concentrations and urbanization in Dallas-Fort Worth and Denver was likely due in part to high sulfate and chloride concentrations in ground-water inflow, which would have obscured any pattern of increasing concentration with urbanization. Pesticides often were detected at multiple sites within a study area, so that the pesticide 'signature' for a given study area - the mixtures of pesticides detected, and their relative concentrations, at streams within the study area - tended to show some pesticides as dominant. The type and concentrations of the dominant pesticides varied markedly among sites within a study area. There were differences between pesticide signatures during high and low base-flow conditions in five of the six study areas. Normalization of absolute pesticide concentrations by the pesticide toxicity index (a relative index indicating potential toxicity to aquatic organisms) dramatically changed the pesticide signatures, indicating that the pesticides with the greatest potential to adversely affect cladocerans or fish were not necessarily the pesticides detected at the highest concentrations. In a screening-level assessment, measured contaminant concentrations in individual base-flow water samples were compared with various water-qual

Effects of Elementary School Home Language, Immigrant Generation, Language Classification, and School's English Learner Concentration on Latinos' High School Completion

ERIC Educational Resources Information Center

Zarate, Maria Estela; Pineda, Claudia G.

2014-01-01

Background/Context: Relying largely on high school measures of home language use, the literature examining immigrant incorporation in schools provides contradictory evidence of home language effects on educational outcomes. More recent research has demonstrated that home language use is dynamic and thus it is important to examine the implications…

High-spatial-resolution nanoparticle x-ray fluorescence tomography

NASA Astrophysics Data System (ADS)

Larsson, Jakob C.; Vâgberg, William; Vogt, Carmen; Lundström, Ulf; Larsson, Daniel H.; Hertz, Hans M.

2016-03-01

X-ray fluorescence tomography (XFCT) has potential for high-resolution 3D molecular x-ray bio-imaging. In this technique the fluorescence signal from targeted nanoparticles (NPs) is measured, providing information about the spatial distribution and concentration of the NPs inside the object. However, present laboratory XFCT systems typically have limited spatial resolution (>1 mm) and suffer from long scan times and high radiation dose even at high NP concentrations, mainly due to low efficiency and poor signal-to-noise ratio. We have developed a laboratory XFCT system with high spatial resolution (sub-100 μm), low NP concentration and vastly decreased scan times and dose, opening up the possibilities for in-vivo small-animal imaging research. The system consists of a high-brightness liquid-metal-jet microfocus x-ray source, x-ray focusing optics and an energy-resolving photon-counting detector. By using the source's characteristic 24 keV line-emission together with carefully matched molybdenum nanoparticles the Compton background is greatly reduced, increasing the SNR. Each measurement provides information about the spatial distribution and concentration of the Mo nanoparticles. A filtered back-projection method is used to produce the final XFCT image.

Nanoscale volume confinement and fluorescence enhancement with double nanohole aperture

PubMed Central

Regmi, Raju; Al Balushi, Ahmed A.; Rigneault, Hervé; Gordon, Reuven; Wenger, Jérôme

2015-01-01

Diffraction ultimately limits the fluorescence collected from a single molecule, and sets an upper limit to the maximum concentration to isolate a single molecule in the detection volume. To overcome these limitations, we introduce here the use of a double nanohole structure with 25 nm gap, and report enhanced detection of single fluorescent molecules in concentrated solutions exceeding 20 micromolar. The nanometer gap concentrates the light into an apex volume down to 70 zeptoliter (10−21 L), 7000-fold below the diffraction-limited confocal volume. Using fluorescence correlation spectroscopy and time-correlated photon counting, we measure fluorescence enhancement up to 100-fold, together with local density of optical states (LDOS) enhancement of 30-fold. The distinctive features of double nanoholes combining high local field enhancement, efficient background screening and relative nanofabrication simplicity offer new strategies for real time investigation of biochemical events with single molecule resolution at high concentrations. PMID:26511149

A rapid spin through oil results in higher cell-associated concentrations of antiretrovirals compared with conventional cell washing

PubMed Central

Cory, Theodore J; Winchester, Lee C; Robbins, Brian L; Fletcher, Courtney V

2015-01-01

Background: Determination of cell-associated antiretroviral drug concentrations is necessary for research into reservoirs of HIV. Variation exists in cell-associated drug concentrations among research groups. One cause for this may be washing cells during processing. We explored spinning cells through oil to minimize this variability. Methods & results: Raltegravir, atazanavir, darunavir, efavirenz, lopinavir and ritonavir concentrations were assessed in CEM.ss T cells washed with HBSS and oil-spun cells. Oil-spun cells had significantly higher concentrations for all drugs compared with samples washed with HBSS. Conclusion: The decline in cell-associated drug concentrations with saline washes compared with a single spin through oil shows the utility of a spin through oil. Oil centrifugation results in high cell-associated drug concentrations, and can be done in a fast, efficient manner. PMID:26168252

QUANTITATIVE FLUORESCENCE OF 5-FU-TREATED FETAL RAT LIMBS USING CONFOCAL LASER SCANNING MICROSCOPY AND LYSOTRACKER RED

EPA Science Inventory

Background: LysoTracker Red (LT) is a paraformaldehyde fixable probe that concentrates into acidic compartments of cells and tissues. After cell death a high level of lysosomal activity (acidic enzyme) is expressed resulting from phagocytosis of apoptotic bodies by neighboring ce...

Treatment of concentrated industrial wastewaters originating from oil shale and the like by electrolysis polyurethane foam interaction

DOEpatents

Tiernan, Joan E.

1991-01-01

Highly concentrated and toxic petroleum-based and synthetic fuels wastewaters such as oil shale retort water are treated in a unit treatment process by electrolysis in a reactor containing oleophilic, ionized, open-celled polyurethane foams and subjected to mixing and l BACKGROUND OF THE INVENTION The invention described herein arose in the course of, or under, Contract No. DE-AC03-76SF00098 between the U.S. Department of Energy and the University of California.

Radionuclide Concentrations in Honey Bees from Area G at TA-54 during 1998

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

Haarmann, T.K.; Fresquez, P.R.

Honey bees were collected from two colonies located at Los Alamos National Laboratory's Area G, Technical Area 54, and from one control (background) colony located near Jemez Springs, NM. Samples were analyzed for various radionuclides. Area G sample results from both colonies were higher than the upper (95%) level background concentration for {sup 239,240}Pu, {sup 3}H, and total uranium. Sample results from one colony were higher than the upper (95%) level background concentration for {sup 238}Pu.

Regional and local background ozone in Houston during Texas Air Quality Study 2006

NASA Astrophysics Data System (ADS)

Langford, A. O.; Senff, C. J.; Banta, R. M.; Hardesty, R. M.; Alvarez, R. J.; Sandberg, Scott P.; Darby, Lisa S.

2009-04-01

Principal Component Analysis (PCA) is used to isolate the common modes of behavior in the daily maximum 8-h average ozone mixing ratios measured at 30 Continuous Ambient Monitoring Stations in the Houston-Galveston-Brazoria area during the Second Texas Air Quality Study field intensive (1 August to 15 October 2006). Three principal components suffice to explain 93% of the total variance. Nearly 84% is explained by the first component, which is attributed to changes in the "regional background" determined primarily by the large-scale winds. The second component (6%) is attributed to changes in the "local background," that is, ozone photochemically produced in the Houston area and spatially and temporally averaged by local circulations. Finally, the third component (3.5%) is attributed to short-lived plumes containing high ozone originating from industrial areas along Galveston Bay and the Houston Ship Channel. Regional background ozone concentrations derived using the first component compare well with mean ozone concentrations measured above the Gulf of Mexico by the tunable profiler for aerosols and ozone lidar aboard the NOAA Twin Otter. The PCA regional background values also agree well with background values derived using the lowest daily 8-h maximum method of Nielsen-Gammon et al. (2005), provided the Galveston Airport data (C34) are omitted from that analysis. The differences found when Galveston is included are caused by the sea breeze, which depresses ozone at Galveston relative to sites further inland. PCA removes the effects of this and other local circulations to obtain a regional background value representative of the greater Houston area.

Assessing possible visitor-use impacts on water quality in Yosemite National Park, California

USGS Publications Warehouse

Clow, David W.; Peavler, Rachael S.; Roche, Jim; Panorska, Anna K.; Thomas, James M.; Smith, Steve

2011-01-01

There is concern that visitor-use associated activities, such as bathing, dish washing, wastewater production, and stock animal use near lakes and streams, could cause degradation of water quality in Yosemite National Park. A study was conducted during 2004–2007 to assess patterns in nutrient and Escherichia coli (E. coli) concentrations in the Merced and Tuolumne Rivers and characterize natural background concentrations of nutrients in the park. Results indicated that nutrient and E. coli concentrations were low, even compared to other undeveloped sites in the United States. A multiple linear regression approach was used to model natural background concentrations of nutrients, with basin characteristics as explanatory variables. Modeled nitrogen concentrations increased with elevation, and modeled phosphorus concentrations increased with basin size. Observed concentrations (±uncertainty) were compared to modeled concentrations (±uncertainty) to identify sites that might be impacted by point sources of nutrients, as indicated by large model residuals. Statistically significant differences in observed and modeled concentrations were observed at only a few locations, indicating that most sites were representative of natural background conditions. The empirical modeling approach used in this study can be used to estimate natural background conditions at any point along a study reach in areas minimally impacted by development, and may be useful for setting water-quality standards in many national parks.

Spatial pattern analysis of Cu, Zn and Ni and their interpretation in the Campania region (Italy)

NASA Astrophysics Data System (ADS)

Petrik, Attila; Albanese, Stefano; Jordan, Gyozo; Rolandi, Roberto; De Vivo, Benedetto

2017-04-01

The uniquely abundant Campanian topsoil dataset enabled us to perform a spatial pattern analysis on 3 potentially toxic elements of Cu, Zn and Ni. This study is focusing on revealing the spatial texture and distribution of these elements by spatial point pattern and image processing analysis such as lineament density and spatial variability index calculation. The application of these methods on geochemical data provides a new and efficient tool to understand the spatial variation of concentrations and their background/baseline values. The determination and quantification of spatial variability is crucial to understand how fast the change in concentration is in a certain area and what processes might govern the variation. The spatial variability index calculation and image processing analysis including lineament density enables us to delineate homogenous areas and analyse them with respect to lithology and land use. Identification of spatial outliers and their patterns were also investigated by local spatial autocorrelation and image processing analysis including the determination of local minima and maxima points and singularity index analysis. The spatial variability of Cu and Zn reveals the highest zone (Cu: 0.5 MAD, Zn: 0.8-0.9 MAD, Median Deviation Index) along the coast between Campi Flegrei and the Sorrento Peninsula with the vast majority of statistically identified outliers and high-high spatial clustered points. The background/baseline maps of Cu and Zn reveals a moderate to high variability (Cu: 0.3 MAD, Zn: 0.4-0.5 MAD) NW-SE oriented zone including disrupted patches from Bisaccia to Mignano following the alluvial plains of Appenine's rivers. This zone has high abundance of anomaly concentrations identified using singularity analysis and it also has a high density of lineaments. The spatial variability of Ni shows the highest variability zone (0.6-0.7 MAD) around Campi Flegrei where the majority of low outliers are concentrated. The variability of background/baseline map of Ni reveals a shift to the east in case of highest variability zones coinciding with limestone outcrops. The high segmented area between Mignano and Bisaccia partially follows the alluvial plains of Appenine's rivers which seem to be playing a crucial role in the distribution and redistribution pattern of Cu, Zn and Ni in Campania. The high spatial variability zones of the later elements are located in topsoils on volcanoclastic rocks and are mostly related to cultivation and urbanised areas.

High sensitivity detectors for measurement of diffusion, emanation and low activity of radon

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

Mamedov, Fadahat; Štekl, Ivan; Smolek, Karel

Today's underground experiments require ultra-low background conditions. One of the most important source of background is radon. It is necessary to suppress it and consequently to detect very low radon concentration. In the frame of SuperNEMO collaboration experimental setups for measurement of low radon activity, radon diffusion through shielding foils and radon emanation from construction materials have been constructed in IEAP CTU in Prague and the obtained results are presented. The application of Timepix device in radon detection is briefly discussed.

Environmental implications of high metal content in soils of a titanium mining zone in Kenya.

PubMed

Maina, David M; Ndirangu, Douglas M; Mangala, Michael M; Boman, Johan; Shepherd, Keith; Gatari, Michael J

2016-11-01

Mining activities contribute to an increase of specific metal contaminants in soils. This may adversely affect plant life and consequently impact on animal and human health. The objective of this study was to obtain the background metal concentrations in soils around the titanium mining in Kwale County for monitoring its environmental impacts. Forty samples were obtained with half from topsoils and the other from subsoils. X-ray fluorescence spectrometry was used to determine the metal content of the soil samples. High concentrations of Ti, Mn, Fe, and Zr were observed where Ti concentrations ranged from 0.47 to 2.8 %; Mn 0.02 to 3.1 %; Fe 0.89 to 3.1 %; and Zr 0.05 to 0.85 %. Using ratios of elemental concentrations in topsoil to subsoil method and enrichment factors concept, the metals were observed to be of geogenic origin with no anthropogenic input. The high concentrations of Mn and Fe may increase their concentration levels in the surrounding agricultural lands through deposition, thereby causing contamination on the land and the cultivated food crops. The latter can cause adverse human health effects. In addition, titanium mining will produce tailings containing low-level titanium concentrations, which will require proper disposal to avoid increasing titanium concentrations in the soils of the region since it has been observed to be phytotoxic to plants at high concentrations. The results of this study will serve as reference while monitoring the environmental impact by the titanium mining activities.

Mexico City Aerosol Analysis during MILAGRO using High Resolution Aerosol Mass Spectrometry at the Urban Supersite (T0). Part 2: Analysis of the Biomass Burning Contribution and the Modern Carbon Fraction

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

Aiken, Allison; de Foy, B.; Wiedinmyer, Christine

2010-06-16

Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Aerosol Mass Spectrometer (AMS) and complementary instrumentation. Positive Matrix Factorization (PMF) of high resolution AMS spectra identified a biomass burning OA (BBOA) component, which includes several large plumes that appear to be from forest fires within the region. Here, we show that the AMS BBOA concentration at T0 correlates with fire counts in the vicinity of Mexico City and that most of the BBOA variability is captured when the FLEXPART model is used for the dispersion ofmore » fire emissions as estimated from satellite fire counts. The resulting FLEXPART fire impact index correlates well with the observed BBOA, CH3CN, levoglucosan, and potassium, indicating that wildfires in the region surrounding Mexico City are the dominant source of BBOA at T0 during MILAGRO. The impact of distant BB sources such as the Yucatan is very small during this period. All fire tracers are correlated, with BBOA and levoglucosan showing little background, acetonitrile having a well-known tropospheric background of ~100-150 ppt, and PM2.5 potassium having a background of ~160 ng m-3 (two-thirds of its average concentration), which does not appear to be related to BB sources.« less

Full-Genome Sequencing Identifies in the Genetic Background Several Determinants That Modulate the Resistance Phenotype in Methicillin-Resistant Staphylococcus aureus Strains Carrying the Novel mecC Gene

PubMed Central

de Lencastre, Hermínia; Tomasz, Alexander

2017-01-01

ABSTRACT Most methicillin-resistant Staphylococcus aureus (MRSA) strains are resistant to beta-lactam antibiotics due to the presence of the mecA gene, encoding an extra penicillin-binding protein (PBP2A) that has low affinity for virtually all beta-lactam antibiotics. Recently, a new resistance determinant—the mecC gene—was identified in S. aureus isolates recovered from humans and dairy cattle. Although having typically low MICs to beta-lactam antibiotics, MRSA strains with the mecC determinant are also capable of expressing high levels of oxacillin resistance when in an optimal genetic background. In order to test the impact of extensive beta-lactam selection on the emergence of mecC-carrying strains with high levels of antibiotic resistance, we exposed the prototype mecC-carrying MRSA strain, LGA251, to increasing concentrations of oxacillin. LGA251 was able to rapidly adapt to high concentrations of oxacillin in growth medium. In such laboratory mutants with increased levels of oxacillin resistance, we identified mutations in genes with no relationship to the mecC regulatory system, indicating that the genetic background plays an important role in the establishment of the levels of oxacillin resistance. Our data also indicate that the stringent stress response plays a critical role in the beta-lactam antibiotic resistance phenotype of MRSA strains carrying the mecC determinant. PMID:28069659

Midkine and Pleiotrophin Concentrations in Amniotic Fluid in Healthy and Complicated Pregnancies

PubMed Central

Chaemsaithong, Piya; Yan, Gai; Peran, Ivana; Wellstein, Anton; Romero, Roberto; Baron, Jeffrey

2016-01-01

Background Midkine (MDK) and pleiotrophin (PTN) are heparin-binding growth factors that, in rodents, are highly expressed in early life and decrease to undetectable levels by adulthood. The potential roles of MDK and PTN in human growth and development are not completely elucidated. Method and Findings To delineate the role of MDK and PTN in human development, we developed high sensitivity assays to measure their concentrations in amniotic fluid (AF) at various gestational ages in both healthy and complicated pregnancies. We found that both of these growth factors could be readily measured in AF and that the concentrations were higher than most cytokines previously reported in AF. Conclusion The concentration of MDK but not that of PTN declined with gestational age. Both MDK and PTN concentrations were found to be lower in pregnancies that were complicated by chorioamnionitis at term, raising the possibility that these growth factors might be useful as markers for infection. PMID:27089523

Aspergillus fumigatus and mesophilic moulds in air in the surrounding environment downwind of non-hazardous waste landfill sites.

PubMed

Schlosser, Olivier; Robert, Samuel; Debeaupuis, Catherine

2016-05-01

Non-hazardous waste landfilling has the potential to release biological agents into the air, notably mould spores. Some species, such as Aspergillus fumigatus, may be a cause of concern for at-risk nearby residents. However, air concentration in the surrounding environment of non-hazardous waste landfill sites is poorly documented. An extensive sampling programme was designed to investigate the relationship between culturable mesophilic moulds and A. fumigatus concentrations in air and distance downwind of non-hazardous waste landfill sites. On-site and off-site repeated measurements were performed at four landfill sites during cold and warm seasons. A high-flow air-sampler device was selected so as to allow peak concentration measurement. Linear mixed-effects models were used to explain variability in the concentrations in air over time and across sites, seasons, instantaneous meteorological conditions and discharged waste tonnage. Concentrations of mesophilic moulds and A. fumigatus at off-site upwind sampling locations were compared with concentrations at each of the downwind sampling locations. At the tipping face location, peak concentration reached 480,000CFUm(-3) for mesophilic moulds and 9300CFUm(-3) for A. fumigatus. Compared with upwind background levels, these concentrations were, on average, approximately 20 and 40 times higher respectively. A steep decline in the concentration of both mesophilic moulds and A. fumigatus was observed between the tipping face location and the downwind property boundary (reduction by 77% and 84% respectively), followed by a low decline leading to a 90% and 94% reduction in concentration at 200m from the property boundary and beyond. With the 200m and 500m downwind sampling point values added together, the 97.5th percentile of concentration was 6013CFUm(-3) and 87CFUm(-3) for mesophilic moulds and A. fumigatus, respectively. Other determining factors were the discharged waste tonnage, the season, instantaneous temperature and wind velocity for mesophilic mould, and instantaneous temperature for A. fumigatus. At 200m and 500 downwind from the property boundary, mesophilic moulds and A. fumigatus concentrations were still higher than the local background level. However, whilst statistically significant, this increase does not suggest an excess risk to nearby residents' health when compared with the wide range of outdoor background levels reported in literature. These findings suggest that moulds and A. fumigatus may be transported beyond 200m from the property boundary in concentrations above those found locally upwind of the landfill site. Nevertheless, for exposure assessment purposes, comparison should also be made with background levels in wider areas which are either residential or through which people travel to work for example. Copyright © 2016 Elsevier GmbH. All rights reserved.

Inhalation Dose and Source Term Studies in a Tribal Area of Wayanad, Kerala, India

PubMed Central

Damodaran, Ravikumar C.; Kumar, Visnuprasad Ashok; Panakal John, Jojo; Bangaru, Danalakshmi; Natarajan, Chitra; Sathiamurthy, Bala Sundar; Mundiyanikal Thomas, Jose; Mishra, Rosaline

2017-01-01

Among radiation exposure pathways to human beings, inhalation dose is the most prominent one. Radon, thoron, and their progeny contribute more than 50 per cent to the annual effective dose due to natural radioactivity. South west coast of India is classified as a High Natural Background Radioactivity Area and large scale data on natural radioactivity and dosimetry are available from these coastal regions including the Neendakara-Chavara belt in the south of Kerala. However, similar studies and reports from the northern part of Kerala are scarce. The present study involves the data collection and analysis of radon, thoron, and progeny concentration in the Wayanad district of Kerala. The radon concentration was found to be within a range of 12–378 Bq/m3. The thoron concentration varied from 15 to 621 Bq/m3. Progeny concentration of radon and thoron and the diurnal variation of radon were also studied. In order to assess source term, wall and floor exhalation studies have been done for the houses showing elevated concentration of radon and thoron. The average values of radon, thoron, and their progeny are found to be above the Indian average as well as the average values reported from the High Natural Background Radioactivity Areas of Kerala. Exhalation studies of the soil samples collected from the vicinity of the houses show that radon mass exhalation rate varied from below detectable limit (BDL) to a maximum of 80 mBq/kg/h. The thoron surface exhalation rate ranged from BDL to 17470 Bq/m2/h. PMID:28611847

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

Ding, R.; Rudakov, D. L.; Stangeby, P. C.

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. We have investigated different methods such as electrical biasing and local gas injection to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducingmore » the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local 13CH 4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. The inter-ELM W erosion we measured in H-mode plasmas, rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.« less

BACKGROUND TRACK DENSITY REDUCTION OF 50-HZ-HV ECE-PROCESSED THICK POLYCARBONATE DETECTORS TO IMPROVE LOWER DETECTION LIMIT.

PubMed

Sohrabi, M; Hakimi, A; Soltani, Z

2016-12-01

A recent novel development of 50-Hz-HV ECE of 1-mm-thick and 250-µm-thick polycarbonate track detectors (PCTDs) has proved some promising results for some health physics, dosimetry and ion-beam-related applications. The method while proved having some good characteristics for some applications provided a relatively higher background track density (BGTD) in particular when very high voltages are applied to the PCTDs. In order to decrease the minimum detection limit (MDL) of the PCTDs and to further promote its applications for low dose, the BGTD was reduced by applying a layer removal methodology applying ethylendiamine (EDA). The effects of EDA concentrations (50, 60, 65, 70, 75, 80, 85 and 90 %) in water at room temperature (26°C) and soaking durations up to 100 min at different EDA concentration on BGTD reduction were studied. The thickness of the layer removed from the surface of a PCTD highly depends on the soaking time and EDA concentration; it increases as the EDA concentration increases up to for example 700 µm after 2 h of soaking in the EDA solution. After ∼10 min of soaking duration at any of the above-stated concentrations, the BGTD reaches its minimum value, a value which differs from concentration to concentration. An EDA concentration of 85 % in water provided the lowest BGTD of 64.06 ± 3.12 tracks cm - 2 ; ∼6 times lower than that of its original value. It is shown that the layer removal process does not change the registration characteristics of the PCTD and its appearance significantly. The MDL of the PCTDs depends strongly on the BGTD. The MDL values for a desired confidence level were also studied by three calculation methods. The results of the BGTD and the MDL studies under different conditions applied are presented and discussed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Geochemistry of regional background aerosols in the Western Mediterranean

NASA Astrophysics Data System (ADS)

Pey, J.; Pérez, N.; Castillo, S.; Viana, M.; Moreno, T.; Pandolfi, M.; López-Sebastián, J. M.; Alastuey, A.; Querol, X.

2009-11-01

The chemical composition of regional background aerosols, and the time variability and sources in the Western Mediterranean are interpreted in this study. To this end 2002-2007 PM speciation data from an European Supersite for Atmospheric Aerosol Research (Montseny, MSY, located 40 km NNE of Barcelona in NE Spain) were evaluated, with these data being considered representative of regional background aerosols in the Western Mediterranean Basin. The mean PM 10, PM 2.5 and PM 1 levels at MSY during 2002-2007 were 16, 14 and 11 µg/m 3, respectively. After compiling data on regional background PM speciation from Europe to compare our data, it is evidenced that the Western Mediterranean aerosol is characterised by higher concentrations of crustal material but lower levels of OM + EC and ammonium nitrate than at central European sites. Relatively high PM 2.5 concentrations due to the transport of anthropogenic aerosols (mostly carbonaceous and sulphate) from populated coastal areas were recorded, especially during winter anticyclonic episodes and summer midday PM highs (the latter associated with the transport of the breeze and the expansion of the mixing layer). Source apportionment analyses indicated that the major contributors to PM 2.5 and PM 10 were secondary sulphate, secondary nitrate and crustal material, whereas the higher load of the anthropogenic component in PM 2.5 reflects the influence of regional (traffic and industrial) emissions. Levels of mineral, sulphate, sea spray and carbonaceous aerosols were higher in summer, whereas nitrate levels and Cl/Na were higher in winter. A considerably high OC/EC ratio (14 in summer, 10 in winter) was detected, which could be due to a combination of high biogenic emissions of secondary organic aerosol, SOA precursors, ozone levels and insolation, and intensive recirculation of aged air masses. Compared with more locally derived crustal geological dusts, African dust intrusions introduce relatively quartz-poor but clay mineral-rich silicate PM, with more kaolinitic clays from central North Africa in summer, and more smectitic clays from NW Africa in spring.

Long-term measurements of residential radon, thoron, and thoron progeny concentrations around the Chhatrapur placer deposit, a high background radiation area in Odisha, India.

PubMed

Omori, Yasutaka; Prasad, Ganesh; Sorimachi, Atsuyuki; Sahoo, Sarata Kumar; Ishikawa, Tetsuo; Vidya Sagar, Devulapalli; Ramola, Rakesh Chand; Tokonami, Shinji

2016-10-01

The Chhatrapur placer deposit is found in a high background radiation area which has been recently identified on the southeastern coast of India. Previously, some geochemical studies of this area were carried out to assess external dose from radionuclides-bearing heavy mineral sands. In this study, radon, thoron and thoron progeny concentrations were measured in about 100 dwellings during three seasons (autumn-winter, summer, and rainy) in a 10- to 12-month period and annual doses due to inhalation of them were evaluated. The measurements were made by passive-type radon-thoron discriminative detectors and thoron progeny detectors in which solid state nuclear track detectors were deployed. The results show that radon and thoron concentrations differ by one order of magnitude depending on exposure periods, while thoron progeny concentration is nearly constant throughout the year. Since thorium-rich sand is distributed in the studied area, exposure to thoron is equal to, or exceeds, exposure to radon and is not negligible for dose evaluation. Based on the measurements, doses due to inhalation of radon and thoron are evaluated as 0.1-1.6 mSv y -1 and 0.2-3.8 mSv y -1 , respectively. The total dose is 0.8-4.6 mSv y -1 , which is the same order of magnitude as the worldwide value. Copyright © 2016 Elsevier Ltd. All rights reserved.

Role of Organic Matter in the Removal of Heavy Metals in Stormwater Runoff

NASA Astrophysics Data System (ADS)

Barrett, M.; Ingenloff, C.; Katz, L.

2011-12-01

Heavy metals (copper, zinc, and lead) are common constituents in highway runoff and concentrations in runoff from highway facilities are particularly high. These concentrations are also generally higher than observed in natural water bodies and several studies have demonstrated acute and chronic toxicity to aquatic ecosystems. One focus of this project is to assess the potential of sorption to reduce the concentration of metals in runoff. The difficulty evaluating adsorption in multi-component systems is to capture the impacts of background organic matter and other complexing ions on adsorption behavior. Very few studies have evaluated the ability of surface complexation models to predict adsorption in systems that contain organic matter from highway runoff. Moreover, the composition of the organic matter in stormwater runoff can be significantly different from natural organic matter typically used to assess the impact of background organics on metal ion adsorption. This research project specifically addresses these concerns and examines the impact of highway runoff on the adsorption behavior to determine whether existing surface complexation and chemical speciation models and parameter databases can be used to predict adsorption of target metal ions in these waters. Previous research has employed both actual storm water that has been obtained from actual field highway runoff sites as well as synthetic storm water compositions that have attempted to mimic the major components of natural storm water. Researchers and practitioners in the field generally agree on the importance of capturing the background water matrix; however, concerns associated with required volumes, holding times, aging, consistency and temporal and spatial variability often favor the use of synthetic formulations. While synthetic storm water can achieve the required consistency, numerous artifacts can be introduced due to the high reactivity of trace metal ions with background inorganic and organic ligands. Of particular concern, is the background organic matrix associated with stormwater. While most of the inorganic composition of natural stormwater can be adequately characterized using routine analytical procedures, characterization of organic matter to the same level of detail is not possible. Indeed, methods for characterization of natural organic matter typically only provide operational definitions of the composition. A compromise between using natural and synthetic storm water was therefore made by recognizing the importance of capturing the organic matter from natural storm water, but adding the flexibility of using synthetic storm water to provide the ionic composition. To alleviate concerns associated with storing large volumes and aging of organic solutions, the storm water was concentrated within twenty-four hours of collection using reverse osmosis and then freeze-dried. The freeze-dried organic matter will be reconstituted as needed at concentrations that mimic the initial total organic concentration of the stormwater when it was collected. This paper provides detailed guidance for the preparation of a synthetic water that can be used to simulate stormwater composition.

Detection of Non-Photochemical Superoxide in Coastal and Open Ocean Seawater: Particulate Versus Dissolved Sources

NASA Astrophysics Data System (ADS)

Roe, K. L.; Rand, T.; Hansel, C. M.; Voelker, B. M.

2016-02-01

Superoxide radical (O2-) could have a significant effect on marine metal redox chemistry, but little data exists on its marine concentrations. In this study, we measured superoxide steady-state concentrations in both filtered and unfiltered samples collected near the California coast and at Station ALOHA. Particle-generated superoxide, defined as the difference between unfiltered and filtered concentrations, ranged from undetectable to 0.019 nM at Station ALOHA and from undetectable to 0.052 nM in samples from the southern California Current. We also show that a transient superoxide signal is generated during filtering, an artifact that may have affected previously reported concentrations of particle-generated superoxide in the ocean. High concentrations of superoxide (range) were measured in filtered samples from ALOHA station and the California Current, raising concerns about possible sources of background signals. Further study of background signals revealed that some superoxide production occurs even in artificial seawater and very aged filtered seawater samples, and that a small additional background signal is generated as the sample travels from the container to the flow cell where it is mixed with reagent for CL analysis. However, filtered seawater samples collected from the Scripps Pier had significantly higher superoxide production rates than those measured in artificial seawater, and production rates in unfiltered samples were no higher than those in filtered samples. Therefore, production by dissolved sources was the dominant non-photochemical source of superoxide in these samples. Production rates decreased in the presence of DTPA, suggesting involvement of metal ions in superoxide production. Laboratory experiments with natural organic matter (NOM) indicate that superoxide formation occurs during oxidation of reduced moieties of NOM by oxygen.

Alterations in the programming of energy metabolism in adolescents with background exposure to dioxins, dl-PCBs and PBDEs.

PubMed

Leijs, Marike M; Koppe, Janna G; Vulsma, Thomas; Olie, Kees; van Aalderen, Wim M C; de Voogt, Pim; Legler, Juliette; Ten Tusscher, Gavin W

2017-01-01

Dioxins and PCBs are highly toxic and persistent environmental pollutants that are measurable in humans worldwide. These persistent organic pollutants are associated with a higher incidence of diabetes mellitus. We hypothesise that perinatal (background) exposure to industrial pollutants like dioxins also influences body mass development and energy metabolism in later life. In The Netherlands, the perinatal exposure (prenatal exposure and postnatal lactational intake) to dioxins has been studied prospectively since 1987. Fasting glucose, insulin, HbA1c and leptin were analysed in 33 children of the original cohort of 60. BMI, glucose:insulin and BMI:leptin ratios were calculated. Prenatal exposure, lactational intake and current serum levels of dioxins (PCDD/F), dl-PCBs and PBDE concentrations were determined using (HR)GC-MS. Prenatal dioxin (PCDD/F) exposure was positively correlated to the glucose:insulin ratio (p = 0.024) and negatively correlated to the fasting insulin concentration (p = 0.017) in adolescence. Postnatal lactational PCDD/F intake was also negatively correlated to fasting insulin concentration (p = 0.028). Current serum levels of PCDD/Fs and total TEQ (dl-PCBs+PCDD/Fs) were positively correlated to the fasting serum glucose concentration (p = 0.015 and p = 0.037, respectively).No metabolic effects were seen in association with current serum levels of PBDEs. A positive correlation between the insulin and leptin concentrations (p = 0.034) was observed. No effects were found on leptin levels, BMI:leptin ratio, HbA1c levels or BMI. This study indicates that prenatal and lactational exposure influences glucose metabolism in adolescents, presumably through a negative effect on insulin secretion by pancreatic beta cells. Additionally, the very low recent background exposure to dioxins in puberty possibly has an effect on the glucose level.

Polyunsaturated fatty acid content is increased in the milk of women with pregnancy associated breast cancer

USDA-ARS?s Scientific Manuscript database

Background: Pregnancy associated breast cancer (PABC) is aggressive and difficult to diagnose. High intake of most types of dietary fat is thought to increase breast cancer risk, however results in humans supporting this premise remain equivocal. Fatty acid (FA) concentrations in the body comprise b...

Hybrid Vapor Stripping-Vapor Permeation Process for Recovery and Dehydration of 1-Butanol and Acetone/Butanol/Ethanol from Dilute Aqueous Solutions. Part 1. Process Simulations

EPA Science Inventory

BACKGROUND: Fermentative production of butanol is limited to low concentrations, typically less than 2 wt% solvent, due to product inhibition. The result is high separation energy demand by conventional distillation approaches, despite favorable vapor-liquid equilibrium and parti...

Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland.

PubMed

Stępalska, Danuta; Myszkowska, Dorota; Katarzyna, Leśkiewicz; Katarzyna, Piotrowicz; Katarzyna, Borycka; Kazimiera, Chłopek; Łukasz, Grewling; Idalia, Kasprzyk; Barbara, Majkowska-Wojciechowska; Małgorzata, Malkiewicz; Małgorzata, Nowak; Krystyna, Piotrowska-Weryszko; Małgorzata, Puc; Elżbieta, Weryszko-Chmielewska

2017-04-01

The Asteraceae family is one of the largest families, comprising 67 genera and 264 species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days with high pollen concentrations of both taxa. Artemisia and Ambrosia pollen data were collected, using the volumetric method, at 8 sites in Poland. Daily concentrations of Artemisia pollen equal to 30 grains or more and Ambrosia pollen equal to 10 grains or more were accepted as high values. Concentrations of more than 10 pollen grains were defined as high in the case of Ambrosia because its allergenicity is considered higher. High concentrations were confronted with synoptic situations. Analysis was performed on the basis of two calendars on circulation types of atmosphere in Poland (Niedźwiedź, 2006, 2015). Co-occurrence of Artemisia and Ambrosia pollen seasons is being found most often, when Ambrosia pollen season starts in the first half of August. If it happens in the last 10 days of August high pollen concentrations of Artemisia and Ambrosia do not occur at the same days. At three sites (Sosnowiec, Rzeszów, Lublin) high Ambrosia pollen concentrations during the Artemisia pollen season appear more often than in other sites under question. The high Artemisia pollen concentrations occur, when continental or polar maritime old air masses inflow into Poland. The impact of air masses on high Ambrosia pollen concentrations depends on site localizations. It is likely, that in the south-eastern part of Poland high Ambrosia pollen concentrations result from the pollen transport from east-south-south-westerly directions and the local sources. Co-occurrence of both taxa pollen seasons depends on the air masses inflow and appears more often in a south-eastern part of Poland.

Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland

NASA Astrophysics Data System (ADS)

Stępalska, Danuta; Myszkowska, Dorota; Katarzyna, Leśkiewicz; Katarzyna, Piotrowicz; Katarzyna, Borycka; Kazimiera, Chłopek; Łukasz, Grewling; Idalia, Kasprzyk; Barbara, Majkowska-Wojciechowska; Małgorzata, Malkiewicz; Małgorzata, Nowak; Krystyna, Piotrowska-Weryszko; Małgorzata, Puc; Elżbieta, Weryszko-Chmielewska

2017-04-01

The Asteraceae family is one of the largest families, comprising 67 genera and 264 species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days with high pollen concentrations of both taxa. Artemisia and Ambrosia pollen data were collected, using the volumetric method, at 8 sites in Poland. Daily concentrations of Artemisia pollen equal to 30 grains or more and Ambrosia pollen equal to 10 grains or more were accepted as high values. Concentrations of more than 10 pollen grains were defined as high in the case of Ambrosia because its allergenicity is considered higher. High concentrations were confronted with synoptic situations. Analysis was performed on the basis of two calendars on circulation types of atmosphere in Poland (Niedźwiedź, 2006, 2015). Co-occurrence of Artemisia and Ambrosia pollen seasons is being found most often, when Ambrosia pollen season starts in the first half of August. If it happens in the last 10 days of August high pollen concentrations of Artemisia and Ambrosia do not occur at the same days. At three sites (Sosnowiec, Rzeszów, Lublin) high Ambrosia pollen concentrations during the Artemisia pollen season appear more often than in other sites under question. The high Artemisia pollen concentrations occur, when continental or polar maritime old air masses inflow into Poland. The impact of air masses on high Ambrosia pollen concentrations depends on site localizations. It is likely, that in the south-eastern part of Poland high Ambrosia pollen concentrations result from the pollen transport from east-south-south-westerly directions and the local sources. Co-occurrence of both taxa pollen seasons depends on the air masses inflow and appears more often in a south-eastern part of Poland.

Stable and general-purpose chemiluminescent detection system for horseradish peroxidase employing a thiazole compound enhancer and some additives.

PubMed

Iwata, R; Ito, H; Hayashi, T; Sekine, Y; Koyama, N; Yamaki, M

1995-10-10

A stable and highly sensitive chemiluminescent detection system for horseradish peroxidase (HRP)/luminol/hydrogen peroxide using a newly designed thiazole compound enhancer has been established. Some additives for the chemiluminescent reaction were explored to overcome some defects of the reaction such as rapid decay and high background of light emission. Recrystallization of luminol and the addition of several detergents into the reacting solution were effective to increase specific light emissions. The addition of skim milk into the reacting solution reduced the background. Consequently, skim milk combined with a detergent increased the signal to noise ratio about 20 times compared with the reactions in the absence of both additives. The optimal concentration of enhancer and the addition of egg albumin stabilized the emission. In the new method, 6x 10(-18) mol of HRP was detectable. This would be the most sensitive enhanced chemiluminescent detection system for HRP. Furthermore, we could detect picogram per milliliter (10(-17) mol) concentrations of a trace component in biological materials such as endothelin-1 by employing this reaction.

Summer ammonia measurements in a densely populated Mediterranean city

NASA Astrophysics Data System (ADS)

Pandolfi, M.; Amato, F.; Reche, C.; Alastuey, A.; Otjes, R. P.; Blom, M. J.; Querol, X.

2012-08-01

Real-time measurements of ambient concentrations of gas-phase ammonia (NH3) were performed in Barcelona (NE Spain) in summer between May and September 2011. Two measurement sites were selected: one in an urban background traffic-influenced area (UB) and the other in the historical city centre (CC). Levels of NH3 were higher at CC (5.6 ± 2.1 μg m-3 or 7.5 ± 2.8 ppbv) compared with UB (2.2 ± 1.0 μg m-3 or 2.9 ± 1.3 ppbv). This difference is attributed to the contribution from non-traffic sources such as waste containers, sewage systems, humans and open markets more dense in the densely populated historical city centre. Under high temperatures in summer these sources had the potential to increase the ambient levels of NH3 well above the urban-background-traffic-influenced UB measurement station. Measurements were used to assess major local emissions, sinks and diurnal evolution of NH3. The measured levels of NH3, especially high in the old city, may contribute to the high mean annual concentrations of secondary sulfate and nitrate measured in Barcelona compared with other cities in Spain affected by high traffic intensity. Ancillary measurements, including PM10, PM2.5, PM1 levels (Particulate Matter with aerodynamic diameter smaller than 10 μm, 2.5 μm, and 1 μm), gases and black carbon concentrations and meteorological data, were performed during the measurement campaign. The analysis of specific periods (3 special cases) during the campaign revealed that road traffic was a significant source of NH3. However, its effect was more evident at UB compared with CC where it was masked given the high levels of NH3 from non-traffic sources measured in the old city. The relationship between SO42- daily concentrations and gas-fraction ammonia (NH3/(NH3 + NH4+)) revealed that the gas-to-particle phase partitioning (volatilization or ammonium salts formation) also played an important role in the evolution of NH3 concentration in summer in Barcelona.

Summer ammonia measurements in a densely populated Mediterranean city

NASA Astrophysics Data System (ADS)

Pandolfi, M.; Amato, F.; Reche, C.; Alastuey, A.; Otjes, R. P.; Blom, M. J.; Querol, X.

2012-04-01

Real-time measurements of ambient concentrations of gas-phase ammonia were performed in Barcelona (NE Spain) in summer between May and September 2011. Two measurement sites were selected: one in an urban background traffic-influenced area (UB) and the other in the historical city centre (CC). Levels of ammonia were higher at CC (5.6 ± 2.1 μg m-3 or 7.5 ± 2.8 ppbv) compared with UB (2.2 ± 1.0 μg m-3 or 2.9 ± 1.3 ppbv). This difference is attributed to the contribution from non-traffic sources such as waste containers, sewage systems, humans and open markets more dense in the densely populated historical city centre. Under high temperatures in summer these sources had the potential to increase the ambient levels of ammonia well above the urban-background-traffic-influenced UB measurement station. Measurements were used to assess major local emissions, sinks and diurnal evolution of NH3. The measured levels of NH3, especially high in the old city, may contribute to the high mean annual concentrations of secondary sulfate and nitrate measured in Barcelona compared with other cities in Spain affected by high traffic intensity. Ancillary measurements, including PM10, PM2.5, PM1 levels (Particulate Matter with aerodynamic diameter smaller than 10 μm, 2.5 μm, and 1 μm), gases and black carbon concentrations and meteorological data, were performed during the measurement campaign. The analysis of specific periods (3 special cases) during the campaign revealed that road traffic was a significant source of NH3. However, its effect was more evident at UB compared with CC where it was masked given the high levels of NH3 from non-traffic sources measured in the old city. The relationship between SO42- daily concentrations and gas-fraction ammonia (NH3/(NH3+NH4+)) revealed that the gas-to-phase partitioning (volatilization or ammonium salts formation) also played an important role in the evolution of NH3 concentration in summer in Barcelona.

Soil dioxins levels at agriculture sites and natural preserve areas of Taiwan.

PubMed

Jou, Jin-juh; Lin, Kae-Long; Chung, Jen-Chir; Liaw, Shu-Liang

2007-08-17

In this study, agriculture soil in Taiwan has been sampled and analyzed to determine the background level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DF) in the agricultural and nature preserve areas. Another objective is to investigate relationship between soil characteristics and air deposition in Taiwan. The results indicate that in nature preserve areas the topsoil shows an extraordinary profile of PCDD/DF compared to that in the air deposition. The PCDD/DF levels of the low-contaminated agricultural soils are compatible with those of the nature preserves soils. However, in the highly-contaminated agricultural soils, there is an abrupt jump in their concentrations, 10-100 times higher. The overall I-TEQ values of the background topsoils range from 0.101 to 15.2 ng I-TEQ/kg. Near industrial/urban areas in Taiwan the PCDD/DF are slightly higher compared to those in the low concentration group. Typically, the PCDD/DF background values found in this survey fall in the 90% confidence interval and can thus, be deemed the background levels in Taiwan. Ninety-five percent of these data are below the European and American soil standard of 10 ng I-TEQ/kg d.w. The PCDD/DF profile with one neighborhood soil sample was shown no significant difference.

Field background odour should be taken into account when formulating a pest attractant based on plant volatiles

PubMed Central

Cai, Xiaoming; Bian, Lei; Xu, Xiuxiu; Luo, Zongxiu; Li, Zhaoqun; Chen, Zongmao

2017-01-01

Attractants for pest monitoring and controlling can be developed based on plant volatiles. Previously, we showed that tea leafhopper (Empoasca onukii) preferred grapevine, peach plant, and tea plant odours to clean air. In this research, we formulated three blends with similar attractiveness to leafhoppers as peach, grapevine, and tea plant volatiles; these blends were composed of (Z)-3-hexenyl acetate, (E)-ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene, benzaldehyde, and ethyl benzoate. Based on these five compounds, we developed two attractants, formula-P and formula-G. The specific component relative to tea plant volatiles in formula-P was benzaldehyde, and that in formula-G was ethyl benzoate. These two compounds played a role in attracting leafhoppers. In laboratory assays, the two attractants were more attractive than tea plant volatiles to the leafhoppers, and had a similar level of attractiveness. However, the leafhoppers were not attracted to formula-P in the field. A high concentration of benzaldehyde was detected in the background odour of the tea plantations. In laboratory tests, benzaldehyde at the field concentration was attractive to leafhoppers. Our results indicate that the field background odour can interfere with a point-releasing attractant when their components overlap, and that a successful attractant must differ from the field background odour. PMID:28150728

Illustration of a fingerprinting method to isolate Gold King Release Metals from Background Concentrations in the San Juan River

EPA Science Inventory

Detecting the Gold King Mine metals as the release plume passed was difficult once it entered the San Juan River on August 8, 2015. Plume metals concentrations were relatively low after 200 km of travel and deposition in the Animas River while background concentrations of the sa...

Accelerator mass spectrometry analysis of background (14)C-concentrations in human blood: aiming at reference data for further microdosing studies.

PubMed

Minamimoto, Ryogo; Hamabe, Yoshimi; Miyaoka, Teiji; Hara, Takamitsu; Yoshida, Keisuke; Oka, Takashi; Inoue, Tomio

2008-12-01

Phase 0 clinical studies, which are known as microdose trials, are expected to promote drug development and reduce development costs. The accelerator mass spectrometry (AMS) system is expected to play an important role in the microdosing tests, as it is a highly sensitive measurement system that can be used to determine the drug concentrations in these tests. Using the AMS system, we measured the background (14)C-concentration in human blood and evaluated the data for use as a reference in microdose studies that administer (14)C-labeled compounds in humans. Blood samples of five healthy Japanese volunteers (three men, two women, median age 40.4 +/- 9.8 years) were collected around the same time and just prior to when the subjects ate a meal (between 12:00 noon and 2:00 pm). Centrifugal separations of blood that was allowed to clot and the plasma were performed at 503 g for 2 min at 4 degrees C. Background (14)C-concentration for each of the samples was measured using the AMS system. The Institute of Accelerator Analysis, which is the first contract research organization in Japan that is capable of providing AMS analysis services for carbon dating and bioanalysis work, performed the AMS analysis. The mean (14)C-concentration in blood was 1.613 +/- 0.125 dpm/ml (men 1.668 +/- 0.114 dpm/ml, women 1.514 +/- 0.076 dpm/ml), in clots 2.373 +/- 0.087 dpm/ml (men 2.381 +/- 0.101 dpm/ml, women 2.357 +/- 0.060 dpm/ ml), and in plasma 0.648 +/- 0.049 dpm/ml (men 0.647 +/- 0.059 dpm/ml, women 0.649 +/- 0.032 dpm/ml). The coefficient variation (CV) for blood was 7.8% (men 6.9%, women 5.0%), for clots 3.7% (men 4.3%, women 2.5%), and for plasma 7.6% (men 9.1%, women 4.9%). The (14)C-concentrations of the clot and blood were higher than those of plasma. The (14)C-concentrations in the blood and plasma were slightly different between individuals when compared with the values for the clot, although the differences were quite small, with a CV value less than 7.8%. Even though the (14)C-concentration differed only slightly between individuals, (14)C-concentrations of the clot and blood were higher than those of the plasma. Therefore, the variation and difference of the background data for blood and plasma might be of use as a reference for microdosing test evaluations.

Transfer of vaginal chloramphenicol to circulating blood in pregnant women and its relationship with their maternal background and neonatal health.

PubMed

Harauchi, Satoe; Osawa, Takashi; Kubono, Naoko; Itoh, Hiroaki; Naito, Takafumi; Kawakami, Junichi

2017-07-01

Few clinical studies have determined the quantitative transfer of vaginal chloramphenicol to circulating blood in pregnant women. This study aimed to evaluate the plasma concentration of chloramphenicol in pregnant women treated with trans-vaginal tablets and its relationship with maternal background and neonatal health. Thirty-seven pregnant women treated with 100 mg of trans-vaginal chloramphenicol once daily for bacterial vaginosis and its suspected case were enrolled. The plasma concentration of chloramphenicol was determined using liquid chromatography coupled to tandem mass spectrometry at day 2 or later after starting the medication. The correlations between the maternal plasma concentration of chloramphenicol and the background and neonatal health at birth were investigated. Chloramphenicol was detected from all maternal plasma specimens and its concentration ranged from 0.043 to 73.1 ng/mL. The plasma concentration of chloramphenicol declined significantly with the administration period. The plasma concentration of chloramphenicol was lower at the second than the first blood sampling. No correlations were observed between the maternal plasma concentration of chloramphenicol and background such as number of previous births, gestational age at dosing, and clinical laboratory data. Neonatal infant health parameters such as birth-weight, Apgar score at birth, and gestational age at the time of childbearing were not related to the maternal plasma concentration of chloramphenicol. Vaginal chloramphenicol transfers to circulating blood in pregnant women. The maternal plasma concentration of chloramphenicol varied markedly and was associated with the administration day, but not with maternal background or her neonatal health. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Determination of the origin of groundwater nitrate at an air weapons range using the dual isotope approach.

PubMed

Bordeleau, Geneviève; Savard, Martine M; Martel, Richard; Ampleman, Guy; Thiboutot, Sonia

2008-06-06

Nitrate is one of the most common contaminants in shallow groundwater, and many sources may contribute to the nitrate load within an aquifer. Groundwater nitrate plumes have been detected at several ammunition production sites. However, the presence of multiple potential sources and the lack of existing isotopic data concerning explosive degradation-induced nitrate constitute a limitation when it comes to linking both types of contaminants. On military training ranges, high nitrate concentrations in groundwater were reported for the first time as part of the hydrogeological characterization of the Cold Lake Air Weapons Range (CLAWR), Alberta, Canada. Explosives degradation is thought to be the main source of nitrate contamination at CLAWR, as no other major source is present. Isotopic analyses of N and O in nitrate were performed on groundwater samples from the unconfined and confined aquifers; the dual isotopic analysis approach was used in order to increase the chances of identifying the source of nitrate. The isotopic ratios for the groundwater samples with low nitrate concentration suggested a natural origin with a strong contribution of anthropogenic atmospheric NOx. For the samples with nitrate concentration above the expected background level the isotopic ratios did not correspond to any source documented in the literature. Dissolved RDX samples were degraded in the laboratory and results showed that all reproduced degradation processes released nitrate with a strong fractionation. Laboratory isotopic values for RDX-derived NO(3)(-) produced a trend of high delta(18)O-low delta(15)N to low delta(18)O-high delta(15)N, and groundwater samples with nitrate concentrations above the expected background level appeared along this trend. Our results thus point toward a characteristic field of isotopic ratios for nitrate being derived from the degradation of RDX.

Distribution of uranium, thorium and some stable trace and toxic elements in human hair and nails in Niška Banja Town, a high natural background radiation area of Serbia (Balkan Region, South-East Europe).

PubMed

Sahoo, S K; Žunić, Z S; Kritsananuwat, R; Zagrodzki, P; Bossew, P; Veselinovic, N; Mishra, S; Yonehara, H; Tokonami, S

2015-07-01

Human hair and nails can be considered as bio-indicators of the public exposure to certain natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their levels in other tissues of body. Niška Banja, a spa town located in southern Serbia, with locally high natural background radiation was selected for the study. To assess public exposure to the trace elements, hair and nail samples were collected and analyzed. The concentrations of uranium, thorium and some trace and toxic elements (Mn, Ni, Cu, Sr, Cd, and Cs) were determined using inductively coupled plasma mass spectrometry (ICP-MS). U and Th concentrations in hair varied from 0.0002 to 0.0771 μg/g and from 0.0002 to 0.0276 μg/g, respectively. The concentrations in nails varied from 0.0025 to 0.0447 μg/g and from 0.0023 to 0.0564 μg/g for U and Th, respectively. We found significant correlations between some elements in hair and nails. Also indications of spatial clustering of high values could be found. However, this phenomenon as well as the large variations in concentrations of heavy metals in hair and nail could not be explained. As hypotheses, we propose possible exposure pathways which may explain the findings, but the current data does not allow testing them. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Estimating representative background PM2.5 concentration in heavily polluted areas using baseline separation technique and chemical mass balance model

NASA Astrophysics Data System (ADS)

Gao, Shuang; Yang, Wen; Zhang, Hui; Sun, Yanling; Mao, Jian; Ma, Zhenxing; Cong, Zhiyuan; Zhang, Xian; Tian, Shasha; Azzi, Merched; Chen, Li; Bai, Zhipeng

2018-02-01

The determination of background concentration of PM2.5 is important to understand the contribution of local emission sources to total PM2.5 concentration. The purpose of this study was to exam the performance of baseline separation techniques to estimate PM2.5 background concentration. Five separation methods, which included recursive digital filters (Lyne-Hollick, one-parameter algorithm, and Boughton two-parameter algorithm), sliding interval and smoothed minima, were applied to one-year PM2.5 time-series data in two heavily polluted cities, Tianjin and Jinan. To obtain the proper filter parameters and recession constants for the separation techniques, we conducted regression analysis at a background site during the emission reduction period enforced by the Government for the 2014 Asia-Pacific Economic Cooperation (APEC) meeting in Beijing. Background concentrations in Tianjin and Jinan were then estimated by applying the determined filter parameters and recession constants. The chemical mass balance (CMB) model was also applied to ascertain the effectiveness of the new approach. Our results showed that the contribution of background PM concentration to ambient pollution was at a comparable level to the contribution obtained from the previous study. The best performance was achieved using the Boughton two-parameter algorithm. The background concentrations were estimated at (27 ± 2) μg/m3 for the whole year, (34 ± 4) μg/m3 for the heating period (winter), (21 ± 2) μg/m3 for the non-heating period (summer), and (25 ± 2) μg/m3 for the sandstorm period in Tianjin. The corresponding values in Jinan were (30 ± 3) μg/m3, (40 ± 4) μg/m3, (24 ± 5) μg/m3, and (26 ± 2) μg/m3, respectively. The study revealed that these baseline separation techniques are valid for estimating levels of PM2.5 air pollution, and that our proposed method has great potential for estimating the background level of other air pollutants.

Ice Nucleation and Dehydration in the Tropical Tropopause Layer

NASA Technical Reports Server (NTRS)

Jensen, Eric J.; Diskin, Glenn S.; Lawson, R Paul; Lance, Sara; Bui, Thaopaul Van; Hlavka, Dennis L.; Mcgill, Matthew J.; Pfister, Leonhard; Toon, Owen B.; Gao, Rushan

2013-01-01

Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent highaltitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to approx. 70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L-1 (often less than 20 L-1), whereas the high ice concentration layers (with concentrations up to 10,000 L-1) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as approx. 1.7 times the ice saturation mixing ratio.

Advances in understanding of high- Z material erosion and re-deposition in low- Z wall environment in DIII-D

DOE PAGES

Ding, R.; Rudakov, D. L.; Stangeby, P. C.; ...

2017-03-24

Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. We have investigated different methods such as electrical biasing and local gas injection to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducingmore » the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local 13CH 4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E × B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. The inter-ELM W erosion we measured in H-mode plasmas, rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.« less

Reference levels of background radioactivity for beach sands and soils in İnebolu/Kastamonu-Turkey

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

Kurnaz, Aslı, E-mail: akurnaz@kastamonu.edu.tr; Türkdoğan, Savaş, E-mail: savas-turk-dogan@hotmail.com; Hançerlioğulları, Aybaba, E-mail: aybaba@kastamonu.edu.tr

This paper presents the measurement results of environmental radioactivity levels for İnebolu district (tourist area), Kastamonu-Turkey. The radioactivity concentrations of {sup 238}U, {sup 232}Th, {sup 40}K and the fission product {sup 137}Cs in soil samples collected from 13 region surroundings of study area and in 12 beach sand samples collected from along the coast of İnebolu were determined. To evaluate the radiological hazard of the natural radioactivity, based on the measured concentrations of these radionuclides, the mean absorbed gamma dose and the annual effective dose were evaluated separately, and found to be 112.90 nGy h-1 and 138.46 µSv y-1 for soilmore » samples and 75.19 nGy h-1 and 92.22 µSv y-1 for beach sand samples, respectively. The results show that İnebolu does not have high background.« less

An evaluation of an aptamer for use as an affinity reagent with MS: PCSK9 as an example protein.

PubMed

Gupta, Vinita; Lassman, Michael E; McAvoy, Thomas; Lee, Anita Yh; Chappell, Derek L; Laterza, Omar F

2016-08-01

For quantitative immunoaffinity IA-LC-MS, the utility of antibodies has been demonstrated many times but the utility of aptamers as affinity reagents is unproven. Immunoaffinity reagents including a monoclonal antibody and an aptamer were coupled to magnetic beads and used as part of an enrichment strategy for PCSK9 quantitation in plasma. With limited method development, we have established a comparison of an anti-PCSK9 aptamer with an anti-PCSK9 monoclonal antibody. The background that results from a tryptic digest of affinity enrichment in plasma was demonstrated for each reagent using high-resolution full scan MS. The assay recovery was demonstrated for multiple concentrations of aptamer in plasma with different concentrations of PCSK9 protein. The aptamer achieved comparable enrichment to the antibody, but with lower peptide background, thus demonstrating the potential use of aptamers for IA-LC-MS.

Identification of PM10 air pollution origins at a rural background site

NASA Astrophysics Data System (ADS)

Reizer, Magdalena; Orza, José A. G.

2018-01-01

Trajectory cluster analysis and concentration weighted trajectory (CWT) approach have been applied to investigate the origins of PM10 air pollution recorded at a rural background site in North-eastern Poland (Diabla Góra). Air mass back-trajectories used in this study have been computed with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model for a 10-year period of 2006-2015. A cluster analysis grouped back-trajectories into 7 clusters. Most of the trajectories correspond to fast and moderately moving westerly and northerly flows (45% and 25% of the cases, respectively). However, significantly higher PM10 concentrations were observed for slow moving easterly (11%) and southerly (20%) air masses. The CWT analysis shows that high PM10 levels are observed at Diabla Góra site when air masses are originated and passed over the heavily industrialized areas in Central-Eastern Europe located to the south and south-east of the site.

Reference levels of background radioactivity for beach sands and soils in İnebolu/Kastamonu-Turkey

NASA Astrophysics Data System (ADS)

Kurnaz, Aslı; Türkdoǧan, Savaş; Hançerlioǧulları, Aybaba; ćetiner, M. Atıf

2016-03-01

This paper presents the measurement results of environmental radioactivity levels for İnebolu district (tourist area), Kastamonu-Turkey. The radioactivity concentrations of 238U, 232Th, 40K and the fission product 137Cs in soil samples collected from 13 region surroundings of study area and in 12 beach sand samples collected from along the coast of İnebolu were determined. To evaluate the radiological hazard of the natural radioactivity, based on the measured concentrations of these radionuclides, the mean absorbed gamma dose and the annual effective dose were evaluated separately, and found to be 112.90 nGy h-1 and 138.46 µSv y-1 for soil samples and 75.19 nGy h-1 and 92.22 µSv y-1 for beach sand samples, respectively. The results show that İnebolu does not have high background.

Blood Harmane, Blood Lead, and Severity of Hand Tremor: Evidence of Additive Effects

PubMed Central

Louis, Elan D.; Factor-Litvak, Pam; Gerbin, Marina; Slavkovich, Vesna; Graziano, Joseph H; Jiang, Wendy; Zheng, Wei

2010-01-01

Background Tremor is a widespread phenomenon in human populations. Environmental factors are likely to play an etiological role. Harmane (1-methyl-9H-pyrido[3,4-β]indole) is a potent tremor-producing β-carboline alkaloid. Lead is another tremor-producing neurotoxicant. The effects of harmane and lead with respect to tremor have been studied in isolation. Objectives We tested the hypothesis that tremor would be particularly severe among individuals who had high blood concentrations of both of these toxicants. Methods Blood concentrations of harmane and lead were each quantified in 257 individuals (106 essential tremor cases and 151 controls) enrolled in an environmental epidemiological study. Total tremor score (range = 0 – 36) was a clinical measure of tremor severity. Results The total tremor score ranged from 0 – 36, indicating that a full spectrum of tremor severities was captured in our sample. Blood harmane concentration correlated with total tremor score (p = 0.007), as did blood lead concentration (p = 0.045). The total tremor score was lowest in participants with both low blood harmane and lead concentrations (8.4 ± 8.2), intermediate in participants with high concentrations of either toxicant (10.5 ± 9.8), and highest in participants with high concentrations of both toxicants (13.7 ± 10.4)(p = 0.01). Conclusions Blood harmane and lead concentrations separately correlated with total tremor scores. Participants with high blood concentrations of both toxicants had the highest tremor scores, suggesting an additive effect of these toxicants on tremor severity. Given the very high population prevalence of tremor disorders, identifying environmental determinants is important for primary disease prevention. PMID:21145352

Effects of stormwater infiltration on quality of groundwater beneath retention and detention basins

USGS Publications Warehouse

Fischer, D.; Charles, E.G.; Baehr, A.L.

2003-01-01

Infiltration of storm water through detention and retention basins may increase the risk of groundwater contamination, especially in areas where the soil is sandy and the water table shallow, and contaminants may not have a chance to degrade or sorb onto soil particles before reaching the saturated zone. Groundwater from 16 monitoring wells installed in basins in southern New Jersey was compared to the quality of shallow groundwater from 30 wells in areas of new-urban land use. Basin groundwater contained much lower levels of dissolved oxygen, which affected concentrations of major ions. Patterns of volatile organic compound and pesticide occurrence in basin groundwater reflected the land use in the drainage areas served by the basins, and differed from patterns in background samples, exhibiting a greater occurrence of petroleum hydrocarbons and certain pesticides. Dilution effects and volatilization likely decrease the concentration and detection frequency of certain compounds commonly found in background groundwater. High recharge rates in storm water basins may cause loading factors to be substantial even when constituent concentrations in infiltrating storm water are relatively low.

Towards real-time detection of tumor margins using photothermal imaging of immune-targeted gold nanoparticles

PubMed Central

Jakobsohn, Kobi; Motiei, Menachem; Sinvani, Moshe; Popovtzer, Rachela

2012-01-01

Background One of the critical problems in cancer management is local recurrence of disease. Between 20% and 30% of patients who undergo tumor resection surgery require reoperation due to incomplete excision. Currently, there are no validated methods for intraoperative tumor margin detection. In the present work, we demonstrate the potential use of gold nanoparticles (GNPs) as a novel contrast agent for photothermal molecular imaging of cancer. Methods Phantoms containing different concentrations of GNPs were irradiated with continuous-wave laser and measured with a thermal imaging camera which detected the temperature field of the irradiated phantoms. Results The results clearly demonstrate the ability to distinguish between cancerous cells specifically targeted with GNPs and normal cells. This technique, which allows highly sensitive discrimination between adjacent low GNP concentrations, will allow tumor margin detection while the temperature increases by only a few degrees Celsius (for GNPs in relevant biological concentrations). Conclusion We expect this real-time intraoperative imaging technique to assist surgeons in determining clear tumor margins and to maximize the extent of tumor resection while sparing normal background tissue. PMID:22956871

Atmospheric trace element concentrations in total suspended particles near Paris, France

NASA Astrophysics Data System (ADS)

Ayrault, Sophie; Senhou, Abderrahmane; Moskura, Mélanie; Gaudry, André

2010-09-01

To evaluate today's trace element atmospheric concentrations in large urban areas, an atmospheric survey was carried out for 18 months, from March 2002 to September 2003, in Saclay, nearby Paris. The total suspended particulate matter (TSP) was collected continuously on quartz fibre filters. The TSP contents were determined for 36 elements (including Ag, Bi, Mo and Sb) using two analytical methods: Instrumental Neutron Activation Analysis (INAA) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The measured concentrations were in agreement within the uncertainties with the certified values for the polycarbonate reference material filter SRM-2783 (National Institute for Standard Technology NIST, USA). The measured concentrations were significantly lower than the recommended atmospheric concentrations. In 2003, the Pb atmospheric level at Saclay was 15 ng/m 3, compared to the 500 ng/m 3 guideline level and to the 200 ng/m 3 observed value in 1994. The typical urban background TSP values of 1-2, 0.2-1, 4-6, 10-30 and 3-5 ng/m 3 for As, Co, Cr, Cu and Sb, respectively, were inferred from this study and were compared with the literature data. The typical urban background TSP concentrations could not be realised for Cd, Pb and Zn, since these air concentrations are highly influenced by local features. The Zn concentrations and Zn/Pb ratio observed in Saclay represented a characteristic fingerprint of the exceptionally large extent of zinc-made roofs in Paris and its suburbs. The traffic-related origin of Ba, Cr, Cu, Pb and Sb was demonstrated, while the atmospheric source(s) of Ag was not identified.

Hierarchical modeling of indoor radon concentration: how much do geology and building factors matter?

PubMed

Borgoni, Riccardo; De Francesco, Davide; De Bartolo, Daniela; Tzavidis, Nikos

2014-12-01

Radon is a natural gas known to be the main contributor to natural background radiation exposure and only second to smoking as major leading cause of lung cancer. The main concern is in indoor environments where the gas tends to accumulate and can reach high concentrations. The primary contributor of this gas into the building is from the soil although architectonic characteristics, such as building materials, can largely affect concentration values. Understanding the factors affecting the concentration in dwellings and workplaces is important both in prevention, when the construction of a new building is being planned, and in mitigation when the amount of Radon detected inside a building is too high. In this paper we investigate how several factors, such as geologic typologies of the soil and a range of building characteristics, impact on indoor concentration focusing, in particular, on how concentration changes as a function of the floor level. Adopting a mixed effects model to account for the hierarchical nature of the data, we also quantify the extent to which such measurable factors manage to explain the variability of indoor radon concentration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of selected biological, chemical, and physical conditions at fixed sites in the Upper Colorado River basin, Colorado, 1995-98

USGS Publications Warehouse

Deacon, Jeffrey R.; Mize, Scott V.; Spahr, Norman E.

1999-01-01

Biological community samples were collected at 15 sites in the Upper Colorado River Basin (UCOL) in Colorado as part of the National Water-Quality Assessment (NAWQA) Program. Sites sampled in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateau, represented agriculture, mining, urban and recreation, and mixed land uses and background conditions. Nine measures of water quality, which include information on nutrients, specific conductance (a surrogate for salinity), trace elements in streambed sediment, pesticides in fish tissue, fish communities, and macroinvertebrate richness and composition and stream habitat were used for comparisons among sites within the two physiographic provinces. Sampling sites from three other NAWQA study units?the Rio Grande Valley, the South Platte River Basin, and the Upper Snake River Basin study units?were categorized on the basis of land use and stream size in order to develop a larger data set for comparison to sites in the UCOL. Three categories of land use?forested (includes mining, urban and recreation, and background), agriculture, and mixed?were used for comparison to the UCOL fixed sites. Results indicated that all sites other than the Colorado River below Baker Gulch (a background site) showed some water-quality characteristics to be significantly affected. Results indicated that the concentrations of cadmium and zinc in streambed sediment at mining land-use sites in the Southern Rocky Mountains physiographic province generally were orders of magnitude higher than streambed-sediment concentrations at the background site. Streambed-sediment concentrations at mining land-use sites in the UCOL were greater than the 75th percentile of concentrations from sites in the three other NAWQA study units. Fish communities and habitat conditions were degraded at mining land-use sites compared to the background site. Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness and the percentage of EPT were lower at mining land-use sites than at the background site and were less than the 50th percentile of those for sites from the three other NAWQA study units. Nutrient concentrations at urban and recreation sites in the Southern Rocky Mountain physiographic province generally were greater than concentrations at the background site and generally were between the 25th and 90th percentile of concentrations for sites from the three other NAWQA study units. Habitat conditions and fish communities at urban and recreation sites were slightly degraded compared to the background site. EPT richness and the percentage of EPT were lower at urban and recreation sites than at the background site and were between the 25th and 75th percentile of those for sites from the three other NAWQA study units. The percentage of Chironomidae, which may be indicative of pollutant-tolerant organisms, was higher at urban and recreation sites than at the background site. Mixed land-use sites in the Southern Rocky Mountains physiographic province had similar nutrient concentrations and similar cadmium and zinc streambed-sediment concentrations. Fish-community degradation index values were very different among the three mixed land-use sites in the Southern Rocky Mountains physiographic province. Larger percentages of omnivores and anomalies such as lesions and deformities at two mixed land-use sites resulted in higher degradation values of the fish community. Agriculture land-use sites had higher concentrations of nutrients and selenium than the background site in the Colorado Plateau physiographic province. Concentrations of p,p'-DDE in fish tissue at agriculture sites were higher than the 75th percentile of concentrations for sites from the three other NAWQA study units. Fish communities had degradation values near the 75th percentile for agriculture sites. The percentage of EPT was low at agriculture sites when compared to the background site. Two mixed land-use sites in the Colorado Plateau physiographi

Performance evaluation of an in situ nitrous acid measurement system and continuous measurement of nitrous acid in an indoor environment.

PubMed

Park, Seung Shik; Cho, Sung Yong

2010-12-01

Nitrous acid (HONO) may cause adverse effects to mucous membranes and lung function when people are exposed to higher HONO concentrations than those present in typical indoor residential environments. Therefore, determination of HONO concentration in indoor environments is required to investigate occurrences of high HONO levels. In this work, a high-time-resolution measurement system was utilized to better understand the levels and dynamic behavior of HONO in an indoor environment. The performance of the in situ HONO analyzer applied to this work was evaluated using a 12-hr integrated annular denuder technique under ambient conditions. Both methods for the measurements of HONO were in good agreement, with a regression slope of 0.84, an intercept of 0.09, and correlation coefficient (r2) of 0.67. Indoor HONO and nitrogen oxide concentrations were also observed for approximately 5 days in winter in the living room of an apartment that had a gas range for cooking in the kitchen. Investigation of the relationships among nitric oxide (NO), nitrite (NO2), and HONO concentrations suggests that HONO production during combustion could be the result of direct emission, whereas the heterogeneous NO2 chemistry during the background period and after combustion was the possible pathway of HONO production. Controlled combustion experiments, performed at a burning rate of 50% valve setting, show peak HONO concentrations during the unvented combustion to be approximately 8-10 times higher than background levels depending on the time of day. At a burning rate setting of 50%, the peak concentration of HONO during unvented combustion was found to be 33-37% higher than those from "weak" (airflow = 340 m3/hr) and "strong" (airflow = 540 m3/hr) vented combustions. The decay rate of the HONO concentrations for the unvented combustion conditions was approximately 2-fold higher in the daytime than in the nighttime and significantly less than those of NO and NO2.

[Characteristics of atmospheric CO2 concentration and variation of carbon source & sink at Lin'an regional background station].

PubMed

Pu, Jing-Jiao; Xu, Hong-Hui; Kang, Li-Li; Ma, Qian-Li

2011-08-01

Characteristics of Atmospheric CO2 concentration obtained by Flask measurements were analyzed at Lin'an regional background station from August 2006 to July 2009. According to the simulation results of carbon tracking model, the impact of carbon sources and sinks on CO2 concentration was evaluated in Yangtze River Delta. The results revealed that atmospheric CO2 concentrations at Lin'an regional background station were between 368.3 x 10(-6) and 414.8 x 10(-6). The CO2 concentration varied as seasons change, with maximum in winter and minimum in summer; the annual difference was about 20.5 x 10(-6). The long-term trend of CO2 concentration showed rapid growth year by year; the average growth rate was about 3.2 x 10(-6)/a. CO2 flux of Yangtze River Delta was mainly contributed by fossil fuel burning, terrestrial biosphere exchange and ocean exchange, while the contribution of fire emission was small. CO2 flux from fossil fuel burning played an important role in carbon source; terrestrial biosphere and ocean were important carbon sinks in this area. Seasonal variations of CO2 concentration at Lin'an regional background station were consistent with CO2 fluxes from fossil fuel burning and terrestrial biosphere exchange.

Efficient Incorporation of Mg in Solution Grown GaN Crystals

NASA Astrophysics Data System (ADS)

Freitas, Jaime A., Jr.; Feigelson, Boris N.; Anderson, Travis J.

2013-11-01

Detailed spectrometry and optical spectroscopy studies carried out on GaN crystals grown in solution detect and identify Mg as the dominant shallow acceptor. Selective etching of crystals with higher Mg levels than that of the donor concentration background indicates that Mg acceptors incorporate preferentially in the N-polar face. Electrical transport measurements verified an efficient incorporation and activation of the Mg acceptors. These results suggest that this growth method has the potential to produce p-type doped epitaxial layers or p-type substrates characterized by high hole concentration and low defect density.

Impact of mine and natural sources of mercury on water, sediment, and biota in Harley Gulch adjacent to the Abbott-Turkey Run mine, Lake County, California

USGS Publications Warehouse

Rytuba, James J.; Hothem, Roger L.; Brussee, Brianne E.; Goldstein, Daniel N.

2011-01-01

Sediment with high Hg concentration is present throughout the West Fork of Harley Gulch below the mine and in the upper part of the Harley Gulch main stem to just above sample site HG10. At the sample site furthest downstream, HG10, Hg concentration is at background levels, as are cobalt (Co), nickel (Ni), and tungsten (W), indicating that the sediment is not significantly contaminated with Hg from the mine.

Horizontal and vertical variability of soil properties in a trace element contaminated area

NASA Astrophysics Data System (ADS)

Burgos, Pilar; Madejón, Engracia; Pérez-de-Mora, Alfredo; Cabrera, Francisco

2008-02-01

The spatial distribution of some soil chemical properties and trace element contents of a plot affected by the Aznalcóllar mine spill were investigated using statistical and geostatistical methods to assess the extent of soil contamination. Total and EDTA-extractable soil trace element concentrations and total S content showed great variability and high coefficients of variation in the three examined depths. Soil in the plot was found to be significantly contaminated by As, Cd, Cu, Pb and Zn within a wide range of pH. Total trace element concentrations at all depths (0-60 cm) were much higher than background values of non-affected soil, indicating that despite the clean-up operations, the concentration of trace elements in the experimental plot was still high. The spatial distribution of the different variables was estimated by kriging to design contour maps. These maps allowed the identification of specific zones with high metal concentrations and low pH values corresponding to spots of residual sludge. Moreover, kriged maps showed distinct spatial distribution and hence different behaviour for the elements considered. This information may be applied to optimise remediation strategies in highly and moderately contaminated areas.

Background odour induces adaptation and sensitization of olfactory receptors in the antennae of houseflies.

PubMed

Kelling, F J; Ialenti, F; Den Otter, C J

2002-06-01

The presence of background odour was found to have a small but significant effect on the sensitivity of the antennal olfactory system of houseflies, Musca domestica Linnaeus (Diptera: Muscidae), to new pulses of odour. We show that cross-adaptation and cross-sensitization between a background odour of (+/-)-1-octen-3-ol and pulses of (+/-)-1-octen-3-ol, 2-pentanone and R-(+)-limonene can occur, confirming that olfactory receptor cells are sensitive to different odours. Background odour can increase the responses to low concentration odour pulses and decrease the responses to higher concentration odour pulses. It is suggested that background odour has a larger effect on olfactory receptor cells that respond with a tonic increase of spike frequency, giving information about the level of odour concentration, i.e. the 'static' environment. Cells that respond in a phasic way only provide information on the dynamics of the olfactory environment.

Saharan dust, convective lofting, aerosol enhancement zones, and potential impacts on ice nucleation in the tropical upper troposphere

NASA Astrophysics Data System (ADS)

Twohy, C. H.; Anderson, B. E.; Ferrare, R. A.; Sauter, K. E.; L'Ecuyer, T. S.; van den Heever, S. C.; Heymsfield, A. J.; Ismail, S.; Diskin, G. S.

2017-08-01

Dry aerosol size distributions and scattering coefficients were measured on 10 flights in 32 clear-air regions adjacent to tropical storm anvils over the eastern Atlantic Ocean. Aerosol properties in these regions were compared with those from background air in the upper troposphere at least 40 km from clouds. Median values for aerosol scattering coefficient and particle number concentration >0.3 μm diameter were higher at the anvil edges than in background air, showing that convective clouds loft particles from the lower troposphere to the upper troposphere. These differences are statistically significant. The aerosol enhancement zones extended 10-15 km horizontally and 0.25 km vertically below anvil cloud edges but were not due to hygroscopic growth since particles were measured under dry conditions. Number concentrations of particles >0.3 μm diameter were enhanced more for the cases where Saharan dust layers were identified below the clouds with airborne lidar. Median number concentrations in this size range increased from 100 l-1 in background air to 400 l-1 adjacent to cloud edges with dust below, with larger enhancements for stronger storm systems. Integration with satellite cloud frequency data indicates that this transfer of large particles from low to high altitudes by convection has little impact on dust concentrations within the Saharan Air Layer itself. However, it can lead to substantial enhancement in large dust particles and, therefore, heterogeneous ice nuclei in the upper troposphere over the Atlantic. This may induce a cloud/aerosol feedback effect that could impact cloud properties in the region and downwind.

Emissions from the Bena Landfill

NASA Astrophysics Data System (ADS)

Schafer, C.; Blake, D. R.; Hughes, S.

2016-12-01

In 2013, Americans generated 254 million tons of municipal solid waste (MSW). The gas generated from the decomposition of MSW is composed of approximately 50% methane, 50% carbon dioxide, and a small proportion of non-methane organic compounds (NMOCs). NMOCs constitute less than 1% of landfill emissions, but they can have a disproportionate environmental impact as they are highly reactive ozone precursors. During the 2016 Student Airborne Research Program (SARP), whole air samples were collected at the Bena landfill outside of Bakersfield, CA and throughout Bakersfield and analyzed using gas chromatography in order to quantify NMOC emissions. This area was determined to have elevated concentrations of benzene, trichloroethylene, and tetrachloroethylene, all of which are categorized by the EPA as hazardous to human health. Benzene was found to have a concentration of 145 ± 4 pptv, four times higher than the background levels in Bakersfield (36 ± 1 pptv). Trichloroethylene and tetrachloroethylene had concentrations of 18 ± 1 pptv and 31 ± 1 pptv which were 18 and 10 times greater than background concentrations, respectively. In addition, hydroxyl radical reactivity (ROH) was calculated to determine the potential for tropospheric ozone formation. The total ROH of the landfill was 7.5 ± 0.2 s-1 compared to total background ROH of 1.0 ± 0.1 s-1 . NMOCs only made up 0.6% of total emissions, but accounted for 67% of total ROH.These results can help to shape future landfill emission policies by highlighting the importance of NMOCs in addition to methane. More research is needed to investigate the ozone forming potential of these compounds at landfills across the country.

Some studies related to a new Hexagonal Compound Parabolic Concentrator (HCPC) as a secondary in tandem with a solar tower

NASA Astrophysics Data System (ADS)

Suresh, Deivarajan

Secondary concentrators operate in the focal plane of a point focusing system such as a paraboloidal dish or a tower and, when properly designed, are capable of enhancing the overall concentration ratio of the optical system at least by factor of two to five. The viability of using different shapes was demonstrated both analytically as well as experimentally in recent years, including Compound Parabolic Concentrators (CPCs) of circular cross section and 'trumpets' as secondaries. Current research effort is centered around a HCPC (Hexagonal CPC). Major areas addressed include an overview on the state of development of secondary concentrators, some background information related to the design of a HCPC, the results of an analytical study on the thermal behavior of this HCPC under concentrated flux conditions, and a computer modeling for assessing the possible thermal interactions between the secondary and a high temperature receiver.

Blood Lead Levels in Captive Giant Pandas.

PubMed

Wintle, Nathan J P; Martin-Wintle, Meghan S; Zhou, Xiaoping; Zhang, Hemin

2018-01-01

Fifteen giant pandas (Ailuropoda melanoleuca) from the Chinese Conservation and Research Center for the Giant Panda (CCRCGP) in Bifengxia, Sichuan, China were analyzed for blood lead concentrations (Pb-B) during the 2017 breeding season. Thirteen of the 15 bears showed Pb-B below the method detection limit (MDL) of 3.3 µg/dL. The two remaining bears, although above the MDL, contained very low concentrations of lead of 3.9 and 4.5 µg/dL. All 15 giant pandas in this analysis had Pb-B concentrations that were within normal background concentrations for mammals in uncontaminated environments. For a threatened species, whose native country is plagued by reports of extremely high air pollution, our findings suggest that giant pandas at the CCRCGP are not absorbing lead at concentrations that would adversely affect their health.

A statistical downscaling approach for roadside NO2 concentrations: Application to a WRF-Chem study for Berlin

NASA Astrophysics Data System (ADS)

Kuik, Friderike; Lauer, Axel; von Schneidemesser, Erika; Butler, Tim

2017-04-01

Many European cities continue to struggle with meeting the European air quality limits for NO2. In Berlin, Germany, most of the exceedances in NO2 recorded at monitoring sites near busy roads can be largely attributed to emissions from traffic. In order to assess the impact of changes in traffic emissions on air quality at policy relevant scales, we combine the regional atmosphere-chemistry transport model WRF-Chem at a resolution of 1kmx1km with a statistical downscaling approach. Here, we build on the recently published study evaluating the performance of a WRF-Chem setup in representing observed urban background NO2 concentrations from Kuik et al. (2016) and extend this setup by developing and testing an approach to statistically downscale simulated urban background NO2 concentrations to street level. The approach uses a multilinear regression model to relate roadside NO2 concentrations observed with the municipal monitoring network with observed NO2 concentrations at urban background sites and observed traffic counts. For this, the urban background NO2 concentrations are decomposed into a long term, a synoptic and a diurnal component using the Kolmogorov-Zurbenko filtering method. We estimate the coefficients of the regression model for five different roadside stations in Berlin representing different street types. In a next step we combine the coefficients with simulated urban background concentrations and observed traffic counts, in order to estimate roadside NO2 concentrations based on the results obtained with WRF-Chem at the five selected stations. In a third step, we extrapolate the NO2 concentrations to all major roads in Berlin. The latter is based on available data for Berlin of daily mean traffic counts, diurnal and weekly cycles of traffic as well as simulated urban background NO2 concentrations. We evaluate the NO2 concentrations estimated with this method at street level for Berlin with additional observational data from stationary measurements and mobile measurements conducted during a campaign in summer 2014. The results show that this approach allows us to estimate NO2 concentrations at roadside reasonably well. The approach can be applied when observations show a strong correlation between roadside NO2 concentrations and traffic emissions from a single type of road. The method, however, shows weaknesses for intersections where observed NO2 concentrations are influenced by traffic on several different roads. We then apply this downscaling approach to estimate the impact of different traffic emission scenarios both on urban background and street level NO2 concentrations. References Kuik, F., Lauer, A., Churkina, G., Denier van der Gon, H. A. C., Fenner, D., Mar, K. A., and Butler, T. M.: Air quality modelling in the Berlin-Brandenburg region using WRF-Chem v3.7.1: sensitivity to resolution of model grid and input data, Geosci. Model Dev., 9, 4339-4363, doi:10.5194/gmd-9-4339-2016, 2016.

Concentrations and spatial patterns of organic contaminants in tree swallow (Tachycineta bicolor) eggs at United States and binational Great Lakes Areas of Concern, 2010–2015

USGS Publications Warehouse

Custer, Christine M.; Custer, Thomas W.; Dummer, Paul; Goldberg, Diana R.; Franson, J. Christian

2016-01-01

Tree swallows, Tachycineta bicolor, were sampled across the Great Lakes basin in 2010 through 2015 to provide a system-wide assessment of current exposure to organic contaminants. The results provide information identified as critical by regulators to assess the “bird or animal deformity or reproductive problems” beneficial use impairment. Eggs were collected from 69 sites across all 5 Great Lakes, including 27 Areas of Concern (AOCs), some with multiple sites, and 10 sites not listed as an AOC. Concentrations of organic contaminants in eggs were quantified and compared with background and reproductive effect thresholds. Approximately 30% of AOCs had geometric mean concentrations of total polychlorinated biphenyls (PCBs) at or below average background exposure (0.34 μg/g wet wt). Exposure to polybrominated diphenyl ethers (PBDEs) was minimal, and only 3 of 27 AOCs and 1 non-AOC had geometric mean concentrations that exceeded background for tree swallows (96 ng/g wet wt). Concentrations of both PCBs and PBDEs were 10 to 20 times below the lower limit associated with impaired hatching success. In contrast, geometric mean concentrations of polychlorinated dibenzo-p-dioxin and furan (PCDD-F) toxic equivalents (TEQs) at the Saginaw River and Bay AOC and Midland, Michigan, USA (a non-AOC site), exceeded the lower limit for hatching effects (181 pg/g PCDD-F TEQs). The rest of the sites had geometric mean concentrations of PCDD-F TEQs below background levels (87 pg/g PCDD-F TEQs). Other organic contaminants, including p,p′-dichlorodiphenyldichloroethylene, mirex, heptachlor, and chlordane, were at or below background or adverse effect concentrations.

3. A 40-years record of the polymetallic pollution of the Lot River system, France

NASA Astrophysics Data System (ADS)

Audry, S.; Schäfer, J.; Blanc, G.; Veschambre, S.; Jouanneau, J.-M.

2003-04-01

The Lot River system (southwest France) is known for historic Zn and Cd pollution that originates from Zn ore treatment in the small Riou-Mort watershed and affects seafood production in the Gironde Estuary. We present a sedimentary record from 2 cores taken in a dam lake downstream of the Riou-Mort watershed covering the evolution of metal inputs into the Lot River over the past 40 years (1960-2001). Depth profiles of Cd, Zn, Cu and Pb concentrations are comparable indicating common sources and transport. The constant Zn/Cd ratio (˜50) observed in the sediment cores is similar to that in SPM from the Riou-Mort watershed, indicating the dominance of point source pollution upon the geochemical background signal. Cadmium, Zn, Cu and Pb concentrations in the studied sediment cores show an important peak in 42-44 cm depth with up to 300 mg.kg-1 (Cd), 10,000 mg.kg-1 (Zn), 150 mg.kg-1 (Cu) and 930 mg.kg-1 (Pb). These concentrations are much higher than geochemical background values; For example, Cd concentrations are more than 350-fold higher than those measured in the same riverbed upstream the confluence with the Riou-Mort River. This peak coincides with the upper 137Cs peak resulting from the Chernobyl accident (1986). Therefore, this heavy metal peak is attributed to the latest accidental Cd pollution of the Lot-River in 1986. Several downward heavy metal peaks reflect varying input probably due to changes in industrial activities within the Riou-Mort watershed. Given mean sedimentation rate of about 2 cm.yr-1, the record suggests constant and much lower heavy metal concentrations since the early nineties due to restriction of industrial activities and remediation efforts in the Riou-Mort watershed. Nevertheless, Cd, Zn, Cu and Pb concentrations in the upper sediment remain high, compared to background values from reference sites in the upper Lot River system.

Use of population exposure frequency distributions to simulate effects of policy interventions on NO2 exposure

NASA Astrophysics Data System (ADS)

Dimitroulopoulou, C.; Ashmore, M. R.; Terry, A. C.

2017-02-01

Health effects of air pollution on individuals depend on their personal exposure, but few modelling tools are available which can predict how the distribution of personal exposures within a city will change in response to policies to reduce emissions both indoors and outdoors. We describe a new probabilistic modelling framework (INDAIR-2/EXPAIR), which provides predictions of the personal exposure frequency distribution (PEFD) across a city to assess the effects of both reduced emissions from home sources and reduced roadside concentrations on population exposure. The model uses a national time activity database, which gives the percentage of each population group in different residential and non-residential micro-environments, and links this, for the home, to predictions of concentrations from a three-compartment model, and for non-residential microenvironments to empirical indoor/outdoor ratios. This paper presents modelled PEFDs for NO2 in the city of Leicester, for children, the elderly, and office workers, comparing results in different seasons and on different days of the week. While the mean NO2 population exposure was close to, or below the urban background concentration, the 95%ile of the PEFD was well above the urban background concentration. The relationship between both mean and 95%ile PEFD and urban background concentrations was strongly influenced by air exchange rate. The 24 h mean PEFD showed relative small differences between the population groups, with both removal of home sources and reductions of roadside concentrations on roads with a high traffic density having similar effects in reducing mean exposure. In contrast, the 1 h maximum of the PEFD was significantly higher for children and the elderly than for office workers, and showed a much greater response to reduced home emissions in these groups. The results demonstrate the importance of understanding the dynamics of NO2 exposure at a population level within different groups, if the benefits of policy interventions are to be accurately assessed.

Synoptic survey of septic indicators in streams and springs at Monte Sano Mountain, Madison County, Alabama, January 29-31, 1998

USGS Publications Warehouse

McPherson, Ann K.; Mooty, Will S.

1999-01-01

The U.S. Geological Survey conducted a synoptic investigation of fecal bacterial pollution in headwater streams and springs on Monte Sano Mountain. A total of 18 sites were sampled over a 3 day period in late January 1998. Fifteen of the sites were located hydrologically downgradient from residential areas on top of Monte Sano Mountain. Three additional sites were selected as background sites in unpopulated areas on Huntsville Mountain, south of Monte Sano Mountain. Sampling was conducted during a period of high baseflow after a recent storm when no surface runoff was present. Any contaminants identified in the streams and springs were likely derived from ground-water discharge because overland flow was not evident. Four of the five sites in the Pottsville-Pennington unit (uppermost) with the highest concentration of residential land use had Escherichia coli (E. coli) concentrations that were more than 25 times the background level. In contrast, with the exception of one site, E. coli concentrations in the Bangor-Monteagle unit (middle) and Tuscumbia unit (lowermost) were at or near background levels. Caffeine was also detected in the Pottsville-Pennington unit at a site with one of the highest densities of E. coli. Elevated levels of nitrate and chloride were also identified at sites in the Pottsville-Pennington unit. The results of this synoptic sampling event identified elevated concentrations of fecal bacteria in the Pottsville-Pennington unit at the top of the mountain. These elevated bacterial concentrations occurred in conjunction with caffeine detection and elevated levels of nitrate and chloride. This indicates that there is a potential water-quality problem related to discharge from the shallow ground-water system. These sites are located in close proximity to residential development, indicating that the most probable source of the elevated fecal bacterial concentrations was septic tank effluent.

Pretreatment serum xanthophyll concentrations as predictors of head and neck cancer recurrence and survival

PubMed Central

Arthur, Anna E.; Bellile, Emily L.; Rozek, Laura S.; Peterson, Karen E.; Ren, Jianwei; Harris, Ethan; Mueller, Christie; Jolly, Shruti; Peterson, Lisa A.; Wolf, Gregory T.; Djuric, Zora

2015-01-01

Background The purpose of this study was to examine associations of pretreatment serum carotenoids, tocopherols, and quercetin with prognosis in 154 newly diagnosed head and neck cancer (HNC) patients. Methods Pretreatment blood and health surveys were collected. Serum micronutrients were measured by HPLC. Data on recurrence and death were collected annually. Cox proportional hazards models measured associations of serum nutrient concentrations with recurrence and overall survival. Results During a median follow-up time of 37 months, there were 32 recurrences and 27 deaths. After controlling for covariates, subjects with high versus low serum xanthophyll and total carotenoid concentrations had significantly longer recurrence-free time (P = 0.002 and P = 0.02, respectively). Overall survival time was significantly longer in subjects with high versus low serum xanthophyll concentrations (P = 0.02). Conclusions Future research should evaluate the possible benefits of interventions to increase intakes of rich food sources of xanthophylls in this patient population. PMID:26614223

Emissions and accumulation of metals in the atmosphere due to crackers and sparkles during Diwali festival in India

NASA Astrophysics Data System (ADS)

Kulshrestha, U. C.; Nageswara Rao, T.; Azhaguvel, S.; Kulshrestha, M. J.

In India, Diwali is known as one of the most famous festivals. On the occasion of this festival, people burn crackers and sparkles to express their happiness. The burning of these fireworks leads to metal pollution in air. In this study, metal concentrations in ambient air were observed to be very high as compared to background values on previous days. For some metals the concentrations were observed to be higher than reported at industrial sites. The order of concentration of metals on the day of festival was observed to be in the order—K>Al>Ba>Mg>Fe>Sr>Na>Ca>Cu>Mn>As>V>Ni>Bi. Interestingly, the concentrations of Ba, K, Al and Sr went up to 1091, 25, 18 and 15 times higher than the previous day of Diwali. This study indicated that burning of crackers and sparkles on Diwali is a very strong source of air pollution which contributes significantly high amount of metals in air.

Temporal trends in and influence of wind on PAH concentrations measured near the Great Lakes

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

Cortes, D.R.; Basu, I.; Sweet, C.W.

2000-02-01

This paper reports on temporal trends in gas- and particle-phase PAH concentrations measured at three sites in the Great Lakes' Integrated Atmospheric Deposition Network: Eagle Harbor, near Lake Superior, Sleeping Bear Dunes, near Lake Michigan, and Sturgeon Point, near Lake Erie. While gas-phase concentrations have been decreasing since 1991 at all sites, particle-phase concentrations have been decreasing only at Sleeping Bear Dunes. To determine whether these results represent trends in background levels or regional emissions, the average concentrations are compared to those found in urban and rural studies. In addition, the influence of local wind direction on PAH concentrations ismore » investigated, with the assumption that dependence on wind direction implies regional sources. Using these two methods, it is found that PAH concentrations at Eagle Harbor and Sleeping Bear Dunes represent regional background levels but that PAH from the Buffalo Region intrude on the background levels measured at the Sturgeon Point site. At this site, wind from over Lake Erie reduces local PAH concentrations.« less

Transcobalamin 776C-->G polymorphism is associated with peripheral neuropathy in elderly with high folate intake

USDA-ARS?s Scientific Manuscript database

Background: The 776C-->G polymorphism of the vitamin B-12 transport protein transcobalamin gene (TCN2) (rs1801198; Pro259Arg) is associated with a lower holotranscobalamin concentration in plasma. This effect may reduce the availability of vitamin B-12 to tissues even when vitamin B-12 intake is ade...

Effects of Backpackers and Stock Use on Wilderness Water Quality in Sequoia & Kings Canyon National Parks

NASA Astrophysics Data System (ADS)

Forrester, H.; Roop, H. A.; Clow, D. W.

2011-12-01

Backpackers and pack animals, primarily horses and mules, may impair water quality in high-use zones of federally designated wilderness areas within Sequoia and Kings Canyon National Parks (SEKI). Impacts include erosion from trails, campsites and grazing sites, which increases suspended sediment concentrations and turbidity in downstream water bodies; and fecal matter that may be washed into surface waters during rainstorms or snowmelt periods. The fecal matter also may contain pathogenic bacteria such as Escherichia coli (E. coli) that can pose a health threat to humans. This study aims to establish a working methodology to document and assess effects from backpackers and stock use on physical, chemical and biological water quality parameters. In July 2010, monitoring stations were established within the high-use Crabtree Ranger Station zone. Sites were selected to represent high backpacker use, high pack-animal use, and background conditions. Monitoring stations are instrumented to continuously record water level, temperature, and turbidity and to automatically collect storm samples. Water samples are analyzed for dissolved and particulate nutrients, suspended sediment, and E. coli concentrations. Preliminary data show E. coli counts averaged 4.5 Colony Forming Units/100ml (CFUs) at the high backpacker use, 29.0 CFUs at the high-pack animal use, and 3.4 CFUs at the background sites. Results from the nutrients and suspended sediment analyses are pending. Data collection continued throughout the 2011 field season, with the objective of better quantifying differences in water quality among the study sites.

Feasibility of Topical Applications of Natural High-Concentration Capsaicinoid Solutions in Patients with Peripheral Neuropathic Pain: A Retrospective Analysis.

PubMed

Bauchy, Fanny; Mouraux, Andre; Deumens, Ronald; Leerink, Marjolein; Ulpiano Trillig, Antonio; le Polain de Waroux, Bernard; Steyaert, Arnaud; Joëlle, Quetin-Leclercq; Forget, Patrice

2016-01-01

Background. Capsaicin, one of several capsaicinoid compounds, is a potent TRPV1 agonist. Topical application at high concentration (high concentration, >1%) induces a reversible disappearance of epidermal free nerve endings and is used to treat peripheral neuropathic pain (PNP). While the benefit of low-concentration capsaicin remains controversial, the 8%-capsaicin patch (Qutenza®, 2010, Astellas, Netherlands) has shown its effectiveness. This patch is, however, costly and natural high-concentration capsaicinoid solutions may represent a cheaper alternative to pure capsaicin. Methods. In this retrospective study, 149 patients were screened, 132 were included with a diagnosis of neuropathic pain, and eighty-four were retained in the final analyses (median age: 57.5 years [IQR25-75: 44.7-67.1], male/female: 30/54) with PNP who were treated with topical applications of natural high-concentration capsaicinoid solutions (total number of applications: 137). Indications were postsurgical PNP (85.7%) and nonsurgical PNP (14.3%) (posttraumatic, HIV-related, postherpetic, and radicular PNP). Objectives. To assess the feasibility of topical applications of natural high-concentration capsaicinoid solutions for the treatment of PNP. Results. The median treated area was 250 cm 2 [IQR25-75: 144-531]. The median amount of capsaicinoids was 55.1 mg [IQR25-75: 28.7-76.5] per plaster and the median concentration was 172.3  μ g/cm 2 [IQR25-75: 127.6-255.2]. Most patients had local adverse effects on the day of treatment, such as mild to moderate burning pain and erythema. 13.6-19.4% of the patients experienced severe pain or erythema. Following treatment, 62.5% of patients reported a lower pain intensity or a smaller pain surface, and 35% reported a sustained pain relief lasting for at least 4 weeks. Conclusion. Analgesic topical treatment with natural high-concentration capsaicinoid is feasible and may represent a low cost alternative to alleviate PNP in clinical practice.

Validation of Ogawa passive samplers for the determination of gaseous ammonia concentrations in agricultural settings

NASA Astrophysics Data System (ADS)

Roadman, M. J.; Scudlark, J. R.; Meisinger, J. J.; Ullman, W. J.

The Ogawa passive sampler (Ogawa USA, Pompano Beach, Florida) is a useful tool for monitoring atmospheric ammonia (NH 3(g)) concentrations and assessing the effects of agricultural waste management practices on NH 3(g) emissions. The Ogawa sampler, with filter-discs impregnated with citric acid, was used to trap and determine NH 3(g) concentrations in a variety of agricultural settings. A wide range of NH 3(g) concentrations can be monitored by varying the sampler exposure time, provided that no more than ˜10 μg of NH 3-N are adsorbed on the acid-coated filters. Concentrations less than 1 μg NH 3-N m -3 can be detected using long deployments (⩽14 days), while concentrations as great as 10 mg NH 3-N m -3 may be determined in very short (e.g. 5 min) deployments. Reproducibility ranged from 5% to 10% over the range of concentrations studied and passive determinations of NH 3(g) were similar to those determined using dilute-acid gas scrubbers. Background levels of NH 3(g) at a non-agricultural site in southern Delaware were typically <1 μg NH 3-N m -3. The air entering a chicken house was 10 μg NH 3-N m -3, reflecting the background levels in agricultural settings in this region. Within the house, concentrations ⩽8.5 mg NH 3-N m -3 were observed, reflecting the high rates of NH 3(g) emission from chicken excreta. Using measured NH 3(g) concentrations and poultry house ventilation rates, we estimate that each broiler grown to production size over 6 weeks contributes approximately 19±3 g of NH 3-N to the atmosphere, a value consistent with other published results.

Ultrafine particle levels at an international port of entry between the US and Mexico: exposure implications for users, workers, and neighbors.

PubMed

Olvera, Hector A; Lopez, Mario; Guerrero, Veronica; Garcia, Humberto; Li, Wen-Whai

2013-01-01

Exposure to diesel-emitted particles has been linked to increased cancer risk and cardiopulmonary diseases. Because of their size (<100 nm), exposure to ultrafine particles (UFPs) emitted from heavy-duty diesel vehicles (HDDV) might result in greater health risks than those associated with larger particles. Seasonal UFP levels at the International Bridge of the Americas, which connects the US and Mexico and has high HDDV traffic demands, were characterized. Hourly average UFP concentrations ranged between 1.7 × 10(3)/cc and 2.9 × 10(5)/cc with a mean of 3.5 × 10(4)/cc. Wind speeds <2 m s(-1) and temperatures <15 °C were associated with particle number concentrations above normal conditions. The presence of HDDV had the strongest impact on local UFP levels. Varying particle size distributions were associated with south- and northbound HDDV traffic. Peak exposure occurred on weekday afternoons. Although in winter, high exposure episodes were also observed in the morning. Particle number concentrations were estimated to reach background levels at 400 m away from traffic. The populations exposed to UFP above background levels include law enforcement officers, street vendors, private commuters, and commercial vehicle drivers as well as neighbors on both sides of the border, including a church and several schools.

Development of gas fire detection system using tunable diode laser absorption spectroscopy

NASA Astrophysics Data System (ADS)

Jiang, Y. L.; Li, G.; Yang, T.; Wang, J. J.

2017-01-01

The conventional fire detection methods mainly produce an alarm through detecting the changes in smoke concentration, flame radiation, heat and other physical parameters in the environment, but are unable to provide an early warning of a fire emergency. We have designed a gas fire detection system with a high detection sensitivity and high selectivity using the tunable semiconductor diode laser as a light source and combining wavelength modulation and harmonic detection technology. This system can invert the second harmonic signal obtained to obtain the concentration of carbon monoxide gas (a fire characteristic gas) so as to provide an early warning of fire. We reduce the system offset noise and the background noise generated due to the laser interference by deducting the system background spectrum lines from the second harmonic signal. This can also eliminate the interference of other gas spectral lines to a large extent. We detected the concentration of the carbon monoxide gas generated in smoldering sandalwood fire and open beech wood fire with the homemade fire simulator, and tested the lowest detectable limit of system. The test results show that the lowest detectable limit can reach 5×10-6 the system can maintain stable operation for a long period of time and can automatically trigger a water mist fire extinguishing system, which can fully meet the needs of early fire warning.

Synthetic turf field investigation in Connecticut.

PubMed

Simcox, Nancy J; Bracker, Anne; Ginsberg, Gary; Toal, Brian; Golembiewski, Brian; Kurland, Tara; Hedman, Curtis

2011-01-01

The primary purpose of this study was to characterize the concentrations of volatile organic compounds (VOC), semivolatile organic compounds (SVOC), rubber-related chemicals such as benzothiazole (BZT) and nitrosamine, and particulate matter (PM(10)) in air at synthetic turf crumb rubber fields. Both new and older fields were evaluated under conditions of active use. Three types of fields were targeted: four outdoor crumb rubber fields, one indoor facility with crumb rubber turf, and an outdoor natural grass field. Background samples were collected at each field on grass. Personal air sampling was conducted for VOC, BZT, nitrosamines, and other chemicals. Stationary air samples were collected at different heights to assess the vertical profile of release. Air monitoring for PM(10) was conducted at one height. Bulk samples of turf grass and crumb rubber were analyzed, and meteorological data were recorded. Results showed that personal concentrations were higher than stationary concentrations and were higher on turf than in background samples for certain VOC. In some cases, personal VOC concentrations from natural grass fields were as high as those on turf. Naphthalene, BZT, and butylated hydroxytoluene (BHT) were detected in greater concentration at the indoor field compared to the outdoor fields. Nitrosamine air levels were below reporting levels. PM(10) air concentrations were not different between on-field and upwind locations. All bulk lead (Pb) samples were below the public health target of 400 ppm. More research is needed to better understand air quality at indoor facilities. These field investigation data were incorporated into a separate human health risk assessment.

What do correlations tell us about anthropogenic-biogenic interactions and SOA formation in the Sacramento Plume during CARES?

NASA Astrophysics Data System (ADS)

Kleinman, L.; Kuang, C.; Sedlacek, A.; Senum, G.; Springston, S.; Wang, J.; Zhang, Q.; Jayne, J.; Fast, J.; Hubbe, J.; Shilling, J.; Zaveri, R.

2015-09-01

During the Carbonaceous Aerosols and Radiative Effects Study (CARES) the DOE G-1 aircraft was used to sample aerosol and gas phase compounds in the Sacramento, CA plume and surrounding region. We present data from 66 plume transects obtained during 13 flights in which southwesterly winds transported the plume towards the foothills of the Sierra Nevada Mountains. Plume transport occurred partly over land with high isoprene emission rates. Our objective is to empirically determine whether organic aerosol (OA) can be attributed to anthropogenic or biogenic sources, and to determine whether there is a synergistic effect whereby OA concentrations are enhanced by the simultaneous presence of high concentrations of CO and either isoprene, MVK+MACR (sum of methyl vinyl ketone and methacrolein) or methanol, which are taken as tracers of anthropogenic and biogenic emissions, respectively. Linear and bilinear correlations between OA, CO, and each of three biogenic tracers, "Bio", for individual plume transects indicate that most of the variance in OA over short time and distance scales can be explained by CO. For each transect and species a plume perturbation, (i.e., ΔOA, defined as the difference between 90th and 10th percentiles) was defined and regressions done amongst Δ values in order to probe day to day and location dependent variability. Species that predicted the largest fraction of the variance in ΔOA were ΔO3 and ΔCO. Background OA was highly correlated with background methanol and poorly correlated with other tracers. Because background OA was ~ 60 % of peak OA in the urban plume, peak OA should be primarily biogenic and therefore non-fossil. Transects were split into subsets according to the percentile rankings of ΔCO and ΔBio, similar to an approach used by Setyan et al. (2012) and Shilling et al. (2013) to determine if anthropogenic-biogenic interactions enhance OA production. As found earlier, ΔOA in the data subset having high ΔCO and high ΔBio was several-fold greater than in other subsets. Part of this difference is consistent with a synergistic interaction between anthropogenic and biogenic precursors and part to an independent linear dependence of ΔOA on precursors. Highest values of ΔO3 also occur in the high ΔCO-high ΔBio data set, raising the possibility that the coincidence of high concentrations of anthropogenic and biogenic tracers as well as OA and O3 may be associated with high temperatures, clear skies, and poor ventilation in addition to specific interaction between anthropogenic and biogenic compounds.

Method and source for producing a high concentration of positively charged molecular hydrogen or deuterium ions

DOEpatents

Ehlers, K.W.; Leung, K.N.

1983-07-26

One principal object of the present invention is to provide a novel method and apparatus for generating a high concentration of H/sub 2//sup +/ or D/sub 2//sup +/ ions by using a new and improved multicusp ion source. The basic principle in achieving a high percentage of H/sub 2//sup +/ or D/sub 2//sup +/ ions is to extract them from the source as soon as they are produced. Otherwise they will react with background gas molecules to form tri-atomic ions H/sub 3//sup +/ or D/sub 3//sup +/ or be dissociated by electrons. The former reaction H/sub 2//sup +/ + H/sub 2/ ..-->.. H/sub 3//sup +/ + H can have a very short mean free path length lambda. Assuming a background neutral gas density of approximately 3.3 x 10/sup 13/ cm/sup -3/ and a cross-section sigma of approximately 6 x 10/sup -15/ cm/sup 2/, lambda = (n/sub 0/ sigma)/sup -1/ is estimated to be about 5 cm. Thus the distance traversed by the H/sub 2//sup +/ ion before it arrives at the extractor electrode cannot exceed this value. This in turn sets a limit on the length of the source chamber.

Biogeochemical and microbiological characteristic of the pockmark sediments, the Gdansk Deep, The Baltic Sea

NASA Astrophysics Data System (ADS)

Pimenov, Nikolay; Kanapatskiy, Timur; Sivkov, Vadim; Toshchakov, Stepan; Korzhenkov, Aleksei; Ulyanova, Marina

2016-04-01

Comparison of the biogeochemical and microbial features was done for the gas-bearing and background sediments as well as near-bottom water of the Gdansk Deep, The Baltic Sea. Data were received in October, 2015 during 64th cruise of the R/V Akademik Mstislav Keldysh. Gas-bearing sediments were sampled within the known pockmark (Gas-Point, depth 94 m). Background sediments area (BG-Point, depth 86 m) was located several km off the pockmark area. The sulphate concentration in the pore water of the surface sediment layer (0-5 cm) of Gas-Point was 9,7 mmol/l, and sharply decreased with depth (did not exceed 1 mmol/l deeper than 50 cm). The sulphate concentration decrease at BG-Point also took place but was not so considerable. Sulphate concentration decrease is typical for the organic rich sediments of the high productive areas, both as for the methane seep areas. Fast sulphate depletion occurs due to active processes of its microbial reduction by consortium of the sulphate-reduction bacteria, which may use low-molecular organic compounds or hydrogen, formed at the different stages of the organic matter destruction; as well as within the process of the anaerobic methane oxidation by consortium of the methane-trophic archaea and sulphate-reduction bacteria. Together with sulphate concentration decrease the methane content increase, typical for the marine sediments, occurred. At the Gas-Point the methane concentration varied within 10 μmol/dm3 in the surface layer till its maximum at sediment horizon of 65 cm (5 mmol/dm3), and decreased to 1.5 mmol/dm3 at depth of 300 cm. The BG-Point maximum values were defined at sediment horizon 6 cm (2,6 μmol/dm3). Methane sulfate transition zone at the Gas-Point sediments was at 25-35 cm depth; whereas it was not defined at the BG-Point mud. High methane concentration in the gas-bearing sediments results in the formation of the methane seep from the sediments to the near-bottom water. So the Gas-Point near-bottom waters were characterized by high methane concentration (0.36-0.50 μmol/l) even in the water 2-5 m above the bottom (0.08-0.28 μmol/l), whereas at the BG-Point sediments methane concentration in the near-bottom water was 0.06-0.08 μmol/l. In order to get insights into the structure of microbial community responsible for realization of these redox processes we performed microbial community profiling using high-throughput 16S amplicon sequencing. DNA was extracted from sediments and water column in pockmark and background zones. NGS libraries were prepared with fusion primers for V4 variable region (Caporaso et al., 2012) and sequenced on the MiSeq system. Results well correlated with new data obtained from the analysis of the intensity of microbial processes. The study was financed by the Russian Scientific Fund (grant 14-37-00047). Caporaso JG, Lauber CL, Walters WA, Berg-Lyons D, Huntley J, Fierer N, Owens SM, Betley J, Fraser L, Bauer M, Gormley N, Gilbert JA, Smith G, Knight R. Ultra-high-throughput microbial community analysis on the Illumina HiSeq and MiSeq platforms. ISME J. 2012 Aug;6(8):1621-4

Intracellular magnesium detection by fluorescent indicators.

PubMed

Trapani, Valentina; Schweigel-Röntgen, Monika; Cittadini, Achille; Wolf, Federica I

2012-01-01

Magnesium is essential for a wide variety of biochemical reactions and physiological functions, but its regulatory mechanisms (both at the cellular and at the systemic level) are still poorly characterized. Not least among the reasons for this gap are the technical difficulties in sensing minor changes occurring over a high background concentration. Specific fluorescent indicators are highly sensitive tools for dynamic evaluation of intracellular magnesium concentration. We herein discuss the main criteria to consider when choosing a magnesium-specific fluorescent indicator and provide examples among commercial as well as developmental sensors. We focus on spectrofluorimetric approaches to quantify Mg(2+) concentration in cell or mitochondria suspensions, and on imaging techniques to detect intracellular magnesium distribution and fluxes by live microscopy, reporting a detailed description of standard protocols for each method. The general guidelines we provide should be applicable to specific issues by any researcher in the field. Copyright © 2012 Elsevier Inc. All rights reserved.

Baseline geochemistry of soil and bedrock Tshirege Member of the Bandelier Tuff at MDA-P

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

Warren, R.G.; McDonald, E.V.; Ryti, R.T.

1997-08-01

This report provides baseline geochemistry for soils (including fill), and for bedrock within three specific areas that are planned for use in the remediation of Material Disposal Area P (MDA-P) at Technical Area 16 (TA-16). The baseline chemistry includes leachable element concentrations for both soils and bedrock and total element concentrations for all soil samples and for two selected bedrock samples. MDA-P operated from the early 1950s to 1984 as a landfill for rubble and debris generated by the burning of high explosives (HE) at the TA-16 Burning Ground, HE-contaminated equipment and material, barium nitrate sand, building materials, and trash.more » The aim of this report is to establish causes for recognizable chemical differences between the background and baseline data sets. In many cases, the authors conclude that recognizable differences represent natural enrichments. In other cases, differences are best attributed to analytical problems. But most importantly, the comparison of background and baseline geochemistry demonstrates significant contamination for several elements not only at the two remedial sites near the TA-16 Burning Ground, but also within the entire region of the background study. This contamination is highly localized very near to the surface in soil and fill, and probably also in bedrock; consequently, upper tolerance limits (UTLs) calculated as upper 95% confidence limits of the 95th percentile are of little value and thus are not provided. This report instead provides basic statistical summaries and graphical comparisons for background and baseline samples to guide strategies for remediation of the three sites to be used in the restoration of MDA-P.« less

Long-Term Monitoring of PAH Contamination in Sediment and Recovery After the Hebei Spirit Oil Spill.

PubMed

Kim, Moonkoo; Jung, Jee-Hyun; Ha, Sung Yong; An, Joon Geon; Shim, Won Joon; Yim, Un Hyuk

2017-07-01

Approximately 10,900 t of crude oil was released 10 km off the west coast of Korea after the collision between the oil tanker Hebei Spirit and a barge carrying a crane in December 2007. To assess the areal extent and temporal trends of PAH contamination, 428 sediment samples were collected from December 2007 through May 2015 for PAH analysis. Sedimentary PAH concentrations measured immediately after the spill ranged from 3.2 to 71,200 ng g -1 , with a mean of 3800 ng g -1 . Increases in PAH concentrations were observed at stations 7-23, which were heavily oiled due to tidal currents and northwesterly wind that transported the spilled oil to these locations. Mean and maximum PAH concentrations decreased drastically from 3800 to 88.5 and 71,200 to 1700 ng g -1 , respectively, 4 months after the spill. PAH concentrations highly fluctuated until September 2008 and then decreased slowly to background levels. Reduction rate was much faster at the sandy beaches (k = 0.016) than in the muddy sites (k = 0.001). In muddy sediments, low attenuation due to low flushing rate in the mostly anaerobic sediment possibly contributed the persistence of PAHs. By May 2015 (~7.5 years after the spill), mean and maximum PAH concentrations decreased by 54 and 481 times, respectively, compared with the peak concentrations. The sedimentary PAH concentrations in the monitoring area have returned to regional background levels.

New insight into the levels, distribution and health risk diagnosis of indoor and outdoor dust-bound FRs in colder, rural and industrial zones of Pakistan.

PubMed

Khan, Muhammad Usman; Li, Jun; Zhang, Gan; Malik, Riffat Naseem

2016-09-01

This is the first robust study designed to probe selected flame retardants (FRs) in the indoor and outdoor dust of industrial, rural and background zones of Pakistan with special emphasis upon their occurrence, distribution and associated health risk. For this purpose, we analyzed FRs such as polybrominated diphenylethers (PBDEs), dechlorane plus (DP), novel brominated flame retardants (NBFRs) and organophosphate flame retardants (OPFRs) in the total of 82 dust samples (indoor and outdoor) collected three from each zone: industrial, rural and background. We found higher concentrations of FRs (PBDEs, DP, NBFRs and OPFRs) in industrial zones as compared to the rural and background zones. Our results reveal that the concentrations of studied FRs are relatively higher in the indoor dust samples being compared with the outdoor dust and they are ranked as: ∑OPFRs > ∑NBFRs > ∑PBDEs > ∑DP. A significant correlation in the FRs levels between the indoor and outdoor dust suggest the potential intermixing of these compounds between them. The principal component analysis/multiple linear regression predicts the percent contribution of FRs from different consumer products in the indoor and outdoor dust of industrial, rural and background zones to trace their source origin. The FRs detected in the background zones reveal the dust-bound FRs suspended in the air might be shifted from different warmer zones or consumers products available/used in the same zones. Hazard quotient (HQ) for FRs via indoor and outdoor dust intake at mean and high dust scenarios to the exposed populations (adults and toddlers) are found free of risk (HQ < 1) in the target zones. Furthermore, our nascent results will provide a baseline record of FRs (PBDEs, DP, NBFRs and OPFRs) concentrations in the indoor and outdoor dust of Pakistan. Copyright © 2016 Elsevier Ltd. All rights reserved.

How do background ozone concentrations affect the biosynthesis of rosmarinic acid in Melissa officinalis?

PubMed

Döring, Anne S; Pellegrini, Elisa; Della Batola, Michele; Nali, Cristina; Lorenzini, Giacomo; Petersen, Maike

2014-03-01

Lemon balm (Melissa officinalis; Lamiaceae) plants were exposed to background ozone (O3) dosages (80ppb for 5h), because high background levels of O3 are considered to be as harmful as episodic O3 peaks. Immediately at the end of fumigation the plants appeared visually symptomless, but necrotic lesions were observed later. The biosynthesis of rosmarinic acid (RA) comprises eight enzymes, among them phenylalanine ammonia-lyase (PAL), 4-coumarate:coenzyme A ligase (4CL), tyrosine aminotransferase (TAT) and rosmarinic acid synthase (RAS). The transcript levels of these genes have been investigated by quantitative RT-PCR. There was a quick up-regulation of all genes at 3h of O3 exposure, but at 24h from beginning of exposure (FBE) only RAS and PAL were up-regulated. The specific activity of RAS was closely correlated with a decrease of RA concentration in lemon balm leaves. The specific activity of PAL increased at 12h FBE to 163% in comparison to control levels. This work provides insight into the effect of O3 stress on the formation of the main phenolic ingredient of the pharmaceutically important plant M. officinalis. Copyright © 2013 Elsevier GmbH. All rights reserved.

Analysis of selected volatile organic compounds at background level in South Africa.

NASA Astrophysics Data System (ADS)

Ntsasa, Napo; Tshilongo, James; Lekoto, Goitsemang

2017-04-01

Volatile organic compounds (VOC) are measured globally at urban air pollution monitoring and background level at specific locations such as the Cape Point station. The urban pollution monitoring is legislated at government level; however, the background levels are scientific outputs of the World Meteorological Organisation Global Atmospheric Watch program (WMO/GAW). The Cape Point is a key station in the Southern Hemisphere which monitors greenhouse gases and halocarbons, with reported for over the past decade. The Cape Point station does not have the measurement capability VOC's currently. A joint research between the Cape Point station and the National Metrology Institute of South Africa (NMISA) objective is to perform qualitative and quantitative analysis of volatile organic compounds listed in the GAW program. NMISA is responsible for development, maintain and disseminate primary reference gas mixtures which are directly traceable to the International System of Units (SI) The results of some volatile organic compounds which where sampled in high pressure gas cylinders will be presented. The analysis of samples was performed on the gas chromatography with flame ionisation detector and mass selective detector (GC-FID/MSD) with a dedicate cryogenic pre-concentrator system. Keywords: volatile organic compounds, gas chromatography, pre-concentrator

Spatial variation of ultrafine particles and black carbon in two cities: results from a short-term measurement campaign.

PubMed

Klompmaker, Jochem O; Montagne, Denise R; Meliefste, Kees; Hoek, Gerard; Brunekreef, Bert

2015-03-01

Recently, short-term monitoring campaigns have been carried out to investigate the spatial variation of air pollutants within cities. Typically, such campaigns are based on short-term measurements at relatively large numbers of locations. It is largely unknown how well these studies capture the spatial variation of long term average concentrations. The aim of this study was to evaluate the within-site temporal and between-site spatial variation of the concentration of ultrafine particles (UFPs) and black carbon (BC) in a short-term monitoring campaign. In Amsterdam and Rotterdam (the Netherlands) measurements of number counts of particles larger than 10nm as a surrogate for UFP and BC were performed at 80 sites per city. Each site was measured in three different seasons of 2013 (winter, spring, summer). Sites were selected from busy urban streets, urban background, regional background and near highways, waterways and green areas, to obtain sufficient spatial contrast. Continuous measurements were performed for 30 min per site between 9 and 16 h to avoid traffic spikes of the rush hour. Concentrations were simultaneously measured at a reference site to correct for temporal variation. We calculated within- and between-site variance components reflecting temporal and spatial variations. Variance ratios were compared with previous campaigns with longer sampling durations per sample (24h to 14 days). The within-site variance was 2.17 and 2.44 times higher than the between-site variance for UFP and BC, respectively. In two previous studies based upon longer sampling duration much smaller variance ratios were found (0.31 and 0.09 for UFP and BC). Correction for temporal variation from a reference site was less effective for the short-term monitoring campaign compared to the campaigns with longer duration. Concentrations of BC and UFP were on average 1.6 and 1.5 times higher at urban street compared to urban background sites. No significant differences between the other site types and urban background were found. The high within to between-site concentration variances may result in the loss of precision and low explained variance when average concentrations from short-term campaigns are used to develop land use regression models. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of feeding treatment during the backgrounding phase of beef production from pasture on: II. Longissimus muscle proximate composition, cholesterol and fatty acids.

PubMed

Pordomingo, A J; García, T P; Volpi Lagreca, G

2012-04-01

This study evaluated effects of feedlot backgrounding strategies (40, 70 or 100% alfalfa hay diets) or pasture grazing on moisture, protein, total lipids, ash, cholesterol concentration, and lipid profiles of the longissimus dorsi muscle (LM) of pasture finished Angus heifers. Ninety six calves were allocated to the strategies over a 114-day period, followed by pasture grazing over 132 days. At the end of the backgrounding stage, the concentration of omega-3 (n-3) fatty acids was highest in the Pasture group and this difference persisted (P<0.032) until the end of the 132 day pasture finishing phase. Similarly, the n-6/n-3 ratio was lowest in the Pasture group at the end of backgrounding and after pasture finishing. Backgrounding diets based on 70 and 100% hay or pasture grazing showed greater (P<0.041) conjugated linoleic acid (CLA) concentration in the lipid fraction than 40% hay. Results suggested that residual effects of backgrounding strategies could be detected in intramuscular fat of pasture finished heifers. Copyright © 2011 Elsevier Ltd. All rights reserved.

Parental exposure to natural mixtures of persistent organic pollutants (POP) induced changes in transcription of apoptosis-related genes in offspring zebrafish embryos.

PubMed

Lyche, Jan L; Grześ, Irena M; Karlsson, Camilla; Nourizadeh-Lillabadi, Rasoul; Aleström, Peter; Ropstad, Erik

2016-01-01

Apoptosis is an integral element of development that may also be initiated by environmental contaminants. The aim of the present study was to assess potential changes in the regulation of apoptotic genes in zebrafish embryos following parental exposure to two natural mixtures of persistent organic pollutants (POP). The mixture from Lake Mjøsa contained exceptionally high concentrations of polybrominated diphenyl ethers (PBDE), as well as relatively high levels of polychlorinated biphenyls (PCB) and dichlorodiphenyltrichloroethane (DDT). The mixture from Lake Losna contained background concentrations of POP. Genes involved in the apoptotic machinery were screened for their expression profile at four time points during embryonic development. Thirteen and 15 genes involved in apoptosis were found to be significantly upregulated in the high-exposure and background exposure groups, respectively, compared with controls. Modulation of apoptotic genes was restricted only to the first time point, which corresponds with the blastula stage. Although there were substantial differences in POP concentrations between mixtures, genes underlying the apoptosis process showed almost similar responses to the two mixtures. In both exposure groups the main executors of apoptosis p53, casp 2, casp 6, cassp 8, and BAX displayed upregulation compared to controls, suggesting that these POP induce apoptosis via a p53-dependent mechanism. Upregulation of genes that play a critical role in apoptosis suggests that disturbance of normal apoptotic signaling during gametogenesis and embryogenesis may be one of the central mechanisms involved in adverse reproductive effects produced by POP in zebrafish.

Ground-water quality near an inactive landfill and sludge-spreading area, Tallahassee, Florida

USGS Publications Warehouse

Berndt, M.P.

1993-01-01

Groundwater quality at and near a landfill southwest of Tallahassee, Florida, where sludge from a municipal sewage-treatment plant was also applied, was assessed by sampling 21 monitoring wells and analyzing for various constituents. Water quality in the Upper Floridan aquifer at the site was compared to the water quality of 20 background wells in Leon County. Water quality in all samples from wells at the site was evaluated in relation to the landfill and sludge-spreading and nonsludge- spreading areas. Results from nonparametric statistical tests showed that potassium and nitrate concentrations were significantly different in samples from the Upper Floridan aquifer at the site and in samples from background wells. Median potassium concentrations were 0.7 mg/L in samples collected at the site and 0.4 mg/L in samples collected from background wells, whereas median nitrate concentration was 6.48 mg/L at the site and 0.51 mg/L in background wells. Graphical comparison of concentration distributions in six categories of wells; upgradient, landfill, adjacent to the landfill, downgradient onsite, downgradient offsite, and from background wells in Leon County, indicated that sodium, bicarbonate, sulfate, iron, manganese, dissolved solids, and specific conductance had highest concentrations in water from wells within the landfill. Nitrate concentrations were lowest in samples from wells in the landfill compared to the other categories. Concentrations of trace metals and organic constituents were mostly below detection limits although State maximum contaminant levels of 1.0 microg/L for benzene and vinyl chloride and 3.0 microg/L for tetrachloroethene were exceeded in water from some wells. Nitrate and chloride concentrations were significantly different in sludge-spreading and nonsludge-spreading areas. Median nitrate and chloride concentrations of 6.9 microg/L and 2.9 microg/L were detected in groundwater in sludge-spreading areas compared to 1.1 mg/L and 1.8 mg/L in nonsludge-spreading areas.

Vascular Graft Impregnation with Antibiotics: The Influence of High Concentrations of Rifampin, Vancomycin, Daptomycin, and Bacteriophage Endolysin HY-133 on Viability of Vascular Cells.

PubMed

Herten, Monika; Idelevich, Evgeny A; Sielker, Sonja; Becker, Karsten; Scherzinger, Anna S; Osada, Nani; Torsello, Giovanni B; Bisdas, Theodosios

2017-06-27

BACKGROUND Rifampin-soaked synthetic prosthetic grafts have been widely used for prevention or treatment of vascular graft infections (VGIs). This in vitro study investigated the effect of the antibiotics daptomycin and vancomycin and the new recombinant bacteriophage endolysin HY-133 on vascular cells, as potential alternatives compared to rifampin. MATERIAL AND METHODS Primary human ECs, vascular smooth muscle cells (vSMC), and fibroblasts were cultivated in 96-well plates and incubated with rifampin, daptomycin, vancomycin, and endolysin HY-133 for 24 h. Subsequently, after washing, cell viability was determined by measuring mitochondrial ATP concentration. Antibiotics were used in their corresponding minimum and maximum serum concentrations, in decimal multiples and in maximum soaking concentration. The experiments were performed in triplicate. RESULTS The 10-fold max serum concentrations of rifampin, daptomycin, and vancomycin did not influence viability of EC and vSMC (100 µg/ml, p>0.170). Higher concentrations of rifampin (>1 mg/ml) significantly (p<0.001) reduced cell viability of all cell types. For the other antibiotics, high concentrations (close to maximum soaking concentration) were most cytotoxic for EC and vSMC and fibroblasts (p<0.001). Endolysin did not display any cytotoxicity towards vascular cells. CONCLUSIONS Results of this in vitro study show the high cytotoxicity of rifampin against vascular cells, and may re-initiate the discussion about the benefit of prophylactic pre-soaking in high concentrations of rifampin. Further studies are necessary to determine the influence of rifampin on the restoration of vessel functionality versus its prophylactic effect against VGIs. Future use of recombinant phage endolysins for alternative prophylactic strategies needs further investigations.

[Impacts of meteorological factors on atmospheric methane mole fractions in the background area of Yangtze River delta].

PubMed

Pu, Jing-Jiao; Xu, Hong-Hui; Gu, Jun-Qiang; Ma, Qian-Li; Fang, Shuang-Xi; Zhou, Ling-Xi

2013-03-01

Impacts of surface wind direction, surface wind speed, surface air temperature and sunshine hours on the CH4 concentration at Lin'an regional atmospheric background station were studied based on the results from Jan. 2009 to Dec. 2011. The results revealed that the diurnal variation of atmospheric CH4 concentration presented a single-peak curve at Lin'an regional background station. The diurnal amplitude varied from 19.0 x 10(-9) to 74.7 x 10(-9), with the lowest value observed in the afternoon and the highest at dawn. The monthly mean CH4 concentrations varied from 1955.7 x 10(-9) to 2036.2 x 10(-9), with the highest concentration observed in autumn and the lowest in spring. The wind directions NE-SSE could induce higher CH4 concentrations while SW-NNW wind directions had negative effects on the observed results. The CH4 concentration turned out to be lower with higher surface wind speed. With the increase of surface air temperature or sunshine hours, the CH4 concentration went up first till reaching a peak, and then decreased.

Surface chemistry of selected lunar regions. [using gamma ray spectrometers

NASA Technical Reports Server (NTRS)

Bielefeld, M. J.; Reedy, R. C.; Metzger, A. E.; Trombka, A. I.; Arnold, J. R.

1976-01-01

A completely new analysis has been carried out on the data from the Apollo 15 and 16 gamma ray spectrometer experiments. The components of the continuum background have been estimated. The elements Th, K, Fe and Mg give useful results; results for Ti are significant only for a few high Ti regions. Errors are given, and the results are checked by other methods. Concentrations are reported for about sixty lunar regions; the ground track has been subdivided in various ways. The borders of the maria seem well-defined chemically, while the distribution of KREEP is broad. This wide distribution requires emplacement of KREEP before the era of mare formation. Its high concentration in western mare soils seems to require major vertical mixing.

Surface chemistry of selected lunar regions

NASA Technical Reports Server (NTRS)

Bielefeld, M. J.; Reedy, R. C.; Metzger, A. E.; Trombka, J. I.; Arnold, J. R.

1976-01-01

A completely new analysis has been carried out on the data from the Apollo 15 and 16 gamma ray spectrometer experiments. The components of the continuum background have been estimated. The elements Th, K, Fe and Mg give useful results; results for Ti are significant only for a few high Ti regions. Errors are given, and the results are checked by other methods. Concentrations are reported for about sixty lunar regions; the ground track has been subdivided in various ways. The borders of the maria seem well-defined chemically, while the distribution of KREEP is broad. This wide distribution requires emplacement of KREEP before the era of mare formation. Its high concentration in western mare soils seems to require major vertical mixing.

Effects of highway deicing chemicals on shallow unconsolidated aquifers in Ohio, interim report, 1988-93

USGS Publications Warehouse

Jones, A.L.; Sroka, B.N.

1997-01-01

Effects of the application of highway deicing chemicals during winter months on ground- water quality are being studied by the U.S. Geological Survey in cooperation with the Ohio Department of Transportation and the Federal Highway Administration. Eight sites throughout the State were selected along major undivided highways where drainage is by open ditches and ground-water flow is approximately perpendicular to the highway. At these sites, records of deicer application rates are being kept and apparent movement of deicing chemicals through shallow, unconsolidated aquifers is being monitored by means of periodic measurements of specific con ductance and concentrations of dissolved sodium, calcium, and chloride. The counties and corre sponding sections of state routes being monitored are the following: State Route (SR) 3 in Ashland County, SR 84 in Ashtabula County, SR 29 in Champaign County, SR 4 in Clark County, SR 2 in Lucas County, SR 104 in Pickaway County, SR 14 in Portage County, and SR 97 in Richland County. The study began in January 1988 with background data collection, extensive literature review, and site selection. This process, including drilling of wells at the eight selected sites, lasted 3 years. Routine ground-water sampling at 4- to 6-week intervals began in January 1991. A relatively new type of multilevel, passive flow ground-water sampling device was constructed and used. Other conditions monitored on a regular basis included ground-water level (monitored con tinuously), specific conductance, air and soil temperature, precipitation, chloride concentration in soil samples, ground conductivity, and deicing chemical application times and rates. For the interim reporting period, water samples were collected from January 1991 through September 1993. Evidence from water analysis, specific conductance measurements, and surface geophysical measurements indicates that four of the eight sites (Ashtabula County, Lucas County, Portage County, and Richland County sites) are potentially affected by direct application of deic ing chemicals. Climatic data from the period January 1991 through September 1993 show that cold weather, and therefore deicing chemical application rates, varied widely across the State. As a consequence, only minor traces of dissolved chloride above background concentrations (mean, 12-25 mg/L) were determined in ground-water samples from the Pickaway County, Clark County, and Champaign County sites. At the Ashland and Richland County sites, dissolved chlo ride concentrations increased above background concentrations (from the upgradient well, pre sumably unaffected by road salt) only intermittently (mean background concentrations of 3-25 mg/L, rising to a mean of 49-77 mg/L). For the interim reporting period, the mean dissolved chloride concentration for all downgradient wells was about 2 times the background concentra tion (25mg/L) at the Ashland County site (50 mg/L) and 14 times the background concentration (3 mg/L) at the Richland County site (40 mg/L). At the Lucas County, Portage County, and Ash tabula County sites, deicing-chemical application was consistent throughout the winter, and downgradient dissolved chloride concentrations rarely returned to background concentrations (mean 6-32 mg/L) throughout the period. For the interim reporting period, the mean dissolved chloride concentration for all downgradient wells was about 3 times the background concentra tion at the Lucas County site (92 mg/L), 72 times the background concentration at the Portage County site (432 mg/L, 2 downgradient wells), and 21 times the background concentration at the Ashtabula County site (279 mg/L). Other factors that may affect the movement of deicing chemicals through the aquifer were examined, such as precipitation amounts; the types of subsurface materials; ground-water velocity and gradient; hydraulic conductivity; soil type; land use; and ODOT deicing priority. A final report is planned for 2001 afte

Assessment of impact of unaccounted emission on ambient concentration using DEHM and AERMOD in combination with WRF

NASA Astrophysics Data System (ADS)

Kumar, Awkash; Patil, Rashmi S.; Dikshit, Anil Kumar; Kumar, Rakesh; Brandt, Jørgen; Hertel, Ole

2016-10-01

The accuracy of the results from an air quality model is governed by the quality of emission and meteorological data inputs in most of the cases. In the present study, two air quality models were applied for inverse modelling to determine the particulate matter emission strengths of urban and regional sources in and around Mumbai in India. The study takes outset in an existing emission inventory for Total Suspended Particulate Matter (TSPM). Since it is known that the available TSPM inventory is uncertain and incomplete, this study will aim for qualifying this inventory through an inverse modelling exercise. For use as input to the air quality models in this study, onsite meteorological data has been generated using the Weather Research Forecasting (WRF) model. The regional background concentration from regional sources is transported in the atmosphere from outside of the study domain. The regional background concentrations of particulate matter were obtained from model calculations with the Danish Eulerian Hemisphere Model (DEHM) for regional sources. The regional background concentrations obtained from DEHM were then used as boundary concentrations in AERMOD calculations of the contribution from local urban sources. The results from the AERMOD calculations were subsequently compared with observed concentrations and emission correction factors obtained by best fit of the model results to the observed concentrations. The study showed that emissions had to be up-scaled by between 14 and 55% in order to fit the observed concentrations; this is of course when assuming that the DEHM model describes the background concentration level of the right magnitude.

Observations of Atmospheric Δ14CO2 at the Global and Regional Background Sites in China: Implication for Fossil Fuel CO2 Inputs.

PubMed

Niu, Zhenchuan; Zhou, Weijian; Cheng, Peng; Wu, Shugang; Lu, Xuefeng; Xiong, Xiaohu; Du, Hua; Fu, Yunchong

2016-11-15

Six months to more than one year of atmospheric Δ 14 CO 2 were measured in 2014-2015 at one global background site in Waliguan (WLG) and four regional background sites at Shangdianzi (SDZ), Lin'an (LAN), Longfengshan (LFS) and Luhuitou (LHT), China. The objectives of the study are to document the Δ 14 CO 2 levels at each site and to trace the variations in fossil fuel CO 2 (CO 2ff ) inputs at regional background sites. Δ 14 CO 2 at WLG varied from 7.1 ± 2.9‰ to 32.0 ± 3.2‰ (average 17.1 ± 6.8‰) in 2015, with high values generally in autumn/summer and low values in winter/spring. During the same period, Δ 14 CO 2 values at the regional background sites were found to be significantly (p < 0.05) lower than those at WLG, indicating different levels of CO 2ff inputs at those sites. CO 2ff concentrations at LAN (12.7 ± 9.6 ppm) and SDZ (11.5 ± 8.2 ppm) were significantly (p < 0.05) higher than those at LHT (4.6 ± 4.3 ppm) in 2015. There were no significant (p > 0.05) seasonal differences in CO 2ff concentrations for the regional sites. Regional sources contributed in part to the CO 2ff inputs at LAN and SDZ, while local sources dominated the trend observed at LHT. These data provide a preliminary understanding of atmospheric Δ 14 CO 2 and CO 2ff inputs for a range of Chinese background sites.

Development of Atmospheric Air 85Kr Monitoring Methodology on the Territory of the USSR

NASA Astrophysics Data System (ADS)

Pakhomov, Sergei; Dubasov, Yury

2014-05-01

Highly sensitive, low-background and high-performance method of beta-radioactivity measurements of the gas samples was developed in mid-eighties at Khlopin Radium institute. This method was based on the use of the serial automated installation for liquid scintillation measurements and special scintillating cells. Cells were equipped with the gas valve, and their internal surface were covered by a thin layer of organic scintillator. This method found was successfully was applied for 85Kr activity measurements in atmospheric krypton samples and for 85Kr concentration measurements in atmospheric air. For the first time, method developed for 85Kr activity measurements, was practically tested in May - June, 1986, while studying radioactive pollution characteristics in the air basin of Russia and Ukraine after the Chernobyl NPP accident. Thus for sampling of atmospheric krypton the industrial krypton-xenon mix manufactured at air-separating plants, located in the cities of Cherepovets, Lipetsk, Krivoi Rog and Enakiyevo was used. In the end of April and in the first half of May it was determined that 1,5-fold excess concentrations of 85Kr in atmospheric air were observed in atmospheric air of considerable part of the European territory of Russia and Ukraine During the period from 1987 to 1991 this method was used for monitoring of 85Kr on the territory of the former USSR in the air basin of Russia, Ukraine and Kazakhstan. Industrial krypton-xenon mix manufactured at 14 large air-separating plants was also used for sampling. Six of them were situated in Russia (Novomoskovsk, Lipetsk, Cherepovets, Chelyabinsk, Nizhni Tagil, Orsk). Seven - in Ukraine (Enakiyevo, Kommunarsk, Krivoi Rog, Makeyevka, Mariupol, Severodonetsk, Dneprodzerzhinsk). One plant was situated in Temirtau, in Kazakhstan. The analysis indicated that in Krivoi Rog; Dneprozhzerzhinsk; Severodonetsk; Makeyevka; Mariupol; Enakiyevo; Kommunarsk; Novomoskovsk and Cherepovets the average 85Kr concentration in atmospheric air was close to background level during monitoring. But in Lipetsk; Orsk; Nizhni Tagil and Temirtau 10-20% excess of background level was systematically observed. In Chelyabinsk concentration of 85Kr steadily exceeded this level by 2-3 times, and incidentally exceeded it for order. Generally, during this period about 1500 values of concentration 85Kr were obtained. Actually, the large-scale monitoring system of atmospheric 85Kr with a binding of sampling points to 14 air-separating plants covered the territory 1000 x 3000 km was created. The developed method of 85Kr activity measurement was successfully applied also when carrying out expedition works in Northern Atlantic during the period from 1987 to 1994 with use o ZIF-1000 cryogenic installation for sampling, which initially was intended for liquid nitrogen manufacturing at the ship. Generally, 80 measurements of 85Kr concentration were obtained using this method. It was determined, that the average concentration of 85Kr in atmospheric air in the open regions of the Atlantic Ocean, were close to background level during monitoring. The concentrations of 85Kr steadily exceeded this level by 2-3 times in English Channel, and incidentally exceeded it in tens times.

Estimating background and threshold nitrate concentrations using probability graphs

USGS Publications Warehouse

Panno, S.V.; Kelly, W.R.; Martinsek, A.T.; Hackley, Keith C.

2006-01-01

Because of the ubiquitous nature of anthropogenic nitrate (NO 3-) in many parts of the world, determining background concentrations of NO3- in shallow ground water from natural sources is probably impossible in most environments. Present-day background must now include diffuse sources of NO3- such as disruption of soils and oxidation of organic matter, and atmospheric inputs from products of combustion and evaporation of ammonia from fertilizer and livestock waste. Anomalies can be defined as NO3- derived from nitrogen (N) inputs to the environment from anthropogenic activities, including synthetic fertilizers, livestock waste, and septic effluent. Cumulative probability graphs were used to identify threshold concentrations separating background and anomalous NO3-N concentrations and to assist in the determination of sources of N contamination for 232 spring water samples and 200 well water samples from karst aquifers. Thresholds were 0.4, 2.5, and 6.7 mg/L for spring water samples, and 0.1, 2.1, and 17 mg/L for well water samples. The 0.4 and 0.1 mg/L values are assumed to represent thresholds for present-day precipitation. Thresholds at 2.5 and 2.1 mg/L are interpreted to represent present-day background concentrations of NO3-N. The population of spring water samples with concentrations between 2.5 and 6.7 mg/L represents an amalgam of all sources of NO3- in the ground water basins that feed each spring; concentrations >6.7 mg/L were typically samples collected soon after springtime application of synthetic fertilizer. The 17 mg/L threshold (adjusted to 15 mg/L) for well water samples is interpreted as the level above which livestock wastes dominate the N sources. Copyright ?? 2006 The Author(s).

High-throughput quantitative analysis by desorption electrospray ionization mass spectrometry.

PubMed

Manicke, Nicholas E; Kistler, Thomas; Ifa, Demian R; Cooks, R Graham; Ouyang, Zheng

2009-02-01

A newly developed high-throughput desorption electrospray ionization (DESI) source was characterized in terms of its performance in quantitative analysis. A 96-sample array, containing pharmaceuticals in various matrices, was analyzed in a single run with a total analysis time of 3 min. These solution-phase samples were examined from a hydrophobic PTFE ink printed on glass. The quantitative accuracy, precision, and limit of detection (LOD) were characterized. Chemical background-free samples of propranolol (PRN) with PRN-d(7) as internal standard (IS) and carbamazepine (CBZ) with CBZ-d(10) as IS were examined. So were two other sample sets consisting of PRN/PRN-d(7) at varying concentration in a biological milieu of 10% urine or porcine brain total lipid extract, total lipid concentration 250 ng/microL. The background-free samples, examined in a total analysis time of 1.5 s/sample, showed good quantitative accuracy and precision, with a relative error (RE) and relative standard deviation (RSD) generally less than 3% and 5%, respectively. The samples in urine and the lipid extract required a longer analysis time (2.5 s/sample) and showed RSD values of around 10% for the samples in urine and 4% for the lipid extract samples and RE values of less than 3% for both sets. The LOD for PRN and CBZ when analyzed without chemical background was 10 and 30 fmol, respectively. The LOD of PRN increased to 400 fmol analyzed in 10% urine, and 200 fmol when analyzed in the brain lipid extract.

An improved patch for radiative coolers

NASA Astrophysics Data System (ADS)

Bly, Vincent T.

1993-09-01

A unique structure for constructing the emissive patch of a spaceborne radiative cooler is shown. The structure has very high emissivity for all angles up to a designed-in maximum angle and near zero emissivity for greater angles. The structure also allows the use of high emissivity, nonconducting paints while fully complying with the NASA Electrostatic Discharge Susceptibility requirements for spacecraft. To accomplish these tasks, two previous disadvantages of prior art methods are addressed; eliminating background thermal radiation sources and problems concerning the high emissivity paints used in association with the black body radiator. A reflector consisting of an array of parabolic concentrators is separated from a black body element by an electrically conductive spacer. The concentrators serve to limit the field of view while the conductive spacer eliminates the need to use a conductive paint on the emissive element.

An improved patch for radiative coolers

NASA Astrophysics Data System (ADS)

Bly, Vincent T.

1993-01-01

A unique structure for constructing the emissive patch of a spaceborne radiative cooler is shown. The structure has very high emissivity for all angles up to a designed-in maximum angle and near zero emissivity for greater angles. The structure also allows the use of high emissivity, nonconducting paints while fully complying with the NASA Electrostatic Discharge Susceptibility requirements for spacecraft. To accomplish these tasks, two previous disadvantages of prior art methods are addressed; eliminating background thermal radiation sources and problems concerning the high emissivity paints used in association with the black body radiator. A reflector consisting of an array of parabolic concentrators is separated from a black body element by an electrically conductive spacer. The concentrators serve to limit the field of view while the conductive spacer eliminates the need to use a conductive paint on the emissive element.

Characterization of background concentrations of contaminants using a mixture of normal distributions.

PubMed

Qian, Song S; Lyons, Regan E

2006-10-01

We present a Bayesian approach for characterizing background contaminant concentration distributions using data from sites that may have been contaminated. Our method, focused on estimation, resolves several technical problems of the existing methods sanctioned by the U.S. Environmental Protection Agency (USEPA) (a hypothesis testing based method), resulting in a simple and quick procedure for estimating background contaminant concentrations. The proposed Bayesian method is applied to two data sets from a federal facility regulated under the Resource Conservation and Restoration Act. The results are compared to background distributions identified using existing methods recommended by the USEPA. The two data sets represent low and moderate levels of censorship in the data. Although an unbiased estimator is elusive, we show that the proposed Bayesian estimation method will have a smaller bias than the EPA recommended method.

High mercury wet deposition at a “clean Air” site in Puerto Rico

USGS Publications Warehouse

Shanley, James B.; Engle, Mark A.; Scholl, Martha A.; Krabbenhoft, David P.; Brunette, Robert; Olson, Mark L.; Conroy, Mary E.

2015-01-01

Atmospheric mercury deposition measurements are rare in tropical latitudes. Here we report on seven years (April 2005 to April 2012, with gaps) of wet Hg deposition measurements at a tropical wet forest in the Luquillo Mountains, northeastern Puerto Rico, U.S. Despite receiving unpolluted air off the Atlantic Ocean from northeasterly trade winds, during two complete years the site averaged 27.9 μg m–2 yr–1 wet Hg deposition, or about 30% more than Florida and the Gulf Coast, the highest deposition areas within the U.S. These high Hg deposition rates are driven in part by high rainfall, which averaged 2855 mm yr–1. The volume-weighted mean Hg concentration was 9.8 ng L–1, and was highest during summer and lowest during the winter dry season. Rainout of Hg (decreasing concentration with increasing rainfall depth) was minimal. The high Hg deposition was not supported by gaseous oxidized mercury (GOM) at ground level, which remained near global background concentrations (<10 pg m–3). Rather, a strong positive correlation between Hg concentrations and the maximum height of rain detected within clouds (echo tops) suggests that droplets in high convective cloud tops scavenge GOM from above the mixing layer. The high wet Hg deposition at this “clean air” site suggests that other tropical areas may be hotspots for Hg deposition as well.

High Mercury Wet Deposition at a "Clean Air" Site in Puerto Rico.

PubMed

Shanley, James B; Engle, Mark A; Scholl, Martha; Krabbenhoft, David P; Brunette, Robert; Olson, Mark L; Conroy, Mary E

2015-10-20

Atmospheric mercury deposition measurements are rare in tropical latitudes. Here we report on seven years (April 2005 to April 2012, with gaps) of wet Hg deposition measurements at a tropical wet forest in the Luquillo Mountains, northeastern Puerto Rico, U.S. Despite receiving unpolluted air off the Atlantic Ocean from northeasterly trade winds, during two complete years the site averaged 27.9 μg m(-2) yr(-1) wet Hg deposition, or about 30% more than Florida and the Gulf Coast, the highest deposition areas within the U.S. These high Hg deposition rates are driven in part by high rainfall, which averaged 2855 mm yr(-1). The volume-weighted mean Hg concentration was 9.8 ng L(-1), and was highest during summer and lowest during the winter dry season. Rainout of Hg (decreasing concentration with increasing rainfall depth) was minimal. The high Hg deposition was not supported by gaseous oxidized mercury (GOM) at ground level, which remained near global background concentrations (<10 pg m(-3)). Rather, a strong positive correlation between Hg concentrations and the maximum height of rain detected within clouds (echo tops) suggests that droplets in high convective cloud tops scavenge GOM from above the mixing layer. The high wet Hg deposition at this "clean air" site suggests that other tropical areas may be hotspots for Hg deposition as well.

Modeled summer background concentration nutrients and suspended sediment in the mid-continent (USA) great rivers

EPA Science Inventory

We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. F...

Background Indoor Air Concentrations of Volatile Organic Compounds in North American Residences (1990 – 2005): A Compilation of Statistics for Assessing Vapor Intrusion

EPA Pesticide Factsheets

This technical report presents a summary of indoor air studies that measured background concentrations of VOCs in the indoor air of thousands of North American residences and an evaluation and compilation of their reported statistical information.

Variation of radiation level and radionuclide enrichment in high background area.

PubMed

Shetty, P K; Narayana, Y

2010-12-01

Significantly high radiation level and radionuclide concentration along Quilon beach area of coastal Kerala have been reported by several investigators. Detailed gamma radiation level survey was carried out using a portable scintillometer. Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Kayankulam, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The absorbed gamma dose rates in air in high background area are in the range 43-17,400nGyh⁻¹. Gamma radiation level is found to be maximum at a distance of 20m from the sea waterline in all beaches. The soil samples collected from different locations were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of soil to study the enrichment pattern. The highest activity of (232)Th and (226)Ra was found to be enriched in 125-63μ size fraction. The preferential accumulation of (40)K was found in <63μ fraction. The minimum (232)Th activity was 30.2Bqkg⁻¹, found in 1000-500μ particle size fraction at Kollam and maximum activity of 3250.4Bqkg⁻¹ was observed in grains of size 125-63μ at Neendakara. The lowest (226)Ra activity observed was 33.9Bqkg⁻¹ at Neendakara in grains of size 1000-500μ and the highest activity observed was 482.6Bqkg⁻¹ in grains of size 125-63μ in Neendakara. The highest (40)K activity found was 1923Bqkg⁻¹ in grains of size <63μ for a sample collected from Neendakara. A good correlation was observed between computed dose and measured dose in air. The correlation between (232)Th and (226)Ra was also moderately high. The results of these investigations are presented and discussed in this paper. Copyright © 2010 Elsevier Ltd. All rights reserved.

Ingestion of polonium ((210)Po) via dietary sources in high background radiation areas of south India.

PubMed

Arunachalam, Kantha Deivi; Baskaran, Kamesh Viswanathan; Rao, D D; Sathyapriya, R; Annamalai, Sathesh Kumar; Kuruva, Jaya Krishna; Hari, Shanmugamsundaram

2014-10-01

To study the distribution of Polonium ((210)Po) activity in dietary sources in the high background radiation zone of Puttetti in southern Tamil Nadu. (210)Po was analyzed in the food materials consumed by the male and female individual representatives living in the high background areas by 24-h Duplicate Diet Study (DDS) and Market Basket Study (MBS). The MBS was performed by collecting the food samples such as, cereals, fruits, leafy vegetables, roots and tubers, other vegetables, fish, meat and milk grown in the high background radiation zone of southern Tamil Nadu as a part of baseline study in this region. The DDS was done by collecting the food materials consumed including the beverages in 24 h from different age groups of male and female individuals living in the village of Puttetti. The intake and ingestion dose of the radionuclide (210)Po was estimated. The average concentration of (210)Po in DDS (n = 33) was found to be 74 mBq.kg(- 1) of fresh weight. The MBS was collected based on food consumption representing more than 85-95% of annual supply, and were divided into eight food groups. The average concentration of (210)Po in the eight food groups namely leafy vegetables was 2176 mBq.kg(- 1) (n = 3), vegetables 55 mBq.kg(- 1) (n = 10), roots and tubers 251 mBq.kg(- 1) (n = 4), fruits 65 mBq.kg(- 1) (n = 5), fish 345 mBq.kg(- 1) (n = 2), meat food 117 mBq.kg(- 1) (n = 3), milk 20 mBq.kg(- 1) (n = 1) and cereal 290 (n = 1) mBq.kg(- 1) of fresh weight, respectively. The annual intake and ingestion dose due to (210)Po was estimated by DDS and MBS in adults, adolescents and children. The overall results showed that the MBS was moderately higher than the DDS in all age groups. Moreover, a DDS approach may even be more realistic, as cooked foodstuffs are used for dietary exposure assessment. The study confirms that the current levels of (210)Po do not pose a significant radiological risk to the local inhabitants.

High sensitivity fluorescent single particle and single molecule detection apparatus and method

DOEpatents

Mathies, Richard A.; Peck, Konan; Stryer, Lubert

1990-01-01

Apparatus is described for ultrasensitive detection of single fluorescent particles down to the single fluorescent molecule limit in a fluid or on a substrate comprising means for illuminating a predetermined volume of the fluid or area of the substrate whereby to emit light including background light from the fluid and burst of photons from particles residing in the area. The photon burst is detected in real time to generate output representative signal. The signal is received and the burst of energy from the fluorescent particles is distinguished from the background energy to provide an indication of the number, location or concentration of the particles or molecules.

Serum concentrations of polychlorinated dibenzo-p-dioxins among ceramicists.

PubMed

Demond, Avery; Jiang, Xiaohui; Broadwater, Kendra; Meeker, John; Luksemburg, William; Maier, Martha; Garabrant, David; Franzblau, Alfred

2015-01-01

Polychlorinated dibenzo-p-dioxins (PCDDs) occur naturally in ball clay at elevated concentrations. Thus, persons who habitually work with clay may be at risk for exposure to PCDDs. An earlier case report provided some evidence of elevated PCDD levels in serum for long-term hobby ceramicists; however, no previous study has measured serum dioxin concentrations among ceramicists. This study measured PCDD serum levels for 27 individuals involved in ceramics making. The average residual, defined as the average of the [log measured serum lipid concentration – log background serum lipid concentration], was calculated and then tested to determine whether it was significantly different from zero. The p-values for the average residuals indicated that the serum lipid concentrations for several PCDD congeners were elevated relative to background. The number of significant residuals increased dramatically if the background concentrations were adjusted to account for the fact that they were not contemporaneous with the measurements for the ceramicists. The ratio of the 1,2,3,6,7,8-HxCDD concentration to the 1,2,3,7,8,9-HxCDD concentration was greater than 1.0, unlike in ball clay, suggesting that although long-term working with ball clay elevates the PCDD levels in serum somewhat, it is not the predominant source of the PCDD body burden for ceramicists.

Totomatix: a novel automatic set-up to control diurnal, diel and long-term plant nitrate nutrition

PubMed Central

Adamowicz, Stéphane; Le Bot, Jacques; Huanosto Magaña, Ruth; Fabre, José

2012-01-01

Background Stand-alone nutritional set-ups are useful tools to grow plants at defined nutrient availabilities and to measure nutrient uptake rates continuously, in particular that for nitrate. Their use is essential when the measurements are meant to cover long time periods. These complex systems have, however, important drawbacks, including poor long-term reliability and low precision at high nitrate concentration. This explains why the information dealing with diel dynamics of nitrate uptake rate is scarce and concerns mainly young plants grown at low nitrate concentration. Scope The novel system detailed in this paper has been developed to allow versatile use in growth rooms, greenhouses or open fields at nitrate concentrations ranging from a few micro- to several millimoles per litres. The system controls, at set frequencies, the solution nitrate concentration, pH and volumes. Nitrate concentration is measured by spectral deconvolution of UV spectra. The main advantages of the set-up are its low maintenance (weekly basis), an ability to diagnose interference or erroneous analyses and high precision of nitrate concentration measurements (0·025 % at 3 mm). The paper details the precision of diurnal nitrate uptake rate measurements, which reveals sensitivity to solution volume at low nitrate concentration, whereas at high concentration, it is mostly sensitive to the precision of volume estimates. Conclusions This novel set-up allows us to measure and characterize the dynamics of plant nitrate nutrition at high temporal resolution (minutes to hours) over long-term experiments (up to 1 year). It is reliable and also offers a novel method to regulate up to seven N treatments by adjusting the daily uptake of test plants relative to controls, in variable environments such as open fields and glasshouses. PMID:21985796

Effect of oxygen concentration on the magnetic properties of La2CoMnO6 thin films

NASA Astrophysics Data System (ADS)

Guo, H. Z.; Gupta, A.; Zhang, Jiandi; Varela, M.; Pennycook, S. J.

2007-11-01

The dependence of the magnetic properties on oxygen concentration in epitaxial La2CoMnO6 thin films deposited on (100)-oriented SrTiO3 substrates has been investigated by varying the oxygen background pressure during growth using pulsed laser deposition. Two distinct ferromagnetic (FM) phases are revealed, and the relative fraction varies with the oxygen concentration. The existence of oxygen vacancies induces the local vibronic Mn3+-O -Co3+ superexchange interactions in direct competition with the static FM Mn4+-O-Co2+ interactions. This results in the appearance of a new low temperature FM phase and suppression of the high-temperature FM phase, creating two distinct magnetic phase transitions.

Calculating background levels for ecological risk parameters in toxic harbor sediment

USGS Publications Warehouse

Leadon, C.J.; McDonnell, T.R.; Lear, J.; Barclift, D.

2007-01-01

Establishing background levels for biological parameters is necessary in assessing the ecological risks from harbor sediment contaminated with toxic chemicals. For chemicals in sediment, the term contaminated is defined as having concentrations above background and significant human health or ecological risk levels. For biological parameters, a site could be considered contaminated if levels of the parameter are either more or less than the background level, depending on the specific parameter. Biological parameters can include tissue chemical concentrations in ecological receptors, bioassay responses, bioaccumulation levels, and benthic community metrics. Chemical parameters can include sediment concentrations of a variety of potentially toxic chemicals. Indirectly, contaminated harbor sediment can impact shellfish, fish, birds, and marine mammals, and human populations. This paper summarizes the methods used to define background levels for chemical and biological parameters from a survey of ecological risk investigations of marine harbor sediment at California Navy bases. Background levels for regional biological indices used to quantify ecological risks for benthic communities are also described. Generally, background stations are positioned in relatively clean areas exhibiting the same physical and general chemical characteristics as nearby areas with contaminated harbor sediment. The number of background stations and the number of sample replicates per background station depend on the statistical design of the sediment ecological risk investigation, developed through the data quality objective (DQO) process. Biological data from the background stations can be compared to data from a contaminated site by using minimum or maximum background levels or comparative statistics. In Navy ecological risk assessments (ERA's), calculated background levels and appropriate ecological risk screening criteria are used to identify sampling stations and sites with contaminated sediments.

C2-C6 background hydrocarbon concentrations monitored at a roof top and green park site, in Dublin City centre.

PubMed

O'Donoghue, R T; Broderick, B M

2007-09-01

A 5 week monitoring campaign was carried out in Dublin City centre, to establish which site gave a more accurate background city centre estimation: a roof-top or green field site. This background represented a conservative estimate of HC exposure in Dublin City centre, useful for quantifying health effects related to this form of pollution and also for establishing a local background relative to the four surrounding main roads when the wind direction is travelling towards each road with the background receptor upwind. Over the entire monitoring campaign, the lowest concentrations and relative standard deviations were observed at the green field site, regardless of time of day or meteorological effects.

Non-Destructive Evaluation of the Leaf Nitrogen Concentration by In-Field Visible/Near-Infrared Spectroscopy in Pear Orchards.

PubMed

Wang, Jie; Shen, Changwei; Liu, Na; Jin, Xin; Fan, Xueshan; Dong, Caixia; Xu, Yangchun

2017-03-08

Non-destructive and timely determination of leaf nitrogen (N) concentration is urgently needed for N management in pear orchards. A two-year field experiment was conducted in a commercial pear orchard with five N application rates: 0 (N0), 165 (N1), 330 (N2), 660 (N3), and 990 (N4) kg·N·ha -1 . The mid-portion leaves on the year's shoot were selected for the spectral measurement first and then N concentration determination in the laboratory at 50 and 80 days after full bloom (DAB). Three methods of in-field spectral measurement (25° bare fibre under solar conditions, black background attached to plant probe, and white background attached to plant probe) were compared. We also investigated the modelling performances of four chemometric techniques (principal components regression, PCR; partial least squares regression, PLSR; stepwise multiple linear regression, SMLR; and back propagation neural network, BPNN) and three vegetation indices (difference spectral index, normalized difference spectral index, and ratio spectral index). Due to the low correlation of reflectance obtained by the 25° field of view method, all of the modelling was performed on two spectral datasets-both acquired by a plant probe. Results showed that the best modelling and prediction accuracy were found in the model established by PLSR and spectra measured with a black background. The randomly-separated subsets of calibration ( n = 1000) and validation ( n = 420) of this model resulted in high R² values of 0.86 and 0.85, respectively, as well as a low mean relative error (<6%). Furthermore, a higher coefficient of determination between the leaf N concentration and fruit yield was found at 50 DAB samplings in both 2015 (R² = 0.77) and 2014 (R² = 0.59). Thus, the leaf N concentration was suggested to be determined at 50 DAB by visible/near-infrared spectroscopy and the threshold should be 24-27 g/kg.

Compliance with the annual NO 2 air quality standard in Athens. Required NO x levels and expected health implications

NASA Astrophysics Data System (ADS)

Chaloulakou, A.; Mavroidis, I.; Gavriil, I.

Recent risk assessment studies have shown that high outdoor NO 2 levels observed in residential areas contribute to increased respiratory and cardiovascular diseases and mortality. Detailed information on present NO 2 levels as well as predictions of NO 2 concentrations corresponding to reduced NO x levels in urban areas are very useful to decision and policy makers in order to protect the public health. In the present paper, monitoring stations of the Athens network are initially classified into two main groups, traffic affected and urban background, using effectively a criterion based on the ratio of annual mean NO:NO 2 concentrations. Two empirical methodologies are then considered and compared for assessing the effect of different NO x levels on the attainment of the annual NO 2 air quality standard at urban-background locations in the Athens area. An interesting finding is that these two methodologies, one more general and one both year and site dependent, give similar results for the specific study area and can be applied alternatively based on the length of available concentration time series. The results show that in order to meet the EU annual mean NO 2 objective at all the urban-background locations of the Athens area, annual NO x concentrations should be reduced to approximately 60 μg m -3, requiring NO x emission reductions of up to 30%. An analysis of the health implications of the currently observed NO 2 levels is conducted, based on a dose-response relationship, and is coupled with available health-related data for the Athens area. This analysis suggests that if NO 2 concentrations were reduced to the levels of the annual EU air quality standard, then a decrease of hospital admissions of up to 2.6% would be observed, depending on the levels of NO 2 measured at different monitoring sites of the Athens conurbation.

Alterations in the programming of energy metabolism in adolescents with background exposure to dioxins, dl-PCBs and PBDEs

PubMed Central

Koppe, Janna G.; Vulsma, Thomas; Olie, Kees; van Aalderen, Wim M. C.; de Voogt, Pim; Legler, Juliette; ten Tusscher, Gavin W.

2017-01-01

Objectives Dioxins and PCBs are highly toxic and persistent environmental pollutants that are measurable in humans worldwide. These persistent organic pollutants are associated with a higher incidence of diabetes mellitus. We hypothesise that perinatal (background) exposure to industrial pollutants like dioxins also influences body mass development and energy metabolism in later life. Study design In The Netherlands, the perinatal exposure (prenatal exposure and postnatal lactational intake) to dioxins has been studied prospectively since 1987. Fasting glucose, insulin, HbA1c and leptin were analysed in 33 children of the original cohort of 60. BMI, glucose:insulin and BMI:leptin ratios were calculated. Prenatal exposure, lactational intake and current serum levels of dioxins (PCDD/F), dl-PCBs and PBDE concentrations were determined using (HR)GC-MS. Results Prenatal dioxin (PCDD/F) exposure was positively correlated to the glucose:insulin ratio (p = 0.024) and negatively correlated to the fasting insulin concentration (p = 0.017) in adolescence. Postnatal lactational PCDD/F intake was also negatively correlated to fasting insulin concentration (p = 0.028). Current serum levels of PCDD/Fs and total TEQ (dl-PCBs+PCDD/Fs) were positively correlated to the fasting serum glucose concentration (p = 0.015 and p = 0.037, respectively).No metabolic effects were seen in association with current serum levels of PBDEs. A positive correlation between the insulin and leptin concentrations (p = 0.034) was observed. No effects were found on leptin levels, BMI:leptin ratio, HbA1c levels or BMI. Discussion/Conclusion This study indicates that prenatal and lactational exposure influences glucose metabolism in adolescents, presumably through a negative effect on insulin secretion by pancreatic beta cells. Additionally, the very low recent background exposure to dioxins in puberty possibly has an effect on the glucose level. PMID:28898241

A statistical approach to investigating enhancement of polonium-210 in the Eastern Irish Sea arising from discharges from a former phosphate processing plant.

PubMed

Dewar, Alastair; Camplin, William; Barry, Jon; Kennedy, Paul

2014-12-01

Since the cessation of phosphoric acid production (in 1992) and subsequent closure and decommissioning (2004) of the Rhodia Consumer Specialties Limited plant in Whitehaven, the concentration levels of polonium-210 ((210)Po) in local marine materials have declined towards a level more typical of natural background. However, enhanced concentrations of (210)Po and lead-210 ((210)Pb), due to this historic industrial activity (plant discharges and ingrowth of (210)Po from (210)Pb), have been observed in fish and shellfish samples collected from this area over the last 20 years. The results of this monitoring, and assessments of the dose from these radionuclides, to high-rate aquatic food consumers are published annually in the Radioactivity in Food and the Environment (RIFE) report series. The RIFE assessment uses a simple approach to determine whether and by how much activity is enhanced above the normal background. As a potential tool to improve the assessment of enhanced concentrations of (210)Po in routine dose assessments, a formal statistical test, where the null hypothesis is that the Whitehaven area is contaminated with (210)Po, was applied to sample data. This statistical, modified "green", test has been used in assessments of chemicals by the OSPAR commission. It involves comparison of the reported environmental concentrations of (210)Po in a given aquatic species against its corresponding Background Assessment Concentration (BAC), which is based upon environmental samples collected from regions assumed to be not enhanced by industrial sources of (210)Po, over the period for which regular monitoring data are available (1990-2010). Unlike RIFE, these BAC values take account of the variability of the natural background level. As an example, for 2010 data, crab, lobster, mussels and winkles passed the modified "green" test (i.e. the null hypothesis is rejected) and as such are deemed not to be enhanced. Since the cessation of phosphoric acid production in 1992, the modified "green" test pass rate for crustaceans is ∼53% and ∼64% for molluscs. Results of dose calculations are made (i) using the RIFE approach and (ii) with the application of the modified "green" test, where samples passing the modified "green" test are assumed to have background levels and hence zero enhancement of (210)Po. Applying the modified "green" test reduces the dose on average by 44% over the period of this study (1990-2010). Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona.

PubMed

Marsac, Kara E; Burnley, Pamela C; Adcock, Christopher T; Haber, Daniel A; Malchow, Russell L; Hausrath, Elisabeth M

2016-12-01

This study compares high resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (National Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

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

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

Modeling background radiation using geochemical data: A case study in and around Cameron, Arizona

DOE PAGES

Marsac, Kara E.; Burnley, Pamela C.; Adcock, Christopher T.; ...

2016-09-16

Here, this study compares high-resolution forward models of natural gamma-ray background with that measured by high resolution aerial gamma-ray surveys. The ability to predict variations in natural background radiation levels should prove useful for those engaged in measuring anthropogenic contributions to background radiation for the purpose of emergency response and homeland security operations. The forward models are based on geologic maps and remote sensing multi-spectral imagery combined with two different sources of data: 1) bedrock geochemical data (uranium, potassium and thorium concentrations) collected from national databases, the scientific literature and private companies, and 2) the low spatial resolution NURE (Nationalmore » Uranium Resource Evaluation) aerial gamma-ray survey. The study area near Cameron, Arizona, is located in an arid region with minimal vegetation and, due to the presence of abandoned uranium mines, was the subject of a previous high resolution gamma-ray survey. We found that, in general, geologic map units form a good basis for predicting the geographic distribution of the gamma-ray background. Predictions of background gamma-radiation levels based on bedrock geochemical analyses were not as successful as those based on the NURE aerial survey data sorted by geologic unit. The less successful result of the bedrock geochemical model is most likely due to a number of factors including the need to take into account the evolution of soil geochemistry during chemical weathering and the influence of aeolian addition. Refinements to the forward models were made using ASTER visualizations to create subunits of similar exposure rate within the Chinle Formation, which contains multiple lithologies and by grouping alluvial units by drainage basin rather than age.« less

[Study on atmospheric VOCs in Gongga Mountain base station].

PubMed

Zhang, Jun-Ke; Wang, Yue-Si; Wu, Fang-Kun; Sun, Jie

2012-12-01

Volatile organic compounds (VOCs) play important roles in the atmosphere as precursors of secondary air pollutants. The regional background concentrations and variation characteristics of VOCs in the atmosphere of southwestern China were studied. Meanwhile, a receptor model based on principal component analysis (PCA) was used to identify the major sources of VOCs. Weekly samples were collected in 2007 in the Gongga Mountain base station and analyzed with a three-stage preconcentration method coupled with GC-MS. The annual mean concentration of TVOCs and NMHCs were 9.40 x 10(-9) +/- 4.55 x 10(-9) and 7.73 x 10(-9) +/- 4.43 x 10(-9), respectively. Aromatic hydrocarbons provided the largest contribution to TVOCs (37.3%), follow by alkanes (30.0%) and halogenated hydrocarbons (19.8%), the smallest contribution was from alkenes (12.9%). Three major sources were resolved by the receptor model, traffic sources, biogenic sources and combustion sources. The seasonal variation of TVOCs in this area was obviously, and the order was autumn > winter > spring > summer. TVOCs concentration in autumn was very significantly higher than that in summer (P < 0.01). The seasonal variation of the four types of VOCs showed different characteristics due to the differences in photochemical properties. Isoprene emissions were from biogenic sources. Regression analysis revealed a good exponential relationship between the isoprene concentration and temperature. High temperatures increased the isoprene concentrations. However, the isoprene concentration remained constant when the ambient air temperature was below 20 degrees C. The TVOCs in Gongga Mountain were at a medium level comparing with the results of other regions, and there was a clear background station emission characteristic.

Water quality effects of herded stream crossings by domestic sheep bands.

PubMed

Clark, Patrick E; Moffet, Corey A; Lewis, Gregory S; Seyfried, Mark S; Hardegree, Stuart P; Pierson, Fredrick B

2012-01-01

Livestock impacts on total suspended solids (TSS) and pathogen (e.g., ) levels in rangeland streams are a serious concern worldwide. Herded stream crossings by domestic sheep () are periodic, necessary managerial events on high-elevation rangelands, but their impacts on stream water quality are largely unknown. We evaluated the effects of herded, one-way crossings by sheep bands (about 2000 individuals) on TSS and concentration and load responses in downstream waters. Crossing trials were conducted during the summers of 2005 and 2006 on two reaches within each of three perennial streams in the Centennial Mountains of eastern Idaho and southwestern Montana. Water samples were collected at 2-min intervals at an upstream background station and at stations 25, 100, 500, and 1500 m downstream just before and during each crossing trial. Crossings produced substantial increases in TSS and concentrations and loads downstream, but these concentration increases were localized and short lived. Maximum TSS concentration was highest 25 m downstream, declined as a function of downstream distance, and at 500 m downstream was similar to background. Post-peak TSS concentrations at all downstream stations decreased to <25 mg L within 24 to 48 min after reaching their maxima. Findings for concentration and load responses were similar to that of TSS but less clear cut. Stream-crossing sheep do affect water quality; therefore, producers and resource managers should continue to evaluate the efficacy of herdsmanship techniques for reducing water quality impact. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Strontium-90 activity concentration in soil samples from the exclusion zone of the Fukushima daiichi nuclear power plant

NASA Astrophysics Data System (ADS)

Sahoo, Sarata Kumar; Kavasi, Norbert; Sorimachi, Atsuyuki; Arae, Hideki; Tokonami, Shinji; Mietelski, Jerzy Wojciech; Łokas, Edyta; Yoshida, Satoshi

2016-04-01

The radioactive fission product 90Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing 90Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (<30 km) of the earthquake-damaged Fukushima Daiichi nuclear power plant, to measure 90Sr activity concentration using liquid scintillation counting. 137Cs activity concentration was also measured with gamma-spectroscopy in order to investigate correlation with 90Sr. The 90Sr activity concentrations ranged from 3.0 ± 0.3 to 23.3 ± 1.5 Bq kg-1 while the 137Cs from 0.7 ± 0.1 to 110.8 ± 0.3 kBq kg-1. The fact that radioactive contamination originated from the Fukushima nuclear accident was obvious due to the presence of 134Cs. However, 90Sr contamination was not confirmed in all samples although detectable amounts of 90Sr can be expected in Japanese soils, as a background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between 90Sr and 137Cs activity concentrations provides a potentially powerful tool to discriminate background 90Sr level from its Fukushima contribution.

Strontium-90 activity concentration in soil samples from the exclusion zone of the Fukushima daiichi nuclear power plant.

PubMed

Sahoo, Sarata Kumar; Kavasi, Norbert; Sorimachi, Atsuyuki; Arae, Hideki; Tokonami, Shinji; Mietelski, Jerzy Wojciech; Łokas, Edyta; Yoshida, Satoshi

2016-04-06

The radioactive fission product (90)Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing (90)Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (<30 km) of the earthquake-damaged Fukushima Daiichi nuclear power plant, to measure (90)Sr activity concentration using liquid scintillation counting. (137)Cs activity concentration was also measured with gamma-spectroscopy in order to investigate correlation with (90)Sr. The (90)Sr activity concentrations ranged from 3.0 ± 0.3 to 23.3 ± 1.5 Bq kg(-1) while the (137)Cs from 0.7 ± 0.1 to 110.8 ± 0.3 kBq kg(-1). The fact that radioactive contamination originated from the Fukushima nuclear accident was obvious due to the presence of (134)Cs. However, (90)Sr contamination was not confirmed in all samples although detectable amounts of (90)Sr can be expected in Japanese soils, as a background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between (90)Sr and (137)Cs activity concentrations provides a potentially powerful tool to discriminate background (90)Sr level from its Fukushima contribution.

Strontium-90 activity concentration in soil samples from the exclusion zone of the Fukushima daiichi nuclear power plant

PubMed Central

Sahoo, Sarata Kumar; Kavasi, Norbert; Sorimachi, Atsuyuki; Arae, Hideki; Tokonami, Shinji; Mietelski, Jerzy Wojciech; Łokas, Edyta; Yoshida, Satoshi

2016-01-01

The radioactive fission product 90Sr has a long biological half-life (˜18 y) in the human body. Due to its chemical similarity to calcium it accumulates in bones and irradiates the bone marrow, causing its high radio-toxicity. Assessing 90Sr is therefore extremely important in case of a nuclear disaster. In this work 16 soil samples were collected from the exclusion zone (<30 km) of the earthquake-damaged Fukushima Daiichi nuclear power plant, to measure 90Sr activity concentration using liquid scintillation counting. 137Cs activity concentration was also measured with gamma-spectroscopy in order to investigate correlation with 90Sr. The 90Sr activity concentrations ranged from 3.0 ± 0.3 to 23.3 ± 1.5 Bq kg−1 while the 137Cs from 0.7 ± 0.1 to 110.8 ± 0.3 kBq kg−1. The fact that radioactive contamination originated from the Fukushima nuclear accident was obvious due to the presence of 134Cs. However, 90Sr contamination was not confirmed in all samples although detectable amounts of 90Sr can be expected in Japanese soils, as a background, stemming from global fallout due to the atmospheric nuclear weapon tests. Correlation analysis between 90Sr and 137Cs activity concentrations provides a potentially powerful tool to discriminate background 90Sr level from its Fukushima contribution. PMID:27048779

Development of criteria used to establish a background environmental monitoring station

DOE PAGES

Fritz, Brad G.; Barnett, J. Matthew; Snyder, Sandra F.; ...

2015-03-02

It is generally considered necessary to measure concentrations of contaminants-of-concern at a background location when conducting atmospheric environmental surveillance. This is because it is recognized that measurements of background concentrations can enhance interpretation of environmental monitoring data. Despite the recognized need for background measurements, there is little published guidance available that describes how to identify an appropriate atmospheric background monitoring location. This paper develops generic criteria that can guide the decision making process for identifying suitable locations for background atmospheric monitoring station. Detailed methods for evaluating some of these criteria are also provided and a case study for establishment ofmore » an atmospheric background surveillance station as part of an environmental surveillance program is described. While the case study focuses on monitoring for radionuclides, the approach is equally valid for any airborne constituent being monitored. The case study shows that implementation of the developed criteria can result in a good, defensible choice for a background atmospheric monitoring location.« less

Contaminant exposure of willets feeding in agricultural drainages of the lower Rio Grande valley of south Texas USA

USGS Publications Warehouse

Custer, T.W.; Mitchell, C.A.

1991-01-01

Willets (Catoptrophorus semipalmatus) were collected in June and August 1986 at the outlets of two agricultural drainages into the Lower Languna Madre of south Texas and at two other Texas coastal sites. Mean liver concentrations of arsenic was higher in August than June. Over 20% of the livers had arsenic concentrations elevated above a suggested background level of 5.0 ppm dry weight (DW), but concentrations (maximum 15 ppm) were below those associated with acute toxicity. Selenium concentration in livers varied from 2.3 to 8.3 ppm DW for all locations and represented background levels. Mercury concentrations in liver for all locations (mean = 2.0 to 3.4, maximum 17 ppm DW) were below those associated with avian mortality and similar to levels found in other estuarine/marine birds. DDE in carcasses was higher in adults (mean = 1.0 ppm wet weight) than juveniles (0.2 ppm), and higher in August (1.0 ppm) than June (0.5 ppm); however, DDE concentrations were generally at background levels. Based on brain cholinesterase activity, willets were not recently exposed to organophosphate pesticides.

Seasonal and diurnal variations of methane and carbon dioxide in the highly polluted Kathmandu Valley, Nepal

NASA Astrophysics Data System (ADS)

Mahata, Khadak; Panday, Arnico; Rupakheti, Maheswar; Lawrence, Mark

2016-04-01

Anthropogenic emissions of carbon dioxide and methane - key greenhouse gases (GHGs) - are primary causes of global warming and resultant impacts. The atmospheric warming is more pronounced and likely to cause more serious damage in vulnerable areas such as the Hindukush-Karakorum-Himalayan region (HKH). The HKH region is a data gap region according to the 5th Assessment report of the intergovernmental panel on climate change (IPCC). In order to understand the mixing ratios and variability of the key GHGs in the foothills of the Central Himalaya, we carried out continuous measurements of CO2, CH4, CO, and water vapor at Bode (an urban site in the Kathmandu valley, Nepal) for a year (March 2013 - Feb 2014), and again at Bode and at Chanban (a background outside the Valley) for 3 months (July 15 - Oct 3, 2015), with two state-of-the-art cavity ring-down instruments (Picarro G2401). The measurements were carried out as a part of the international air pollution measurement campaign: SusKat- ABC (Sustainable atmosphere for the Kathmandu Valley - Atmospheric Brown Clouds). The annual average CO2 and CH4 concentrations at Bode were 419 ± 24 and 2.192 ± 0.224 ppm, respectively, which are notably higher than those observed at the background site at Mauna Loa Observatory in the same period. The CO2concentration at Bode was high during the pre-monsoon period and low during the monsoon, while CH4 was high in winter and lower during the pre-monsoon period. The monthly CO2concentration was highest in April. Forest fires and agro-waste burning in the region, and the local emissions in the Kathmandu valley were the main sources of the high CO2 in the pre-monsoon period. CH4 showed a maximum in September due to additional emissions from paddy fields. Seasonally, winter has the highest CH4 concentration which is due to brick production, which is a seasonal activity, and other local sources combined with the shallow mixing layer height in winter. The diurnal pattern of CO2 and CH4 showed a high morning peak (7:00-8:00 local time), a daytime low and a nighttime high in all seasons. CO showed similar diurnal patterns in the pre-monsoon and winter. The high concentrations of CO2 and CH4 from January to April were primarily due to emissions from brick industries located in the south-east and eastern side of the valley. The concentrations of CO2, CH4 and CO at the rural site outside the valley (Chanban) were 3.8%, 12% and 64% lower than corresponding concentrations at Bode (urban site) during 3 months of observations. The difference in CO2, CH4 and CO concentrations between urban and rural sites indicates that the the Kathmandu Valley is highly affected by local emission sources, which, if addressed with appropriate mitigation measures, can bring substantial benefits to both local air quality and GHG reduction.

C5-C12 volatile organic compounds at roadside, residential, and background locations in Ankara, Turkey: temporal and spatial variations and sources.

PubMed

Kuntasal, Oznur Oğuz; Kilavuz, Seda Aslan; Karman, Deniz; Wang, Daniel; Tuncel, Gürdal

2013-10-01

Concentrations of 91 volatile organic compounds (VOCs) ranging from C5 to C12 were measured at three sites in Ankara, the capital of Turkey, in the summer of 2003 and winter of 2004. Samples were collected at roadside, residential and background stations at consecutive 4-hr intervals over a 24-hr period for six weeks in each season. Air samples were collected onto cartridges packed with Tenax TA and Carbopack B resins and analyzed by thermal desorption, followed by gas chromatography coupled to a mass selective detector (GC/MSD). Time resolved data provided information on ambient levels, temporal and spatial variations and sources of VOCs in Ankara. Toluene is the most abundant compound at all sites with and average concentration of 13.1 ?g m(-3). The mean concentrations of benzene are 12.6, 5.2, and 2.4 ?g m(-3) during winter at roadside, residential and background stations, respectively. Diurnal variation in the data together with toluene to benzene concentration ratio (T:B) that is close to 2.0 indicated the influence of traffic related emissions at residential and roadside stations during winter season. Higher T:B ratio observed at residential and background stations during summer period and correlation analysis indicated additional VOC sources. Temporal variations and low m,p-xylene to ethylbenzene ratio (mpX:E) indicated that transported air mass is the major VOC source influencing VOC concentrations measured at the background station.

Oral Fluid and Plasma Cannabinoid Ratios after Around-the-Clock Controlled Oral Δ9-Tetrahydrocannabinol Administration

PubMed Central

Milman, Garry; Schwope, David M.; Schwilke, Eugene W.; Darwin, William D.; Kelly, Deanna L.; Goodwin, Robert S.; Gorelick, David A.; Huestis, Marilyn A.

2013-01-01

BACKGROUND Oral fluid (OF) testing is increasingly important for drug treatment, workplace, and drugged-driving programs. There is interest in predicting plasma or whole-blood concentrations from OF concentrations; however, the relationship between these matrices is incompletely characterized because of few controlled drug-administration studies. METHODS Ten male daily cannabis smokers received around-the-clock escalating 20-mg oral Δ9-tetrahydrocannabinol (THC, dronabinol) doses (40–120 mg/day) for 8 days. Plasma and OF samples were simultaneously collected before, during, and after dosing. OF THC, 11-hydroxy-THC and 11-nor-9-carboxy-THC (THCCOOH) were quantified by GC-MS at 0.5-μg/L, 0.5-μg/L, and 7.5-ng/L limits of quantification (LOQs), respectively. In plasma, the LOQs were 0.25 μg/L for THC and THCCOOH, and 0.5 μg/L for 11-hydroxy-THC. RESULTS Despite multiple oral THC administrations each day and increasing plasma THC concentrations, OF THC concentrations generally decreased over time, reflecting primarily previously self-administered smoked cannabis. The logarithms of the THC concentrations in oral fluid and plasma were not significantly correlated (r = −0.10; P = 0.065). The OF and plasma THCCOOH concentrations, albeit with 1000-fold higher concentrations in plasma, increased throughout dosing. The logarithms of OF and plasma THCCOOH concentrations were significantly correlated (r = 0.63; P < 0.001), although there was high interindividual variation. A high OF/plasma THC ratio and a high OF THC/THCCOOH ratio indicated recent cannabis smoking. CONCLUSIONS OF monitoring does not reliably detect oral dronabinol intake. The time courses of THC and THCCOOH concentrations in plasma and OF were different after repeated oral THC doses, and high inter-individual variation was observed. For these reasons, OF cannabinoid concentrations cannot predict concurrent plasma concentrations. PMID:21875944

Measurement and estimated health risks of semivolatile organic compounds (PCBs, PAHs, pesticides, and phthalates) in ambient air at the Hanford Site

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

Patton, G.W.; Cooper, A.T.; Blanton, M.L.

1997-09-01

Air samples for polychlorinated biphenyls (PCBs), chlorinated pesticides, phthalate plasticizers, and polycyclic aromatic hydrocarbons (PAHs) were collected at three Hanford Site locations (300-Area South Gate, southeast of 200-East Area, and a background location near Rattlesnake Springs). Samples were collected using high-volume air samplers equipped with a glass fiber filter and polyurethane foam plug sampling train. Target compounds were extracted from the sampling trains and analyzed using capillary gas chromatography with either electron capture detection or mass selective detection. Twenty of the 28 PCB congeners analyzed were found above the detection limits, with 8 of the congeners accounting for over 80%more » of the average PCB concentrations. The average sum of all individual PCB congeners ranged from 500-740 pg/m{sup 3}, with little apparent difference between the sampling locations. Twenty of the 25 pesticides analyzed were found above the detection limits, with endosulfan I, endosulfan II, and methoxychlor having the highest average concentrations. With the exception of the endosulfans, all other average pesticide concentrations were below 100 pg/m{sup 3}. There was little apparent difference between the air concentrations of pesticides measured at each location. Sixteen of the 18 PAHs analyzed were found above the detection limit. Phenanthrene, fluoranthene, pyrene, fluorene, chrysene, benzo(b)fluoranthene, and naphthalene were the only PAHs with average concentrations above 100 pg/m{sup 3}. Overall, the 300 Area had higher average PAH concentrations compared to the 200-East Area and the background location at Rattlesnake Springs; however, the air concentrations at the 300-Area also are influenced by sources on the Hanford Site and from nearby communities.« less

Determination of lead and cadmium concentration limits in agricultural soil and municipal solid waste compost through an approach of zero tolerance to food contamination.

PubMed

Saha, Jayanta Kumar; Panwar, N R; Singh, M V

2010-09-01

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4-150 mg/kg and Cd at 0.02-20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C(ul)) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers' fields. Lead and Cd concentration limits in soil were calculated by dividing C(ul) with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.

CXCL13 as a Cerebrospinal Fluid Marker for Neurosyphilis in HIV-infected Patients with Syphilis

PubMed Central

Marra, Christina M.; Tantalo, Lauren C.; Sahi, Sharon K.; Maxwell, Clare L.; Lukehart, Sheila A.

2010-01-01

Background Asymptomatic neurosyphilis is more difficult to diagnose in HIV-infected patients because HIV itself can cause cerebrospinal fluid (CSF) pleocytosis. The proportion of CSF lymphocytes that are B cells is elevated in neurosyphilis, suggesting that the CSF concentration of the B cell chemoattractant, chemokine (C-X-C motif) ligand 13 (CXCL13) concentration may also be elevated. Methods CSF and blood were collected from 199 HIV-infected patients with syphilis and neurosyphilis. Serum and CSF CXCL13 concentrations were determined. Results Patients with neurosyphilis had higher CSF and serum CXCL13 concentrations compared to patients with syphilis but not neurosyphilis. The odds of having symptomatic neurosyphilis were increased by 2.23 fold for every log increase in CSF CXCL13 concentration and were independent of CSF WBC and plasma HIV RNA concentrations, peripheral blood CD4+ T cell count and use of antiretroviral medications. A cut-off of 10 pg/mL CSF CXCL13 had high sensitivity and a cut-off of 250 pg/mL or evidence of intrathecal synthesis of CXCL13 had high specificity for diagnosis of both symptomatic and asymptomatic neurosyphilis. CSF concentrations of CXCL13 declined after treatment for neurosyphilis. Conclusions CSF CXCL13 concentration may be particularly useful for diagnosis of neurosyphilis in HIV-infected patients because it is independent of CSF pleocytosis and markers of HIV disease. PMID:20393380

A review on natural background radiation

PubMed Central

Shahbazi-Gahrouei, Daryoush; Gholami, Mehrdad; Setayandeh, Samaneh

2013-01-01

The world is naturally radioactive and approximately 82% of human-absorbed radiation doses, which are out of control, arise from natural sources such as cosmic, terrestrial, and exposure from inhalation or intake radiation sources. In recent years, several international studies have been carried out, which have reported different values regarding the effect of background radiation on human health. Gamma radiation emitted from natural sources (background radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series, and their decay products, as well as 40K, which exist at trace levels in the earth's crust. Their concentrations in soil, sands, and rocks depend on the local geology of each region in the world. Naturally occurring radioactive materials generally contain terrestrial-origin radionuclides, left over since the creation of the earth. In addition, the existence of some springs and quarries increases the dose rate of background radiation in some regions that are known as high level background radiation regions. The type of building materials used in houses can also affect the dose rate of background radiations. The present review article was carried out to consider all of the natural radiations, including cosmic, terrestrial, and food radiation. PMID:24223380

Large inter-individual variation in isoflavone plasma concentration limits use of isoflavone intake data for risk assessment

PubMed Central

van der Velpen, V; Hollman, P C; van Nielen, M; Schouten, E G; Mensink, M; van't Veer, P; Geelen, A

2014-01-01

Background/objectives: Isoflavones are present in soy foods and soy-based supplements. Despite low plasma isoflavone concentrations in the general Western population, concentrations in supplement users exceed those suggested to be beneficial for health in Asian populations, raising concerns for adverse effects. To aid risk assessment, quantification of the relation between isoflavone intake and plasma concentrations is essential. Subjects/methods: Plasma samples were collected from postmenopausal women in three placebo-controlled crossover studies with 8-week periods for supplements (two studies, ~100 mg isoflavones/day, n=88) or 4-week periods for soy foods (one study, ~48 mg isoflavones/day, n=15). Plasma isoflavone concentrations (daidzein, equol, genistein and glycitein) were quantified using high-performance liquid chromatography and electrochemical detection. The association between plasma concentrations and isoflavone intake, equol producer status, intake–producer interaction and background dietary intake was assessed based on the assumption of a log-linear relation. Results: Median plasma total isoflavone concentrations after the soy food and supplement interventions were respectively 2.16 and 3.47 μmol/l for equol producers and 1.30 and 2.39 μmol/l for non-producers. Regression analysis showed that doubling isoflavone intake increased plasma concentrations by 55–62% (±s.e. 1–2%, R2>0.87) for daidzein, genistein, equol (only for producers) and total isoflavones; for glycitein the association was weaker (15±1%, R2=0.48). Adjustments for energy, carbohydrate and fat intake did not affect these estimates. Inter-individual variation, estimated based on repeated measures in one of the studies, was 30–96%. Conclusions: Although the relation between isoflavone intake and plasma concentrations was adequately quantified, the use of isoflavone intake data for risk assessment needs caution due to large inter-individual variation in plasma concentrations. PMID:24939433

The removal of heavy metals from contaminated soil by a combination of sulfidisation and flotation.

PubMed

Vanthuyne, Mathias; Maes, André

2002-05-06

The possibility of removing cadmium, copper, lead and zinc from Belgian loamy soil by a combination of sulfidisation pre-treatment and Denver flotation was investigated. The potentially available--sulfide convertible--metal content of the metal polluted soil was estimated by EDTA (0.1 M, pH 4.65) extraction and BCR sequential extraction. EDTA extraction is better at approximating the metal percentage that is expected to be convertible into a metal sulfide phase, in contrast to the sequential extraction procedure of 'Int. J. Environ. Anal. Chem. 51 (1993) pp. 135-151' in which transition metals present as iron oxide co-precipitates are dissolved by hydroxylammoniumchloride in the second extraction step. To compare the surface characteristics of metal sulfides formed by sulfidisation with those of crystalline metal sulfides, two types of synthetic sediments were prepared and extracted with 0.1 M EDTA (pH 4.65) in anoxic conditions. Separate metal sulfides or co-precipitates with iron sulfide were formed by sulfide conditioning. The Denver flotation of both types of synthetic sediments (kerosene as collector at high background electrolyte concentrations) resulted in similar concentrating factors for freshly formed metal sulfides as for fine-grained crystalline metal sulfides. The selective flotation of metal sulfides after sulfide conditioning of a polluted soil, using kerosene or potassium ethyl xanthate as collectors and MIBC as frother, was studied at high background electrolyte concentrations. The sulfidisations were made in ambient air and inside an anoxic glove box. The concentrating factors corrected by the potentially available metal percentage, determined by 0.1 M EDTA extraction, lie between 2 and 3. The selective flotation of these finely dispersed, amorphous, metal sulfides can possibly be improved by optimising the bubble-particle interaction.

Pollution characteristics, risk assessment, and source apportionment of heavy metals in road dust in Beijing, China.

PubMed

Men, Cong; Liu, Ruimin; Xu, Fei; Wang, Qingrui; Guo, Lijia; Shen, Zhenyao

2018-01-15

To analyze the spatial distribution patterns, risks, and sources of heavy metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Zn, Fe), 36 road dust samples were collected from an urbanized area of Beijing in June 2016. The mean concentration of most metals, except As and Mn, exceeded their corresponding background values, with the mean concentration of Cd being 8 times that of its background. Spatially, for most heavy metals, except As and Mn, the high concentration areas were mainly within the 5th ring road, especially the northern area. The geo-accumulation index of Cd and Cu indicated moderate contamination at many sites. The entire study area was prone to potential ecological risks, with higher risks within the 4th ring road. Cd caused high potential ecological risk at most sites. According to the health risk assessment results, the non-carcinogenic risks that human beings suffered from heavy metals were insignificant. However, the carcinogenic risks due to Ni and Cr exceeded the acceptable level. Based on the source apportionment using positive matrix factorization, four factors were defined for the heavy metals. Factor 1, which was traffic-related exhaust, accounted for 34.47% of the concentration of heavy metals. The contributions of Factors 2 and 3 were approximately 25% each. Factor 2 was potentially related to coal combustion, while Factor 3 could be related to the manufacture and use of metal components. Factor 4, which could be related to the use of pesticides, fertilizers, and medical devices, accounted for 14.88%, which was the lowest. Copyright © 2017 Elsevier B.V. All rights reserved.

Airborne CH2O measurements over the North Atlantic during the 1997 NARE campaign: Instrument comparisons and distributions

NASA Astrophysics Data System (ADS)

Fried, Alan; Lee, Yin-Nan; Frost, Greg; Wert, Bryan; Henry, Bruce; Drummond, James R.; Hübler, Gerd; Jobson, Tom

2002-02-01

Airborne CH2O measurements were acquired by tunable diode laser absorption spectroscopy (TDLAS) and coil/2,4-dinitrophenylhydrazine (CDNPH) techniques over remote regions of the North Atlantic Ocean from the surface to 8 km during the North Atlantic Regional Experiment (NARE-97) in September of 1997. There were eight aircraft flights when both instruments were simultaneously operating, producing 665 overlapping time intervals for comparisons. A number of approaches were used in the comparisons, and indicated that on average both instruments measured identical ambient CH2O concentrations to within 0.1 ppbv, and more typically within 0.08 ppbv, over the 0 to 0.8 ppbv-concentration range. However, significant differences, larger than the combined 2σ total uncertainty estimates, were observed in 29% of the full time-coincident data set. The two instruments produced very similar altitude trends. Under clean background conditions in the 35° to 55°N latitude band, the median TDLAS and CDNPH CH2O concentrations were 0.399 and 0.410 ppbv for 0-2 km, 0.250 and 0.355 ppbv for 2-4 km, and 0.217 and 0.280 ppbv for 4-8 km, respectively. Elevated CH2O concentrations were observed in this study at both high altitudes (4-8 km) and in the marine boundary layer by both instruments. Thus vertical transport of CH2O and/or its precursors may provide a greater contribution to upper tropospheric HOx than previously thought. The results of this study, which are based upon instruments employing entirely different measurement principles, calibration, and sampling approaches, not only reinforce this conclusion but also provide a high-quality database necessary to further explore CH2O measurement-model relationships in the clean background atmosphere.

Long open-path TDL based system for monitoring background concentration for deployment at Jungfraujoch High Altitude Research Station- Switzerland

NASA Astrophysics Data System (ADS)

Simeonov, Valentin; van den Bergh, Hubert; Parlange, Marc

2010-05-01

A new, long open-path instrument for monitoring of path-averaged methane and water vapor concentrations will be presented. The instrument is built on the monostatic scheme (transceiver - distant retroreflector). A VCSEL tunable diode laser (TDL) with a central wavelength of 1654 nm is used as a light source. A specially designed, single-cell, hollow-cube retroreflector with 150 mm aperture will be installed at 1200 m from the transceiver in the final deployment at Jungfraujjoch and 100 mm retroreflectors will be used in the other applications. The receiver is built around a 20 cm Newtonian telescope. To avoid distortions in the shape of a methane line, caused by atmospheric turbulences, the line is scanned within 1 µs. Fast InGaAs photodiodes and 200 MHz are used to achieve this scanning rate. The expected concentration resolution for the above mentioned path lengths is of the order of 2 ppb. The instrument is developed at the Swiss Federal Institute of Technology - Lausanne (EPFL) Switzerland and will be used within the GAW+ CH program for long-term monitoring of background methane concentration in the Swiss Alps. After completing the initial tests at EPFL the instrument will be installed in 2012 at the High Altitude Research Station Jungfraujoch (HARSJ) located at 3580 m ASL. The HARSJ is one of the 24 global GAW stations and carries on continuous observations of a number of trace gasses, including methane. One of the goals of the project is to compare path-averaged to ongoing point measurements of methane in order to identify possible influence of the station. Future deployments of a copy of the instrument include the Colombian part of Amazonia and Siberian wetlands.

Occurrence and air-soil exchange of organochlorine pesticides and polychlorinated biphenyls at a CAWNET background site in central China: Implications for influencing factors and fate.

PubMed

Zhan, Lingxi; Lin, Tian; Wang, Zuwu; Cheng, Zhineng; Zhang, Gan; Lyu, Xiaopu; Cheng, Hairong

2017-11-01

Ambient air and soil samples were collected between March 2012 and March 2013 at Jinsha, a regional background site in central China, to measure the concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The average concentrations of total OCPs and total PCBs were 191 ± 107 and 39.4 ± 27.1 pg/m 3 in air (gaseous and particulate phase) and 0.585 ± 0.437 and 0.083 ± 0.039 ng/g in soil, respectively. The higher concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) and p,p'-DDT/p,p'-DDE ratios in the soil indicated recent p,p'-DDT input to the soil. A strong positive temperature dependence and average fugacity fraction value > 0.5 were observed for p,p'-DDT, suggesting that volatilization of residual DDT in the soil was the main influencing factor on atmospheric p,p'-DDT. Highly average fugacity fractions (>0.7) of trans-chlordane (TC) and cis-chlordane (CC) and high TC/CC ratios both in the soil and atmosphere suggested fresh inputs. Higher gaseous concentrations of hexachlorobenzene (HCB) were observed in winter and negative temperature dependence was directly attributed to the surrounding ongoing source (e.g. fuel consuming activities), especially in winter. Overall, most targeted OCPs and PCBs were influenced by long-range transport, and fugacity fraction values indicated highly volatile compounds (e.g. α-hexachlorocyclohexane (α-HCH) and lower chlorinated PCBs) were volatilized and low volatility compounds (e.g. p,p'-DDE and higher chlorinated PCBs) were deposited at the air-soil interface. Knowing the source and sink of OCPs and PCBs can help to control their pollution in this area and provide a reference for other studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Oral administration of curcumin and salsalate attenuates high fat diet-induced up-regulation of pro-inflammatory colonic cytokines via suppression of Akt/NFkappaB in azoxymethane-treated mice

USDA-ARS?s Scientific Manuscript database

Background: Obesity, a robust risk factor for colorectal cancer (CRC), is known to elevate the concentrations of proinflammatory cytokines in the murine colon. Also, signaling through the Akt pathway, which is known to be activated by proinflammatory cytokines, is thought to play a role in colorecta...

Ground Level Ozone Regional Background Characteristics In North-west Pacific Rim

NASA Astrophysics Data System (ADS)

Chiang, C.; Fan, J.; Chang, J. S.

2007-12-01

Understanding the ground level ozone regional background characteristics is essential in understanding the contribution of long-range transport of pollutants from Asia Mainland to air quality in downwind areas. In order to understand this characteristic in north-west Pacific Rim, we conducted a coupled study using ozone observation from regional background stations and 3-D regional-scale chemical transport model simulations. We used O3, CO, wind speed and wind direction data from two regional background stations and ¡§other stations¡¨ over a ten year period and organized several numerical experiments to simulate one spring month in 2003 to obtain a deeper understanding. The so called ¡§other stations¡¨ had actually been named as background stations under various governmental auspices. But we found them to be often under strong influence of local pollution sources with strong diurnal or slightly longer time variations. We found that the Yonagunijima station (24.74 N, 123.02 E) and Heng-Chuen station (21.96 N,120.78 E), about a distance of 400 km apart, have almost the same ozone time series pattern. For these two stations in 2003, correlation coefficients (R2) for annual observed ozone concentration is about 0.64, in the springtime it is about 0.7, and in a one-month period at simulation days it is about 0.76. These two stations have very little small scale variations in all the variables studied. All variations are associated with large scale circulation changes. This is especially so at Yonagunijima station. Using a 3-D regional-scale chemical transport model for East Asia region including contribution from Asia continental outflow and neighboring island pollution areas we found that the Yonagunijima and HengChuen station are indeed free of pollutants from all neighboring areas keeping in mind that pollutants from Taiwan area is never far away. Ozone concentrations in these two stations are dominated by synoptic scale weather patterns, with diffused pollutant contribution from distant sources. When the weather system brings in air mass from the low latitude of western Pacific Ocean, ozone concentrations are about 10-20 ppb. When the China high pressure system moves eastward and with the accompanying Asian continental outflow plume, ozone concentrations are about 65-80 ppb.

Time evolution of atmospheric particle number concentration during high-intensity pyrotechnic events

NASA Astrophysics Data System (ADS)

Crespo, Javier; Yubero, Eduardo; Nicolás, Jose F.; Caballero, Sandra; Galindo, Nuria

2014-10-01

The Mascletàs are high-intensity pyrotechnic events, typical of eastern Spanish festivals, in which thousands of firecrackers are burnt at ground level in an intense, short-time (<8 min) deafening spectacle that generates short-lived, thick aerosol clouds. In this study, the impact of such events on air quality has been evaluated by means of particle number concentration measurements performed close to the venue during the June festival in Alicante (southeastern Spain). Peak concentrations and dilution times observed throughout the Mascletàs have been compared to those measured when conventional aerial fireworks were launched 2 km away from the monitoring site. The impact of the Mascletàs on the total number concentration of particles larger than 0.3 μm was higher (maximum ∼2·104 cm-3) than that of fireworks (maximum ∼2·103 cm-3). The effect of fireworks depended on whether the dominant meteorological conditions favoured the transport of the plume to the measurement location. However, the time required for particle concentrations to return to background levels is longer and more variable for firework displays (minutes to hours) than for the Mascletàs (<25 min).

Bees' subtle colour preferences: how bees respond to small changes in pigment concentration

NASA Astrophysics Data System (ADS)

Papiorek, Sarah; Rohde, Katja; Lunau, Klaus

2013-07-01

Variability in flower colour of animal-pollinated plants is common and caused, inter alia, by inter-individual differences in pigment concentrations. If and how pollinators, especially bees, respond to these small differences in pigment concentration is not known, but it is likely that flower colour variability impacts the choice behaviour of all flower visitors that exhibit innate and learned colour preferences. In behavioural experiments, we simulated varying pigment concentrations and studied its impact on the colour choices of bumblebees and honeybees. Individual bees were trained to artificial flowers having a specific concentration of a pigment, i.e. Acridine Orange or Aniline Blue, and then given the simultaneous choice between three test colours including the training colour, one colour of lower and one colour of higher pigment concentration. For each pigment, two set-ups were provided, covering the range of low to middle and the range of middle to high pigment concentrations. Despite the small bee-subjective perceptual contrasts between the tested stimuli and regardless of training towards medium concentrations, bees preferred neither the training stimuli nor the stimuli offering the highest pigment concentration but more often chose those stimuli offering the highest spectral purity and the highest chromatic contrast against the background. Overall, this study suggests that bees choose an intermediate pigment concentration due to its optimal conspicuousness. It is concluded that the spontaneous preferences of bees for flower colours of high spectral purity might exert selective pressure on the evolution of floral colours and of flower pigmentation.

Influence of plumes from biomass burning on atmospheric chemistry over the equatorial and tropical South Atlantic during CITE 3

NASA Technical Reports Server (NTRS)

Andreae, M. O.; Anderson, B. E.; Blake, D. R.; Bradshaw, J. D.; Collins, J. E.; Gregory, G. L.; Sachse, G. W.; Shipham, M. C.

1994-01-01

During all eight flights conducted over the equatorial and tropical South Atlantic in the course of the Chemical Instrumentation Test and Evaluation (CITE 3) experiment, we observed haze layers with elevated concentrations of aerosols, O3, CO, and other trace gases related to biomass burning emissions. They occurred at altitudes between 1000 and 5200 m and were usually only some 100-300 m thick. These layers extended horizontally over several 100 km and were marked by the presence of visible brownish haze. Air mass trajectories indicate that these layers originate in the biomass burning regions of Africa and South America and typically have aged at least 10 days since the time of emission. In the haze layers, O3 and CO concentrations up to 90 and 210 ppb were observed, respectively. The two species were highly correlated. The ratio concentrations in plume minus background concentrations of O3/CO is typically in the range 0.2-0.7, much higher than the ratios in the less aged plumes investigated previously in Amazonia. In most cases, aerosol (0.12-3 micrometer diameter) number concentrations were also elevated by up to 400/cu cm in the layers; aerosol enrichments were also strongly correlated with elevated CO levels. Clear correlations between CO and NO(x) enrichments were not apparent due to the age of the plumes, in which most NO(x) would have already reacted away within 1-2 days. Only in some of the plumes could clear correlations between NO(y) and CO be identified; the absence of a general correlation between NO(y) and CO may be due to instrumental limitations and to variable sinks for NO(y). The average enrichment of the ratio concentrations in plume minus background concentrations of NO(y)/CO was quite high, consistent with the efficient production of ozone observed in the plumes. The chemical characteristics of the haze layers, together with remote sensing information and trajectory calculations, suggest that fire emissions (in Africa and/or South America) are the primary source of the haze layer components.

Characterization of the NOx-Ox relationship in a mountain gap rural area of interchange of air masses southeast of the Metropolitan Area of Mexico City

NASA Astrophysics Data System (ADS)

Ruiz Suarez, L.; Garcia-Yee, J.; Torres-JArdon, R.; Barrera Huertas, H.; Torres-Jaramillo, A.; Ortinez, A.

2013-05-01

Varying levels of oxidants (Ox = O3 + NO2) with respect to NOx were registered at three sites in a mountain southeast of the Mexico City Metropolitan Area (MCMA) in February and March 2011. The Ox-NOx ratio was used to gain a better understanding of the photochemical and transport processes happening over this mountain pass. Relatively high concentrations of O3 (moving average concentrations of 8 hours) exceeded maximum levels of the World Health Organization, and the European Union. The cumulative exceedances above background level of O3 in the one month-long campaign also exceeded the three months accumulative UN-ECE AOT40 critical level for crop protection. It was observed that the level of Ox in the mountain gap sites consisted of two contributions: One, independent of NOx emissions, extremely dominant and considered equivalent to the regional background O3 concentration; the second and much smaller was dependent of NOx local concentrations. Evidence was found that the oxidation of NO provided the major contribution of NO2 to Ox, rather than direct NO2 emissions. The contribution of regional Ox dominated from midmorning to noon when the boundary layer height began to increase due to sunlight heating of the surface leading to the mixing of higher concentrations of O3 above the nighttime thermal inversion. After noon, when the ozone vertical distribution was uniform, the Ox and O3 concentrations reached their maximum; they were very similar with very low levels of NO2. The analysis of wind data collected at the monitoring sites showed that from mid-morning to early afternoon, a northerly weak flow was common. Afterwards stronger southerly winds became dominant bringing in O3 rich air parcels into the atmospheric basin where MCMA is located. The high regional ozone concentrations add evidence for the need of coordinated air quality management policies for the complete central part of Mexico. Keywords: mountain gap, oxidant, ground level ozone, Central Mexico

Phytoplankton transport to coral reefs by internal solitons in the northern South China Sea

NASA Astrophysics Data System (ADS)

Wang, Yu-Huai

2016-09-01

Evidence is presented that waters containing high concentrations of chlorophyll are transported by internal waves to the fore-reef slope of Dongsha Atoll in the northern South China Sea. High vertical resolution mooring measurements of temperature, pressure, and chlorophyll fluorescence revealed that the internal soliton cores could transport chlorophyll vertically downward and increase concentrations by an order of magnitude near the seafloor, compared to background levels. The reef areas that are potentially nourished by the pulses of phytoplankton are dominated by alcyonacean soft corals, while other reef areas that are less or not at all affected by internal waves are dominated by scleractinian hard corals. This suggests that the delivery of phytoplankton by internal solitons provides a plentiful food source that benefits the growth of soft corals.

Annealing studies of heteroepitaxial InSbN on GaAs grown by molecular beam epitaxy for long-wavelength infrared detectors

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

Patra, Nimai C.; Bharatan, Sudhakar; Li Jia

2012-10-15

We report the effect of annealing on the structural, vibrational, electrical, and optical properties of heteropepitaxially grown InSbN epilayers on GaAs substrate by molecular beam epitaxy for long-wavelength infrared detector applications. As-grown epilayers exhibited high N incorporation in the both substitutional and interstitial sites, with N induced defects as evidenced from high resolution x-ray diffraction, secondary ion mass spectroscopy, and room temperature (RT) micro-Raman studies. The as-grown optical band gap was observed at 0.132 eV ({approx}9.4 {mu}m) and the epilayer exhibited high background carrier concentration at {approx}10{sup 18} cm{sup -3} range with corresponding mobility of {approx}10{sup 3} cm{sup 2}/Vs. Exmore » situ and in situ annealing at 430 Degree-Sign C though led to the loss of N but improved InSb quality due to effective annihilation of N related defects and other lattice defects attested to enhanced InSb LO phonon modes in the corresponding Raman spectra. Further, annealing resulted in the optical absorption edge red shifting to 0.12 eV ({approx}10.3 {mu}m) and the layers were characterized by reduced background carrier concentration in the {approx}10{sup 16} cm{sup -3} range with enhanced mobility in {approx}10{sup 4} cm{sup 2}/Vs range.« less

Application of a DNA-based luminescence switch-on method for the detection of mercury(II) ions in water samples from Hong Kong

NASA Astrophysics Data System (ADS)

He, Hong-Zhang; Leung, Ka-Ho; Fu, Wai-Chung; Shiu-Hin Chan, Daniel; Leung, Chung-Hang; Ma, Dik-Lung

2012-12-01

Mercury is a highly toxic environmental contaminant that damages the endocrine and central nervous systems. In view of the contamination of Hong Kong territorial waters with anthropogenic pollutants such as trace heavy metals, we have investigated the application of our recently developed DNA-based luminescence methodology for the rapid and sensitive detection of mercury(II) ions in real water samples. The assay was applied to water samples from Shing Mun River, Nam Sang Wai and Lamma Island sea water, representing natural river, wetland and sea water media, respectively. The results showed that the system could function effectively in real water samples under conditions of low turbidity and low metal ion concentrations. However, high turbidity and high metal ion concentrations increased the background signal and reduced the performance of this assay.

Feasibility of Topical Applications of Natural High-Concentration Capsaicinoid Solutions in Patients with Peripheral Neuropathic Pain: A Retrospective Analysis

PubMed Central

Mouraux, Andre; Deumens, Ronald; Leerink, Marjolein; le Polain de Waroux, Bernard; Joëlle, Quetin-Leclercq

2016-01-01

Background. Capsaicin, one of several capsaicinoid compounds, is a potent TRPV1 agonist. Topical application at high concentration (high concentration, >1%) induces a reversible disappearance of epidermal free nerve endings and is used to treat peripheral neuropathic pain (PNP). While the benefit of low-concentration capsaicin remains controversial, the 8%-capsaicin patch (Qutenza®, 2010, Astellas, Netherlands) has shown its effectiveness. This patch is, however, costly and natural high-concentration capsaicinoid solutions may represent a cheaper alternative to pure capsaicin. Methods. In this retrospective study, 149 patients were screened, 132 were included with a diagnosis of neuropathic pain, and eighty-four were retained in the final analyses (median age: 57.5 years [IQR25–75: 44.7–67.1], male/female: 30/54) with PNP who were treated with topical applications of natural high-concentration capsaicinoid solutions (total number of applications: 137). Indications were postsurgical PNP (85.7%) and nonsurgical PNP (14.3%) (posttraumatic, HIV-related, postherpetic, and radicular PNP). Objectives. To assess the feasibility of topical applications of natural high-concentration capsaicinoid solutions for the treatment of PNP. Results. The median treated area was 250 cm2 [IQR25–75: 144–531]. The median amount of capsaicinoids was 55.1 mg [IQR25–75: 28.7–76.5] per plaster and the median concentration was 172.3 μg/cm2 [IQR25–75: 127.6–255.2]. Most patients had local adverse effects on the day of treatment, such as mild to moderate burning pain and erythema. 13.6–19.4% of the patients experienced severe pain or erythema. Following treatment, 62.5% of patients reported a lower pain intensity or a smaller pain surface, and 35% reported a sustained pain relief lasting for at least 4 weeks. Conclusion. Analgesic topical treatment with natural high-concentration capsaicinoid is feasible and may represent a low cost alternative to alleviate PNP in clinical practice. PMID:28115879

Method for mapping a natural gas leak

DOEpatents

Reichardt, Thomas A [Livermore, CA; Luong, Amy Khai [Dublin, CA; Kulp, Thomas J [Livermore, CA; Devdas, Sanjay [Albany, CA

2009-02-03

A system is described that is suitable for use in determining the location of leaks of gases having a background concentration. The system is a point-wise backscatter absorption gas measurement system that measures absorption and distance to each point of an image. The absorption measurement provides an indication of the total amount of a gas of interest, and the distance provides an estimate of the background concentration of gas. The distance is measured from the time-of-flight of laser pulse that is generated along with the absorption measurement light. The measurements are formatted into an image of the presence of gas in excess of the background. Alternatively, an image of the scene is superimposed on the image of the gas to aid in locating leaks. By further modeling excess gas as a plume having a known concentration profile, the present system provides an estimate of the maximum concentration of the gas of interest.

Natural gas leak mapper

DOEpatents

Reichardt, Thomas A [Livermore, CA; Luong, Amy Khai [Dublin, CA; Kulp, Thomas J [Livermore, CA; Devdas, Sanjay [Albany, CA

2008-05-20

A system is described that is suitable for use in determining the location of leaks of gases having a background concentration. The system is a point-wise backscatter absorption gas measurement system that measures absorption and distance to each point of an image. The absorption measurement provides an indication of the total amount of a gas of interest, and the distance provides an estimate of the background concentration of gas. The distance is measured from the time-of-flight of laser pulse that is generated along with the absorption measurement light. The measurements are formated into an image of the presence of gas in excess of the background. Alternatively, an image of the scene is superimosed on the image of the gas to aid in locating leaks. By further modeling excess gas as a plume having a known concentration profile, the present system provides an estimate of the maximum concentration of the gas of interest.

Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

PubMed Central

Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

2015-01-01

Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

Heavy metal fluxes at the sediment-water interface of three coastal ecosystems from south-west of the Iberian Peninsula

PubMed

Blasco; Saenz; Gomez-Parra

2000-03-20

Concentrations of the heavy metals Cr, Cu, Fe and Mn were measured in sediments and porewater samples collected in three coastal ecosystems southwest of the Iberian Peninsula: the Odiel and Barbate River Salt Marshes and the Bay of Cadiz. Both the sediment and the porewater metal concentrations in the Odiel River Salt Marshes are higher than the values found in the Bay of Cadiz and Barbate River Salt Marsh, particularly for copper, a metal associated with mining activity. In porewater, the profiles were not the same as those in the solid phase and reflect the different behaviours of the elements in relation to the redox conditions. The heavy metals Cr and Cu show a typical enrichment in the porewater of the oxic zone. The heavy metals Mn and Fe show an increase in the porewater at the depths where the maximum nitrate and phosphate concentrations occur, respectively. Significant differences between background levels for each heavy metal in the various studied zones exist. Iron and Cu showed larger background levels in the Odiel River Salt Marshes than those in the Cadiz Bay and the Barbate River Salt Marshes. In the Bay of Cadiz the background levels are also high, particularly for Cr. At the Odiel River Salt Marshes the diffusive flux of Cu is high (1.3-230.1 microg cm(-2) year(-1)), which suggests that the Odiel River Salt Marshes are subject to strong contamination by Cu, which is presumably introduced to the sediment in particulate form. In the Bay of Cadiz, Cr is the only metal with positive diffusive flux (2.15 microg cm(-2) year(-1)). It is higher than those obtained in other coastal ecosystems including the Odiel River Salt Marshes. The positive diffusive flux of Cr has been associated with the input of this metal by the naval industry and the manufacturing of car and aircraft components.

Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

PubMed

Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

2015-09-30

Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

International Airport Impacts to Air Quality: Size and Related Properties of Large Increases in Ultrafine Particle Number Concentrations.

PubMed

Hudda, N; Fruin, S A

2016-04-05

We measured particle size distributions and spatial patterns of particle number (PN) and particle surface area concentrations downwind from the Los Angeles International Airport (LAX) where large increases (over local background) in PN concentrations routinely extended 18 km downwind. These elevations were mostly comprised of ultrafine particles smaller than 40 nm. For a given downwind distance, the greatest increases in PN concentrations, along with the smallest mean sizes, were detected at locations under the landing jet trajectories. The smaller size of particles in the impacted area, as compared to the ambient urban aerosol, increased calculated lung deposition fractions to 0.7-0.8 from 0.5-0.7. A diffusion charging instrument (DiSCMini), that simulates alveolar lung deposition, measured a fivefold increase in alveolar-lung deposited surface area concentrations 2-3 km downwind from the airport (over local background), decreasing steadily to a twofold increase 18 km downwind. These ratios (elevated lung-deposited surface area over background) were lower than the corresponding ratios for elevated PN concentrations, which decreased from tenfold to twofold over the same distance, but the spatial patterns of elevated concentrations were similar. It appears that PN concentration can serve as a nonlinear proxy for lung deposited surface area downwind of major airports.

Electrochemical sample matrix elimination for trace-level potentiometric detection with polymeric membrane ion-selective electrodes.

PubMed

Chumbimuni-Torres, Karin Y; Calvo-Marzal, Percy; Wang, Joseph; Bakker, Eric

2008-08-01

Potentiometric sensors are today sufficiently well understood and optimized to reach ultratrace level (subnanomolar) detection limits for numerous ions. In many cases of practical relevance, however, a high electrolyte background hampers the attainable detection limits. A particularly difficult sample matrix for potentiometric detection is seawater, where the high saline concentration forms a major interfering background and reduces the activity of most trace metals by complexation. This paper describes for the first time a hyphenated system for the online electrochemically modulated preconcentration and matrix elimination of trace metals, combined with a downstream potentiometric detection with solid contact polymeric membrane ion-selective microelectrodes. Following the preconcentration at the bismuth-coated electrode, the deposited metals are oxidized and released to a medium favorable to potentiometric detection, in this case calcium nitrate. Matrix interferences arising from the saline sample medium are thus circumvented. This concept is successfully evaluated with cadmium as a model trace element and offers potentiometric detection down to low parts per billion levels in samples containing 0.5 M NaCl background electrolyte.

Electrochemical Sample Matrix Elimination for Trace Level Potentiometric Detection with Polymeric Membrane Ion-Selective Electrodes

PubMed Central

Chumbimuni-Torres, Karin Y.; Calvo-Marzal, Percy; Wang, Joseph; Bakker, Eric

2008-01-01

Potentiometric sensors are today sufficiently well understood and optimized to reach ultra-trace level (sub-nanomolar) detection limits for numerous ions. In many cases of practical relevance, however, a high electrolyte background hampers the attainable detection limits. A particularly difficult sample matrix for potentiometric detection is seawater, where the high saline concentration forms a major interfering background and reduces the activity of most trace metals by complexation. This paper describes for the first time a hyphenated system for the online electrochemically modulated preconcentration and matrix elimination (EMPM) of trace metals, combined with a downstream potentiometric detection with solid contact polymeric membrane ion-selective microelectrodes. Following the preconcentration at the bismuth coated electrodes, the deposited metals are oxidized and released to a medium favorable to potentiometric detection, in this case calcium nitrate. Matrix interferences arising from the saline sample medium are thus circumvented. This concept is successfully evaluated with cadmium as a model trace element and offers potentiometric detection down to low parts per billion levels in samples containing 0.5 M NaCl background electrolyte. PMID:18570385

Assessment of metal contamination in a small mining- and smelting-affected watershed: high resolution monitoring coupled with spatial analysis by GIS.

PubMed

Coynel, Alexandra; Blanc, Gérard; Marache, Antoine; Schäfer, Jörg; Dabrin, Aymeric; Maneux, Eric; Bossy, Cécile; Masson, Matthieu; Lavaux, Gilbert

2009-05-01

The Riou Mort River watershed (SW France), representative of a heavily polluted, small, heterogeneous watershed, represents a major source for the polymetallic pollution of the Lot-Garonne-Gironde fluvial-estuarine system due to former mining and ore-treatment activities. In order to assess spatial distribution of the metal/metalloid contamination in the watershed, a high resolution hydrological and geochemical monitoring were performed during one year at four permanent observation stations. Additionally, thirty-five stream sediment samples were collected at representative key sites and analyzed for metal/metalloid (Cd, Zn, Cu, Pb, As, Sb, Mo, V, Cr, Co, Ni, Th, U and Hg) concentrations. The particulate concentrations in water and stream sediments show high spatial differences for most of the studied elements suggesting strong anthropogenic and/or lithogenic influences; for stream sediments, the sequence of the highest variability, ranging from 100% to 300%, is the following: Mo < Cu < Hg < As < Sb < Cd < Zn < Pb. Multidimensional statistical analyses combined with metal/metalloid maps generated by GIS tool were used to establish relationships between elements, to identify metal/metalloid sources and localize geochemical anomalies attributed to local geochemical background, urban and industrial activities. Finally, this study presents an approach to assess anthropogenic trace metal inputs within this watershed by combining lithology-dependent geochemical background values, metal/metalloid concentrations in stream sediments and mass balances of element fluxes at four key sites. The strongest anthropogenic contributions to particulate element fluxes are 90-95% for Cd, Zn and Hg in downstream sub-catchments. The localisation of anthropogenic metal/metalloid sources in restricted areas offers a great opportunity to further significantly reduce metal emissions and restore the Lot-Garonne-Gironde fluvial-estuarine ecosystem.

Lower total and percent of high-molecular-weight adiponectin concentration in South Asian kidney transplant recipients

PubMed Central

Vorobeichik, Leon; Nash, Michelle M.; Huang, Michael; Rapi, Lindita; Maguire, Graham; Mamdani, Muhammad; Yan, Andrew T.; Connelly, Philip W.

2012-01-01

Background. Ethnicity is an important determinant of post-renal transplant outcomes. Limited data are available on cardiovascular risk differences in kidney transplant recipients (KTR) based on ethnicity. Methods. A group of 129 clinically stable age-matched KTR [43 South Asian (SA), 86 Caucasian]) were assessed for plasma total and high-molecular-weight (HMW) adiponectin, cystatin C, apolipoproteins A1 and B, C-reactive protein, uric acid, urine albumin-to-creatinine ratio, estimated glomerular filtration rate (eGFR) and transplant-specific plus traditional Framingham risk factors. SA and Caucasians were compared by t-tests, Wilcoxon rank-sum or chi-square testing. Accounting for the matched design, multivariable linear regression was performed to determine predictors of adiponectin concentrations. Results. SA did not differ from Caucasians in background cardiac disease or cardioprotective medication use or risk factors other than smoking (26 versus 56%, P = 0.001). Total adiponectin (9.5 ± 3.5 versus 12.9 ± 6.7 μmg/mL, P < 0.001) and HMW adiponectin (22 ± 9 versus 29 ± 11%, P < 0.001) were significantly lower in SA. Determinants of total adiponectin included SA ethnicity (P = 0.02), cystatin C-eGFR (P < 0.001), high-density lipoprotein (HDL) cholesterol (P < 0.0001) and waist-to-hip ratio (P < 0.001), while those of HMW adiponectin included SA ethnicity (P < 0.001), cystatin C-eGFR (P = 0.03) and HDL cholesterol (P = 0.001). There were no important differences in the other measured biomarkers. Conclusion. Total and HMW adiponectin concentrations are lower in SA KTR and may be promising exploratory biomarkers of post-transplant cardiovascular risk. PMID:24744849

Influence of biomass burning from South Asia at a high-altitude mountain receptor site in China

NASA Astrophysics Data System (ADS)

Zheng, Jing; Hu, Min; Du, Zhuofei; Shang, Dongjie; Gong, Zhaoheng; Qin, Yanhong; Fang, Jingyao; Gu, Fangting; Li, Mengren; Peng, Jianfei; Li, Jie; Zhang, Yuqia; Huang, Xiaofeng; He, Lingyan; Wu, Yusheng; Guo, Song

2017-06-01

Highly time-resolved in situ measurements of airborne particles were conducted at Mt. Yulong (3410 m above sea level) on the southeastern edge of the Tibetan Plateau in China from 22 March to 14 April 2015. The detailed chemical composition was measured by a high-resolution time-of-flight aerosol mass spectrometer together with other online instruments. The average mass concentration of the submicron particles (PM1) was 5.7 ± 5.4 µg m-3 during the field campaign, ranging from 0.1 up to 33.3 µg m-3. Organic aerosol (OA) was the dominant component in PM1, with a fraction of 68 %. Three OA factors, i.e., biomass burning organic aerosol (BBOA), biomass-burning-influenced oxygenated organic aerosol (OOA-BB) and oxygenated organic aerosol (OOA), were resolved using positive matrix factorization analysis. The two oxygenated OA factors accounted for 87 % of the total OA mass. Three biomass burning events were identified by examining the enhancement of black carbon concentrations and the f60 (the ratio of the signal at m/z 60 from the mass spectrum to the total signal of OA). Back trajectories of air masses and satellite fire map data were integrated to identify the biomass burning locations and pollutant transport. The western air masses from South Asia with active biomass burning activities transported large amounts of air pollutants, resulting in elevated organic concentrations up to 4-fold higher than those of the background conditions. This study at Mt. Yulong characterizes the tropospheric background aerosols of the Tibetan Plateau during pre-monsoon season and provides clear evidence that the southeastern edge of the Tibetan Plateau was affected by the transport of anthropogenic aerosols from South Asia.

Long-term monitoring of black carbon across Germany

NASA Astrophysics Data System (ADS)

Kutzner, Rebecca D.; von Schneidemesser, Erika; Kuik, Friderike; Quedenau, Jörn; Weatherhead, Elizabeth C.; Schmale, Julia

2018-07-01

Lately, black carbon (BC) has received significant attention due to its climate-warming properties and adverse health effects. Nevertheless, long-term observations in urban areas are scarce, most likely because BC monitoring is not required by environmental legislation. This, however, handicaps the evaluation of air quality models which can be used to assess the effectiveness of policy measures which aim to reduce BC concentrations. Here, we present a new dataset of atmospheric BC measurements from Germany constructed from over six million measurements at over 170 stations. Data covering the period between 1994 and 2014 were collected from twelve German Federal States and the Federal Environment Agency, quality checked and harmonized into a database with comprehensive metadata. The final data in original time resolution are available for download (https://doi.org/10.1594/PANGAEA.881173) Our analysis focuses on 2009, the year with the largest data coverage with one single methodology, as well as on the relative changes in long-term trends over ten years. For 2009, we find that BC concentrations at traffic sites were at least twice as high as at urban background, industrial and rural sites. Weekly cycles are most prominent at traffic stations, however, the presence of differences in concentrations during the week and on weekends at other station types suggests that traffic plays an important role throughout the full network. Generally higher concentrations and weaker weekly cycles during the winter months point towards the influence of other sources such as domestic heating. Regarding the long-term trends, advanced statistical techniques allow us to account for instrumentation changes and to separate seasonal and long-term changes in our dataset. Analysis shows a downward trend in BC at nearly all locations and in all conditions, with a high level of confidence for the period of 2005-2014. In depth analysis indicates that background BC is decreasing slowly, while the occurrences of high concentrations are decreasing more rapidly. In summary, legislation - both in Europe and locally - to reduce particulate emissions and indirectly BC appear to be working, based on this analysis. Adverse human health and climate impacts are likely to be diminished because of the improvements in air quality.

Population-based study of high plasma C-reactive protein concentrations among the Inuit of Nunavik

PubMed Central

Labonté, Marie-Eve; Dewailly, Eric; Chateau-Degat, Marie-Ludivine; Couture, Patrick; Lamarche, Benoît

2012-01-01

Background The shift away from traditional lifestyle in the Inuit population over the past few decades has been associated with an increased prevalence of coronary heart disease (CHD) risk factors such as obesity, high blood pressure (BP) and diabetes. However, the impact of this transition on the pro-inflammatory marker high-sensitivity C-reactive protein (hs-CRP) has not been documented. Objectives To examine the prevalence of elevated plasma hs-CRP concentrations in Inuit from Nunavik in the province of Quebec (Canada) and identify anthropometric, biochemical and lifestyle risk factors associated with elevated hs-CRP. Design A population-representative sample of 801 Inuit residents from 14 villages of Nunavik, aged between 18 and 74 years, was included in the analyses. Subjects participated in a clinical session and completed questionnaires on lifestyle. Multivariate logistic regression was used to determine risk factors for elevated hs-CRP. Results Elevated plasma hs-CRP concentrations (≥2 mg/L) were present in 32.7% (95% confidence interval (CI) 29.5–35.8) of the Inuit adult population and were more prevalent among women than among men (36.7% vs. 29.0%, p=0.007). Multivariate logistic regression analysis indicated that every 1 mmHg increase in systolic BP was associated with a 3% increase in the odds of having hs-CRP concentrations ≥2 mg/L in the Inuit population (95% CI 1.01–1.04). The combination of older age (≥50 vs. <30 years) and elevated waist circumference (gender-specific cut-off values) in a multivariate logistic model was also associated with a 13.3-fold increase in the odds of having plasma hs-CRP concentrations ≥2 mg/L (95% CI 5.8–30.9). Conclusions These data indicate that elevated hs-CRP is relatively prevalent among Inuit with values that are similar to those seen in Canadian Caucasian populations. Sex, age, waist circumference and systolic BP are major factors that increase the risk of this inflammatory phenotype among Inuit from Nunavik, despite their different lifestyle background compared with Caucasians. PMID:23087913

TISSUE CONCENTRATION OF PCBS IN ANIMAL EXPERIMENTS AS COMPARED WITH THOSE IN HUMANS WITH BACKGROUND-LEVEL EXPOSURE

EPA Science Inventory

TISSUE CONCENTRATION OF PCBS IN ANIMAL EXPERIMENTS AS COMPARED WITH THOSE IN HUMANS WITH BACKGROUND-LEVEL EXPOSURE. M J DeVito1 and M P Longnecker2. 1NHEERL, ORD, USEPA; Research Triangle Park, NC, USA; 2Epidemiology
Branch, NIEHS, Research Triangle Park, NC, USA.

To ...

Spatial distribution of chemical constituents in the Kuskokwim River, Alaska

USGS Publications Warehouse

Wang, Bronwen

1999-01-01

The effects of lithologic changes on the water quality of the Kuskokwim River, Alaska, were evaluated by the U.S. Geological Survey in June 1997. Water, suspended sediments, and bed sediments were sampled from the Kusko-kwim River and from three tributaries, the Holitna River, Red Devil Creek, and Crooked Creek. Dissolved boron, chromium, copper, manganese, zinc, aluminum, lithium, barium, iron, antimony, arsenic, mercury, and strontium were detected. Dissolved manganese and iron concentrations were three and four times higher in the Holitna River than in the Kusko-kwim River. Finely divided ferruginous materials found in the graywacke and shale units of the Kuskokwim Group are the probable source of the iron. The highest concentrations of dissolved strontium and barium were found at McGrath, and the limestone present in the upper basin was the most probable source of strontium. The total mercury concentrations on the Kuskokwim River decreased downstream from McGrath. Dissolved mercury was 24 to 32 percent of the total concentration. The highest concentrations of total mercury, and of dissolved antimony and arsenic were found in Red Devil Creek. The higher concentrations from Red Devil Creek did not affect the main stem mercury transport because the tributary was small relative to the Kuskokwim River. In Red Devil Creek, total mercury exceeded the concentration at which the U.S. Environmental Protection Agency (USEPA) indicates that aquatic life is affected and dissolved arsenic exceeded the USEPA's drinking-water standard. Background mercury and antimony concentrations in bed sediments ranged from 0.09 to 0.15 micrograms per gram for mercury and from 1.6 to 2.1 micrograms per gram for antimony. Background arsenic concentrations were greater than 27 micrograms per gram. Sites near the Red Devil mercury mine had mercury and antimony concentrations greater than background concentrations. These concentrations probably reflect the proximity to the ore body and past mining. Crooked Creek had mercury concentrations greater than the background concentration. The transport of suspended sediment-associated trace elements was lower for all elements in the lower river than in the upper river, indicating storage of sediments and their associated metals within the river system.

Inappropriately low aldosterone concentrations in adults with AIDS-related diarrhoea in Zambia: a study of response to fluid challenge

PubMed Central

Kaile, Trevor; Zulu, Isaac; Lumayi, Ruth; Ashman, Neil; Kelly, Paul

2008-01-01

Background Chronic diarrhoea is one of the most debilitating consequences of HIV infection in sub-Saharan Africa and it carries a high mortality rate. We report unexpectedly low concentrations of circulating aldosterone in 12 patients (6 men, 6 women) in the University Teaching Hospital, Lusaka, who all had diarrhoea for over one month. Changes in serum electrolytes, blood pressure, Karnofsky score and serum aldosterone concentration were being monitored during a short study of responses to saline infusion (3 litres/24 h) over 72 hours. Findings At baseline, 9/12 (75%) of the patients were hyponatraemic, 10/11 (91%) were hypokalaemic, and 6/12 (50%) had undetectable aldosterone concentrations. Blood pressure and Karnofsky score rose and creatinine concentration fell in response to the infusion. Conclusion Circulating aldosterone concentrations were inappropriately low and complicate the profound electrolyte deficiencies resulting from chronic diarrhoea. Management of these deficiencies needs to be more aggressive than is currently practised and consideration should be given to a formal clinical trial of mineralocorticoid replacement in these severely ill patients. If the inappropriately low aldosterone reflects a general adrenal failure, it may explain a considerable proportion of the high mortality seen both before and after initiation of anti-retroviral therapy. PMID:18710534

Uptake and depuration of PCB-153 in edible shrimp Palaemonetes varians and human health risk assessment.

PubMed

Grilo, T F; Cardoso, P G; Pato, P; Duarte, A C; Pardal, M A

2014-03-01

A medium-term mesocosm exposure study was conducted to elucidate bioaccumulation and depuration of polychlorinated biphenyl congener 153 (PCB-153) in edible shrimp Palaemonetes varians. Over the 15-day exposure period, shrimp under different exposure concentrations exhibited a significant increase in PCB-153 concentration compared with control organisms. Distinct bioaccumulation patterns and uptake rates were observed depending on the exposure concentrations. For low PCB-153 exposure levels (0.25μgL(-1)), accumulation followed a saturation model, reaching an apparent steady state after fifteen days exposure. For intermediate (2.5μgL(-1)) and high PCB-153 levels (25μgL(-1)), accumulation was faster and linear. In addition, the bioaccumulation rate was not proportional to PCB-153 concentration, and the bioaccumulation was higher at intermediate exposure concentrations. Regarding the depuration phase, P. varians lost up to 30% of PCB-153 after 72h and levels continued slowly to decrease until the end of the 30-d experimental period. However, PCB-153 levels in shrimp did not reach background values, and those exposed to moderate and high PCB-153 concentrations presented contamination levels much higher than the regulatory limit for human food consumption (75ngg(-1) ww for Σ6 PCB). Copyright © 2013 Elsevier Inc. All rights reserved.

Effects of Building‒roof Cooling on Flow and Distribution of Reactive Pollutants in street canyons

NASA Astrophysics Data System (ADS)

Park, S. J.; Choi, W.; Kim, J.; Jeong, J. H.

2016-12-01

The effects of building‒roof cooling on flow and dispersion of reactive pollutants were investigated in the framework of flow dynamics and chemistry using a coupled CFD‒chemistry model. For this, flow characteristics were analyzed first in street canyons in the presence of building‒roof cooling. A portal vortex was generated in street canyon, producing dominant reverse and outward flows near the ground in all the cases. The building‒roof cooling increased horizontal wind speeds at the building roof and strengthened the downward motion near the downwind building in the street canyon, resultantly intensifying street canyon vortex strength. The flow affected the distribution of primary and secondary pollutants. Concentrations of primary pollutants such as NOx, VOC and CO was high near the upwind building because the reverse flows were dominant at street level, making this area the downwind region of emission sources. Concentration of secondary pollutant such as O3 was lower than the background near the ground, where NOX concentrations were high. Building‒roof cooling decreased the concentration of primary pollutants in contrasted to those under non‒cooling conditions. In contrast, building‒roof cooling increased O3 by reducing NO concentrations in urban street canyon compared to concentrations under non‒cooling conditions.

Simulations of Ground-Water Flow and Particle Pathline Analysis in the Zone of Contribution of a Public-Supply Well in Modesto, Eastern San Joaquin Valley, California

USGS Publications Warehouse

Burow, Karen R.; Jurgens, Bryant C.; Kauffman, Leon J.; Phillips, Steven P.; Dalgish, Barbara A.; Shelton, Jennifer L.

2008-01-01

Shallow ground water in the eastern San Joaquin Valley is affected by high nitrate and uranium concentrations and frequent detections of pesticides and volatile organic compounds (VOC), as a result of ground-water development and intensive agricultural and urban land use. A single public-supply well was selected for intensive study to evaluate the dominant processes affecting the vulnerability of public-supply wells in the Modesto area. A network of 23 monitoring wells was installed, and water and sediment samples were collected within the approximate zone of contribution of the public-supply well, to support a detailed analysis of physical and chemical conditions and processes affecting the water chemistry in the well. A three-dimensional, steady-state local ground-water-flow and transport model was developed to evaluate the age of ground water reaching the well and to evaluate the vulnerability of the well to nonpoint source input of nitrate and uranium. Particle tracking was used to compute pathlines and advective travel times in the ground-water flow model. The simulated ages of particles reaching the public-supply well ranged from 9 to 30,000 years, with a median of 54 years. The age of the ground water contributed to the public-supply well increased with depth below the water table. Measured nitrate concentrations, derived primarily from agricultural fertilizer, were highest (17 milligrams per liter) in shallow ground water and decreased with depth to background concentrations of less than 2 milligrams per liter in the deepest wells. Because the movement of water is predominantly downward as a result of ground-water development, and because geochemical conditions are generally oxic, high nitrate concentrations in shallow ground water are expected to continue moving downward without significant attenuation. Simulated long-term nitrate concentrations indicate that concentrations have peaked and will decrease in the public-supply well during the next 100 years because of the low nitrate concentrations in recharge beneath the urban area and the increasing proportion of urban-derived ground water reaching the well. The apparent lag time between peak input concentrations and peak concentrations in the well is about 20 to 30 years. Measured uranium concentrations were also highest (45 micrograms per liter) in shallow ground water, and decreased with depth to background concentrations of about 0.5 microgram per liter. Naturally-occurring uranium adsorbed to aquifer sediments is mobilized by oxygen-rich, high-alkalinity water. Alkalinity increased in shallow ground water in response to agricultural development. As ground-water pumping increased in the 1940s and 1950s, this alkaline water moved downward through the ground-water flow system, mobilizing the uranium adsorbed to aquifer sediments. Ground water with high alkalinity and high uranium concentrations is expected to continue to move deeper in the system, resulting in increased uranium concentrations with depth in ground water. Because alkalinity (and correspondingly uranium) concentrations were high in shallow ground water beneath both the urban and the agricultural land, long-term uranium concentrations in the public-supply well are expected to increase as the proportion of uranium-affected water contributed to the well increases. Assuming that the alkalinity near the water table remains the same, the simulation of long-term alkalinity in the public-supply well indicates that uranium concentrations in the public-supply well will likely approach the maximum contaminant level; however, the time to reach this level is more than 100 years because of the significant proportion of old, unaffected water at depth that is contributed to the public-supply well.

Effects of Offshore Oil Exploration and Development in the Alaskan Beaufort Sea: A Three-Decade Record for Sediment Metals.

PubMed

Trefry, John H; Neff, Jerry M

2018-06-19

Impacts from oil exploration, development and production in the Beaufort Sea, Alaska, are assessed using concentrations of metals in sediments collected during 2014-15, combined with a large dataset for 1985-2006. Concentrations of 7 (1980 s) or 17 (1999-2015) metals in 423 surface sediments from 134 stations, plus 563 samples from 30 cores were highly variable, primarily as a function of sediment granulometry with naturally greater metal concentrations in fine-grained, Al-rich sediment. Metals versus Al correlation plots were used to normalize metal concentrations and identify values significantly above background. Barium, Cr, Cu, Hg and Pb concentrations were above background, but variable, within 250 m of some offshore sites where drilling occurred between 1981-2001; these areas totaled <6 km 2 of 11,000 km 2 in the total lease area. Random and fixed sampling along the coastal Beaufort Sea from 1985-2015 yielded 40 positive anomalies for metals in surface sediments (∼0.8% of 5,082 data points). About 85% of the anomalies were from developed areas. Half the anomalies were for the five metals found enhanced near drilling sites. No metals concentrations, except As, exceeded accepted sediment quality criteria. Interannual shifts in metals values for surface sediments at inner shelf sites were common and linked to storm-induced transitions in granulometry; however, metal/Al ratios were uniform during these shifts. Sediment cores generally recorded centuries of background values, except for As, Fe and Mn. These three metals were naturally enriched in sediments from deeper water (>100 m) via diagenetic remobilization at sediment depths of 5-15 cm, upward diffusion, and precipitation in surface oxic layers. Minimal evidence for anthropogenic inputs of metals, except near some exploratory drilling sites, is consistent with extraction of most oil from land or barrier islands in the Alaskan Arctic and restricted offshore activity to date. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hotspots of Very Short Lived Halocarbons in the Tropical Ocean and Atmosphere

NASA Astrophysics Data System (ADS)

Jia, Y.; Tegtmeier, S.; Quack, B.; Atlas, E. L.

2017-12-01

Very short lived halocarbons (VSLH) with atmospheric lifetimes shorter than 6 months are known to have natural oceanic sources. VSLH have drawn lots of attentions due to their contribution to stratospheric ozone depletion and tropospheric chemistry. VSLH in the ocean show a large spatial variability often with enhanced concentrations in coastal and upwelling regions. It is unclear how this variability in oceanic concentration and emissions impacts the atmospheric VSLH distribution. Such knowledge however is relevant in order to understand their impact on atmospheric chemistry and in order to design meaningful aircraft campaigns and measurement stations. Measurements from three tropical ship campaigns (TransBrom 2009, SHIVA 2011, and OASIS, 2014) suggest localized oceanic "hotspot", regions with very high VSLH emissions from the ocean into the atmosphere. It is also an open question if there's significant impact of these hotspots on the concentrations of VSLH in the atmosphere or if atmospheric transport and mixing obliterates their signals in the atmosphere. In our study, the Lagrangian transport model FLEXPART is used to investigate the atmospheric transport of CHBr3, CH2Br2, and CH3I emitted from the ocean into atmosphere. First, we derive typical atmospheric background concentrations of VSLH from (uniform and non-uniform) oceanic emissions found in the open ocean. In these simulations, the clear structures of meteorological processes (i.e. typhoons and other convective systems) are captured in the VSLHs background concentrations. In a second step, we apply VSLH emissions derived during the ship campaigns to analyze the impacts of the strong oceanic hotspots on the atmospheric VSLH distributions. These hotspots do not show an atmospheric signature if their regional extent is limited, even if their emissions are orders of magnitudes larger than the background emissions. However, if the hotspots extend over a region larger than roughly 0.3° x 0.3° (latitude x longitude), they produce a clear signal of enhanced atmospheric VSLH abundance. Our results will help to understand how oceanic VSLH concentrations, atmospheric transport patterns and atmospheric VSLH distributions are coupled, and predict the maximum mixing ratios that can be expected in the vicinity of oceanic hotspots.

Variability of Organophosphorous Pesticide Metabolite Levels in Spot and 24-hr Urine Samples Collected from Young Children during 1 Week

PubMed Central

Kogut, Katherine; Eisen, Ellen A.; Jewell, Nicholas P.; Quirós-Alcalá, Lesliam; Castorina, Rosemary; Chevrier, Jonathan; Holland, Nina T.; Barr, Dana Boyd; Kavanagh-Baird, Geri; Eskenazi, Brenda

2012-01-01

Background: Dialkyl phosphate (DAP) metabolites in spot urine samples are frequently used to characterize children’s exposures to organophosphorous (OP) pesticides. However, variable exposure and short biological half-lives of OP pesticides could result in highly variable measurements, leading to exposure misclassification. Objective: We examined within- and between-child variability in DAP metabolites in urine samples collected during 1 week. Methods: We collected spot urine samples over 7 consecutive days from 25 children (3–6 years of age). On two of the days, we collected 24-hr voids. We assessed the reproducibility of urinary DAP metabolite concentrations and evaluated the sensitivity and specificity of spot urine samples as predictors of high (top 20%) or elevated (top 40%) weekly average DAP metabolite concentrations. Results: Within-child variance exceeded between-child variance by a factor of two to eight, depending on metabolite grouping. Although total DAP concentrations in single spot urine samples were moderately to strongly associated with concentrations in same-day 24-hr samples (r ≈ 0.6–0.8, p < 0.01), concentrations in spot samples collected > 1 day apart and in 24-hr samples collected 3 days apart were weakly correlated (r ≈ –0.21 to 0.38). Single spot samples predicted high (top 20%) and elevated (top 40%) full-week average total DAP excretion with only moderate sensitivity (≈ 0.52 and ≈ 0.67, respectively) but relatively high specificity (≈ 0.88 and ≈ 0.78, respectively). Conclusions: The high variability we observed in children’s DAP metabolite concentrations suggests that single-day urine samples provide only a brief snapshot of exposure. Sensitivity analyses suggest that classification of cumulative OP exposure based on spot samples is prone to type 2 classification errors. PMID:23052012

Do high blood folate concentrations exacerbate metabolic abnormalities in people with low vitamin B-12 status?123

PubMed Central

Mills, James L; Carter, Tonia C; Scott, John M; Troendle, James F; Gibney, Eileen R; Shane, Barry; Kirke, Peadar N; Ueland, Per M; Brody, Lawrence C; Molloy, Anne M

2011-01-01

Background: In elderly individuals with low serum vitamin B-12, those who have high serum folate have been reported to have greater abnormalities in the following biomarkers for vitamin B-12 deficiency: low hemoglobin and elevated total homocysteine (tHcy) and methylmalonic acid (MMA). This suggests that folate exacerbates vitamin B-12–related metabolic abnormalities. Objective: We determined whether high serum folate in individuals with low serum vitamin B-12 increases the deleterious effects of low vitamin B-12 on biomarkers of vitamin B-12 cellular function. Design: In this cross-sectional study, 2507 university students provided data on medical history and exposure to folic acid and vitamin B-12 supplements. Blood was collected to measure serum and red blood cell folate (RCF), hemoglobin, plasma tHcy, and MMA, holotranscobalamin, and ferritin in serum. Results: In subjects with low vitamin B-12 concentrations (<148 pmol/L), those who had high folate concentrations (>30 nmol/L; group 1) did not show greater abnormalities in vitamin B-12 cellular function in any area than did those with lower folate concentrations (≤30 nmol/L; group 2). Group 1 had significantly higher holotranscobalamin and RCF, significantly lower tHcy, and nonsignificantly lower (P = 0.057) MMA concentrations than did group 2. The groups did not differ significantly in hemoglobin or ferritin. Compared with group 2, group 1 had significantly higher mean intakes of folic acid and vitamin B-12 from supplements and fortified food. Conclusions: In this young adult population, high folate concentrations did not exacerbate the biochemical abnormalities related to vitamin B-12 deficiency. These results provide reassurance that folic acid in fortified foods and supplements does not interfere with vitamin B-12 metabolism at the cellular level in a healthy population. PMID:21653798

Characterization of the scope and magnitude of biotin interference in susceptible Roche Elecsys competitive and sandwich immunoassays.

PubMed

Trambas, Christina; Lu, Zhong; Yen, Tina; Sikaris, Ken

2018-03-01

Background Biotin interference is a significant problem to which at-risk laboratories must now be attuned. We sought to systematically characterize the nature of this interference in Roche immunoassays. Methods Known concentrations of biotin were titrated into serum samples and the effects on competitive and sandwich immunoassays were analysed. The maximum and minimum concentrations examined reflect those likely to be achieved in individuals on 5 to 10 mg supplements at the lower end, and 100 to 300 mg biotin at the high end. Results A high variability in biotin tolerance was observed. Some assays, such as troponin T, TSH and antithyroid antibodies, were extremely sensitive to the lower concentrations of biotin (15.6 and 31.3 ng/mL), whereas the majority of assays were relatively resistant. At concentrations ≥500 ng/mL, all assays showed significant interference from biotin but, again, the magnitude of the interference was variable. The more sensitive assays showed profound analytical bias at biotin concentrations that occur with high-dose therapy. Conclusion Our data demonstrate high variability in biotin tolerance across Roche immunoassays. The shape of the dose-response curves provides more detailed information than the single manufacturer-quoted figure for biotin tolerance. Accordingly, these data may be used by laboratories for more accurate risk assessment in predicting the effects of biotin. Our data may also be extrapolated to guide timing of blood tests in patients on high-dose biotin therapy: it demonstrates the number of half-lives required to withhold biotin in order to decrease its concentration to below a given assay tolerance.

Endothelial Function and Serum Concentration of Toxic Metals in Frequent Consumers of Fish

PubMed Central

Buscemi, Silvio; Vasto, Sonya; Di Gaudio, Francesca; Grosso, Giuseppe; Bergante, Sonia; Galvano, Fabio; Massenti, Fatima Maria; Amodio, Emanuele; Rosafio, Giuseppe; Verga, Salvatore

2014-01-01

Background Endothelial dysfunction is involved in the pathogenesis of atherosclerosis. Consumption of fish is associated with reduced cardiovascular risk, but there is paucity of data concerning its effect on endothelial function. Furthermore, investigation of the effects of fish consumption on health must take into account the ingestion of contaminants, including transition metals and some metalloids, which may have unfavorable effects on health, including those on the cardiovascular system. We investigated the association between fish consumption, endothelial function (flow mediated dilation of the brachial artery), and serum concentration of some toxic metals in apparently healthy people. Methods Twenty-nine high fish consumers (at least 3 portions a week) were compared with 25 low fish consumers (less than 1 portion a week). All participants were free of diabetes, cardiovascular or other systemic diseases. Serum metal (antimonium, arsenic, mercury, lead, cobalt, copper, zinc, selenium, strontium) concentrations were measured in subgroups of 24 high fish consumers and 19 low fish consumers. Results Both groups exhibited similar habitual dietary patterns, age and anthropometric characteristics. The high fish consumers had higher flow mediated dilation (9.7±1.8 vs. 7.3±1.9%; P<0.001), but also higher serum concentrations of mercury (5.87±2.69 vs. 1.65±1.10 mcg/L; P<0.001) and arsenic (6.04±3.25 vs. 2.30±1.58 mcg/L; P<0.001). The fasting plasma glucose concentrations were significantly correlated with both mercury (r = 0.39; P = 0.01) and arsenic concentrations (r = 0.55; P<0.001). Conclusions Habitual consumption of high amounts of fish is associated with better endothelial function despite higher serum concentrations of mercury and arsenic. PMID:25401695

Prediction of sub-surface 37Ar concentrations at locations in the Northwestern United States.

PubMed

Fritz, Bradley G; Aalseth, Craig E; Back, Henning O; Hayes, James C; Humble, Paul H; Ivanusa, Pavlo; Mace, Emily K

2018-01-01

The Comprehensive Nuclear-Test-Ban Treaty, which is intended to prevent nuclear weapon test explosions and any other nuclear explosions, includes a verification regime, which provides monitoring to identify potential nuclear explosions. The presence of elevated 37 Ar is one way to identify subsurface nuclear explosive testing. However, the naturally occurring formation of 37 Ar in the subsurface adds a complicating factor. Prediction of the naturally occurring concentration of 37 Ar can help to determine if a measured 37 Ar concentration is elevated relative to background. The naturally occurring 37 Ar background concentration has been shown to vary between less than 1 mBq/m 3 to greater than 100 mBq/m 3 (Riedmann and Purtschert, 2011). The purpose of this work was to enhance the understanding of the naturally occurring background concentrations of 37 Ar, allowing for better interpretation of results. To that end, we present and evaluate a computationally efficient model for predicting the average concentration of 37 Ar at any depth under transient barometric pressures. Further, measurements of 37 Ar concentrations in samples collected at multiple locations are provided as validation of the concentration prediction model. The model is shown to compare favorably with concentrations of 37 Ar measured at multiple locations in the Northwestern United States. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of Elevated CO2 on Trace Element Release from Aquifer Sediments of the San Joaquin Valley, CA

NASA Astrophysics Data System (ADS)

Fox, P. M.; Nico, P. S.; Davis, J. A.; Spycher, N.

2014-12-01

Carbon capture and storage (CCS) is a promising technique for mitigating climate change by storing large volumes of carbon dioxide in deep saline aquifers. In California, the thick marine sediments of the Central and Salinas Valleys have been identified as prime targets for future CO2 storage. However, the potential impacts on water quality of overlying drinking-water aquifers must be studied before CCS can be implemented. In this study, we compare trace element release from San Joaquin Valley aquifer sediments with a wide range of textural and redox properties. Kinetic batch experiments were performed with artificial groundwater continuously equilibrated under CO2-saturated (at 1 atm) and background CO2 (0.002-0.006 atm) conditions, resulting in a shift of nearly 3 pH units. In addition, the reversibility of trace element release was studied by sequentially lowering the CO2 from 1.0 atm to 0.5 atm to background concentrations (0.002-0.006 atm) for CO2-saturated systems in order to mimic the dissipation of a CO2 plume in the aquifer. During exposure to high CO2, a number of elements displayed enhanced release compared to background CO2 experiments (Ca, Mg, Li, Si, B, As, Sr, Ni, Fe, Mn, V, Ti, and Co) with concentrations of As, Fe, and Mn exceeding EPA maximum contaminant levels in some cases. On the other hand, Mo and U showed suppressed release. Most intriguing, many of the elements showing enhanced release displayed at least some degree of irreversibility when CO2 concentrations were decreased to background levels. In fact, in some cases (i.e., for V), an element showed further release when CO2 concentrations were decreased. These results suggest that there may be longer-term effects on groundwater quality that persist even after the CO2 plume has dissipated. Several different mechanisms of trace element release including ion exchange, desorption, and carbonate mineral dissolution are explored. Preliminary modeling results suggest that carbonate mineral dissolution can play a key role in driving trace element release even in sediments where carbonates are in low abundance.

Characterization and aerosol mass balance of PM2.5 and PM10 collected in Conakry, Guinea during the 2004 Harmattan period.

PubMed

Weinstein, Jason P; Hedges, Scott R; Kimbrough, Sue

2010-02-01

Background PM(2.5) and PM(10) levels were determined during Harmattan (West African wind blown dust) at a background site in Conakry, Guinea. The study was conducted from January to February, 2004 when Harmattan dust appeared to be most pronounced. PM(2.5) concentrations at the Nongo American housing compound ranged from 38mugm(-3) to 177mugm(-3), and PM(10) ranged from 80mugm(-3) to 358mugm(-3), exceeding standards set by EPA and European Commission Environment Directorate-General. PTFE filter samples were analyzed for insoluble and soluble inorganic constituents by XRF and IC, respectively. Sulfur and associated SO(4)(2-) concentrations were notably consistent among PM(2.5) and PM(10) samples which marked a relatively stable S background signal from anthropogenic sources. Enrichment factor (EF) analysis and aerosol mass reconstruction (AMR) techniques were used to isolate potential PM source contributors. The EF's for SiO(2), TiO(2), Al(2)O(3), Fe(2)O(3), and MnO were near unity which suggests a crustal origin for these elements. EF's for Na(2)O and K(2)O were above unity and highly variable, these elements were elevated due to widespread mangrove wood combustion as a fuel source in Conakry. The EF's for Cr were notably high with a median of 7 and interquartile range from 5 to 16, the elevated levels were attributed to unregulated point source and mobile source emitters in and around Conakry.

Vertical distributions of (99)Tc and the (99)Tc/(137)Cs activity ratio in the coastal water off Aomori, Japan.

PubMed

Nakanishi, Takahiro; Zheng, Jian; Aono, Tatsuo; Yamada, Masatoshi; Kusakabe, Masashi

2011-08-01

Using a sector-field ICP-MS the vertical distributions of the (99)Tc concentration and (99)Tc/(137)Cs activity ratio were measured in the coastal waters off Aomori Prefecture, Japan, where a spent-nuclear-fuel reprocessing plant has begun test operation. The (99)Tc concentrations in surface water ranged from 1.8 to 2.4 mBq/m(3), no greater than the estimated background level. Relatively high (99)Tc/(137)Cs activity ratios (10-12 × 10(-4)) would be caused by the inflow of the high-(99)Tc/(137)Cs water mass from the Japan Sea. There is no observable contamination from the reprocessing plant in the investigated area. The (99)Tc concentration and the (99)Tc/(137)Cs activity ratio in water column showed gradual decreases with depth. Our results implied that (99)Tc behaves in a more conservative manner than (137)Cs in marine environments. Copyright © 2011 Elsevier Ltd. All rights reserved.

Adsorption characteristics of selected pharmaceuticals and an endocrine disrupting compound-Naproxen, carbamazepine and nonylphenol-on activated carbon.

PubMed

Yu, Zirui; Peldszus, Sigrid; Huck, Peter M

2008-06-01

The adsorption of two representative pharmaceutically active compounds (PhACs) (naproxen and carbamazepine) and one endocrine disrupting compound (nonylphenol) were evaluated on two types of activated carbon. When determining their isotherms at environmentally relevant concentration levels, it was found that at this low concentration range (10-800 ng/L), removals of the target compounds were contrary to expectations based on their hydrophobicity. Nonylphenol (log K(ow) 5.8) was most poorly adsorbed, whereas carbamazepine (log K(ow) 2.45) was most adsorbable. Nonylphenol Freundlich isotherms at this very low concentration range had a much higher 1/n compared to isotherms at much higher concentrations. This indicates that extrapolation from an isotherm obtained at a high concentration range to predict the adsorption of nonylphenol at a concentration well below the range of the original isotherm, leads to a substantial overestimation of its removals. Comparison of isotherms for the target compounds to those for other conventional micropollutants suggested that naproxen and carbamazepine could be effectively removed by applying the same dosage utilized to remove odorous compounds (geosmin and MIB) at very low concentrations. The impact of competitive adsorption by background natural organic matter (NOM) on the adsorption of the target compounds was quantified by using the ideal adsorbed solution theory (IAST) in combination with the equivalent background compound (EBC) approach. The fulfilment of the requirements for applying the simplified IAST-EBC model, which leads to the conclusion that the percentage removal of the target compounds at a given carbon dosage is independent of the initial contaminant concentration, was confirmed for the situation examined in the paper. On this basis it is suggested that the estimated minimum carbon usage rates (CURs) to achieve 90% removal of these emerging contaminants would be valid at concentrations of less than 500 ng/L in natural water.

Background nuclei measurements and implications for cavitation inception in hydrodynamic test facilities

NASA Astrophysics Data System (ADS)

Venning, J. A.; Khoo, M. T.; Pearce, B. W.; Brandner, P. A.

2018-04-01

Water susceptibility and background nuclei content in a water tunnel are investigated using a cavitation susceptibility meter. The measured cumulative histogram of nuclei concentration against critical pressure shows a power law dependence over a large range of concentrations and pressures. These results show that the water strength is not characterised by a single tension but is susceptible to `all' tensions depending on the relevant timescale. This background nuclei population is invariant to tunnel conditions showing that it is stabilised against dissolution. Consideration of a practical cavitating flow about a sphere shows that although background nuclei may be activated, their numbers are so few compared with other sources that they are insignificant for this case.

Bioconcentration factors (BCF) of silver in wild Agaricus campestris

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

Falandysz, J.; Danisiewicz, D.

Silver is an element naturally occurring in small concentrations in different environmental sites. However, many anthropogenic sources of silver led to contamination of this element in soil surfaces, pastures, and coastal marine areas in different parts of the world. Estimates are that 40% of the 1.15x10{sup 4}t of silver produced annually worldwide, will escape into the environment. Due to municipal waste discharge and/or industrial effluents with high silver concentrations, 100 x above the background level have been reported in invertebrate species from polluted marine areas. The meta-stabile radioisotope, {sup 110m}Ag, is a main component of the liquid effluents from nuclearmore » facilities under normal operating conditions. The presence of {sup 111}Ag and {sup 110m}Ag also has been widely found throughout Europe in the 1986 Chernobyl fallout. Silver ions are environmentally harmful. High toxic effects have been observed at low concentrations, especially in aquatic species. Species of lower fungi as well as the mushroom Agaricus bisporus are know to bioaccumulate high concentrations of silver when grown on an artificially enriched substrate. This study looks at the relationship between the silver content of soil and bioconcentration potential of wild Agaricus campestris from sites under different use and with different concentrations of heavy metals. 28 refs., 2 figs., 2 tabs.« less

Mercury Pollution in Soils from the Yacuambi River (Ecuadorian Amazon) as a Result of Gold Placer Mining.

PubMed

López-Blanco, Charo; Collahuazo, Luis; Torres, Sandra; Chinchay, Luis; Ayala, Diana; Benítez, Paulina

2015-09-01

Gold mining is known to generate important economic products but also to produce several types of contamination/pollution. We report here the first data about Hg concentrations in the soils of the Yacuambi River in the Ecuadorian Amazon. We analyzed soil samples to assess the extent of contamination caused by gold placer mining in this area. Hg concentrations in soils exceeded the local background concentrations. High concentrations of Mn, As, Pb, Cr, Cu, Fe and Zn in some soil samples were probably derived from the geology of the site, which is rich in polysulfides and metamorphic rocks. Placer mining may accelerate the natural release of these elements to the environment by the exposure of the bedrock to the atmosphere. Accumulation of Hg in the river soils may be a potential source of toxicity for aquatic life and a risk to human health in the future.

Effect of home-used water purifier on fluoride concentration of drinking water in southern Iran

PubMed Central

Jaafari-Ashkavandi, Zohreh; Kheirmand, Mehdi

2013-01-01

Background: Fluoride in drinking water plays a key role in dental health. Due to the increasing use of water-purifier, the effect of these devices on fluoride concentration of drinking water was evaluated. Materials and Methods: Drinking water samples were collected before and after passing through a home water-purifier, from four different water sources. The fluoride, calcium and magnesium concentration of the samples were measured using the quantitative spectrophotometery technique. Data were analyzed by the Wilcoxon test. P value < 0.1 was considered as significant. Results: The result showed that the concentration of fluoride was 0.05-0.61 ppm before purification and was removed completely afterward. Furthermore, other ions reduced significantly after treatment by the water purifier. Conclusion: This study revealed that this device decreases the fluoride content of water, an issue which should be considered in low and high-fluoridated water sources. PMID:24130584

Progress toward accurate high spatial resolution actinide analysis by EPMA

NASA Astrophysics Data System (ADS)

Jercinovic, M. J.; Allaz, J. M.; Williams, M. L.

2010-12-01

High precision, high spatial resolution EPMA of actinides is a significant issue for geochronology, resource geochemistry, and studies involving the nuclear fuel cycle. Particular interest focuses on understanding of the behavior of Th and U in the growth and breakdown reactions relevant to actinide-bearing phases (monazite, zircon, thorite, allanite, etc.), and geochemical fractionation processes involving Th and U in fluid interactions. Unfortunately, the measurement of minor and trace concentrations of U in the presence of major concentrations of Th and/or REEs is particularly problematic, especially in complexly zoned phases with large compositional variation on the micro or nanoscale - spatial resolutions now accessible with modern instruments. Sub-micron, high precision compositional analysis of minor components is feasible in very high Z phases where scattering is limited at lower kV (15kV or less) and where the beam diameter can be kept below 400nm at high current (e.g. 200-500nA). High collection efficiency spectrometers and high performance electron optics in EPMA now allow the use of lower overvoltage through an exceptional range in beam current, facilitating higher spatial resolution quantitative analysis. The U LIII edge at 17.2 kV precludes L-series analysis at low kV (high spatial resolution), requiring careful measurements of the actinide M series. Also, U-La detection (wavelength = 0.9A) requires the use of LiF (220) or (420), not generally available on most instruments. Strong peak overlaps of Th on U make highly accurate interference correction mandatory, with problems compounded by the ThMIV and ThMV absorption edges affecting peak, background, and interference calibration measurements (especially the interference of the Th M line family on UMb). Complex REE bearing phases such as monazite, zircon, and allanite have particularly complex interference issues due to multiple peak and background overlaps from elements present in the activation volume, as well as interferences from fluorescence at a distance from adjacent phases or distinct compositional domains in the same phase. Interference corrections for elements detected during boundary fluorescence are further complicated by X-ray focusing geometry considerations. Additional complications arise from the high current densities required for high spatial resolution and high count precision, such as fluctuations in internal charge distribution and peak shape changes as satellite production efficiency varies from calibration to analysis. No flawless method has yet emerged. Extreme care in interference corrections, especially where multiple and sometime mutual overlaps are present, and maximum care (and precision) in background characterization to account for interferences and curvature (e.g., WDS scan or multipoint regression), are crucial developments. Calibration curves from multiple peak and interference calibration measurements at different concentrations, and iterative software methodologies for incorporating absorption edge effects, and non-linearities in interference corrections due to peak shape changes and off-axis X-ray defocussing during boundary fluorescence at a distance, are directions with significant potential.

Performance of a high-sensitivity dedicated cardiac SPECT scanner for striatal uptake quantification in the brain based on analysis of projection data

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

Park, Mi-Ae; Moore, Stephen C.; McQuaid, Sarah J.

Purpose: The authors have previously reported the advantages of high-sensitivity single-photon emission computed tomography (SPECT) systems for imaging structures located deep inside the brain. DaTscan (Isoflupane I-123) is a dopamine transporter (DaT) imaging agent that has shown potential for early detection of Parkinson disease (PD), as well as for monitoring progression of the disease. Realizing the full potential of DaTscan requires efficient estimation of striatal uptake from SPECT images. They have evaluated two SPECT systems, a conventional dual-head gamma camera with low-energy high-resolution collimators (conventional) and a dedicated high-sensitivity multidetector cardiac imaging system (dedicated) for imaging tasks related to PD.more » Methods: Cramer-Rao bounds (CRB) on precision of estimates of striatal and background activity concentrations were calculated from high-count, separate acquisitions of the compartments (right striata, left striata, background) of a striatal phantom. CRB on striatal and background activity concentration were calculated from essentially noise-free projection datasets, synthesized by scaling and summing the compartment projection datasets, for a range of total detected counts. They also calculated variances of estimates of specific-to-nonspecific binding ratios (BR) and asymmetry indices from these values using propagation of error analysis, as well as the precision of measuring changes in BR on the order of the average annual decline in early PD. Results: Under typical clinical conditions, the conventional camera detected 2 M counts while the dedicated camera detected 12 M counts. Assuming a normal BR of 5, the standard deviation of BR estimates was 0.042 and 0.021 for the conventional and dedicated system, respectively. For an 8% decrease to BR = 4.6, the signal-to-noise ratio were 6.8 (conventional) and 13.3 (dedicated); for a 5% decrease, they were 4.2 (conventional) and 8.3 (dedicated). Conclusions: This implies that PD can be detected earlier with the dedicated system than with the conventional system; therefore, earlier identification of PD progression should be possible with the high-sensitivity dedicated SPECT camera.« less

Air quality comparison between two European ceramic tile clusters

NASA Astrophysics Data System (ADS)

Minguillón, M. C.; Monfort, E.; Escrig, A.; Celades, I.; Guerra, L.; Busani, G.; Sterni, A.; Querol, X.

2013-08-01

The European ceramic tile industry is mostly concentrated in two clusters, one in Castelló (Spain) and another one in Modena (Italy). Industrial clusters may have problems to accomplish the EU air quality regulations because of the concentration of some specific pollutants and, hence, the feasibility of the industrial clusters can be jeopardised. The present work assesses the air quality in these ceramic clusters in 2008, when the new EU emission regulations where put into force. PM10 samples were collected at two sampling sites in the Modena ceramic cluster and one sampling site in the Castelló ceramic cluster. PM10 annual average concentrations were 12-14 μg m-3 higher in Modena than in Castelló, and were close to or exceeded the European limit. Air quality in Modena was mainly influenced by road traffic and, in a lower degree, the metalmechanical industry, as evidenced by the high concentrations of Mn, Cu, Zn, Sn and Sb registered. The stagnant weather conditions from Modena hindering dispersion of pollutants also contributed to the relatively high pollution levels. In Castelló, the influence of the ceramic industry is evidenced by the high concentrations of Ti, Se, Tl and Pb, whereas this influence is not seen in Modena. The difference in the impact of the ceramic industry on the air quality in the two areas was attributed to: better abatement systems in the spray-drier facilities in Modena, higher coverage of the areas for storage and handling of dusty raw materials in Modena, presence of two open air quarries in the Castelló region, low degree of abatement systems in the ceramic tile kilns in Castelló, and abundance of ceramic frit, glaze and pigment manufacture in Castelló as opposed to scarce manufacture of these products in Modena. The necessity of additional measures to fulfil the EU air quality requirements in the Modena region is evidenced, despite the high degree of environmental measures implemented in the ceramic industry. The Principal Component Analysis (PCA) identified four factors in Modena, attributed to: road traffic + metalmechanical industry, mineral, ceramic, and background; and three factors in Castelló, attributed to: mineral, ceramic (with influence of road traffic) and regional background. The additional measures to improve the air quality should be focused mainly on road traffic in Modena, and on the ceramic industry in Castelló.

Environmental and Body Concentrations of Heavy Metals at Sites Near and Distant from Industrial Complexes in Ulsan, Korea

PubMed Central

2017-01-01

Background Industrial pollution may affect the heavy metal body burden of people living near industrial complexes. We determined the average concentrations of atmospheric heavy metals in areas close to and distant from industrial complexes in Korea, and the body concentrations of these heavy metals in residents living near and distant from these facilities. Methods The atmospheric data of heavy metals (lead and cadmium) were from the Regional Air Monitoring Network in Ulsan. We recruited 1,148 participants, 872 who lived near an industrial complex (“exposed” group) and 276 who lived distant from industrial complexes (“non-exposed” group), and measured their concentrations of blood lead, urinary cadmium, and urinary total mercury. Results The results showed that atmospheric and human concentrations of heavy metals were higher in areas near industrial complexes. In addition, residents living near industrial complexes had higher individual and combined concentrations (cadmium + lead + mercury) of heavy metals. Conclusion We conclude that residents living near industrial complexes are exposed to high concentrations of heavy metals, and should be carefully monitored. PMID:29349943

THE COMPARATIVE MUTAGENIC EFFECT OF ETHYLENIMINE, ULTRAVIOLET AND X-RAYS (in Russian)

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

Alikhanyan, S.I.; Zhdanova, N.I.

1960-07-11

The mutagenic effects of ethylenimine were determined by the use of Actinomyces alivaceus (the product of B/sub 12/ vitamin) and compared with ultraviolet, and x ray effects. The spores were exposed to high concentrations of ethylenimine (solution of 1: 1000) for various times (30 min, 1, 2, 3, 4, and 5 hr) and to diluted concentrations (1: 3000, produced by short-time exposure to a concentrated solution; lethality at various treatments is nearly identical. The results of the comparison with ultraviolet and x rays indicate a large advantage in the use of ethylenimine. Curves of reverse mutation frequencies indicate prevailing frequenciesmore » of ethylenimine mutations over ultraviolet. This shows that regardless of genetic background changes. the advantages of ethylenimine are retained. (R.V.J.)« less

Search for Ultra-High-Energy Neutrinos with AMANDA-II

NASA Astrophysics Data System (ADS)

Ackermann, M.; Adams, J.; Ahrens, J.; Andeen, K.; Auffenberg, J.; Bai, X.; Baret, B.; Barwick, S. W.; Bay, R.; Beattie, K.; Becka, T.; Becker, J. K.; Becker, K.-H.; Beimforde, M.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Blaufuss, E.; Boersma, D. J.; Bohm, C.; Bolmont, J.; Böser, S.; Botner, O.; Bouchta, A.; Braun, J.; Burgess, T.; Castermans, T.; Chirkin, D.; Christy, B.; Clem, J.; Cowen, D. F.; D'Agostino, M. V.; Davour, A.; Day, C. T.; De Clercq, C.; Demirörs, L.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; DeYoung, T.; Diaz-Velez, J. C.; Dreyer, J.; Dumm, J. P.; Duvoort, M. R.; Edwards, W. R.; Ehrlich, R.; Eisch, J.; Ellsworth, R. W.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Filimonov, K.; Finley, C.; Foerster, M. M.; Fox, B. D.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Ganugapati, R.; Geenen, H.; Gerhardt, L.; Goldschmidt, A.; Goodman, J. A.; Gozzini, R.; Griesel, T.; Groß, A.; Grullon, S.; Gunasingha, R. M.; Gurtner, M.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Hardtke, D.; Hardtke, R.; Hasegawa, Y.; Hauschildt, T.; Heise, J.; Helbing, K.; Hellwig, M.; Herquet, P.; Hill, G. C.; Hodges, J.; Hoffman, K. D.; Hommez, B.; Hoshina, K.; Hubert, D.; Hughey, B.; Hülß, J.-P.; Hulth, P. O.; Hultqvist, K.; Hundertmark, S.; Inaba, M.; Ishihara, A.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Joseph, J. M.; Kampert, K.-H.; Kappes, A.; Karg, T.; Karle, A.; Kawai, H.; Kelley, J. L.; Kiryluk, J.; Kislat, F.; Kitamura, N.; Klein, S. R.; Klepser, S.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kuehn, K.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Lauer, R.; Leich, H.; Leier, D.; Liubarsky, I.; Lundberg, J.; Lünemann, J.; Madsen, J.; Maruyama, R.; Mase, K.; Matis, H. S.; McCauley, T.; McParland, C. P.; Meagher, K.; Meli, A.; Messarius, T.; Mészáros, P.; Miyamoto, H.; Montaruli, T.; Morey, A.; Morse, R.; Movit, S. M.; Münich, K.; Nahnhauer, R.; Nam, J. W.; Nießen, P.; Nygren, D. R.; Olivas, A.; Ono, M.; Patton, S.; Pérez de los Heros, C.; Piegsa, A.; Pieloth, D.; Pohl, A. C.; Porrata, R.; Pretz, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Razzaque, S.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Rizzo, A.; Robbins, S.; Robbins, W. J.; Roth, P.; Rothmaier, F.; Rott, C.; Roucelle, C.; Rutledge, D.; Ryckbosch, D.; Sander, H.-G.; Sarkar, S.; Satalecka, K.; Schlenstedt, S.; Schmidt, T.; Schneider, D.; Schultz, O.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, A. J.; Song, C.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stoufer, M. C.; Stoyanov, S.; Strahler, E. A.; Straszheim, T.; Sulanke, K.-H.; Sullivan, G. W.; Sumner, T. J.; Swillens, Q.; Taboada, I.; Tarasova, O.; Tepe, A.; Thollander, L.; Tilav, S.; Tluczykont, M.; Toale, P. A.; Tosi, D.; Turčan, D.; van Eijndhoven, N.; Vandenbroucke, J.; Van Overloop, A.; Viscomi, V.; Vogt, C.; Voigt, B.; Wagner, W.; Walck, C.; Waldmann, H.; Waldenmaier, T.; Walter, M.; Wang, Y.-R.; Wendt, C.; Wiebusch, C. H.; Wiedemann, C.; Wikström, G.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Woschnagg, K.; Xu, X. W.; Yodh, G.; Yoshida, S.; Zornoza, J. D.; IceCube Collaboration

2008-03-01

A search for diffuse neutrinos with energies in excess of 105 GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 107 GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra-high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrino flux of E2Φ90% CL < 2.7 × 10-7 GeV cm-2 s-1 sr-1 valid over the energy range of 2 × 105 to 109 GeV. A number of models that predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.

Determination of the activity concentration levels of the artificial radionuclide137Cs in soil samples collected from Qatar using high-resolution gamma-ray spectrometry

NASA Astrophysics Data System (ADS)

Al-Sulaiti, Huda; Nasir, Tabassum; Al Mugren, K. S.; Alkhomashi, N.; Al-Dahan, N.; Al-Dosari, M.; Bradley, D. A.; Bukhari, S.; Regan, P. H.; Santawamaitre, T.; Malain, D.; Habib, A.; Al-Dosari, Hanan; Daar, Eman

2016-09-01

The goal of this study was to establish the first baseline measurements for radioactivity concentration of the artificial radionuclide 137Cs in soil samples collected from the Qatarian peninsula. The work focused on the determination of the activity concentrations levels of man-made radiation in 129 soil samples collected across the landscape of the State of Qatar. All the samples were collected before the most recent accident in Japan, “the 2011 Fukushima Dai-ichi nuclear power plant accident”. The activity concentrations have been measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector situated in a low-background environment with a copper inner-plated passive lead shield. A radiological map showing the activity concentrations of 137Cs is presented in this work. The concentration wasfound to range from 0.21 to 15.41 Bq/kg. The highest activity concentration of 137Cs was observed in sample no. 26 in North of Qatar. The mean value was found to be around 2.15 ± 0.27 Bq/kg. These values lie within the expected range relative to the countries in the region. It is expected that this contamination is mainly due to the Chernobyl accident on 26 April 1986, but this conclusion cannot be confirmed because of the lack of data before this accident.

Clues on the origin of post-2000 earthquakes at Campi Flegrei caldera (Italy).

PubMed

Chiodini, G; Selva, J; Del Pezzo, E; Marsan, D; De Siena, L; D'Auria, L; Bianco, F; Caliro, S; De Martino, P; Ricciolino, P; Petrillo, Z

2017-06-30

The inter-arrival times of the post 2000 seismicity at Campi Flegrei caldera are statistically distributed into different populations. The low inter-arrival times population represents swarm events, while the high inter-arrival times population marks background seismicity. Here, we show that the background seismicity is increasing at the same rate of (1) the ground uplift and (2) the concentration of the fumarolic gas specie more sensitive to temperature. The seismic temporal increase is strongly correlated with the results of recent simulations, modelling injection of magmatic fluids in the Campi Flegrei hydrothermal system. These concurrent variations point to a unique process of temperature-pressure increase of the hydrothermal system controlling geophysical and geochemical signals at the caldera. Our results thus show that the occurrence of background seismicity is an excellent parameter to monitor the current unrest of the caldera.

Attention Drainage Effect: How Background Music Effects Concentration in Taiwanese College Students

ERIC Educational Resources Information Center

Chou, Peter Tze-Ming

2010-01-01

The purpose of this study was to see whether different types of background music affect the performance of a reading comprehension task in Taiwanese college students. There are two major research questions in this study. First, this study tries to find out whether listening to music affect the learner's concentration when they are doing a task…

Improving Air Pollution Modeling Over The Po Valley Using Saharan Dust Transport Forecasts

NASA Astrophysics Data System (ADS)

Kishcha, P.; Carnevale, C.; Finzi, G.; Pisoni, E.; Volta, M.; Nickovic, S.; Alpert, P.

2012-04-01

Our study shows that Saharan dust can contribute significantly to PM10 concentrations in the Po Valley. This dust contribution should be taken into account when estimating the exceedance of pollution limits. The DREAM dust model has been used for several years for producing operational dust forecasts at Tel-Aviv University, Israel. DREAM has been producing daily forecasts of 3-D distribution of dust concentrations over the Mediterranean region, Middle East, Europe, and over the Atlantic Ocean (http://wind.tau.ac.il/dust8/dust.html). In the current study, DREAM dust forecasts were used to give better model estimates of the contribution of Saharan dust to PM10 concentration over the Po Valley, in Northern Italy. This was carried out by the integration of daily Saharan dust forecasts into a mesoscale Transport Chemical Aerosol Model (TCAM). The Po Valley in Northern Italy is frequently affected by high PM10 concentrations, where both natural and anthropogenic sources play a significant role. Our study of TCAM and DREAM integration was carried out for the period May 15 - June 30, 2007, when four significant dust events were observed. The integrated TCAM-DREAM model performance was evaluated by comparing PM10 measurements with modeled PM10 concentrations. First, Saharan dust impact on TCAM performance was analyzed at eleven remote PM10 sites which had the lowest level of air pollution (PM10 ≤ 14 μg/m3) over the period under consideration. For those remote sites, the observed high PM10 concentrations during dust events stood prominently on the background of low PM10 concentrations. At the remote sites, such a strong deviation from the background level can not be attributed to anthropogenic aerosol emissions because of their distance from anthropogenic sources. The observed maxima in PM10 concentration during dust events is evidence of dust aerosol near the surface in Northern Italy. During all dust events under consideration, the integrated TCAM-DREAM model produced more accurate PM10 concentrations than the base TCAM model. Then, a comparison between modeled concentrations and PM10 measurements was carried out at 230 PM10 monitoring sites, distributed within the model domain. This model-vs.-measurement comparison showed that the integrated TCAM -DREAM model more accurately reproduced PM10 concentrations than the base TCAM model, both in term of correlation and mean error. Our results are of importance to countries which have to pay a penalty for exceeding the pollution limit. By extracting dust contribution from PM10 measurements, these countries could show lower rates of man-made pollution.

Flooding event impacts soil pH, Ca, and P concentration distribution in a cattle backgrounding site on karst topography.

USDA-ARS?s Scientific Manuscript database

Beef cattle backgrounding in US, function as an intermediate between cow-calf enterprises and feedlot finishing. Beef cattle backgrounding receives weaned calves of different growth stages from cow-calf operations and prepare them ready for feed lot finishing. Many beef cattle backgrounding operati...

Multiplex Degenerate Primer Design for Targeted Whole Genome Amplification of Many Viral Genomes

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

Gardner, Shea N.; Jaing, Crystal J.; Elsheikh, Maher M.

Background . Targeted enrichment improves coverage of highly mutable viruses at low concentration in complex samples. Degenerate primers that anneal to conserved regions can facilitate amplification of divergent, low concentration variants, even when the strain present is unknown. Results . A tool for designing multiplex sets of degenerate sequencing primers to tile overlapping amplicons across multiple whole genomes is described. The new script, run_tiled_primers, is part of the PriMux software. Primers were designed for each segment of South American hemorrhagic fever viruses, tick-borne encephalitis, Henipaviruses, Arenaviruses, Filoviruses, Crimean-Congo hemorrhagic fever virus, Rift Valley fever virus, and Japanese encephalitis virus. Eachmore » group is highly diverse with as little as 5% genome consensus. Primer sets were computationally checked for nontarget cross reactions against the NCBI nucleotide sequence database. Primers for murine hepatitis virus were demonstrated in the lab to specifically amplify selected genes from a laboratory cultured strain that had undergone extensive passage in vitro and in vivo. Conclusions . This software should help researchers design multiplex sets of primers for targeted whole genome enrichment prior to sequencing to obtain better coverage of low titer, divergent viruses. Applications include viral discovery from a complex background and improved sensitivity and coverage of rapidly evolving strains or variants in a gene family.« less

NATURAL RADIOACTIVITY LEVEL AND ELEMENTAL COMPOSITION OF SOIL SAMPLES FROM A HIGH BACKGROUND RADIATION AREA ON EASTERN COAST OF INDIA (ODISHA).

PubMed

Sahoo, S K; Kierepko, R; Sorimachi, A; Omori, Y; Ishikawa, T; Tokonami, S; Prasad, G; Gusain, G S; Ramola, R C

2016-10-01

A comprehensive study was carried out to determine the radioactivity concentration of soil samples from different sites of a high background radiation area in the eastern coast of India, Odisha state. The dose rate measured in situ varied from 0.25 to 1.2 µSv h -1 The gamma spectrometry measurements indicated Th series elements as the main contributors to the enhanced level of radiation and allowed the authors to find the mean level of the activity concentration (±SD) for 226 Ra, 228 Th and 40 K as 130±97, 1110±890 and 360±140 Bq kg -1 , respectively. Human exposure from radionuclides occurring outdoor was estimated based on the effective dose rate, which ranged from 0.14±0.02 to 2.15±0.26 mSv and was higher than the UNSCEAR annual worldwide average value 0.07 mSv. Additionally, X-ray fluorescence analysis provided information about the content of major elements in samples and indicated the significant amount of Ti (7.4±4.9 %) in soils. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Multiplex Degenerate Primer Design for Targeted Whole Genome Amplification of Many Viral Genomes

DOE PAGES

Gardner, Shea N.; Jaing, Crystal J.; Elsheikh, Maher M.; ...

2014-01-01

Background . Targeted enrichment improves coverage of highly mutable viruses at low concentration in complex samples. Degenerate primers that anneal to conserved regions can facilitate amplification of divergent, low concentration variants, even when the strain present is unknown. Results . A tool for designing multiplex sets of degenerate sequencing primers to tile overlapping amplicons across multiple whole genomes is described. The new script, run_tiled_primers, is part of the PriMux software. Primers were designed for each segment of South American hemorrhagic fever viruses, tick-borne encephalitis, Henipaviruses, Arenaviruses, Filoviruses, Crimean-Congo hemorrhagic fever virus, Rift Valley fever virus, and Japanese encephalitis virus. Eachmore » group is highly diverse with as little as 5% genome consensus. Primer sets were computationally checked for nontarget cross reactions against the NCBI nucleotide sequence database. Primers for murine hepatitis virus were demonstrated in the lab to specifically amplify selected genes from a laboratory cultured strain that had undergone extensive passage in vitro and in vivo. Conclusions . This software should help researchers design multiplex sets of primers for targeted whole genome enrichment prior to sequencing to obtain better coverage of low titer, divergent viruses. Applications include viral discovery from a complex background and improved sensitivity and coverage of rapidly evolving strains or variants in a gene family.« less

Polychlorinated biphenyls (PCBs) in air and soil from a high-altitude pasture in the Italian Alps: evidence of CB-209 contamination.

PubMed

Tremolada, Paolo; Guazzoni, Niccolò; Comolli, Roberto; Parolini, Marco; Lazzaro, Serena; Binelli, Andrea

2015-12-01

This study analyses the seasonal trend of polychlorinated biphenyls (PCB) concentrations in air and soil from a high-altitude mountain pasture in the Italian Alps. PCB concentrations in soil were generally comparable to background levels and were lower than those previously measured in the same area. Only CB-209 unexpectedly showed high concentrations with respect to the other congeners. GC-MS-MS identification was very clear, rising a new problem of increasing PCB contamination concerning only CB-209, which is not present in commercial mixtures used in the past in Italy and Europe. Considering all of the congeners, seasonal PCB trends were observed both in air and in soil that were related to the temperature and precipitation measured specifically in the study area. Highly significant relationships were found between the temperature-normalised concentrations in soil and the precipitation amounts. A north/south enrichment factor was present only in soil with rapid early summer re-volatilisation kinetics from soil to air and autumn re-deposition events from air to soil. Fugacity ratio calculations confirmed these trends. Surface soils respond rapidly to meteorological variables, while subsurface soils respond much more slowly. Seasonal trends were different for the northern and southern sides of the mountain. A detailed picture of the interactions among temperature, precipitation, mountain aspects and soil features was obtained.

High concentrations of heavy metals in PM from ceramic factories of Southern Spain

NASA Astrophysics Data System (ADS)

Sánchez de la Campa, Ana M.; de la Rosa, Jesús D.; González-Castanedo, Yolanda; Fernández-Camacho, Rocío; Alastuey, Andrés; Querol, Xavier; Pio, Casimiro

2010-06-01

In this study, physicochemical characterization of Atmospheric Particulate Matter (PM) was performed in an urban-industrial site background (Bailén, Southern Spain), highly influenced by the impact of emission plumes from ceramic factories. This area is considered one of the towns with the highest PM 10 levels and average SO 2 concentration in Spain. A three stages methodology was used: 1) real-time measurements of levels of PM 10 and gaseous pollutants, and sampling of PM; 2) chemical characterization using ICP-MS, ICP-OES, CI and TOT, and source apportionment analysis (receptor modelling) of PM; and 3) chemical characterization of emission plumes derived from representative factories. High ambient air concentrations were found for most major components and trace elements compared with other industrialized towns in Spain. V and Ni are considered fingerprints of PM derived from the emissions of brick factories in this area, and were shown to be of particular interest. This highlights the high V and Ni concentrations in PM 10 (122 ngV/m 3 and 23.4 ngNi/m 3), with Ni exceeding the 2013 annual target value for the European Directive 2004/107/EC (20 ng/m 3). The methodology of this work can be used by Government departments responsible for Environment and Epidemiology in planning control strategies for improving air quality.

An exploration hydrogeochemical study at the giant Pebble porphyry Cu-Au-Mo deposit, Alaska, USA, using high-resolution ICP-MS

USGS Publications Warehouse

Eppinger, Robert G.; Fey, David L.; Giles, Stuart A.; Kelley, Karen D.; Smith, Steven M.

2012-01-01

A hydrogeochemical study using high resolution ICP-MS was undertaken at the giant Pebble porphyry Cu-Au-Mo deposit and surrounding mineral occurrences. Surface water and groundwater samples from regional background and the deposit area were collected at 168 sites. Rigorous quality control reveals impressive results at low nanogram per litre (ng/l) levels. Sites with pH values below 5.1 are from ponds in the Pebble West area, where sulphide-bearing rubble crop is thinly covered. Relative to other study area waters, anomalous concentrations of Cu, Cd, K, Ni, Re, the REE, Tl, SO42− and F− are present in water samples from Pebble West. Samples from circum-neutral waters at Pebble East and parts of Pebble West, where cover is much thicker, have anomalous concentrations of Ag, As, In, Mn, Mo, Sb, Th, U, V, and W. Low-level anomalous concentrations for most of these elements were also found in waters surrounding nearby porphyry and skarn mineral occurrences. Many of these elements are present in low ng/l concentration ranges and would not have been detected using traditional quadrupole ICP-MS. Hydrogeochemical exploration paired with high resolution ICP-MS is a powerful new tool in the search for concealed deposits.

Tissue distribution of metals in white-fronted geese and spot-billed ducks from Korea.

PubMed

Kim, Jungsoo; Oh, Jong-Min

2013-07-01

This study presents concentrations of Fe, Zn, Mn, Cu, Pb and Cd in livers, kidneys, muscles and bones of white-fronted geese Anser albifrons (geese) and spot-billed ducks Anas poecilorhyncha (ducks). Iron in livers, kidneys and muscles, Zn in muscles, Mn and Cd in every tissue, Cu in livers, muscles and bones and Pb in bones differed between species, and there were significant differences among tissues in both species. Essential elements such as Fe, Zn, Mn and Cu concentrations were within the background levels. Lead concentrations in livers of 7 of 14 geese and 7 of 19 ducks and in bones of 4 of 19 ducks exceeded background concentrations for waterfowl (5 μg/g dw for the liver, 10 μg/g dw for the bone). Almost all samples of both species had the background Cd concentrations in the liver (33 of 33 geese and ducks) and kidney (14 geese and 18 ducks). Tissue concentrations of Cd were greater in geese than ducks. In contrast, tissue concentrations of Pb in bones were greater in ducks than in geese. These different trends for Cd and Pb reflect a short and/or long term difference in exposure and degree of accumulation of these metals.

Evaluation of VOC concentrations in indoor and outdoor microenvironments at near-road schools.

PubMed

Raysoni, Amit U; Stock, Thomas H; Sarnat, Jeremy A; Chavez, Mayra C; Sarnat, Stefanie Ebelt; Montoya, Teresa; Holguin, Fernando; Li, Wen-Whai

2017-12-01

A 14-week air quality study, characterizing the indoor and outdoor concentrations of 18 VOCs at four El Paso, Texas elementary schools, was conducted in Spring 2010. Three schools were in an area of high traffic density and the fourth school, considered as a background school, was situated in an area affected minimally by stationary and mobile sources of air pollution. Passive samplers were deployed for monitoring and analyzed by GC/MS. Differences in the concentration profiles of the BTEX species between the high and low traffic density schools confirmed the pre-defined exposure patterns. Toluene was the predominant compound within the BTEX group and the 96-hr average outdoor concentrations varied from 1.16 to 4.25 μg/m 3 across the four schools. Outdoor BTEX species were strongly correlated with each other (0.63 < r < 1.00, p < 0.05) suggesting a common source: vehicular traffic emissions. As expected, the strength of the associations between these compounds was more intense at each of the three high-exposure schools in contrast to the low-exposure school. This was further corroborated by the results obtained from the BTEX inter-species ratios (toluene: benzene and m, p- xylenes: ethylbenzene). Certain episodic events during the study period resulted in very elevated concentrations of some VOCs such as n-pentane. Indoor concentration of compounds with known indoor sources such as α -pinene, d-limonene, p-dichlorobenzene, and chloroform were generally higher than their corresponding outdoor concentrations. Cleaning agents, furniture polishes, materials used in arts and crafts activities, hot-water usage, and deodorizing cakes used in urinal pots were the likely major sources for these high indoor concentrations. Finally, retrospective assessment of average ambient BTEX concentrations over the last twenty years suggest a gradual decrement in this border region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cancer and Blood Concentrations of the Co-mutagen Harmane in Essential Tremor

PubMed Central

Louis, Elan D.; Pellegrino, Kathryn M.; Factor-Litvak, Pam; Rios, Eileen; Jiang, Wendy; Henchcliffe, Claire; Zheng, Wei

2008-01-01

Background Blood concentrations of harmane, a tremor-producing neurotoxin, are elevated in essential tremor (ET). Harmane is also a co-mutagen. Objective To compare the prevalence of cancer in ET cases vs. controls, and determine whether blood harmane concentrations are elevated among ET cases with cancer. Methods Case-control design. Results 66/267 (24.7%) ET cases vs. 55/331 (16.6%) controls had cancer (adjusted OR 1.52, 95% CI 1.01 – 2.30, p = 0.04). Among specific cancer types, colon cancer was more prevalent in ET cases than controls (2.6% vs. 0.6%, p = 0.04). Log blood harmane concentration was higher in ET cases vs. controls (p = 0.02) and in participants with vs. without cancer (p = 0.02). Log blood harmane concentration was highest in ET cases with cancer when compared with other groups (p = 0.009). Discussion These links between cancer and ET and between high blood harmane and cancer in ET deserve further study. PMID:18709680

PB-210 concentrations in cigarettes tobaccos and radiation doses to the smokers.

PubMed

Tahir, S N A; Alaamer, A S

2008-01-01

Cigarette smoking is a source of radiation exposure due to the concentrations of natural radionuclides in the tobacco leaves. From the health point of view, measurement of (210)Pb and (210)Po contents in cigarette tobacco is important to assess the radiological effects associated with the tobacco smoking for the smokers. In the present study, activity concentrations of (210)Pb, which is a (210)Po precursor in the (238)U-decay series, were measured in cigarette tobaccos. Samples of nine different commonly sold brands of cigarette tobaccos were analysed by employing a planar high purity germanium (HPGe) low background detector. Activity concentrations of (210)Pb were measured from its gamma peak at 47 keV. Mean activity concentration of (210)Pb was measured to be 13 +/- 4 Bq kg(-1) from all samples analysed. The annual committed effective dose for a smoker and the collective committed effective dose corresponding to annual cigarettes production were estimated to be 64 +/- 20 microSv and 0.6 x 10(2) man-Sv, respectively.

Comparison of optimised germanium gamma spectrometry and multicollector inductively coupled plasma mass spectrometry for the determination of 134Cs, 137Cs and 154Eu single ratios in highly burnt UO 2

NASA Astrophysics Data System (ADS)

Caruso, S.; Günther-Leopold, I.; Murphy, M. F.; Jatuff, F.; Chawla, R.

2008-05-01

Non-destructive and destructive methods have been compared to validate their corresponding assessed accuracies in the measurement of 134Cs/137Cs and 154Eu/137Cs isotopic concentration ratios in four spent UO2 fuel samples with very high (52 and 71 GWd/t) and ultra-high (91 and 126 GWd/t) burnup values, and about 10 (in the first three samples) and 4 years (in the latter sample) cooling time. The non-destructive technique tested was high-resolution gamma spectrometry using a high-purity germanium detector (HPGe) and a special tomographic station for the handling of highly radioactive 400 mm spent fuel segments that included a tungsten collimator, lead filter (to enhance the signal to Compton background ratio and reduce the dead time) and paraffin wax (to reduce neutron damage). The non-destructive determination of these isotopic concentration ratios has been particularly challenging for these segments because of the need to properly derive non-Gaussian gamma-peak areas and subtract the background from perturbing capture gammas produced by the intrinsic high-intensity neutron emissions from the spent fuel. Additionally, the activity distribution within each pin was determined tomographically to correct appropriately for self-attenuation and geometrical effects. The ratios obtained non-destructively showed a 1σ statistical error in the range 1.9-2.9%. The destructive technique used was a high-performance liquid chromatographic separation system, combined online to a multicollector inductively coupled plasma mass spectrometer (HPLC-MC-ICP-MS), for the analysis of dissolved fuel solutions. During the mass spectrometric analyses, special care was taken in the optimisation of the chromatographic separation for Eu and the interfering element Gd, as also in the mathematical correction of the 154Gd background from the 154Eu signal. The ratios obtained destructively are considerably more precise (1σ statistical error in the range 0.4-0.8% for most of the samples, but up to 2.8% for one sample). The HPGe gamma spectrometry can achieve a high degree of accuracy (agreement with HPLC-MC-ICP-MS within a few percent), only by virtue of the optimised setup, and the refined measurement strategy and data treatment employed.

Simplified production and concentration of HIV-1-based lentiviral vectors using HYPERFlask vessels and anion exchange membrane chromatography

PubMed Central

Kutner, Robert H; Puthli, Sharon; Marino, Michael P; Reiser, Jakob

2009-01-01

Background During the past twelve years, lentiviral (LV) vectors have emerged as valuable tools for transgene delivery because of their ability to transduce nondividing cells and their capacity to sustain long-term transgene expression in target cells in vitro and in vivo. However, despite significant progress, the production and concentration of high-titer, high-quality LV vector stocks is still cumbersome and costly. Methods Here we present a simplified protocol for LV vector production on a laboratory scale using HYPERFlask vessels. HYPERFlask vessels are high-yield, high-performance flasks that utilize a multilayered gas permeable growth surface for efficient gas exchange, allowing convenient production of high-titer LV vectors. For subsequent concentration of LV vector stocks produced in this way, we describe a facile protocol involving Mustang Q anion exchange membrane chromatography. Results Our results show that unconcentrated LV vector stocks with titers in excess of 108 transduction units (TU) per ml were obtained using HYPERFlasks and that these titers were higher than those produced in parallel using regular 150-cm2 tissue culture dishes. We also show that up to 500 ml of an unconcentrated LV vector stock prepared using a HYPERFlask vessel could be concentrated using a single Mustang Q Acrodisc with a membrane volume of 0.18 ml. Up to 5.3 × 1010 TU were recovered from a single HYPERFlask vessel. Conclusion The protocol described here is easy to implement and should facilitate high-titer LV vector production for preclinical studies in animal models without the need for multiple tissue culture dishes and ultracentrifugation-based concentration protocols. PMID:19220915

Aerosol accumulation intensity and composition variations under different weather conditions in urban environment

NASA Astrophysics Data System (ADS)

Steinberga, Iveta; Bikshe, Janis; Eindorfa, Aiva

2014-05-01

During the last decade aerosol (PM10, PM2.5) mass and composition measurements were done in different urban environments - parallel street canyons, industrial sites and at the background level in Riga, Latvia. Effect of meteorological parameters on the accumulation and ventilation intensity was investigated in order to understand microclimatological parameters affecting aerosol pollution level and chemical composition changes. In comparison to industrial sites (shipping activities, bulk cargo, oil and naphtha processing), urban street canyon aerosol mass concentration was significantly higher, for PM10 number of daily limit exceedances are higher by factor 3.4 - 3.9 in street canyons. Exceedances of PM2.5 annual limits were identified only in street canyons as well. Precipitation intensity, wind speed, days with mist highly correlates with aerosol concentration; in average during the year about 1 - 2 % presence of calm wind days, 20 - 30 days with mist facilitate accumulation of aerosols and mitigating growing of secondary aerosols. It has been assessed that about 25 % of daily exceedances in street canyons are connected with sea salt/street sanding factor. Strong dependency of wind speed and direction were identified in winter time - low winds (0.4 - 1.7 m/s) blowing from south, south-east (cross section of the street) contributing to PM10 concentrations over 100 - 150 ug/m3. Seasonal differences in aerosol concentrations were identified as a result of recombination of direct source impact, specific meteorological and synoptical conditions during the period from January until April when usually dominates extremely high aerosol concentrations. While aerosol mass concentration levels in monitoring sites significantly differs, concentrations of heavy metals (Pb, Ni, Cd, and As) are almost at the same level, even more - concentration of Cd for some years was higher in industrial area where main pollution is caused by oil processing and storage, heavy traffic activities and transportation by rail. The type of prevailing secondary aerosol formation was estimated by linear regression analysis which shows NOx prevalence in street canyons and urban background and SO2 associated reactions in industrial sites. Linear regression of traffic intensity in connection with aerosol pollution level shows domination of exhaust emissions during traffic jams and resuspension intensity during middle of the week.

Ions in motor vehicle exhaust and their dispersion near busy roads

NASA Astrophysics Data System (ADS)

Jayaratne, E. R.; Ling, X.; Morawska, L.

2010-09-01

Measurements in the exhaust plume of a petrol-driven motor car showed that molecular cluster ions of both signs were present in approximately equal amounts. The emission rate increased sharply with engine speed while the charge symmetry remained unchanged. Measurements at the kerbside of nine motorways and five city roads showed that the mean total cluster ion concentration near city roads (603 cm -3) was about one-half of that near motorways (1211 cm -3) and about twice as high as that in the urban background (269 cm -3). Both positive and negative ion concentrations near a motorway showed a significant linear increase with traffic density ( R2 = 0.3 at p < 0.05) and correlated well with each other in real time ( R2 = 0.87 at p < 0.01). Heavy duty diesel vehicles comprised the main source of ions near busy roads. Measurements were conducted as a function of downwind distance from two motorways carrying around 120-150 vehicles per minute. Total traffic-related cluster ion concentrations decreased rapidly with distance, falling by one-half from the closest approach of 2 m to 5 m of the kerb. Measured concentrations decreased to background at about 15 m from the kerb when the wind speed was 1.3 m s -1, this distance being greater at higher wind speed. The number and net charge concentrations of aerosol particles were also measured. Unlike particles that were carried downwind to distances of a few hundred metres, cluster ions emitted by motor vehicles were not present at more than a few tens of metres from the road.

Drug Concentration Thresholds Predictive of Therapy Failure and Death in Children With Tuberculosis: Bread Crumb Trails in Random Forests

PubMed Central

Swaminathan, Soumya; Pasipanodya, Jotam G.; Ramachandran, Geetha; Hemanth Kumar, A. K.; Srivastava, Shashikant; Deshpande, Devyani; Nuermberger, Eric; Gumbo, Tawanda

2016-01-01

Background. The role of drug concentrations in clinical outcomes in children with tuberculosis is unclear. Target concentrations for dose optimization are unknown. Methods. Plasma drug concentrations measured in Indian children with tuberculosis were modeled using compartmental pharmacokinetic analyses. The children were followed until end of therapy to ascertain therapy failure or death. An ensemble of artificial intelligence algorithms, including random forests, was used to identify predictors of clinical outcome from among 30 clinical, laboratory, and pharmacokinetic variables. Results. Among the 143 children with known outcomes, there was high between-child variability of isoniazid, rifampin, and pyrazinamide concentrations: 110 (77%) completed therapy, 24 (17%) failed therapy, and 9 (6%) died. The main predictors of therapy failure or death were a pyrazinamide peak concentration <38.10 mg/L and rifampin peak concentration <3.01 mg/L. The relative risk of these poor outcomes below these peak concentration thresholds was 3.64 (95% confidence interval [CI], 2.28–5.83). Isoniazid had concentration-dependent antagonism with rifampin and pyrazinamide, with an adjusted odds ratio for therapy failure of 3.00 (95% CI, 2.08–4.33) in antagonism concentration range. In regard to death alone as an outcome, the same drug concentrations, plus z scores (indicators of malnutrition), and age <3 years, were highly ranked predictors. In children <3 years old, isoniazid 0- to 24-hour area under the concentration-time curve <11.95 mg/L × hour and/or rifampin peak <3.10 mg/L were the best predictors of therapy failure, with relative risk of 3.43 (95% CI, .99–11.82). Conclusions. We have identified new antibiotic target concentrations, which are potential biomarkers associated with treatment failure and death in children with tuberculosis. PMID:27742636

Accuracy of Rhenium-188 SPECT/CT activity quantification for applications in radionuclide therapy using clinical reconstruction methods.

PubMed

Esquinas, Pedro L; Uribe, Carlos F; Gonzalez, M; Rodríguez-Rodríguez, Cristina; Häfeli, Urs O; Celler, Anna

2017-07-20

The main applications of 188 Re in radionuclide therapies include trans-arterial liver radioembolization and palliation of painful bone-metastases. In order to optimize 188 Re therapies, the accurate determination of radiation dose delivered to tumors and organs at risk is required. Single photon emission computed tomography (SPECT) can be used to perform such dosimetry calculations. However, the accuracy of dosimetry estimates strongly depends on the accuracy of activity quantification in 188 Re images. In this study, we performed a series of phantom experiments aiming to investigate the accuracy of activity quantification for 188 Re SPECT using high-energy and medium-energy collimators. Objects of different shapes and sizes were scanned in Air, non-radioactive water (Cold-water) and water with activity (Hot-water). The ordered subset expectation maximization algorithm with clinically available corrections (CT-based attenuation, triple-energy window (TEW) scatter and resolution recovery was used). For high activities, the dead-time corrections were applied. The accuracy of activity quantification was evaluated using the ratio of the reconstructed activity in each object to this object's true activity. Each object's activity was determined with three segmentation methods: a 1% fixed threshold (for cold background), a 40% fixed threshold and a CT-based segmentation. Additionally, the activity recovered in the entire phantom, as well as the average activity concentration of the phantom background were compared to their true values. Finally, Monte-Carlo simulations of a commercial [Formula: see text]-camera were performed to investigate the accuracy of the TEW method. Good quantification accuracy (errors  <10%) was achieved for the entire phantom, the hot-background activity concentration and for objects in cold background segmented with a 1% threshold. However, the accuracy of activity quantification for objects segmented with 40% threshold or CT-based methods decreased (errors  >15%), mostly due to partial-volume effects. The Monte-Carlo simulations confirmed that TEW-scatter correction applied to 188 Re, although practical, yields only approximate estimates of the true scatter.

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.

Higher Blood Harmane (1-Methyl-9h-Pyrido[3,4-B]Indole) Concentrations Correlate With Lower Olfactory Scores In Essential Tremor

PubMed Central

Louis, Elan D.; Rios, Eileen; Pellegrino, Kathryn M.; Jiang, Wendy; Factor-Litvak, Pam; Zheng, Wei

2008-01-01

Background Harmane (1-methyl-9H-pyrido[3,4-b]indole), a neurotoxin, may be an environmental risk factor for essential tremor (ET). Harmane and related chemicals are toxic to the cerebellum. Whether it is through this mechanism (cerebellar toxicity) that harmane leads to ET is unknown. Impaired olfaction may be a feature of cerebellar disease. Objective To determine whether blood harmane concentrations correlate with olfactory test scores in patients with ET. Methods Blood harmane concentrations were quantified using high performance liquid chromatography. Odor identification testing was performed with the University of Pennsylvania Smell Identification Test (UPSIT). Results In 83 ET cases, higher log blood harmane concentration was correlated with lower UPSIT score (rho = −0.46, p < 0.001). 25/40 (62.5%) cases with high log blood harmane concentration (based on a median split) had low UPSIT scores (based on a median split) vs. 12/43 (27.9%) ET cases with low log blood harmane concentration (adjusted OR 4.04, 95% CI 1.42 – 11.50, p = 0.009). When compared with the low log blood harmane tertile, the odds of olfactory dysfunction were 2.64 times higher in cases in the middle tertile and 10.95 times higher in cases in the high tertile. In 69 control subjects, higher log blood harmane concentration was not correlated with lower UPSIT score (rho = 0.12, p = 0.32). Conclusions Blood harmane concentrations were correlated with UPSIT scores in ET cases but not controls. These analyses set the stage for postmortem studies to further explore the role of harmane as a cerebellar toxin in ET. PMID:18417221

Human skeletal muscle ascorbate is highly responsive to changes in vitamin C intake and plasma concentrations123

PubMed Central

Bozonet, Stephanie M; Pullar, Juliet M; Simcock, Jeremy W; Vissers, Margreet CM

2013-01-01

Background: Vitamin C (ascorbate) is likely to be essential for skeletal muscle structure and function via its role as an enzyme cofactor for collagen and carnitine biosynthesis. Vitamin C may also protect these metabolically active cells from oxidative stress. Objective: We investigated the bioavailability of vitamin C to human skeletal muscle in relation to dietary intake and plasma concentrations and compared this relation with ascorbate uptake by leukocytes. Design: Thirty-six nonsmoking men were randomly assigned to receive 6 wk of 0.5 or 2 kiwifruit/d, an outstanding dietary source of vitamin C. Fasting blood samples were drawn weekly, and 24-h urine and leukocyte samples were collected before intervention, after intervention, and after washout. Needle biopsies of skeletal muscle (vastus lateralis) were carried out before and after intervention. Results: Baseline vastus lateralis ascorbate concentrations were ∼16 nmol/g tissue. After intervention with 0.5 or 2 kiwifruit/d, these concentrations increased ∼3.5-fold to 53 and 61 nmol/g, respectively. There was no significant difference between the responses of the 2 groups. Mononuclear cell and neutrophil ascorbate concentrations increased only ∼1.5- and ∼2-fold, respectively. Muscle ascorbate concentrations were highly correlated (P < 0.001) with dietary intake (R = 0.61) and plasma concentrations (R = 0.75) in the range from 5 to 80 μmol/L. Conclusions: Human skeletal muscle is highly responsive to vitamin C intake and plasma concentrations and exhibits a greater relative uptake of ascorbate than leukocytes. Thus, muscle appears to comprise a relatively labile pool of ascorbate and is likely to be prone to ascorbate depletion with inadequate dietary intake. This trial was registered at the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) as ACTRN12611000162910. PMID:23446899

Pollution characteristics, source apportionment, and health risk of heavy metals in street dust of Suzhou, China.

PubMed

Lin, Manli; Gui, Herong; Wang, Yao; Peng, Weihua

2017-01-01

To analyze the pollution characteristics, source apportionment, and health risk of heavy metals (HMs) in street dust of Suzhou, China, 23 sampling sites were selected and periodically sampled for 12 months. A total of 276 samples were collected, and the concentrations of selected HMs (e.g., Cr, Cu, Fe, Mn, Pb, V, and Zn) were examined with an X-ray fluorescence spectrum analyzer. Results showed that the mean concentrations of Cr, Cu, Fe, Mn, Pb, V, and Zn in the street dust of Suzhou were 112.9, 27.5, 19941.3, 410.3, 45.2, 75.6, and 225.3 mg kg -1 , respectively. Cr, Cu, Pb, and Zn exceeded their background values in local natural soils by 1.3-3.6-fold, whereas Fe, Mn, and V were all within their background values. However, enrichment factor analysis revealed that Cr, Cu, Mn, Pb, V, and Zn, especially Cr, Cu, Pb, and Zn, were enriched in Suzhou street dust. The HMs showed no significant seasonal changes overall, but spatial distribution analysis implied that the high values of Cr, Cu, Mn, Pb, V, and Zn were mainly distributed in areas with frequent human activities. Results of multivariate techniques (e.g., Pearson correlation, hierarchical cluster, and principal components analyses) suggested that Pb and Zn had complicated sources; Cu and V mainly originated from traffic sources; Fe and Mn mainly came from natural sources; and Cr was dominantly related to industrial district. Health risk assessment revealed that a single heavy metal might not cause both non-cancer and carcinogenic risks to local residents. Nevertheless, the sum of the hazard index of all selected HMs for children slightly exceeded the safety value, thereby implying that the HMs from Suzhou street dust can possibly produce significant risk to children. Cr was the priority pollutant in the study area because of its high concentration, high enrichment, and high contribution to non-cancer risk values.

Quantifying spatiotemporal variability of fine particles in an urban environment using combined fixed and mobile measurements

NASA Astrophysics Data System (ADS)

Sullivan, R. C.; Pryor, S. C.

2014-06-01

Spatiotemporal variability of fine particle concentrations in Indianapolis, Indiana is quantified using a combination of high temporal resolution measurements at four fixed sites and mobile measurements with instruments attached to bicycles during transects of the city. Average urban PM2.5 concentrations are an average of ˜3.9-5.1 μg m-3 above the regional background. The influence of atmospheric conditions on ambient PM2.5 concentrations is evident with the greatest temporal variability occurring at periods of one day and 5-10 days corresponding to diurnal and synoptic meteorological processes, and lower mean wind speeds are associated with episodes of high PM2.5 concentrations. An anthropogenic signal is also evident. Higher PM2.5 concentrations coincide with morning rush hour, the frequencies of PM2.5 variability co-occur with those for carbon monoxide, and higher extreme concentrations were observed mid-week compared to weekends. On shorter time scales (

Sampling and Analysis of Atmospheric Pcdd/fs in South China Sea and Background Area in Vietnam

NASA Astrophysics Data System (ADS)

Chi, K.; Thuan, N. T.; Anh, N. X.; Lin, N.

2011-12-01

During the Vietnam conflict, United States (US) forces sprayed a greater volume of defoliant (Agent Orange) with higher PCDD/F content in central Vietnam. The Vietnamese have been exposed to these levels during spraying primarily through contact with former US military infrastructure. In this study, the concentrations of atmospheric PCDD/Fs observed at three background stations (Fig. 1) at Dongsha Island (Sites A) in South China Sea, Da Nang (Site B) city and Son La (Site C) in central and northern Vietnam, respectively, to further understand the PCDD/F contamination in Vietnam. The Measurements indicated that the atmospheric PCDD/F concentrations at Sites A, B and C were 1.66~10.8, 23.4~146 and 11.1~59.5 fg I-TEQ/m3, respectively, during the spring season in 2010 and 2011. The significantly lower PCDD/F concentrations and contents in suspended particles (23.7~33.9 pg I-TEQ/g-TSP) measured at Site A in the South China Sea can be attributed to the lack of any combustion sources within almost 300 km of this island. However, the significantly higher PCDD/F contents in suspended particles (270~300 pg I-TEQ/g-TSP) were measured at Site B in central Vietnam. In addition, Fig. 2 shows that the distribution of PCDD/F congeners measured at Da Nang station was quite different from those measured at other station with high PCDD distribution (>85%) especially in OCDD (>70%). We consider that the high fraction of PCDDs observed at Da Nang probably originated as anthropogenic emission from specific source in Vietnam.

Dietary (n-3) fatty acids reduce plasma F2-isoprostanes but not prostaglandin F2alpha in healthy humans.

PubMed

Nälsén, Cecilia; Vessby, Bengt; Berglund, Lars; Uusitupa, Matti; Hermansen, Kjeld; Riccardi, Gabrielle; Rivellese, Angela; Storlien, Len; Erkkilä, Arja; Ylä-Herttuala, Seppo; Tapsell, Linda; Basu, Samar

2006-05-01

(n-3) Fatty acids are unsaturated and are therefore easily subject to oxidization; however, they have several beneficial health effects, which include protection against cardiovascular diseases. The aim of this study was to investigate whether (n-3) fatty acids, with a controlled fat quality in the background diet, affect nonenzymatic and enzymatic lipid peroxidation and antioxidant status in humans. A total of 162 men and women in a multicenter study (The KANWU study) were randomly assigned to a diet containing a high proportion of saturated fatty acids or monounsaturated fatty acids (MUFA) for 3 mo. Within each diet group, there was a second random assignment to supplementation with fish-oil capsules [3.6 g (n-3) fatty acids/d] or placebo. Biomarkers of nonenzymatic and enzymatic lipid peroxidation in vivo were determined by measuring 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) and prostaglandin F(2alpha) (PGF(2alpha)) concentrations in plasma at baseline and after 3 mo. Antioxidant status was determined by measuring plasma antioxidant capacity with an enhanced chemiluminescence assay. The plasma 8-iso-PGF(2alpha) concentration was significantly decreased after 3 mo of supplementation with (n-3) fatty acids (P = 0.015), whereas the PGF(2alpha) concentration was not affected. The antioxidant status was not affected by supplementation of (n-3) fatty acids, but was improved by the background diet with a high proportion of MUFA. We conclude that supplementation with (n-3) fatty acids decreases nonenzymatic free radical-catalyzed isoprostane formation, but does not affect cyclooxygenase-mediated prostaglandin formation.

Occurrence and distribution of contaminants in bottom sediment and water of the Barron River Canal, Big Cypress National Preserve, Florida

USGS Publications Warehouse

Miller, Ronald L.; McPherson, Benjamin F.

2001-01-01

Trace elements and organic contaminants in bottom-sediment samples collected from 10 sites on the Barron River Canal and from one site on the Turner River in October 1998 had patterns of distribution that indicated different sources. At some sites on the Barron River Canal, lead, copper, and zinc, normalized to aluminum, exceeded limits normally considered as background and may be enriched by human activities. Polynuclear aromatic hydrocarbons and p-cresol, normalized against organic carbon, had patterns of distribution that indicated local sources of input from a road or vehicular traffic or from an old creosote wood treatment facility. Phthalate esters and the traces elements arsenic, cadmium, and zinc were more widely distributed with the highest normalized concentrations occurring at the Turner River background site, probably due to the high percentage of fine sediment (74% less than 63 micrometers) and high organic carbon concentration (42%) at that site and the binding effect of organic carbon on trace elements and trace organic compounds. Low concentrations of pesticides or pesticide degradation products were detected in bottom sediment (DDD and DDE, each less than 3.5 µg/kg) and water (9 pesticides, each less than 0.06 µ/L), primarily in the northern reach of the Barron River Canal where agriculture is a likely source. Although a few contaminants approached criteria that would indicate adverse effects on aquatic life, none exceeded the criteria, but the potential synergistic effects of mixtures of contaminants found at most sites are not included in the criteria.

Wintertime Reactive Chlorine Sources and Speciation in the Great Salt Lake, UT Region

NASA Astrophysics Data System (ADS)

Goldberger, L.; Franchin, A.; Middlebrook, A. M.; Brown, S.; Womack, C.; Moravek, A.; McDuffie, E. E.; Fibiger, D. L.; Baasandorj, M.; Thornton, J. A.

2017-12-01

Several chlorine species were measured in both gas and particle phase using a high-resolution time of flight chemical ionization mass spectrometer (HRToF-CIMS) and an Aerosol Mass Spectrometer (AMS) aboard the NOAA Twin Otter aircraft as part of the Utah Winter Fine Particle Study (UWFPS). The abundance and speciation of gas-phase reactive chlorine species are presented, evaluated during both night and day flights across a range of meteorological conditions and repeated flight paths conducted over the Great Salt Lake region from January 16th to February 12th 2017. Mean, or background, concentrations of HCl, Cl2, ClNO2, and HOCl are measured near zero or on order of tens of ppt. Maximum concentrations of these species are found consistently in Tooele County on order of several ppb to ppm. Elevated levels of HCl and ClNO2 (at night) on order of hundreds of ppt have been observed over urban areas in Salt Lake and Utah Counties as well. Both of these species can form by heterogeneous reactions of acidic gases with sodium chloride in salt particles. The high concentrations of HCl and ClNO2 indicate large point sources of these species or acidic gases in the region, which are characterized by enhancement ratios of species to NOx and SO2 measured by the CIMS and a cavity ring down spectrometer also on board the aircraft. The emission fluxes of these point sources are characterized and their contribution to the regional background of reactive chlorine are evaluated.

Validation Studies of the Accuracy of Various SO2 Gas Retrievals in the Thermal InfraRed (8-14 μm)

NASA Astrophysics Data System (ADS)

Gabrieli, A.; Wright, R.; Lucey, P. G.; Porter, J. N.; Honniball, C.; Garbeil, H.; Wood, M.

2016-12-01

Quantifying hazardous SO2 in the atmosphere and in volcanic plumes is important for public health and volcanic eruption prediction. Remote sensing measurements of spectral radiance of plumes contain information on the abundance of SO2. However, in order to convert such measurements into SO2 path-concentrations, reliable inversion algorithms are needed. Various techniques can be employed to derive SO2 path-concentrations. The first approach employs a Partial Least Square Regression model trained using MODTRAN5 simulations for a variety of plume and atmospheric conditions. Radiances at many spectral wavelengths (8-14 μm) were used in the algorithm. The second algorithm uses measurements inside and outside the SO2 plume. Measurements in the plume-free region (background sky) make it possible to remove background atmospheric conditions and any instrumental effects. After atmospheric and instrumental effects are removed, MODTRAN5 is used to fit the SO2 spectral feature and obtain SO2 path-concentrations. The two inversion algorithms described above can be compared with the inversion algorithm for SO2 retrievals developed by Prata and Bernardo (2014). Their approach employs three wavelengths to characterize the plume temperature, the atmospheric background, and the SO2 path-concentration. The accuracy of these various techniques requires further investigation in terms of the effects of different atmospheric background conditions. Validating these inversion algorithms is challenging because ground truth measurements are very difficult. However, if the three separate inversion algorithms provide similar SO2 path-concentrations for actual measurements with various background conditions, then this increases confidence in the results. Measurements of sky radiance when looking through SO2 filled gas cells were collected with a Thermal Hyperspectral Imager (THI) under various atmospheric background conditions. These data were processed using the three inversion approaches, which were tested for convergence on the known SO2 gas cell path-concentrations. For this study, the inversion algorithms were modified to account for the gas cell configuration. Results from these studies will be presented, as well as results from SO2 gas plume measurements at Kīlauea volcano, Hawai'i.

Use of sediment-trace element geochemical models for the identification of local fluvial baseline concentrations

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Demas, C.R.; Demcheck, D.K.

1991-01-01

Studies have demonstrated the utility of fluvial bed sediment chemical data in assesing local water-quality conditions. However, establishing local background trace element levels can be difficult. Reference to published average concentrations or the use of dated cores are often of little use in small areas of diverse local petrology, geology, land use, or hydrology. An alternative approach entails the construction of a series of sediment-trace element predictive models based on data from environmentally diverse but unaffected areas. Predicted values could provide a measure of local background concentrations and comparison with actual measured concentrations could identify elevated trace elements and affected sites. Such a model set was developed from surface bed sediments collected nationwide in the United States. Tests of the models in a small Louisiana basin indicated that they could be used to establish local trace element background levels, but required recalibration to account for local geochemical conditions outside the range of samples used to generate the nationwide models.

Life Sciences Laboratory 2 Fan Exhaust Mixing Study

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

Flaherty, Julia E.; Antonio, Ernest J.

An SF 6 tracer release was performed in the LSL-II ventilation stack over the weekend of March 5, 2016. The primary purpose of this study was to experimentally determine the gaseous concentration of material from a fume hood to the fan outlet, as well as at typical worker locations, to gain an understanding of potential worker exposures impacts. Five different fan operating configurations were utilized to ensure that the full spectrum of historical operating configurations was addressed. Some summary points from this study include: •Relatively high concentrations were observed within the stack area. –Between 50 and 100% of the exhaustmore » concentration may be observed within the stack. •Background concentrations were observed outside the stack area. –Workers outside the stack itself, but on the roof, are unlikely to be impacted by the exhaust. •Elevated concentrations on the order of 25% of the exhaust concentrations were observed within the Penthouse. •Transport time from a laboratory fume hood to the exhaust fan is within one to two minutes. •Penthouse concentrations climb from background levels to steady state over 15+ minutes. •Wind speed and wind direction did not play a significant role in the test outcomes. –A slight bias in the concentration distribution may be discernable based on wind speed and direction. •When both fans are operating, material from fume hoods on the east side preferentially flow through the east fan, while material from fume hoods on the west side preferentially flow through the west fan. This effectively doubles the concentration at that fan. This mixing study will inform other study components to develop a more complete picture of the worker potential exposure from LSL-II Rooftop activities. Estimating the mean concentration in the stack from chemical inventories and fume hood emissions for both current and historical laboratory activities is a separate effort. These estimates of mean ventilation concentrations will utilize this mixing study to estimate the potential exposure to workers working in and around the LSL-II stack.« less

Magmatic carbon dioxide emissions at Mammoth Mountain, California

USGS Publications Warehouse

Farrar, Christopher D.; Neil, John M.; Howle, James F.

1999-01-01

Carbon dioxide (CO2) of magmatic origin is seeping out of the ground in unusual quantities at several locations around the flanks of Mammoth Mountain, a dormant volcano in Eastern California. The most recent volcanic activity on Mammoth Mountain was steam eruptions about 600 years ago, but seismic swarms and long-period earthquakes over the past decade are evidence of an active magmatic system at depth. The CO2 emission probably began in 1990 but was not recognized until 1994. Seismic swarms and minor ground deformation during 1989, believed to be results of a shallow intrusion of magma beneath Mammoth Mountain, probably triggered the release of CO2, which persists in 1998. The CO2 gas is at ambient temperatures and emanates diffusely from the soil surface rather than flowing from distinct vents. The CO2 has collected in the soil by displacing air in the pore spaces and reaches concentrations of greater than 95 percent by volume in places. The total area affected by high CO2 concentrations and high CO2 flux from the soil surface was estimated at 60 hectares in 1997. Coniferous forest covering about 40 hectares has been killed by high CO2 concentrations in the root zone. In more than 300 soil-gas samples collected from depths of 0.5 to 2 m in 1995, CO2 concentrations ranged from background levels (less than 1 percent) to greater than 95 percent by volume. At 250 locations, CO2 flux was measured using a closed chamber in 1996; values, in grams per square meter per day, ranged from background (less than 25) to more than 30,000. On the basis of these data, the total emission of magmatic CO2 in 1996 is estimated to be about 530 megagrams per day. Concentrations of CO2 exceeding Occupational Safety and Health Administration standards have been measured in pits dug in soil and snow, in poorly ventilated buildings, and in below-ground valve-boxes around Mammoth Mountain. CO2 concentrations greater than 10 percent in poorly ventilated spaces are not uncommon on some parts of Mammoth Mountain. Humans and other animals exposed to CO2 concentrations greater than 10 percent could lose consciousness and die rapidly. With knowledge of the problem and reasonable caution, however, the health hazard to humans can be avoided. As noted earlier, the CO2 emission is related to magmatic activity at depth, but at present (1998) it does not portend an imminent volcanic eruption.

Determination of 137Cs activity in soil from Qatar using high-resolution gamma-ray spectrometry

NASA Astrophysics Data System (ADS)

Al-Sulaiti, Huda; Nasir, Tabassum; Al Mugren, K. S.; Alkhomashi, N.; Al-Dahan, N.; Al-Dosari, M.; Bradley, D. A.; Bukhari, S.; Matthews, M.; Regan, P. H.; Santawamaitre, T.; Malain, D.; Habib, A.; Al-Dosari, Hanan; Al Sadig, Ibrahim; Daar, Eman

2016-10-01

With interest in establishing baseline concentrations of 137Cs in soil from the Qatarian peninsula, we focus on determination of the activity concentrations in 129 soil samples collected across the State of Qatar prior to the 2011 Fukushima Dai-ichi nuclear power plant accident. As such, the data provides the basis of a reference map for the detection of releases of this fission product. The activity concentrations were measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector enclosed in a copper-lined passive lead shield that was situated in a low-background environment. The activity concentrations ranged from 0.21 to 15.41 Bq/kg, with a median value of 1 Bq/kg, the greatest activity concentration being observed in a sample obtained from northern Qatar. Although it cannot be confirmed, it is expected that this contamination is mainly due to releases from the Chernobyl accident of 26 April 1986, there being a lack of data from Qatar before the accident. The values are typically within but are sometimes lower than the range indicated by data from other countries in the region. The lower values than those of others is suggested to be due to variation in soil characteristics as well as metrological factors at the time of deposition.

Source apportionment and pollution evaluation of heavy metals in water and sediments of Buriganga River, Bangladesh, using multivariate analysis and pollution evaluation indices.

PubMed

Bhuiyan, Mohammad Amir Hossain; Dampare, Samuel B; Islam, M A; Suzuki, Shigeyuki

2015-01-01

Concentrations of heavy metals in water and sediment samples of Buriganga River in the capital city Dhaka, Bangladesh, were studied to understand the level of heavy metals and their source apportionment. The results showed that the mean concentrations of heavy metals both in water and sediment samples were very high and, in most cases, exceeded the permissible limits recommended by the Bangladesh government and other international organizations. Significantly higher concentrations of Pb, Cr, Mn, Co, Ni, Cu, Zn, As, and Cd were found in sediment samples. However, average concentrations of metals both in water and sediment samples were above the effect range median. The heavy metal pollution index (HPI) and degree of contamination (Cd) yielded different results in water samples despite significant correlations between them. The heavy metal evaluation index (HEI) showed strong correlations with HPI and Cd and provided better assessment of pollution levels. The enrichment factor (EF) and geoaccumulation index (Igeo) showed the elevated value of Cr, Pb, and Cd in access of background values. The measured elements were subjected to positive matrix factorization (PMF) and examining correlations in order to explain the content, behavior, and source apportionment of metals. PMF resulted in a successful partitioning of variances into sources related to background geochemistry and contaminant influences. However, the PMF approach successfully demarcated the major sources of metals from tannery, paint, municipal sewage, textiles, and agricultural activities.

Isoprene photochemistry over the Amazon rainforest.

PubMed

Liu, Yingjun; Brito, Joel; Dorris, Matthew R; Rivera-Rios, Jean C; Seco, Roger; Bates, Kelvin H; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N; Kim, Saewung; Goldstein, Allen H; Guenther, Alex B; Manzi, Antonio O; Souza, Rodrigo A F; Springston, Stephen R; Watson, Thomas B; McKinney, Karena A; Martin, Scot T

2016-05-31

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.

Isoprene photochemistry over the Amazon rainforest

NASA Astrophysics Data System (ADS)

Liu, Yingjun; Brito, Joel; Dorris, Matthew R.; Rivera-Rios, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sergio; Keutsch, Frank N.; Kim, Saewung; Goldstein, Allen H.; Guenther, Alex B.; Manzi, Antonio O.; Souza, Rodrigo A. F.; Springston, Stephen R.; Watson, Thomas B.; McKinney, Karena A.; Martin, Scot T.

2016-05-01

Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest.

Geo-Spatial Characterization of Soil Mercury and Arsenic at a High-Altitude Bolivian Gold Mine.

PubMed

Johnson, Glen D; Pavilonis, Brian; Caravanos, Jack; Grassman, Jean

2018-02-01

Soil mercury concentrations at a typical small-scale mine site in the Bolivian Andes were elevated (28-737 mg/kg or ppm) in localized areas where mercury amalgams were either formed or vaporized to release gold, but was not detectable beyond approximately 10 m from its sources. Arsenic was measurable, exceeding known background levels throughout the mine site (77-137,022 ppm), and was also measurable through the local village of Ingenio (36-1803 ppm). Although arsenic levels were high at all surveyed locations, its spatial pattern followed mercury, being highest where mercury was high.

Concentrations, sources and human health risk of inhalation exposure to air toxics in Edmonton, Canada.

PubMed

Bari, Md Aynul; Kindzierski, Warren B

2017-04-01

With concern about levels of air pollutants in recent years in the Capital Region of Alberta, an investigation of ambient concentrations, sources and potential human health risk of hazardous air pollutants (HAPs) or air toxics was undertaken in the City of Edmonton over a 5-year period (2009-2013). Mean concentrations of individual HAPs in ambient air including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and trace metals ranged from 0.04 to 1.73 μg/m 3 , 0.01-0.54 ng/m 3 , and 0.05-3.58 ng/m 3 , respectively. Concentrations of benzene, naphthalene, benzo(a)pyrene (BaP), arsenic, manganese and nickel were far below respective annual Alberta Ambient Air Quality Objectives. Carcinogenic and non-carcinogenic risk of air toxics were also compared with risk levels recommended by regulatory agencies. Positive matrix factorization identified six air toxics sources with traffic as the dominant contributor to total HAPs (4.33 μg/m 3 , 42%), followed by background/secondary organic aerosol (SOA) (1.92 μg/m 3 , 25%), fossil fuel combustion (0.92 μg/m 3 , 11%). On high particulate air pollution event days, local traffic was identified as the major contributor to total HAPs compared to background/SOA and fossil fuel combustion. Carcinogenic risk values of traffic, background/SOA and metals industry emissions were above the USEPA acceptable level (1 × 10 -6 ), but below a tolerable risk (1 × 10 -4 ) and Alberta benchmark (1 × 10 -5 ). These findings offer useful preliminary information about current ambient air toxics levels, dominant sources and their potential risk to public health; and this information can support policy makers in the development of appropriate control strategies if required. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of highway traffic on spatial and temporal distributions of air pollutants in a Swiss Alpine valley.

PubMed

Ducret-Stich, Regina E; Tsai, Ming-Yi; Ragettli, Martina S; Ineichen, Alex; Kuenzli, Nino; Phuleria, Harish C

2013-07-01

Traffic-related air pollutants show high spatial variability near roads, posing a challenge to adequately assess exposures. Recent modeling approaches (e.g. dispersion models, land-use regression (LUR) models) have addressed this but mostly in urban areas where traffic is abundant. In contrast, our study area was located in a rural Swiss Alpine valley crossed by the main North-south transit highway of Switzerland. We conducted an extensive measurement campaign collecting continuous nitrogen dioxide (NO₂), particulate number concentrations (PN), daily respirable particulate matter (PM10), elemental carbon (EC) and organic carbon (OC) at one background, one highway and seven mobile stations from November 2007 to June 2009. Using these measurements, we built a hybrid model to predict daily outdoor NO₂ concentrations at residences of children participating in an asthma panel study. With the exception of OC, daily variations of the pollutants followed the temporal trends of heavy-duty traffic counts on the highway. In contrast, variations of weekly/seasonal means were strongly determined by meteorological conditions, e.g., winter inversion episodes. For pollutants related to primary exhaust emissions (i.e. NO₂, EC and PN) local spatial variation strongly depended on proximity to the highway. Pollutant concentrations decayed to background levels within 150 to 200 m from the highway. Two separate daily NO₂ prediction models were built using LUR approaches with (a) short-term traffic and weather data (model 1) and (b) subsequent addition of daily background NO₂ to previous model (model 2). Models 1 and 2 explained 70% and 91% of the variability in outdoor NO₂ concentrations, respectively. The biweekly averaged predictions from the final model 2 agreed very well with the independent biweekly integrated passive measurements taken at thirteen homes and nine community sites (validation R(2)=0.74). The excellent spatio-temporal performance of our model provides a very promising basis for the health effect assessment of the panel study. Copyright © 2013 Elsevier B.V. All rights reserved.

Surgical smoke and ultrafine particles

PubMed Central

Brüske-Hohlfeld, Irene; Preissler, Gerhard; Jauch, Karl-Walter; Pitz, Mike; Nowak, Dennis; Peters, Annette; Wichmann, H-Erich

2008-01-01

Background Electrocautery, laser tissue ablation, and ultrasonic scalpel tissue dissection all generate a 'surgical smoke' containing ultrafine (<100 nm) and accumulation mode particles (< 1 μm). Epidemiological and toxicological studies have shown that exposure to particulate air pollution is associated with adverse cardiovascular and respiratory health effects. Methods To measure the amount of generated particulates in 'surgical smoke' during different surgical procedures and to quantify the particle number concentration for operation room personnel a condensation particle counter (CPC, model 3007, TSI Inc.) was applied. Results Electro-cauterization and argon plasma tissue coagulation induced the production of very high number concentration (> 100000 cm-3) of particles in the diameter range of 10 nm to 1 μm. The peak concentration was confined to the immediate local surrounding of the production side. In the presence of a very efficient air conditioning system the increment and decrement of ultrafine particle occurrence was a matter of seconds, with accumulation of lower particle number concentrations in the operation room for only a few minutes. Conclusion Our investigation showed a short term very high exposure to ultrafine particles for surgeons and close assisting operating personnel – alternating with longer periods of low exposure. PMID:19055750

Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)

NASA Astrophysics Data System (ADS)

Birmili, W.; Weinhold, K.; Merkel, M.; Rasch, F.; Sonntag, A.; Wiedensohler, A.; Bastian, S.; Schladitz, A.; Löschau, G.; Cyrys, J.; Pitz, M.; Gu, J.; Kusch, T.; Flentje, H.; Quass, U.; Kaminski, H.; Kuhlbusch, T. A. J.; Meinhardt, F.; Schwerin, A.; Bath, O.; Ries, L.; Wirtz, K.; Fiebig, M.

2015-11-01

The German Ultrafine Aerosol Network (GUAN) is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both, climate and health related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at seventeen observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan).

Long-term observations of tropospheric particle number size distributions and equivalent black carbon mass concentrations in the German Ultrafine Aerosol Network (GUAN)

NASA Astrophysics Data System (ADS)

Birmili, Wolfram; Weinhold, Kay; Rasch, Fabian; Sonntag, André; Sun, Jia; Merkel, Maik; Wiedensohler, Alfred; Bastian, Susanne; Schladitz, Alexander; Löschau, Gunter; Cyrys, Josef; Pitz, Mike; Gu, Jianwei; Kusch, Thomas; Flentje, Harald; Quass, Ulrich; Kaminski, Heinz; Kuhlbusch, Thomas A. J.; Meinhardt, Frank; Schwerin, Andreas; Bath, Olaf; Ries, Ludwig; Gerwig, Holger; Wirtz, Klaus; Fiebig, Markus

2016-08-01

The German Ultrafine Aerosol Network (GUAN) is a cooperative atmospheric observation network, which aims at improving the scientific understanding of aerosol-related effects in the troposphere. The network addresses research questions dedicated to both climate- and health-related effects. GUAN's core activity has been the continuous collection of tropospheric particle number size distributions and black carbon mass concentrations at 17 observation sites in Germany. These sites cover various environmental settings including urban traffic, urban background, rural background, and Alpine mountains. In association with partner projects, GUAN has implemented a high degree of harmonisation of instrumentation, operating procedures, and data evaluation procedures. The quality of the measurement data is assured by laboratory intercomparisons as well as on-site comparisons with reference instruments. This paper describes the measurement sites, instrumentation, quality assurance, and data evaluation procedures in the network as well as the EBAS repository, where the data sets can be obtained (doi:10.5072/guan).

Recording of absorption spectra by a three-beam integral technique with a tunable laser and external cavity

NASA Astrophysics Data System (ADS)

Korolenko, P. V.; Nikolaev, I. V.; Ochkin, V. N.; Tskhai, S. N.

2014-04-01

An integral method is considered for recording absorption using three laser beams transmitted through and reflected from an external cavity with the absorbing medium (R-ICOS). The method is the elaboration of a known single-beam ICOS method and allows suppression of the influence of radiation phase fluctuations in the resonator on recording weak absorption spectra. First of all, this reduces high-frequency instabilities and gives a possibility to record spectra during short time intervals. In this method, mirrors of the resonator may have moderate reflection coefficients. Capabilities of the method have been demonstrated by the examples of weak absorption spectra of atmospheric methane and natural gas in a spectral range around 1650 nm. With the mirrors having the reflection coefficients of 0.8-0.99, a spectrum can be recorded for 320 μs with the accuracy sufficient for detecting a background concentration of methane in atmosphere. For the acquisition time of 20 s, the absorption coefficients of ~2×10-8 cm-1 can be measured, which corresponds to a 40 times less molecule concentration than the background value.

Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

PubMed

Tanaka, Kazuhiko; Mori, Masanobu; Xu, Qun; Helaleh, Murad I H; Ikedo, Mikaru; Taoda, Hiroshi; Hu, Wenzhi; Hasebe, Kiyoshi; Fritz, James S; Haddad, Paul R

2003-05-16

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

Biogeochemical features of maple and dandelion in Eastern Administrative District of Moscow

NASA Astrophysics Data System (ADS)

Vlasov, Dmitry

2014-05-01

Today more than half of world population and 73% of population in Russia live in cities. Moscow is the only one megacity in Russia with the population more than 11 million. The main source of technogenic impact in Moscow is transport. Plants can be used as indicators of urban environment heavy metals and metalloids (HM) pollution. Large scale biogeochemical research was done in Eastern Administrative District of Moscow. Apart from transport there are many industrial sources of pollution: metalworking, mechanical engineering, chemical, energetic and incinerator. This study focuses on detection of HM composition of woody plant leaves (maple - Acer platanoides) and herbaceous species leaves (dandelion - Taraxacum officinale). Plant material was collected on a regular greed with a step of 500-700 m. Background plants were sampled at 40 km west away from the city. Determination of Fe, Mn, Mo, Cd, Pb, Zn, Cu, As, Sb in plants was done using atomic absorption spectrometry after washing, drying and digestion with HNO3+H2O2. It was revealed that dandelion accumulates (index - concentration factors CF relatively background) Mo13Fe6Pb5Cd4.5As4Sb3, while maple Sb13As5.5Fe3Mo2Pb,Zn1.5. Geochemical specialization of plants in functional zones (industrial, transport, recreational, agricultural, residential areas with high-, middle- and low-rise buildings) was identified. The highest CF were determined for Mo in dandelion of all zones except industrial. In which the most accumulated elements are Fe and Mo, as well as Pb10As6Sb5Cu2. Arsenic is accumulated by dandelion in all zones. Copper is not concentrated by herbaceous species because of antagonism between Mo and Cu. The highest CF were determined for HM in maple of industrial zone. There trees concentrate Sb and As9Fe7Mo6Pb3Zn2. In the other zones levels of CF are lower in 2-5 times. Dandelion and maple don't accumulate Mn because of antagonism between Zn, Mo and Mn. Urban plants condition is estimated by the ratio between toxic (Cd, As, Sb, Pb) and essential (Cu, Fe, Mn, Mo, Zn) elements. For evaluation of intensity of photosynthesis and plants growth can be used Fe/Mn, Zn/Mn, Cu/Mn and Mo/Mn ratios. In dandelion and maple Fe/Mn is 6.6 and 3.3 times higher than in background vegetation, Pb/Mn - 5.5 and 2.5 times, (Cd+As+Sb+Pb)/(Cu+Fe+Mn+Mo+Zn) - 2.9 and 1.6 times respectively. In industrial, transport zones and residential area with high-rise buildings the largest increase of those ratios were discovered. Differences in geochemical specialization were shown by Sb/Mo ratio: in dandelion it is 5 times lower than in background plants, while in maple it is 4.5 times higher. The same situation was defined for As/Mo. Strong positive linear relationship between Sb deposition rates and Sb concentrations in maple was calculated (r=0.86). Furthermore moderate positive linear relationships between Cd concentrations in soils and dandelion (r=0.69), concentrations of mobile forms of Pb and Sb in soils and maple (r=0.67 and 0.66), Fe deposition rates and concentrations of this element in maple (r=0.51) were revealed.

Surface-water-quality assessment of the upper Illinois River basin in Illinois, Indiana, and Wisconsin; spatial distribution of geochemicals in the fine fraction of streambed sediment, 1987

USGS Publications Warehouse

Fitzpatrick, Faith A.; Arnold, Terri L.; Colman, John A.

1998-01-01

Geochemical data for the upper Illinois River Basin are presented for concentrations of 39 elements in streambed sediment collected by the U.S. Geological Survey in the fall of 1987. These data were collected as part of the pilot phase of the National Water-Quality Assessment Program. A total of 372 sites were sampled, with 238 sites located on first- and second-order streams, and 134 sites located on main stems. Spatial distribution maps and exceedance probability plots are presented for aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, calcium, carbon (total, inorganic, and organic), cerium, chromium, cobalt, copper, gallium, iron, lanthanum, lead, lithium, magnesium, manganese, mercury, molybdenum, neodymium, nickel, niobium, phosphorus, potassium, scandium, selenium, silver, sodium, strontium, sulfur, thorium, titanium, uranium, vanadium, yttrium, and zinc. For spatial distribution maps, concentrations of the elements are grouped into four ranges bounded by the minimum concentration, the 10th, 50th, and 90th percentiles, and the maximum concentrations. These ranges were selected to highlight streambed sediment with very low or very high element concentrations relative to the rest of the streambed sediment in the upper Illinois River Basin. Exceedance probability plots for each element display the differences, if any, in distributions between high- and low-order streams and may be helpful in determining differences between background and elevated concentrations.

Oily wastewaters treatment using Pseudomonas sp. isolated from the compost fertilizer

PubMed Central

2014-01-01

Background Discharging the oily wastewater in the environment causes serious problems, because of the oil compounds and organic materials presence. Applying biological methods using the lipase enzyme producer microorganisms can be an appropriate choice for treatment of these wastewaters. The aim of this study is to treat those oil wastewaters having high concentration of oil by applying lipase enzyme producer bacteria. Materials and methods Oil concentration measurement was conducted using the standard method of gravimetric and the wastewater under study was synthetically made and contained olive, canola and sunflower oil. The strain used in this study was Pseudomonas strain isolated from compost fertilizer. The oil under study had concentration of 1.5 to 22 g/l. Results The oil removal amount in concentrations lower than 8.4 g/l was over 95 ± 1.5%. Increase of the oil's concentration to 22 g/l decreases the amount of removal in retention time of 44 hours to 85 ± 2.5%. The best yield of removing this strain in retention time of 44 hours and temperature of 30°C was achieved using Ammonium Nitrate as the nitrogen resource which yield was about 95 percent. Conclusion The findings of the research showed that Pseudomonas bacteria isolated from the compost fertilizer can degrade high concentration oils. PMID:24876932

Hyperaccumulation of zinc by Corydalis davidii in Zn-polluted soils.

PubMed

Lin, Wenjie; Xiao, Tangfu; Wu, Yunying; Ao, Ziqiang; Ning, Zengping

2012-02-01

A field survey was conducted to identify potential Zn accumulators from an artisanal Zn smelting area in southwest China's Guizhou Province. Hydroponic and soil culture experiments were performed to investigate the accumulation ability of Zn in Corydalis davidii. Zn concentrations in roots, stems and leaves of C. davidii in the smelting site were 1.1-3.5, 1.2-11.2, and 3.3-14 mg g(-)(1), respectively, whereas Zn concentrations in roots, stems and leaves of C. davidii in the contaminated site impacted by the Zn smelting were 1.0-2.4, 1.9-6.5, and 3.0-1.1 mg g(-1), respectively. Zn concentrations in leaves and stems of C. davidii were observed at above 10 mg g(-1) that refers to the threshold of Zn hyperaccumulator. The concentration distribution of Zn in C. davidii was leaf>stem>root, and the Zn bioaccumulation factors of C. davidii were above 1. It is concluded that C. davidii has high tolerance to concentrate Zn stress, and that C. davidii is a newly discovered Zn-hyperaccumulator with high biomass in the aboveground parts. Based on the cultivation experiments, C. davidii could reduce Zn concentration by 26.6, 21.2, and 10.2 mg kg(-1)yr(-1) by phytoextraction from the smelting slag, Zn-contaminated soil, and background soil, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mutagenic potential assessment associated with human exposure to natural radioactivity.

PubMed

Marcon, Alexandre Endres; Navoni, Julio Alejandro; de Oliveira Galvão, Marcos Felipe; Garcia, Anuska Conde Fagundes Soares; do Amaral, Viviane Souza; Petta, Reinaldo Antônio; Campos, Thomas Ferreira da Costa; Panosso, Renata; Quinelato, Antônio Luiz; de Medeiros, Sílvia Regina Batistuzzo

2017-01-01

Lucrécia city, known to harbor a high cancer rate, is located in a semiarid region characterized by the presence of mineral reservoirs, facing a high exposure to metal and natural radioactivity. The present study aimed to assess the environmental scenario at a semiarid region located in Northeastern Brazil. Metal concentration, alpha and beta radiation, and cyanobacteria content in tap water along with indoor radon and gamma emitters (U, K and Th) concentrations were measured. In addition, mutagenic and nuclear instability effects were assessed using buccal micronucleus cytome assay. The study included five samplings corresponding to a period between 2007 and 2009. Drinking water from Lucrécia city presented levels of Mn, Ni and Cr along with cyanobacteria in concentrations one to four times higher than regulatory guidelines considered. Furthermore, high levels of all the tested radionuclides were found. A high percentage of the houses included in this study presented indoor radon concentrations over 100 Bq m -3 . The mean annual effective dose from Lucrécia houses was six times higher than observed in a control region. The levels of exposure in most of the Lucrécia houses were classified as middle to high. A significant mutagenic effect, represented as an increase of micronuclei (MN) frequency and nuclear abnormalities as nuclear buds (NB), binucleated cells (BN), and pyknotic cells (PYC) were found. The results obtained highlight the role of high background radioactivity on the observed mutagenic effect and could help to explain the exacerbated cancer rate reported in this locality. Copyright © 2016. Published by Elsevier Ltd.

Cytokine activation is predictive of mortality in Zambian patients with AIDS-related diarrhoea

PubMed Central

Zulu, Isaac; Hassan, Ghaniah; Njobvu RN, Lungowe; Dhaliwal, Winnie; Sianongo, Sandie; Kelly, Paul

2008-01-01

Background Mortality in Zambian AIDS patients is high, especially in patients with diarrhoea, and there is still unacceptably high mortality in Zambian patients just starting anti-retroviral therapy. We set out to determine if high concentrations of serum cytokines correlate with mortality. Methods Serum samples from 30 healthy controls (HIV seropositive and seronegative) and 50 patients with diarrhoea (20 of whom died within 6 weeks) were analysed. Concentrations of tumour necrosis factor receptor p55 (TNFR p55), macrophage migration inhibitory factor (MIF), interleukin (IL)-6, IL-12, interferon (IFN)-γ and C-reactive protein (CRP) were measured by ELISA, and correlated with mortality after 6 weeks follow-up. Results Apart from IL-12, concentrations of all cytokines, TNFR p55 and CRP increased with worsening severity of disease, showing highly statistically significant trends. In a multivariable analysis high TNFR p55, IFN-γ, CRP and low CD4 count (CD4 count <100) were predictive of mortality. Although nutritional status (assessed by body mass index, BMI) was predictive in univariate analysis, it was not an independent predictor in multivariate analysis. Conclusion High serum concentrations of TNFR p55, IFN-γ, CRP and low CD4 count correlated with disease severity and short-term mortality in HIV-infected Zambian adults with diarrhoea. These factors were better predictors of survival than BMI. Understanding the cause of TNFR p55, IFN-γ and CRP elevation may be useful in development of interventions to reduce mortality in AIDS patients with chronic diarrhoea in Africa. PMID:19014537

High Concentrations of Ozone Air Pollution on Mount Everest: Health Implications for Sherpa Communities and Mountaineers.

PubMed

Semple, John L; Moore, G W Kent; Koutrakis, Petros; Wolfson, Jack M; Cristofanelli, Paolo; Bonasoni, Paolo

2016-12-01

Semple, John L., G.W. Kent Moore, Petros Koutrakis, Jack M. Wolfson, Paolo Cristofanelli, and Paolo Bonasoni. High concentrations of ozone air pollution on Mount Everest: health implications for Sherpa communities and mountaineers. High Alt Med Biol. 17:365-369, 2016.-Introduction: Populations in remote mountain regions are increasingly vulnerable to multiple climate mechanisms that influence levels of air pollution. Few studies have reported on climate-sensitive health outcomes unique to high altitude ecosystems. In this study, we report on the discovery of high-surface ozone concentrations and the potential impact on health outcomes on Mount Everest and the high Himalaya. Surface ozone measurements were collected during ascending transects in the Mount Everest region of Nepal with passive nitrite-coated Ogawa filter samplers to obtain 8-hour personal exposures (2860-5364 m asl). In addition, the Nepal Climate Observatory-Pyramid, a GAW-WMO Global Station sited in the Khumbu Valley (5079 m asl), collected ozone mixing ratios with photometric gas analyzer. Surface ozone measurements increased with altitude with concentrations that exceed 100 ppb (8-hour exposure). Highest values were during the spring season and the result of diverse contributions: hemispheric background values, the descent of ozone-rich stratospheric air, and the transport of tropospheric pollutants occurring at different spatial scales. Multiple climate factors, including descending stratospheric ozone and imported anthropogenic air masses from the Indo-Gangetic Plain, contribute to ambient ozone exposure levels in the vicinity of Mount Everest that are similar to if not higher than those reported in industrialized cities.

Fluorescence quencher improves SCANSYSTEM for rapid bacterial detection.

PubMed

Schmidt, M; Hourfar, M K; Wahl, A; Nicol, S-B; Montag, T; Roth, W K; Seifried, E

2006-05-01

The optimized scansystem could detect contaminated platelet products within 24 h. However, the system's sensitivity was reduced by a high fluorescence background even in sterile samples, which led to the necessity of a well-trained staff for confirmation of microscope results. A new protocol of the optimized scansystem with the addition of a fluorescence quencher was evaluated. Pool platelet concentrates contaminated with five transfusion-relevant bacterial strains were tested in a blind study. In conjunction with new analysis software, the new quenching dye was able to reduce significantly unspecific background fluorescence. Sensitivity was best for Bacillus cereus and Escherichia coli (3 CFU/ml). The application of a fluorescence quencher enables automated discrimination of positive and negative test results in 60% of all analysed samples.

A new technique for collection, concentration and determination of gaseous tropospheric formaldehyde

NASA Astrophysics Data System (ADS)

Cofer, Wesley R.; Edahl, Robert A.

This article describes an improved technique for making in situ measurements of gaseous tropospheric formaldehyde (CH 2O). The new technique is based on nebulization/reflux principles that have proved very effective in quantitatively scrubbing water soluble trace gases (e.g. CH 2O) into aqueous mediums, which are subsequently analyzed. Atmospheric formaldehyde extractions and analyses have been performed with the nebulization/reflux concentrator using an acidified dinitrophenylhydrazine solution that indicate that quantitative analysis of CH 2O at global background levels (˜ 0.1 ppbv) is feasible with 20-min extractions. Analysis of CH 2O, once concentrated, is accomplished using high performance liquid chromatography (HPLC) with ultraviolet photometric detection. The CH 2O-hydrazone derivative, produced by the reaction of 2,4-dinitrophenylhydrazine in H 2SO 4 acidified aqueous solution, is detected as CH 2O.

A new technique for collection, concentration and determination of gaseous tropospheric formaldehyde

NASA Technical Reports Server (NTRS)

Cofer, W. R., III; Edahl, R. A., Jr.

1986-01-01

This article describes an improved technique for making in situ measurements of gaseous tropospheric formaldehyde (CH2O). The new technique is based on nebulization/reflux principles that have proved very effective in quantitatively scrubbing water soluble trace gases (e.g., CH2O) into aqueous mediums, which are subsequently analyzed. Atmospheric formaldehyde extractions and analyses have been performed with the nebulization/reflux concentrator using an acidified dinitrophenylhydrazine solution that indicate that quantitative analysis of CH2O at global background levels (about 0.1 ppbv) is feasible with 20-min extractions. Analysis of CH2O, once concentrated, is accomplished using high performance liquid chromatography with ultraviolet photometric detection. The CH2O-hydrazone derivative, produced by the reaction of 2,4-dinitrophenylhydrazine in H2SO4 acidified aqueous solution, is detected as CH2O.

Co-digestion of manure and industrial waste--The effects of trace element addition.

PubMed

Nordell, Erik; Nilsson, Britt; Nilsson Påledal, Sören; Karisalmi, Kaisa; Moestedt, Jan

2016-01-01

Manure is one of the most common substrates for biogas production. Manure from dairy- and swine animals are often considered to stabilize the biogas process by contributing nutrients and trace elements needed for the biogas process. In this study two lab-scale reactors were used to evaluate the effects of trace element addition during co-digestion of manure from swine- and dairy animals with industrial waste. The substrate used contained high background concentrations of both cobalt and nickel, which are considered to be the most important trace elements. In the reactor receiving additional trace elements, the volatile fatty acids (VFA) concentration was 89% lower than in the control reactor. The lower VFA concentration contributed to a more digested digestate, and thus lower methane emissions in the subsequent storage. Also, the biogas production rate increased with 24% and the biogas production yield with 10%, both as a result of the additional trace elements at high organic loading rates. All in all, even though 50% of the feedstock consisted of manure, trace element addition resulted in multiple positive effects and a more reliable process with stable and high yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study of pollutant distribution in the Guaxindiba Estuarine System--SE Brazil.

PubMed

Fonseca, E M; Baptista Neto, J A; Pereira, M P S; Silva, C G; Arantes, J D

2014-05-15

The Guaxindiba Estuarine System is located in the northeast portion of Guanabara Bay. Despite the location inside an environmental protection zone, the main affluent of the river runs through the extremely urbanized area of the cities of Niterói and São Gonçalo. In order to understand the contamination levels of the estuary, 35 surface sediment samples were collected along the river and estuarine area and analyzed for the presence of heavy metals, PAHs, organochlorated pesticides, polychlorinated biphenyl and other contaminants. The analyzed data revealed a greatly affected environment with respect to most of these substances. The results suggested propitious deposits of contaminants, with high concentrations of organic matter and fine sediment. The levels of heavy metal in the entire estuarine system were high compared with the local background. The total mean concentrations of As, Cd, Pb, Cu, Zn, Hg, Cr and Ni in the surface sediments were: 3.74; 0.03; 19.3; 15.0; 99.0; n.d.; 29.0; and 22.0mg/kg, respectively, confirming, in certain cases, the high capacity of the environment to concentrate pollution. Copyright © 2014 Elsevier Ltd. All rights reserved.

Review: Water recovery from brines and salt-saturated solutions: operability and thermodynamic efficiency considerations for desalination technologies

PubMed Central

Vane, Leland M.

2017-01-01

BACKGROUND When water is recovered from a saline source, a brine concentrate stream is produced. Management of the brine stream can be problematic, particularly in inland regions. An alternative to brine disposal is recovery of water and possibly salts from the concentrate. RESULTS This review provides an overview of desalination technologies and discusses the thermodynamic efficiencies and operational issues associated with the various technologies particularly with regard to high salinity streams. CONCLUSION Due to the high osmotic pressures of the brine concentrates, reverse osmosis, the most common desalination technology, is impractical. Mechanical vapor compression which, like reverse osmosis, utilizes mechanical work to operate, is reported to have the highest thermodynamic efficiency of the desalination technologies for treatment of salt-saturated brines. Thermally-driven processes, such as flash evaporation and distillation, are technically able to process saturated salt solutions, but suffer from low thermodynamic efficiencies. This inefficiency could be offset if an inexpensive source of waste or renewable heat could be used. Overarching issues posed by high salinity solutions include corrosion and the formation of scales/precipitates. These issues limit the materials, conditions, and unit operation designs that can be used. PMID:29225395

Journal Article: Atmospheric Measurements of CDDs, CDFs, and Coplanar PCBs in Rural and Remote Locations of the U.S. for the Years 1998-2001 from the National Dioxin Air Monitoring Network (Ndamn)

EPA Science Inventory

The U.S. EPA established a National Dioxin Air Monitoring Network (NDAMN) to determine background air concentrations of PCDDs, PCDFs, and cp-PCBs in rural and remote areas of the United States. Background is defined as average ambient air concentrations inferred from long-term a...

Mobile assessment of on-road air pollution and its sources along the East-West Highway in Bhutan

NASA Astrophysics Data System (ADS)

Wangchuk, Tenzin; Knibbs, Luke D.; He, Congrong; Morawska, Lidia

2015-10-01

Human exposures in transportation microenvironments are poorly represented by ambient stationary monitoring. A number of on-road studies using vehicle-based mobile monitoring have been conducted to address this. Most previous studies were conducted on urban roads in developed countries where the primary emission source was vehicles. Few studies have examined on-road pollution in developing countries in urban settings. Currently, no study has been conducted for roadways in rural environments where a substantial proportion of the population live. This study aimed to characterize on-road air quality on the East-West Highway (EWH) in Bhutan and identify its principal sources. We conducted six mobile measurements of PM10, particle number (PN) count and CO along the entire 570 km length of the EWH. We divided the EWH into five segments, R1-R5, taking the road length between two district towns as a single road segment. The pollutant concentrations varied widely along the different road segments, with the highest concentrations for R5 compared with other road segments (PM10 = 149 μg/m3, PN = 5.74 × 104 particles/cm-3, CO = 0.19 ppm), which is the final segment of the road to the capital. Apart from vehicle emissions, the dominant sources were road works, unpaved roads and roadside combustion activities. Overall, the highest contributions above the background levels were made by unpaved roads for PM10 (6 times background), and vehicle emissions for PN and CO (5 and 15 times background, respectively). Notwithstanding the differences in instrumentation used and particle size range measured, the current study showed lower PN concentrations compared with similar on-road studies. However, concentrations were still high enough that commuters, road maintenance workers and residents living along the EWH, were potentially exposed to elevated pollutant concentrations from combustion and non-combustion sources. Future studies should focus on assessing the dispersion patterns of roadway pollutants and defining the short- and long-term health impacts of exposure in Bhutan, as well as in other developing countries with similar characteristics.

Total particle, sulfate, and acidic aerosol emissions from kerosene space heaters

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

Leaderer, B.P.; Boone, P.M.; Hammond, S.K.

1990-06-01

Chamber studies were conducted on four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine particles ({<=} 2.5-{mu}m diameter), sulfate, and acidic aerosol indoors. Fine particle concentrations in homes in which the heaters are used may be increased in excess of 20 {mu}g/m{sup 3} over background levels. Sulfate and acidic aerosol levels in such homes could exceed average and peak outdoor concentrations. Maltuned heaters could produce exceptionally high levels of all air contaminantsmore » measured.« less

Total particle, sulfate, and acidic aerosol emissions from kerosene space heaters

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

Leaderer, B.P.; Boone, P.M.; Hammond, S.K.

1990-01-01

The article discusses chamber studies of four unvented kerosene space heaters to assess emissions of total particle, sulfate, and acidic aerosol. The heaters tested represented four burner designs currently in use by the public. Kerosene space heaters are a potential source of fine particles (= or < 2.5 micrometer diameter), sulfate, and acidic aerosol indoors. Fine particle concentrations in houses in which the heaters are used may be increased in excess of 20 micrograms/m3 over background levels. Sulfate and acidic aerosol levels in such houses could exceed average and peak outdoor concentrations. Maltuned heaters could produce exceptionally high levels ofmore » all air contaminants measured.« less

Tritium concentrations in bees and honey at Los Alamos National Laboratory: 1979-1996

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

Fresquez, P.R.; Armstrong, D.R.; Pratt, L.H.

Honeybees are effective monitors of environmental pollution. The objective of this study was to summarize tritium ({sup 3}H) concentrations in bees and honey collected from within and around Los Alamos National Laboratory (LANL) over an 18-year period. Based on the long-term average, bees from nine out of eleven hives and honey from six out of eleven hives on LANL lands contained {sup 3}H that was significantly higher (p <0.05) than background. The highest average concentration of {sup 3}H in bees (435 pCi mL{sup -1}) collected over the years was from LANL`s Technical Area (TA) 54-a low-level radioactive waste disposal sitemore » (Area G). Similarly, the highest average concentration of {sup 3}H in honey (709 pCi mL{sup - 1}) was collected from a hive located near three {sup 3}H storage ponds at LANL TA-53. The average concentrations of {sup 3}H in bees and honey from background hives was 1.0 pCi mL{sup -1} and 1.5 pCi ML{sup -1}, respectively. Although the concentrations of 3H in bees and honey from most LANL and perimeter (White Rock/Pajarito Acres) areas were significantly higher than background, most areas, with the exception of TA-53 and TA-54, generally exhibited decreasing 3H concentrations over time.« less

Impacts of roadway emissions on urban particulate matter concentrations in sub-Saharan Africa: new evidence from Nairobi, Kenya

NASA Astrophysics Data System (ADS)

van Vliet, E. D. S.; Kinney, P. L.

2007-10-01

Air quality is a serious and worsening problem in the rapidly growing cities of sub-Saharan Africa (SSA). However, the lack of ambient monitoring data, and particularly urban roadside concentrations for particulate matter in SSA cities severely hinders our ability to describe temporal and spatial patterns of concentrations, characterize exposure response relationships for key health outcomes, estimate disease burdens, and promote policy initiatives to address air quality. As part of a collaborative transportation planning exercise between Columbia University and the University of Nairobi, air monitoring was carried out in February 2006 in Nairobi, Kenya. The objective of the monitoring was to collect pilot data on air concentrations (PM2.5 and black carbon) encountered while driving in the Nairobi metropolitan area, and to compare those data to simultaneous 'urban background' concentrations measured in Nairobi but away from roadways. For both the background and roadway monitoring, we used portable air sampling systems that collect integrated filter samples. Results from this pilot study found that roadway concentrations of PM2.5 were approximately 20-fold higher than those from the urban background site, whereas black carbon concentrations differed by 10-fold. If confirmed by more extensive sampling, these data would underscore the need for air quality and transportation planning and management directed at mitigating roadway pollution.

Inhalation exposures due to radon and thoron ((222)Rn and (220)Rn): Do they differ in high and normal background radiation areas in India?

PubMed

Mishra, Rosaline; Sapra, B K; Prajith, R; Rout, R P; Jalaluddin, S; Mayya, Y S

2015-09-01

In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes ((222)Rn and (220)Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to (222)Rn and (220)Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated (222)Rn and (220)Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to (222)Rn and (220)Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. Copyright © 2015 Elsevier Ltd. All rights reserved.

Metabolic and physiological adjustment of Suaeda maritima to combined salinity and hypoxia

PubMed Central

Behr, Jan H.; Bouchereau, Alain; Berardocco, Solenne; Seal, Charlotte E.; Flowers, Timothy J.

2017-01-01

Background and Aims Suaeda maritima is a halophyte commonly found on coastal wetlands in the intertidal zone. Due to its habitat S. maritima has evolved tolerance to high salt concentrations and hypoxic conditions in the soil caused by periodic flooding. In the present work, the adaptive mechanisms of S. maritima to salinity combined with hypoxia were investigated on a physiological and metabolic level. Methods To compare the adaptive mechanisms to deficient, optimal and stressful salt concentrations, S. maritima plants were grown in a hydroponic culture under low, medium and high salt concentrations. Additionally, hypoxic conditions were applied to investigate the impact of hypoxia combined with different salt concentrations. A non-targeted metabolic approach was used to clarify the biochemical pathways underlying the metabolic and physiological adaptation mechanisms of S. maritima. Key Results Roots exposed to hypoxic conditions showed an increased level of tricarboxylic acid (TCA)-cycle intermediates such as succinate, malate and citrate. During hypoxia, the concentration of free amino acids increased in shoots and roots. Osmoprotectants such as proline and glycine betaine increased in concentrations as the external salinity was increased under hypoxic conditions. Conclusions The combination of high salinity and hypoxia caused an ionic imbalance and an increase of metabolites associated with osmotic stress and photorespiration, indicating a severe physiological and metabolic response under these conditions. Disturbed proline degradation in the roots induced an enhanced proline accumulation under hypoxia. The enhanced alanine fermentation combined with a partial flux of the TCA cycle might contribute to the tolerance of S. maritima to hypoxic conditions. PMID:28110268

The role of mesoscale meteorology in modulating the (222)Rn concentrations in Huelva (Spain)--impact of phosphogypsum piles.

PubMed

Hernández-Ceballos, M A; Vargas, A; Arnold, D; Bolívar, J P

2015-07-01

The combined analysis of (222)Rn activity concentrations and mesoscale meteorological conditions at Huelva city (Spain) was addressed in this study to understand the potential impact of phosphogypsum piles on the (222)Rn activity concentrations registered at this area. Hourly mean data from April 2012 to February 2013 registered at two sampling sites (Huelva city and in the background station of El Arenosillo, located 27 km to the south-east) have been used in the study. The results of the present study showed a large difference in mean radon concentrations between the two stations during the sampling period, 6.3 ± 0.4 Bq m(-3) at Huelva and 3.0 ± 0.2 Bq m(-3) at El Arenosillo. The analysis has demonstrated that hourly (222)Rn concentrations at Huelva city above 22 Bq m(-3), with nocturnal peaks up to 50 Bq/m(3), mainly coincided with the occurrence of a pure sea-land breeze cycle. Mesoscale circulations in this region are mainly characterized by two patterns of sea-land breeze, pure and non-pure, with the phosphosypsum piles directly upstream (south) of the city during the afternoon on pure sea-breeze days. The difference between mean (222)Rn activity concentrations at Huelva city were 9.9 ± 1.5 Bq m(-3) for the pure pattern and 3.3 ± 0.5 Bq m(-3) for the non-pure pattern, while in the background station concentrations were 3.9 ± 0.4 Bq m(-3) and 2.8 ± 0.4 Bq m(-3) respectively. Considering these large differences, a detailed analysis of composites and case studies of representative sea-land breeze cycles of both types and their impact on (222)Rn activity concentration was performed. The results suggested that the presence of the phosphogypsum piles was necessary in order to justify the high (222)Rn activity concentrations observed at Huelva compared with the background station in the afternoons on pure sea breeze days (1.5-2.0 Bq m(-3)). On the other hand, large night time differences between the two sites on these days were likely to be associated with a combination of shallow density currents travelling down the Guadalquivir valley and, again, the presence of phosphogypsum piles. The results have demonstrated a significant impact of the phosphogypsum piles on (222)Rn activity concentrations in Huelva city during the occurrence of pure sea breeze days. Copyright © 2015 Elsevier Ltd. All rights reserved.

Exploring atmospheric radon with airborne gamma-ray spectroscopy

NASA Astrophysics Data System (ADS)

Baldoncini, Marica; Albéri, Matteo; Bottardi, Carlo; Minty, Brian; Raptis, Kassandra G. C.; Strati, Virginia; Mantovani, Fabio

2017-12-01

222Rn is a noble radioactive gas produced along the 238U decay chain, which is present in the majority of soils and rocks. As 222Rn is the most relevant source of natural background radiation, understanding its distribution in the environment is of great concern for investigating the health impacts of low-level radioactivity and for supporting regulation of human exposure to ionizing radiation in modern society. At the same time, 222Rn is a widespread atmospheric tracer whose spatial distribution is generally used as a proxy for climate and pollution studies. Airborne gamma-ray spectroscopy (AGRS) always treated 222Rn as a source of background since it affects the indirect estimate of equivalent 238U concentration. In this work the AGRS method is used for the first time for quantifying the presence of 222Rn in the atmosphere and assessing its vertical profile. High statistics radiometric data acquired during an offshore survey are fitted as a superposition of a constant component due to the experimental setup background radioactivity plus a height dependent contribution due to cosmic radiation and atmospheric 222Rn. The refined statistical analysis provides not only a conclusive evidence of AGRS 222Rn detection but also a (0.96 ± 0.07) Bq/m3 222Rn concentration and a (1318 ± 22) m atmospheric layer depth fully compatible with literature data.

Degradation of indoor limonene by outdoor ozone: A cascade of secondary organic aerosols.

PubMed

Rösch, Carolin; Wissenbach, Dirk K; Franck, Ulrich; Wendisch, Manfred; Schlink, Uwe

2017-07-01

In indoor air, terpene-ozone reactions can form secondary organic aerosols (SOA) in a transient process. 'Real world' measurements conducted in a furnished room without air conditioning were modelled involving the indoor background of airborne particulate matter, outdoor ozone infiltrated by natural ventilation, repeated transient limonene evaporations, and different subsequent ventilation regimes. For the given setup, we disentangled the development of nucleated, coagulated, and condensed SOA fractions in the indoor air and calculated the time dependence of the aerosol mass fraction (AMF) by means of a process model. The AMF varied significantly between 0.3 and 5.0 and was influenced by the ozone limonene ratio and the background particles which existed prior to SOA formation. Both influencing factors determine whether nucleation or adsorption processes are preferred; condensation is strongly intensified by particulate background. The results provide evidence that SOA levels in natural indoor environments can surpass those known from chamber measurements. An indicator for the SOA forming potential of limonene was found to be limona ketone. Multiplying its concentration (in μg/m 3 ) by 450(±100) provides an estimate of the concentration of the reacted limonene. This can be used to detect a high particle formation potential due to limonene pollution, e.g. in epidemiological studies considering adverse health effects of indoor air pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sample processing approach for detection of ricin in surface samples.

PubMed

Kane, Staci; Shah, Sanjiv; Erler, Anne Marie; Alfaro, Teneile

2017-12-01

With several ricin contamination incidents reported over the past decade, rapid and accurate methods are needed for environmental sample analysis, especially after decontamination. A sample processing method was developed for common surface sampling devices to improve the limit of detection and avoid false negative/positive results for ricin analysis. Potential assay interferents from the sample matrix (bleach residue, sample material, wetting buffer), including reference dust, were tested using a Time-Resolved Fluorescence (TRF) immunoassay. Test results suggested that the sample matrix did not cause the elevated background fluorescence sometimes observed when analyzing post-bleach decontamination samples from ricin incidents. Furthermore, sample particulates (80mg/mL Arizona Test Dust) did not enhance background fluorescence or interfere with ricin detection by TRF. These results suggested that high background fluorescence in this immunoassay could be due to labeled antibody quality and/or quantity issues. Centrifugal ultrafiltration devices were evaluated for ricin concentration as a part of sample processing. Up to 30-fold concentration of ricin was observed by the devices, which serve to remove soluble interferents and could function as the front-end sample processing step to other ricin analytical methods. The procedure has the potential to be used with a broader range of environmental sample types and with other potential interferences and to be followed by other ricin analytical methods, although additional verification studies would be required. Published by Elsevier B.V.

Adsorption Removal of 17β-Estradiol from Water by Rice Straw-Derived Biochar with Special Attention to Pyrolysis Temperature and Background Chemistry.

PubMed

Wang, Xiaohua; Liu, Ni; Liu, Yunguo; Jiang, Luhua; Zeng, Guangming; Tan, Xiaofei; Liu, Shaobo; Yin, Zhihong; Tian, Sirong; Li, Jiang

2017-10-11

Rice straw biochar that produced at three pyrolysis temperatures (400, 500 and 600 °C) were used to investigate the adsorption properties of 17β-estradiol (E2). The biochar samples were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), elemental analysis and BET surface area measurements. The influences of pyrolysis temperature, E2 concentration, pH, ionic strength, background electrolyte and humic acid were studied. Kinetic and isotherm results illustrated that the adsorption process could be well described by pseudo-second-order and Freundlich models. Experimental results showed that ionic strength had less influence on the adsorption of E2 by 500 and 600 °C rice straw biochar. Further, multivalent ions had positive impact on E2 removal than monovalent ions and the influence of the pyrolysis temperature was unremarkable when background electrolyte existed in solutions. The adsorption capacity of E2 decreased with the pH ranged from 3.0 to 12.0 and the humic acid concentration from 2 to 10 mg L -1 . Electrostatic attractions and π-π interaction were involved in the adsorption mechanisms. Compared to low-temperature biochar, high-temperature biochar exhibited a better adsorption capacity for E2 in aqueous solution, indicated it had a greater potential for E2 pollution control.

Adsorption Removal of 17β-Estradiol from Water by Rice Straw-Derived Biochar with Special Attention to Pyrolysis Temperature and Background Chemistry

PubMed Central

Wang, Xiaohua; Liu, Ni; Liu, Yunguo; Jiang, Luhua; Zeng, Guangming; Tan, Xiaofei; Liu, Shaobo; Yin, Zhihong; Tian, Sirong; Li, Jiang

2017-01-01

Rice straw biochar that produced at three pyrolysis temperatures (400, 500 and 600 °C) were used to investigate the adsorption properties of 17β-estradiol (E2). The biochar samples were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), elemental analysis and BET surface area measurements. The influences of pyrolysis temperature, E2 concentration, pH, ionic strength, background electrolyte and humic acid were studied. Kinetic and isotherm results illustrated that the adsorption process could be well described by pseudo-second-order and Freundlich models. Experimental results showed that ionic strength had less influence on the adsorption of E2 by 500 and 600 °C rice straw biochar. Further, multivalent ions had positive impact on E2 removal than monovalent ions and the influence of the pyrolysis temperature was unremarkable when background electrolyte existed in solutions. The adsorption capacity of E2 decreased with the pH ranged from 3.0 to 12.0 and the humic acid concentration from 2 to 10 mg L−1. Electrostatic attractions and π-π interaction were involved in the adsorption mechanisms. Compared to low-temperature biochar, high-temperature biochar exhibited a better adsorption capacity for E2 in aqueous solution, indicated it had a greater potential for E2 pollution control. PMID:29019933

Aircraft emission impacts in a neighborhood adjacent to a general aviation airport in southern California.

PubMed

Hu, Shishan; Fruin, Scott; Kozawa, Kathleen; Mara, Steve; Winer, Arthur M; Paulson, Suzanne E

2009-11-01

Real time air pollutant concentrations were measured downwind of Santa Monica Airport (SMA), using an electric vehicle mobile platform equipped with fast response instruments in spring and summer of 2008. SMA is a general aviation airport operated for private aircraft and corporate jets in Los Angeles County, California. An impact area of elevated ultrafine particle (UFP) concentrations was observed extending beyond 660 m downwind and 250 m perpendicular to the wind on the downwind side of SMA. Aircraft operations resulted in average UFP concentrations elevated by factors of 10 and 2.5 at 100 and 660 m downwind, respectively, over background levels. The long downwind impact distance (i.e., compared to nearby freeways at the same time of day) is likely primarily due to the large volumes of aircraft emissions containing higher initial concentrations of UFP than on-road vehicles. Aircraft did not appreciably elevate average levels of black carbon (BC), particle-bound polycyclic aromatic hydrocarbons (PB-PAH), although spikes in concentration of these pollutants were observed associated with jet takeoffs. Jet departures resulted in peak 60-s average concentrations of up to 2.2 x 10(6) cm(-3), 440 ng m(-3), and 30 microg m(-3) for UFP, PB-PAH, and BC, respectively, 100 m downwind of the takeoff area. These peak levels were elevated by factors of 440, 90, and 100 compared to background concentrations. Peak UFP concentrations were reasonably correlated (r(2) = 0.62) with fuel consumption rates associated with aircraft departures, estimated from aircraft weights and acceleration rates. UFP concentrations remained elevated for extended periods associated particularly with jet departures, but also with jet taxi and idle, and operations of propeller aircraft. UFP measured downwind of SMA had a median mode of about 11 nm (electric mobility diameter), which was about half of the 22 nm median mode associated with UFP from heavy duty diesel trucks. The observation of highly elevated ultrafine particle concentrations in a large residential area downwind of this local airport has potential health implications for persons living near general aviation airports.

PM10 Concentration levels at an urban and background site in Cyprus: The impact of urban sources and dust storms

PubMed Central

Achilleos, Souzana; Evans, John S.; Yiallouros, Panayiotis K.; Kleanthous, Savvas; Schwartz, Joel; Koutrakis, Petros

2016-01-01

Air quality in Cyprus is influenced by both local and transported pollution including desert dust storms. We examined PM10 concentration data collected in Nicosia (urban representative) from April 1, 1993 through December 11, 2008, and Ayia Marina (rural background representative) from January 1, 1999 through December 31, 2008. Measurements were conducted using a Tapered Element Oscillating Micro-balance (TEOM). PM10 concentrations, meteorological records and satellite data were used to identify dust storm days. We investigated long term trends using a Generalized Additive Model (GAM) after controlling for day of week, month, temperature, wind speed, and relative humidity. In Nicosia, annual PM10 concentrations ranged from 50.4 to 63.8 μg/m3 and exceeded the EU annual standard limit enacted in 2005 of 40 μg/m3 every year. A large, statistically significant impact of urban sources (defined as the difference between urban and background levels) was seen in Nicosia over the period 2000–2008, and was highest during traffic hours, weekdays, cold months, and low wind conditions. Our estimate of the mean (standard error) contribution of urban sources to the daily ambient PM10 was 24.0 (0.4) μg/m3. The study of yearly trends showed that PM10 levels in Nicosia decreased from 59.4 μg/m3 in 1993 to 49.0 μg/m3 in 2008, probably in part as a result of traffic emission control policies in Cyprus. In Ayia Marina, annual concentrations ranged from 27.3 to 35.6 μg/m3, and no obvious time trends were observed. The levels measured at the Cyprus background site are comparable to background concentrations reported in other Eastern Mediterranean countries. Average daily PM10 concentrations during desert dust storms were around 100 μg/m3 since 2000 and much higher in earlier years. Despite the large impact of dust storms and their increasing frequency over time, dust storms were responsible for a small fraction of the exceedances of the daily PM10 limit. PMID:25562931

Water-quality conditions in the New River, Imperial County, California

USGS Publications Warehouse

Setmire, James G.

1979-01-01

The New River, when entering the United States at Calexico, Calif., often contains materials which have the appearance of industrial and domestic wastes. Passage of some of these materials is recognized by a sudden increase in turbidity over background levels and the presence of white particulate matter. Water samples taken during these events are usually extremely high in organic content. During a 4-day reconnaissance of water quality in May 1977, white-to-brown extremely turbid water crossed the border on three occasions. On one of these occasions , the water was intensively sampled. The total organic-carbon concentration ranged from 80 to 161 milligrams per liter (mg/l); dissolved organic carbon ranged from 34 to 42 mg/l, and the chemical oxygen demand was as high as 510 mg/l. River profiles showed a dissolved-oxygen sag, with the length of the zone of depressed dissolved-oxygen concentrations varying seasonally. During the summer months, dissolved-oxygen concentrations in the river were lower and the zone of depressed dissolved-oxygen concentrations was longer. The largest increases in dissolved-oxygen concentration from reaeration occurred at the three drop structures and the rock weir near Seeley. The effects of oxygen demanding materials crossing the border extended as far as Highway 80, 19.5 miles downstream from the international boundary at Calexico. Fish kills and anaerobic conditions were also detected as far as Highway 80. Standard bacteria indicator tests for fecal contamination showed a very high health-hazard potential near the border. (Woodard-USGS)

Diurnal cycling of urban aerosols under different weather regimes

NASA Astrophysics Data System (ADS)

Gregorič, Asta; Drinovec, Luka; Močnik, Griša; Remškar, Maja; Vaupotič, Janja; Stanič, Samo

2016-04-01

A one month measurement campaign was performed in summer 2014 in Ljubljana, the capital of Slovenia (population 280,000), aiming to study temporal and spatial distribution of urban aerosols and the mixing state of primary and secondary aerosols. Two background locations were chosen for this purpose, the first one in the city center (urban background - KIS) and the second one in the suburban background (Brezovica). Simultaneous measurements of black carbon (BC) and particle number size distribution of submicron aerosols (PM1) were conducted at both locations. In the summer season emission from traffic related sources is expected to be the main local contribution to BC concentration. Concentrations of aerosol species and gaseous pollutants within the planetary boundary layer are controlled by the balance between emission sources of primary aerosols and gases, production of secondary aerosols, chemical reactions of precursor gases under solar radiation and the rate of dilution by mixing within the planetary boundary layer (PBL) as well as with tropospheric air. Only local emission sources contribute to BC concentration during the stable PBL with low mixing layer height, whereas during the time of fully mixed PBL, regionally transported BC and other aerosols can contribute to the surface measurements. The study describes the diurnal behaviour of the submicron aerosol at the urban and suburban background location under different weather regimes. Particles in three size modes - nucleation (< 25 nm, NUM), Aitken (25 - 90 nm, AIM) and accumulation mode (90 - 800 nm, ACM), as well as BC mass concentration were evaluated separately for sunny, cloudy and rainy days, taking into account modelled values of PBL height. Higher particle number and black carbon concentrations were observed at the urban background (KIS) than at the suburban background location (Brezovica). Significant diurnal pattern of total particle concentration and black carbon concentration was observed at both locations, with a distinct morning and late afternoon peak. As a consequence of different PBL dynamics and atmospheric processes (photochemical effects, humidity, wind speed and direction), diurnal profile differs for sunny, cloudy and rainy days. Nucleation mode particles were found to be subjected to lower daily variation and only slightly influenced by weather, as opposed to Aitken and accumulation mode particles. The highest correlation between BC and particle number concentration is observed during stable atmospheric conditions in the night and morning hours and is attributed to different particle size modes, depending on the distance to local BC emission sources. In sunny weather conditions, correlation between BC and particle number concentration decreases during the day due to mixing in the atmosphere and formation of secondary aerosols. Black carbon aging and mixing with secondary aerosols was additionally studied on the aerosol samples taken from the morning to the evening of a sunny day using SEM-EDX technique.

Developmental age strengthens barriers to ethanol accumulation in zebrafish.

PubMed

Lovely, C Ben; Nobles, Regina D; Eberhart, Johann K

2014-09-01

Fetal Alcohol Spectrum Disorders (FASD) describes a wide range of phenotypic defects affecting facial and neurological development associated with ethanol teratogenicity. It affects approximately 1 in 100 children born in the United States each year. Genetic predisposition along with timing and dosage of ethanol exposure are critical in understanding the prevalence and variability of FASD. The zebrafish attributes of external fertilization, genetic tractability, and high fecundity make it a powerful tool for FASD studies. However, a lack of consensus of ethanol treatment paradigms has limited the interpretation of these various studies. Here we address this concern by examining ethanol tissue concentrations across timing and genetic background. We utilize headspace gas chromatography to determine ethanol concentration in the AB, fli1:EGFP, and Tu backgrounds. In addition, we treated these embryos with ethanol over two different developmental time windows, 6-24 h post fertilization (hpf) and 24-48 hpf. Our analysis demonstrates that embryos rapidly equilibrate to a sub-media level of ethanol. Embryos then maintain this level of ethanol for the duration of exposure. The ethanol tissue concentration level is independent of genetic background, but is timing-dependent. Embryos exposed from 6 to 24 hpf were 2.7-4.2-fold lower than media levels, while embryos were 5.7-6.2-fold lower at 48 hpf. This suggests that embryos strengthen one or more barriers to ethanol as they develop. In addition, both the embryo and, to a lesser extent, the chorion, surrounding the embryo are barriers to ethanol. Overall, this work will help tighten ethanol treatment regimens and strengthen zebrafish as a model of FASD. Copyright © 2014 Elsevier Inc. All rights reserved.

Concentration of the Most-Cited Papers in the Scientific Literature: Analysis of Journal Ecosystems

PubMed Central

Ioannidis, John P. A.

2006-01-01

Background A minority of scientific journals publishes the majority of scientific papers and receives the majority of citations. The extent of concentration of the most influential articles is less well known. Methods/Principal Findings The 100 most-cited papers in the last decade in each of 21 scientific fields were analyzed; fields were considered as ecosystems and their “species” (journal) diversity was evaluated. Only 9% of journals in Journal Citation Reports had published at least one such paper. Among this 9%, half of them had published only one such paper. The number of journals that had published a larger number of most-cited papers decreased exponentially according to a Lotka law. Except for three scientific fields, six journals accounted for 53 to 94 of the 100 most-cited papers in their field. With increasing average number of citations per paper (citation density) in a scientific field, concentration of the most-cited papers in a few journals became even more prominent (p<0.001). Concentration was unrelated to the number of papers published or number of journals available in a scientific field. Multidisciplinary journals accounted for 24% of all most-cited papers, with large variability across fields. The concentration of most-cited papers in multidisciplinary journals was most prominent in fields with high citation density (correlation coefficient 0.70, p<0.001). Multidisciplinary journals had published fewer than eight of the 100 most-cited papers in eight scientific fields (none in two fields). Journals concentrating most-cited original articles often differed from those concentrating most-cited reviews. The concentration of the most-influential papers was stronger than the already prominent concentration of papers published and citations received. Conclusions Despite a plethora of available journals, the most influential papers are extremely concentrated in few journals, especially in fields with high citation density. Existing multidisciplinary journals publish selectively most-cited papers from fields with high citation density. PMID:17183679

[Observation study on aerosol optical properties and radiative forcing using the ground-based and satellite remote sensing at background station during the regional pollution episodes].

PubMed

Zhang, Xiao-Ling; Xia, Xiang-Ao; Che, Hui-Zheng; Tang, Jie; Tang, Yi-Xi; Meng, Wei; Dong, Fan

2014-07-01

The significant effect of anthropogenic pollutants transportation on the physical and optical properties of regional background atmospheric aerosol was studied by using ground-based and satellite remote sensing data obtained at the atmospheric background station (Shangdianzi, Beijing) of North China during October 1 to 15 in 2011. The aerosol mass concentration and reactive gases concentration increased obviously during periods of October 4-5, October 7-9, and October 11-12. Comparing with the background period of October 1-3, volume concentration increased by a factor of 3-6 for reactive gases such as NO(x), and CO, and a factor of 10-20 for SO2. Mass concentration of PM2.5 was about 200 microg x m(-3) on October 9. During haze period, the AOD at 500 nm varied between 0.60 to 1.00. The single scattering albedo (SSA) was lower than 0.88. And the black carbon concentration increased 4-8 times, which suggested the aerosol absorption was very strong during this pollution episode. The absorption of aerosol particles could cause 100-400 W x m(-2) increase of atmospheric radiation. The surface radiation decreased by about 100-300 W x m(-2) due to the aerosol scattering and absorption. This could cause higher stability of atmosphere, which will significantly affect the cloud and precipitation, and thus the regional weather and climate.

Assessment of contamination from arsenical pesticide use on orchards in the great valley region, Virginia and West Virginia, USA

USGS Publications Warehouse

Robinson, G.R.; Larkin, S.P.; Boughton, C.J.; Reed, B.W.; Sibrell, P.L.

2007-01-01

Lead arsenate pesticides were widely used in apple orchards from 1925 to 1955. Soils from historic orchards in four counties in Virginia and West Virginia contained elevated concentrations of As and Pb, consistent with an arsenical pesticide source. Arsenic concentrations in approximately 50% of the orchard site soils and approximately 1% of reference site soils exceed the USEPA Preliminary Remediation Goal (PRG) screening guideline of 22 mg kg-1 for As in residential soi, defined on the basis of combined chronic exposure risk. Approximately 5% of orchard site soils exceed the USEPA PRG for Pb of 400 mg kg-1 in residential soil; no reference site soils sampled exceed this value. A variety of statistical methods were used to characterize the occurrence, distribution, and dispersion of arsenical pesticide residues in soils, stream sediments, and ground waters relative to landscape features and likely background conditions. Concentrations of Zn, Pb, and Cu were most strongly associated with high developed land density and population density, whereas elevated concentrations of As were weakly correlated with high orchard density, consistent with a pesticide residue source. Arsenic concentrations in ground water wells in the region are generally <0.005 mg L-1. There was no spatial association between As concentrations in ground water and proximity to orchards. Arsenic had limited mobility into ground water from surface soils contaminated with arsenical pesticide residues at concentrations typically found in orchards. ?? ASA, CSSA, SSSA.

Ambient concentrations of total suspended particulate matter and its elemental constituents at the wider area of the mining facilities of TVX Hellas in Chalkidiki, Greece.

PubMed

Gaidajis, George

2003-01-01

To assess ambient air quality at the wider area of TVX Hellas mining facilities, the Total Suspended Particulate matter (TSP) and its content in characteristic elements, i.e., As, Cd, Cu, Fe, Mn, Pb, Zn are being monitored for more than thirty months as part of the established Environmental Monitoring Program. High Volume air samplers equipped with Tissue Quartz filters were employed for the collection of TSP. Analyses were effected after digestion of the suspended particulate with an HNO3-HCl solution and determination of elemental concentrations with an Atomic Absorption Spectroscopy equipped with graphite furnace. The sampling stations were selected to record representatively the existing ambient air quality in the vicinity of the facilities and at remote sites not affected from industrial activities. Monitoring data indicated that the background TSP concentrations ranged from 5-60 microg/m3. Recorded TSP concentrations at the residential sites close to the facilities ranged between 20-100 microg/m3, indicating only a minimal influence from the mining and milling activities. Similar spatial variation was observed for the TSP constituents and specifically for Pb and Zn. To validate the monitoring procedures, a parallel sampling campaign took place with different High Volume samplers at days where low TSP concentrations were expected. The satisfactory agreement (+/- 11%) at low concentrations (50-100 microg/m3) clearly supported the reproducibility of the techniques employed specifically at the critical range of lower concentrations.

Naturally Elevated Monomethylmercury and Mercury Concentrations of Redwood Trees of Coastal California

NASA Astrophysics Data System (ADS)

Rytuba, J. J.

2014-12-01

Redwood trees (Sequoia sempervirens) of coastal California acquire up to a third of their annual water through direct foliar uptake from summer coastal fog. Coastal fog contains elevated concentrations of monomethylmercury (MMeHg) up to 9.8 ng/L (Weiss-Penzias et al., Geophys Res Letters, 39). MMeHg introduced by fog is concentrated in old growth redwood trees throughout their distribution along the California coast. High concentrations of MMeHg occur in living redwood needles (0.20 to 3.76 ng/g dry weight basis, dwb) and are about 2 orders of magnitude greater than typical in evergreen needles that do not receive coastal fog water. MMeHg concentration in living redwood needles changes seasonally reaching a maximum at the end of the fog season (October) and a minimum at the beginning of the fog season (March). Hg concentrations in living redwood needles range from 21.7 to 80.5 ng/g (dwb), comparable to reported values for evergreen needles from non-coastal trees. Redwoods planted in the suburban landscape inland from the coastal fog belt have considerably lower MMeHg concentrations (<0.20 ng/g) but similar Hg concentrations to redwoods in their natural coastal environment. Redwood needles die after 3 years and contain comparable concentrations of MMeHg to those in living needles from the same old growth redwoods but Hg concentrations are much higher (up to 142 ng/g) since Hg accumulates throughout the life of the needle. Stream waters in old growth redwood forests under low and high flow conditions have very low concentrations of MMeHg (<.02 ng/L). However, under high flow conditions Hg concentrations are elevated, up to 22 ng/L, compared to low flow conditions (1.3-3.15 ng/L) and in rainwater (5.4 ng/L). MMeHg concentrations in stream waters are not elevated because MMeHg is retained in redwood needles. Hg concentrations in high flow stream waters are elevated because soils developed under old growth redwoods have elevated concentrations of Hg, up to 280 ng/g (3 times background), resulting from decomposition of litter and transformation of MMeHg to Hg-humic acid complexes (79-91%), and HgS and Hgo (8-20%) as indicated by sequential selective chemical extractions. Because of the high biomass density and annual litter fall, 850 g of Hg and 23 g of MMeHg per ha are added to the redwood ecosystem over a 2000 year life span.

Phosphorus-defect interactions during thermal annealing of ion implanted silicon

NASA Astrophysics Data System (ADS)

Keys, Patrick Henry

Ion implantation of dopant atoms into silicon generates nonequilibrium levels of crystal defects that can lead to the detrimental effects of transient enhanced diffusion (TED), incomplete dopant activation, and p-n junction leakage. In order to control these effects, it is vital to have a clear understanding of dopant-defect interactions and develop models that account for these interactions. This research focuses on experimentally investigating and modeling the clustering of phosphorus dopant atoms with silicon interstitials. Damage recovery of 40keV Si+ implants in phosphorus doped wells is experimentally analyzed. The effects of background phosphorus concentration, self implant dose, and anneal temperature are investigated. Phosphorus concentrations ranging from 2.0 x 1017 to 4.0 x 1019 cm-3 and Si+ doses ranging from 5.0 x 1013 cm-2 to 2.0 x 1014 cm-2 are studied during 650-800°C anneals. A dramatic reduction in the number of interstitials bound in {311} defects with increasing phosphorus background concentration is observed. It is suggested that the reduction of interstitials in {311} defects at high phosphorus concentrations is due to the formation of phosphorus-interstitial clusters (PICs). The critical concentration for clustering (approximately 1.0 x 1019 cm-3 at 750°C) is strongly temperature dependent and in close agreement with the kink concentration of phosphorus diffusion. Information gained from these "well experiments" is applied to the study of direct phosphorus implantation. An experimental study is conducted on 40keV phosphorus implanted to a dose of 1.0 x 1014 cm-2 during 650-800°C anneals. Electrically inactive PICs are shown to form at concentrations below the solid solubility limit due to high interstitial supersaturations. Data useful for developing a model to accurately predict phosphorus diffusion under nonequilibrium conditions are extracted from the experimental results. A cluster-mediated diffusion model is developed using the Florida Object Oriented Process Simulator (FLOOPS). The nucleation of defects is controlled by the diffusion-limited competition for excess interstitials between PICs and {311} clusters. The release of interstitials is driven by cluster dissolution. Modeling results show a strong correlation to those experimentally observed over a wide temporal and thermal domain using a single set of parameters. Improvements in process simulator accuracy are demonstrated with respect to dopant activation, TED, and dose loss.

Mass-transport limitations in spot-based microarrays.

PubMed

Zhao, Ming; Wang, Xuefeng; Nolte, David

2010-09-20

Mass transport of analyte to surface-immobilized affinity reagents is the fundamental bottleneck for sensitive detection in solid-support microarrays and biosensors. Analyte depletion in the volume adjacent to the sensor causes deviation from ideal association, significantly slows down reaction kinetics, and causes inhomogeneous binding across the sensor surface. In this paper we use high-resolution molecular interferometric imaging (MI2), a label-free optical interferometry technique for direct detection of molecular films, to study the inhomogeneous distribution of intra-spot binding across 100 micron-diameter protein spots. By measuring intra-spot binding inhomogeneity, reaction kinetics can be determined accurately when combined with a numerical three-dimensional finite element model. To ensure homogeneous binding across a spot, a critical flow rate is identified in terms of the association rate k(a) and the spot diameter. The binding inhomogeneity across a spot can be used to distinguish high-affinity low-concentration specific reactions from low-affinity high-concentration non-specific binding of background proteins.

Development of a Pulsed 2-Micron Integrated Path Differential Absorption Lidar for CO2 Measurement

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Refaat, Tamer

2013-01-01

Atmospheric carbon dioxide (CO2) is an important greenhouse gas that significantly contributes to the carbon cycle and global radiation budget on Earth. Active remote sensing of CO2 is important to address several limitations that contend with passive sensors. A 2-micron double-pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This active remote sensing instrument will provide an alternate approach of measuring atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise ratio level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement. Commercial, on the shelf, components are implemented for the detection system. Instrument integration will be presented in this paper as well as a background for CO2 measurement at NASA Langley research Center

Potential Air Toxics Hot Spots in Truck Terminals and Cabs

PubMed Central

Smith, Thomas J.; Davis, Mary E.; Hart, Jaime E.; Blicharz, Andrew; Laden, Francine; Garshick, Eric

2016-01-01

INTRODUCTION Hot spots are areas where concentrations of one or more air toxics — organic vapors or particulate matter (PM) — are expected to be elevated. The U.S. Environmental Protection Agency’s (EPA*) screening values for air toxics were used in our definition of hot spots. According to the EPA, a screening value “is used to indicate a concentration of a chemical in the air to which a person could be continually exposed for a lifetime … and which would be unlikely to result in a deleterious effect (either cancer or noncancer health effects)” (U.S. EPA 2006). Our characterization of volatile organic compounds (VOCs; namely 18 hydrocarbons, methyl tert-butyl ether [MTBE], acetone, and aldehydes) was added onto our ongoing National Cancer Institute–funded study of lung cancer and particulate pollutant concentrations (PM with an aerodynamic diameter ≤ 2.5 µm [PM2.5], elemental carbon [EC], and organic carbon [OC]) and source apportionment of the U.S. trucking industry. We focused on three possible hot spots within the trucking terminals: upwind background areas affected by nearby industrial parks; downwind areas affected by upwind and terminal sources; and the loading docks and mechanic shops within terminal as well as the interior of cabs of trucks being driven on city, suburban, and rural streets and on highways. METHODS In Phase 1 of our study, 15 truck terminals across the United States were each visited for five consecutive days. During these site visits, sorbent tubes were used to collect 12-hour integrated samples of hydrocarbons and aldehydes from upwind and downwind fence-line locations as well as inside truck cabs. Meteorologic data and extensive site information were collected with each sample. In Phase 2, repeat visits to six terminals were conducted to test the stability of concentrations across time and judge the representativeness of our previous measurements. During the repeat site visits, the sampling procedure was expanded to include real-time sampling for total hydrocarbon (HC) and PM2.5 at the terminal upwind and downwind sites and inside the truck cabs, two additional monitors in the yard for four-quadrant sampling to better characterize the influence of wind, and indoor sampling in the loading dock and mechanic shop work areas. RESULTS Mean and median concentrations of VOCs across the sampling locations in and around the truck terminals showed significant variability in the upwind concentrations as well as in the intensity of exposures for drivers, loading-dock workers, and mechanics. The area of highest concentrations varied, although the lowest concentrations were always found in the upwind background samples. However, the downwind samples, which included the terminal’s contribution, were on average only modestly higher than the upwind samples. In the truck terminal, the mechanic-shop-area concentrations were consistently elevated for many of the VOCs (including the xylenes, alkanes, and acetone) and particulates; the loading-dock concentrations had relatively high concentrations of 1,3-butadiene, formaldehyde, and acetaldehyde; and nonsmoking driver exposures were elevated for benzene, MTBE, styrene, and hexane. Also, the loading dock and yard background concentrations for EC and PM2.5 were highly correlated with many of the VOCs (50% of pairs tested with Spearman r > 0.5 and 75% with r > 0.4); in the mechanic shop VOCs were correlated with EC but not PM2.5 (r = 0.4–0.9 where significant); and for driver exposures VOC correlations with EC and PM2.5 were relatively low, with the exception of a few aromatics, primarily benzene (r = 0.4–0.5). A principal component analysis of background source characteristics across the terminal locations that had repeat site visits identified three different groupings of variables (the “components”). This analysis suggested that a strong primary factor for hydrocarbons (alkanes and aromatics) was the major contributor to VOC variability in the yard upwind measurement. Aldehydes and acetone, which loaded onto the second and third components, were responsible for a smaller contribution to VOC variability. A multi-layer exposure model was constructed using structural equation modeling techniques that significantly predicted the yard upwind concentrations of individual VOCs as a function of wind speed, road proximity, and regional location (R2 = 0.5–0.9). This predicted value for the yard background concentration was then used to calculate concentrations for the loading dock and mechanic shop. Finally, we conducted a detailed descriptive analysis of the real-time data collected in the yard and in truck cabs during the six repeat site visits, which included more than 50 12-hour sessions at each sampling location. The real-time yard monitoring results suggested that under some conditions there was a clear upwind-to-downwind trend indicating a terminal contribution, which was not apparent in the integrated sampling data alone. They also suggested a nonlinear relationship with wind speed: calm conditions (wind speed < 2 mph) were associated with erratic upwind–downwind differences, lower wind speeds (2 to 10 mph) favored transport with little dilution, and higher wind speeds (> 10 mph) favored dilution and dispersal (more so for VOCs than for PM). Finally, an analysis of the real-time data for driver exposures in trucks with a global positioning system (GPS) matched with geographic information system (GIS) data suggested a clear influence of traffic and industrial sources along a given route with peaks in driver exposures. These peaks were largely associated with traffic, major intersections, idling at the terminals, and pickup and delivery (P&D) periods. However, VOCs and PM2.5 had different exposure patterns: VOCs exposures increased when the vehicle was stopped, and PM2.5 exposures increased during travel in traffic. CONCLUSIONS All three types of testing sites—upwind and downwind fence-line locations and inside truck cabs while in heavy traffic — met the established definition for a hot spot by having periods with concentrations of pollutants that exceeded the EPA’s screening values. Most frequently, the pollutants with concentrations exceeding the screening values were formaldehyde, acetaldehyde, and EC (which serves as a marker for diesel particulate); less frequently they were 1,3-butadiene and benzene. In the case of the downwind location of a single truck terminal without an aggregation of other sources, high concentrations of VOCs and PM were infrequent. Using structural equation modeling, a model was developed that could identify combinations of conditions and factors likely to produce hot spots. Source apportionment analyses showed that EC came predominantly from diesel emissions. As expected from the sites studied, organic vapors associated with vehicle emissions (C6–C8 alkanes and aromatics) were the predominant components of VOCs, followed by formaldehyde and acetaldehyde. For driver exposures, high VOC values were associated with stopped vehicles, and high PM2.5 values were associated with conditions during driving. PMID:23409510

Assessment of lead, cadmium, and zinc contamination of roadside soils, surface films, and vegetables in Kampala City, Uganda.

PubMed

Nabulo, Grace; Oryem-Origa, Hannington; Diamond, Miriam

2006-05-01

The relationship between traffic density and trace metal concentrations in roadside soils, surface films, and a selected vegetable weed, Amaranthus dubius Mart. Ex Thell., was determined in 11 farming sites along major highways around Kampala City in Uganda. Surface soil, atmospherically deposited surface films on windows, and leaves of Amaranthus dubius were sampled at known distances from the roads and analyzed for lead (Pb), zinc (Zn), and cadmium (Cd) using flame atomic absorption spectrophotometry. Atmospherically deposited trace metal particulates were sampled using window glass as an inert, passive collector. Total trace metal concentrations in soils ranged from 30.0+/-2.3 to 64.6+/-11.7 mg/kg Pb, 78.4+/-18.4 to 265.6+/-63.2 mg/kg Zn, and 0.8+/-0.13 to 1.40+/-0.16 mg/kg Cd. Total trace metal levels in soil decreased rapidly with distance from the road. Total Pb decreased with distance up to 30 m from the road, where it reached a background soil concentration of 28 mg/kg dry weight. The study found background values of 50 and 1.4 mg/kg for Zn and Cd in roadside soils, respectively. Similarly, Pb concentration in Amaranthus dubius leaves decreased with increasing distance from the road edge. The dominant pathway for Pb contamination was from atmospheric deposition, which was consistent with Pb concentrations in surface films. The mean Pb concentrations in leaves of roadside crops were higher than those in their respective roots, with the highest leaf-to-root ratio observed in the Brassica oleraceae acephala group. The lowest Pb and Zn concentrations were found in the fruit compared to the leaves of the same crops. Leaves of roadside vegetables were therefore considered a potential source of heavy metal contamination to farmers and consumers in urban areas. It is recommended that leafy vegetables should be grown 30 m from roads in high-traffic, urban areas.

Evolution of vehicle exhaust particles in the atmosphere.

PubMed

Canagaratna, Manjula R; Onasch, Timothy B; Wood, Ezra C; Herndon, Scott C; Jayne, John T; Cross, Eben S; Miake-Lye, Richard C; Kolb, Charles E; Worsnop, Douglas R

2010-10-01

Aerosol mass spectrometer (AMS) measurements are used to characterize the evolution of exhaust particulate matter (PM) properties near and downwind of vehicle sources. The AMS provides time-resolved chemically speciated mass loadings and mass-weighted size distributions of nonrefractory PM smaller than 1 microm (NRPM1). Source measurements of aircraft PM show that black carbon particles inhibit nucleation by serving as condensation sinks for the volatile and semi-volatile exhaust gases. Real-world source measurements of ground vehicle PM are obtained by deploying an AMS aboard a mobile laboratory. Characteristic features of the exhaust PM chemical composition and size distribution are discussed. PM mass and number concentrations are used with above-background gas-phase carbon dioxide (CO2) concentrations to calculate on-road emission factors for individual vehicles. Highly variable ratios between particle number and mass concentrations are observed for individual vehicles. NRPM1 mass emission factors measured for on-road diesel vehicles are approximately 50% lower than those from dynamometer studies. Factor analysis of AMS data (FA-AMS) is applied for the first time to map variations in exhaust PM mass downwind of a highway. In this study, above-background vehicle PM concentrations are highest close to the highway and decrease by a factor of 2 by 200 m away from the highway. Comparison with the gas-phase CO2 concentrations indicates that these vehicle PM mass gradients are largely driven by dilution. Secondary aerosol species do not show a similar gradient in absolute mass concentrations; thus, their relative contribution to total ambient PM mass concentrations increases as a function of distance from the highway. FA-AMS of single particle and ensemble data at an urban receptor site shows that condensation of these secondary aerosol species onto vehicle exhaust particles results in spatial and temporal evolution of the size and composition of vehicle exhaust PM on urban and regional scales.

Assessment of lead, cadmium, and zinc contamination of roadside soils, surface films, and vegetables in Kampala City, Uganda

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

Nabulo, Grace; Oryem-Origa, Hannington; Diamond, Miriam

2006-05-15

The relationship between traffic density and trace metal concentrations in roadside soils, surface films, and a selected vegetable weed, Amaranthus dubius Mart. Ex Thell., was determined in 11 farming sites along major highways around Kampala City in Uganda. Surface soil, atmospherically deposited surface films on windows, and leaves of Amaranthus dubius were sampled at known distances from the roads and analyzed for lead (Pb), zinc (Zn), and cadmium (Cd) using flame atomic absorption spectrophotometry. Atmospherically deposited trace metal particulates were sampled using window glass as an inert, passive collector. Total trace metal concentrations in soils ranged from 30.0{+-}2.3 to 64.6{+-}11.7more » mg/kg Pb, 78.4{+-}18.4 to 265.6{+-}63.2 mg/kg Zn, and 0.8{+-}0.13 to 1.40{+-}0.16 mg/kg Cd. Total trace metal levels in soil decreased rapidly with distance from the road. Total Pb decreased with distance up to 30 m from the road, where it reached a background soil concentration of 28 mg/kg dry weight. The study found background values of 50 and 1.4 mg/kg for Zn and Cd in roadside soils, respectively. Similarly, Pb concentration in Amaranthus dubius leaves decreased with increasing distance from the road edge. The dominant pathway for Pb contamination was from atmospheric deposition, which was consistent with Pb concentrations in surface films. The mean Pb concentrations in leaves of roadside crops were higher than those in their respective roots, with the highest leaf-to-root ratio observed in the Brassica oleraceae acephala group. The lowest Pb and Zn concentrations were found in the fruit compared to the leaves of the same crops. Leaves of roadside vegetables were therefore considered a potential source of heavy metal contamination to farmers and consumers in urban areas. It is recommended that leafy vegetables should be grown 30 m from roads in high-traffic, urban areas.« less

Li 2Se as a Neutron Scintillator

DOE PAGES

Du, Mao-Hua; Shi, Hongliang; Singh, David J.

2015-06-23

We show that Li 2Se:Te is a potential neutron scintillator material based on density functional calculations. Li 2Se exhibits a number of properties favorable for efficient neutron detection, such as a high Li concentration for neutron absorption, a small effective atomic mass and a low density for reduced sensitivity to background gamma rays, and a small band gap for a high light yield. Our calculations show that Te doping should lead to the formation of deep acceptor complex V Li-Te Se, which can facilitate efficient light emission, similar to the emission activation in Te doped ZnSe.

[Gas pipeline leak detection based on tunable diode laser absorption spectroscopy].

PubMed

Zhang, Qi-Xing; Wang, Jin-Jun; Liu, Bing-Hai; Cai, Ting-Li; Qiao, Li-Feng; Zhang, Yong-Ming

2009-08-01

The principle of tunable diode laser absorption spectroscopy and harmonic detection technique was introduced. An experimental device was developed by point sampling through small multi-reflection gas cell. A specific line near 1 653. 7 nm was targeted for methane measurement using a distributed feedback diode laser as tunable light source. The linearity between the intensity of second harmonic signal and the concentration of methane was determined. The background content of methane in air was measured. The results show that gas sensors using tunable diode lasers provide a high sensitivity and high selectivity method for city gas pipeline leak detection.

Concentration of 129I in aquatic biota collected from a lake adjacent to the spent nuclear fuel reprocessing plant in Rokkasho, Japan.

PubMed

Ueda, Shinji; Kakiuchi, Hideki; Hasegawa, Hidenao; Kawamura, Hidehisa; Hisamatsu, Shun'ichi

2015-11-01

The spent nuclear fuel reprocessing plant in Rokkasho, Japan, has been undergoing final testing since March 2006. During April 2006-October 2008, that spent fuel was cut and chemically processed, the plant discharged (129)I into the atmosphere and coastal waters. To study (129)I behaviour in brackish Lake Obuchi, which is adjacent to the plant, (129)I concentrations in aquatic biota were measured by accelerator mass spectrometry. Owing to (129)I discharge from the plant, the (129)I concentration in the biota started to rise from the background concentration in 2006 and was high during 2007-08. The (129)I concentration has been rapidly decreasing after the fuel cutting and chemically processing were finished. The (129)I concentration factors in the biota were higher than those reported by IAEA for marine organisms and similar to those reported for freshwater biota. The estimated annual committed effective dose due to ingestion of foods with the maximum (129)I concentration in the biota samples was 2.8 nSv y(-1). © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Hydrocarbon concentrations at the Alpine mountain sites Jungfraujoch and Arosa

NASA Astrophysics Data System (ADS)

Li, Yingshi; Campana, Mike; Reimann, Stefan; Schaub, Daniel; Stemmler, Konrad; Staehelin, Johannes; Peter, Thomas

Volatile hydrocarbons have been measured for 1 yr at Arosa (2010 m asl) to determine the contribution of European emissions to the trace gas concentrations at this remote site. Results are compared to concurrent hydrocarbon concentrations at the high Alpine background site Jungfraujoch (3580 m asl). Hydrocarbon concentrations at Arosa are generally much higher than at Jungfraujoch. The influence of the Alpine boundary layer air was studied based on the diurnal variation of hydrocarbon concentrations, i.e. rising pollutant concentrations in the morning at Arosa and in the afternoon at Jungfraujoch. Different hydrocarbon emission sources of the uplifting air were found at the two sites. At Jungfraujoch, several transatlantic events were detected from October 2001 to January 2002 based on analysis of hydrocarbon ratios and air parcel trajectories. The OH concentration during the transatlantic transport was estimated to be around 5×10 5 cm -3, derived from simultaneous hydrocarbon oxidation and dilution in the free troposphere. These transatlantic transport events were tracked back to warm conveyor belts, characterized by uniform dynamics and relatively uniform surface sources. In addition, ozone production in the free tropospheric transport was also documented in these events.

Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

USGS Publications Warehouse

Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.

2015-09-16

Regarding highest concentrations and associated timing of exposure, trace metals analyzed in the sediment core seem to indicate three fairly distinct exposure patterns. For 11 trace metals that had the highest concentration measured in the shallowest and most recently deposited sediment, the most likely explanation is recent exposure by anthropogenic activities. Most of the 11 trace metals with highest concentrations in shallow sediment are relatively innocuous; however, arsenic, copper, selenium, and zinc are among the U.S. Environmental Protection Agency’s 126 priority pollutants. For three trace metals (cadmium, lead, and mercury), for which concentrations were highest in sediments that were 16–20 centimeters down the core, it is likely that a source associated with those contaminants during the period when those sediments were deposited, was reduced or eliminated. The eight remaining trace metals, for which concentrations were highest in sediments that were just below the prereservoir surface, likely had sources that were eliminated soon after lake construction or occurred at relatively high background concentrations in soils in the area around Little Rock Air Force Base.

Ice-nucleating particle concentrations unaffected by urban air pollution in Beijing, China

NASA Astrophysics Data System (ADS)

Chen, Jie; Wu, Zhijun; Augustin-Bauditz, Stefanie; Grawe, Sarah; Hartmann, Markus; Pei, Xiangyu; Liu, Zirui; Ji, Dongsheng; Wex, Heike

2018-03-01

Exceedingly high levels of PM2.5 with complex chemical composition occur frequently in China. It has been speculated whether anthropogenic PM2.5 may significantly contribute to ice-nucleating particles (INP). However, few studies have focused on the ice-nucleating properties of urban particles. In this work, two ice-nucleating droplet arrays have been used to determine the atmospheric number concentration of INP (NINP) in the range from -6 to -25 °C in Beijing. No correlations between NINP and either PM2.5 or black carbon mass concentrations were found, although both varied by more than a factor of 30 during the sampling period. Similarly, there were no correlations between NINP and either total particle number concentration or number concentrations for particles with diameters > 500 nm. Furthermore, there was no clear difference between day and night samples. All these results indicate that Beijing air pollution did not increase or decrease INP concentrations in the examined temperature range above values observed in nonurban areas; hence, the background INP concentrations might not be anthropogenically influenced as far as urban air pollution is concerned, at least in the examined temperature range.

Study on the Relationship between Manganese Concentrations in Rural Drinking Water and Incidence and Mortality Caused by Cancer in Huai'an City

PubMed Central

Zhang, Qin; Pan, Enchun; Liu, Linfei; Hu, Wei; He, Yuan; Xu, Qiujin; Liang, Cunzhen

2014-01-01

Background. Cancer is a significant disease burden in the world. Many studies showed that heavy metals or their compounds had connection with cancer. But the data conflicting about the relationship of manganese (Mn) to cancer are not enough. In this paper, the relationship was discussed between Mn concentrations in drinking water for rural residents and incidence and mortality caused by malignant tumors in Huai'an city. Methods. A total of 158 water samples from 28 villages of 14 towns were, respectively, collected during periods of high flow and low flow in 3 counties of Huai'an city, along Chinese Huai'he River. The samples of deep groundwater, shallow groundwater, and surface water were simultaneously collected in all selected villages. Mn concentrations in all water samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS 7500a). The correlation analysis was used to study the relationship between the Mn concentration and cancer incidence and mortality. Results. Mn concentrations detectable rate was 100% in all water samples. The mean concentration was 452.32 μg/L ± 507.76 μg/L. There was significant difference between the high flow period and low flow period (t = −5.23, P < 0.05) and also among deep groundwater, shallow groundwater, and surface water (F = 5.02, P < 0.05). The ratio of superscale of Mn was 75.32%. There was significant difference of Mn level between samples in the high flow period and low flow period (χ 2 = 45.62, P < 0.05) and also among deep groundwater, shallow groundwater, and surface water (χ 2 = 10.66, P < 0.05). And also we found that, during the low flow period, Mn concentration has positive correlation with cancer incidence and mortality; for a 1 μg/L increase in Mn concentration, there was a corresponding increase of 0.45/100000 new cancer cases and 0.35/100000 cancer deaths (P < 0.05). Conclusions. In Huai'an city, the mean concentration of Mn in drinking water was very high. Mn concentration correlated with cancer incidence and mortality. PMID:25530966

Ion chromatographic determination of lithium at trace level concentrations. Application to a tracer experiment in a high-mountain lake.

PubMed

Nickus, U; Thies, H

2001-06-22

The water residence time of a high-mountain seepage lake in the Austrian Alps was derived from the flushing rate of a tracer substance. A diluted lithium chloride solution was injected into the lake during holomictic conditions in order to favour the homogeneous distribution of the tracer. The exponential decline of the mass of lithium in the lake revealed a water residence time of 1.5 to 3 months for summer and almost no lake water exchange during winter. Lithium concentrations ranged from background values of 0.06 microg l(-1) to about 3 microg l(-1) immediately after the tracer injection. Lake water samples were analyzed with ion-exchange chromatography using a Dionex device with a CS 12A separation column. The method detection limit determined according to the definition of the US Envirinmental Protection Agency amounted to 0.009 microg l(-1).

Classroom Carbon Dioxide Concentration, School Attendance, and Educational Attainment

ERIC Educational Resources Information Center

Gaihre, Santosh; Semple, Sean; Miller, Janice; Fielding, Shona; Turner, Steve

2014-01-01

Background: We tested the hypothesis that classroom carbon dioxide (CO[subscript 2]) concentration is inversely related to child school attendance and educational attainment. Methods: Concentrations of CO[subscript 2] were measured over a 3-5?day period in 60 naturally ventilated classrooms of primary school children in Scotland. Concentrations of…

Profiles of lead in urban dust and the effect of the distance to multi-industry in an old heavy industry city in China.

PubMed

Yu, Yang; Li, Yingxia; Li, Ben; Shen, Zhenyao; Stenstrom, Michael K

2017-03-01

Lead (Pb) concentration in urban dust is often higher than background concentrations and can result in a wide range of health risks to local communities. To understand Pb distribution in urban dust and how multi-industrial activity affects Pb concentration, 21 sampling sites within the heavy industry city of Jilin, China, were analyzed for Pb concentration. Pb concentrations of all 21 urban dust samples from the Jilin City Center were higher than the background concentration for soil in Jilin Province. The analyses show that distance to industry is an important parameter determining health risks associated with Pb in urban dust. The Pb concentration showed an exponential decrease, with increasing distance from industry. Both maximum likelihood estimation and Bayesian analysis were used to estimate the exponential relationship between Pb concentration and distance to multi-industry areas. We found that Bayesian analysis was a better method with less uncertainty for estimating Pb dust concentrations based on their distance to multi-industry, and this approach is recommended for further study. Copyright © 2016. Published by Elsevier Inc.

Measurement of DDT fluxes from a historically treated agricultural soil in Canada.

PubMed

Kurt-Karakus, Perihan Binnur; Bidleman, Terry F; Staebler, Ralf M; Jones, Kevin C

2006-08-01

Organocohlorine pesticide (OCP) residues in agricultural soils are of concern due to the uptake of these compounds by crops, accumulation in the foodchain, and reemission from soils to the atmosphere. Although it has been about three decades since DDT was banned for agricultural uses in Canada, residues persist in soils of some agricultural areas. Emission of DDT compounds to the atmosphere from a historically treated field in southern Ontario was determined in fall 2004 and spring 2005. The sigmaDDTs concentration in the high organic matter (71%) soil was 19 +/- 4 microg g(-1) dry weight. Concentration gradients in the air were measured at 5, 20, 72, and 200 cm above soil using glass fiber filter-polyurethane foam cartridges. Air concentrations of sigmaDDTs averaged 5.7 +/- 5.1 ng m(-3) at 5 cm and decreased to 1.3 +/- 0.8 ng m(-3) at 200 cm and were 60-300 times higher than levels measured at a background site 30 km away. Soil-air fugacity fractions, fs/(fs + fa), of p,p'-DDE, p,p'-DDD, and p,p'-DDT ranged from 0.42 to 0.91 using air concentrations measured above the soil and > or = 0.99 using background air concentrations, indicating that the soil was a net source to the background air. Fractionation of DDT compounds during volatilization was predicted using either liquid-phase vapor pressures (PL) or octanol-air partition coefficients (KOA). Relative emissions of p,p'-DDE and p,p'-DDT were better described by PL than KOA, whereas either PL or KOA successfully accounted for the fractionation of p,p'-DDT and o,p'-DDT. Soil-to-air fluxes were calculated from air concentration gradients and turbulent exchange coefficients determined from micrometeorological measurements. Average fluxes of sigmaDDTs were 90 +/- 24 ng m(-2) h(-1) in fall and 660 +/- 370 ng m(-2) h(-1) in spring. Higher soil temperatures in spring accounted for the higher fluxes. A volatilization half-life of approximately 200 y was estimated for sigmaDDT in the upper 5 cm of the soil column, assuming the average flux rate for 12 h d-(1) over 8 months of the year. Thus, in the absence of other dissipation processes, the soil will continue to be a source of atmospheric contamination for a very long time.

A new method for the determination of Gadolinium in ppq levels

NASA Astrophysics Data System (ADS)

Brünjes, Robert; Bichler, Andrea; Hofmann, Thilo

2015-04-01

The use of Gadolinium (Gd) complexes as a contrast agent in Magnetic Resonance Imaging (MRI) results in an enhanced Gd input in the aquatic environment. Gd-complexes are excreted by humans unmetabolized within 12h after application. Passing the sewage systems with almost no degradation taking place, they successively reach surface waters, which make Gd a capable tracer for surface water/groundwater (SW/GW) interactions. The natural background concentration of Gd and other rare earth elements (REE) occur at ultratrace levels [low ng/L]. Crust-normalized REE patterns show positive Gd-anomalies in surface water, groundwater, and recently also in tap water. The difference between the total concentration and its natural background concentration estimated by the REE pattern is the anthropogenic Gd. Not only densely populated areas are affected by the presence of anthropogenic Gd. Studies have shown that even in rural areas without MRI facilities, anthropogenic Gd can be detected, since people are sent home after treatment. However, low input concentrations and mixing with natural waters lead to a decrease of Gd concentration below the current limit of quantification (LOQ) [1-5ng/L]. Often anthropogenic Gd cannot be calculated, although it is present, because natural background concentration cannot be determined with current methods, in particular in areas with low waste water load (e.g. headwater catchments). A new method using an on-line preconcentration system "SeaFAST" (Elemental Scientific Inc., USA), in combination with a desolvation system "Apex Q" (Elemental Scientific Inc., USA) and a QQQ-ICP-MS instrument (Agilent Technologies, Japan) does lower the LOQ for REE by a factor of 10 to 20. The SeaFAST-system uses a resin with ethylenediaminetriacetic acid and iminodiacetic acid functional groups to preconcentrate specifically REE as they are exclusively trivalent while anions, alkali and alkaline earth cations are washed out. The Apex Q interface is also supposed to significantly lower oxide interferences. We also evaluate a pretreatment in order to degrade the complexes and reach high recoveries of anthropogenic Gd. Our method will provide a determination of REE in ppq-levels, that significantly improves the differentiation between naturally and anthropogenic Gd. This will allow the detection of less than 1% waste water in SW and GW and finally increase the areas where studies of anthropogenic Gd could be conducted. A first application of our method was conducted during a field study in November 2014.

POPs monitoring in Australia and New Zealand using plastic resin pellets, and International Pellet Watch as a tool for education and raising public awareness on plastic debris and POPs.

PubMed

Yeo, Bee Geok; Takada, Hideshige; Taylor, Heidi; Ito, Maki; Hosoda, Junki; Allinson, Mayumi; Connell, Sharnie; Greaves, Laura; McGrath, John

2015-12-15

Persistent organic pollutants (i.e. PCBs, DDTs, and HCHs) were analyzed along Australia and New Zealand North Island coastlines. PCB concentrations were high in urban areas (107-294 ng/g-pellet), with Sydney Harbour the most polluted. Hepta-chlorinated PCB was abundant, with ~30% in urban areas suggesting legacy pollution. DDT concentrations showed similar pattern except in rural agricultural sites, Taupo Bay and Ahipara, New Zealand (23 and 47 ng/g-pellet). p,p'-DDE predominance at these 2 sites suggested historical input; they also had high HCH concentrations (17 and 29 ng/g-pellet). The role of International Pellet Watch (IPW) in science communication was studied through feedbacks from IPW volunteers, case studies and examples. IPW data were categorized into understandable terms and tailored reports based on volunteers' backgrounds complemented with pollution maps. The effectiveness of IPW science communication has led to its use in awareness and education activities focusing on both POPs and plastic debris issues. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mercury concentrations in water from an unconfined aquifer system, New Jersey coastal plain

USGS Publications Warehouse

Barringer, J.L.; Szabo, Z.; Kauffman, L.J.; Barringer, T.H.; Stackelberg, P.E.; Ivahnenko, T.; Rajagopalan, S.; Krabbenhoft, D.P.

2005-01-01

Concentrations of total mercury (Hg) from 2 ??g/L (the USEPA maximum contaminant level) to 72 ??g/L in water from about 600 domestic wells in residential parts of eight counties in southern New Jersey have been reported by State and county agencies. The wells draw water from the areally extensive (7770 km2) unconfined Kirkwood-Cohansey aquifer system, in which background concentrations of Hg are about 0.01 ??g/L or less. Hg is present in most aquifer materials at concentrations 0.1 ??g/L did not correlate significantly with concentrations of the inorganic constituents. Hgf concentrations near or exceeding 2 ??g/L were found only in water from wells in areas with residential land use, but concentrations were at background levels in most water samples from undeveloped land. The spatial distribution of Hg-contaminated ground water appears to be locally and regionally heterogeneous; no extensive plumes of Hg contamination have yet been identified. ?? 2004 Elsevier B.V. All rights reserved.

Nitrogen and carbon flow from rock to water: Regulation through soil biogeochemical processes, Mokelumne River watershed, California, and Grand Valley, Colorado

USGS Publications Warehouse

Holloway, J.M.; Smith, R.L.

2005-01-01

Soil denitrification is an ecologically important nitrogen removal mechanism that releases to the atmosphere the greenhouse gas N2O, an intermediate product from the reduction of NO3- to N 2. In this study we evaluate the relationship between soil carbon and denitrification potential in watersheds with bedrock acting as a nonpoint source of nitrogen, testing the hypothesis that nitrate leaching to stream water is in part regulated by denitrification. Two sites, one in a Mediterranean climate and the other in an arid climate, were investigated to understand the interplay between carbon and denitrification potential. Both sites included carbonaceous bedrock with relatively high nitrogen concentrations (> 1,000 mg N kg-1) and had low background nitrogen concentrations in surface and groundwater. There was a net accumulation of carbon and nitrogen in soil relative to the corresponding bedrock, with the exception of carbonaceous shale from the arid site. There the concentration of carbon in the soil (15,620 mg C kg-1) was less than the shale parent (22,460 mg C kg-1), consistent with the bedrock being a source of soil carbon. Rates of denitrification potential (0.5-83 ??g N kg-1 hr-1) derived from laboratory incubations appeared to be related to the ratio of dissolved organic carbon and nitrate extracted from soils. These data indicate that microbial processes such as denitrification can help maintain background nitrogen concentrations to tens of ??M N in relatively undisturbed ecosystems when nitrogen inputs from weathering bedrock are accompanied by sufficient organic carbon concentrations to promote microbial nitrogen transformations.

Nanomaterial Containing Wall Paints Can Increase Radon Concentration in Houses Located in Radon Prone Areas

PubMed Central

Haghani, M.; Mortazavi, S. M. J.; Faghihi, R.; Mehdizadeh, S.; Moradgholi, J.; Darvish, L.; Fathi-Pour, E.; Ansari, L.; Ghanbar-pour, M. R.

2013-01-01

Background: Nowadays, extensive technological advancements have made it possible to use nanopaints which show exciting properties. In IR Iran excessive radon levels (up to 3700 Bq m–3) have been reported in homes located in radon prone areas. Over the past decades, concerns have been raised about the risk posed by residential radon exposure. Objective: This study aims at investigating the effect of using nanomaterial containing wall paints on radon concentration in homes. Methods: Two wooden model houses were used in this study. Soil samples from Ramsar high background radiation areas were used for simulating the situation of a typical house in radon-prone areas. Conventional water-soluble wall paint was used for painting the walls of the 1st house model; while the 2nd house model was painted with the same wall paint with montmorillonitenanoclay. Results: Three days after sealing the house models, radon level was measured by using a portable radon survey meter. The mean radon level inside the 1st house model (conventional paint) was 515.3 ± 17.8 Bq/m3 while the mean radon concentration in the 2nd house model (nano-painted house model) was 570.8 ± 18.5 Bq/m3. The difference between these means was statistically significant (P<0.001). Conclusion: To the best of our knowledge, this study is the first investigation on the effect of nano-material containing wall paints on indoor radon concentrations.  It can be concluded that nano-material-containing wall paints should not be used in houses with wooden walls located in radon prone areas. Although the mechanism of this effect is not clearly known, decreased porosity in nano-paints might be a key factor in increasing the radon concentration in homes. PMID:25505754

Ambient air concentrations exceeded health-based standards for fine particulate matter and benzene during the Deepwater Horizon oil spill.

PubMed

Nance, Earthea; King, Denae; Wright, Beverly; Bullard, Robert D

2016-02-01

The Deepwater Horizon oil spill is considered one of the largest marine oil spills in the history of the United States. Air emissions associated with the oil spill caused concern among residents of Southeast Louisiana. The purpose of this study was to assess ambient concentrations of benzene (n=3,887) and fine particulate matter (n=102,682) during the oil spill and to evaluate potential exposure disparities in the region. Benzene and fine particulate matter (PM2.5) concentrations in the targeted parishes were generally higher following the oil spill, as expected. Benzene concentrations reached 2 to 19 times higher than background, and daily exceedances of PM2.5 were 10 to 45 times higher than background. Both benzene and PM2.5 concentrations were considered high enough to exceed public health criteria, with measurable exposure disparities in the coastal areas closer to the spill and clean-up activities. These findings raise questions about public disclosure of environmental health risks associated with the oil spill. The findings also provide a science-based rationale for establishing health-based action levels in future disasters. Benzene and particulate matter monitoring during the Deepwater Horizon oil spill revealed that ambient air quality was a likely threat to public health and that residents in coastal Louisiana experienced significantly greater exposures than urban residents. Threshold air pollution levels established for the oil spill apparently were not used as a basis for informing the public about these potential health impacts. Also, despite carrying out the most comprehensive air monitoring ever conducted in the region, none of the agencies involved provided integrated analysis of the data or conclusive statements about public health risk. Better information about real-time risk is needed in future environmental disasters.

Soil chemistry and ground-water quality of the water-table zone of the surficial aquifer, Naval Submarine Base Kings Bay, Camden County, Georgia, 1998 and 1999

USGS Publications Warehouse

Leeth, David C.

2002-01-01

In 1998, the U.S. Geological Survey, in cooperation with the U.S. Department of the Navy, began an investigation to determine background ground-water quality of the water-table zone of the surficial aquifer and soil chemistry at Naval Submarine Base Kings Bay, Camden County, Georgia, and to compare these data to two abandoned solid- waste disposal areas (referred to by the U.S. Navy as Sites 5 and 16). The quality of water in the water-table zone generally is within the U.S. Environmental Protection Agency (USEPA) drinking-water regulation. The pH of ground water in the study area ranged from 4.0 to 7.6 standard units, with a median value of 5.4. Water from 29 wells is above the pH range and 3 wells are within the range of the USEPA secondary drinking-water regulation (formerly known as the Secondary Maximum Contaminant Level or SMCL) of 6.5 to 8.5 standard units. Also, water from one well at Site 5 had a chloride concentration of 570 milligrams per liter (mg/L,), which is above the USEPA secondary drinking-water regulation of 250 mg/L. Sulfate concentrations in water from two wells at Site 5 are above the USEPA secondary drinking-water regulation of 250 mg/L. Of 22 soil-sampling locations for this study, 4 locations had concentrations above the detection limit for either volatile organic compounds (VOCs), base-neutral acids (BNAs), or pesticides. VOCs detected in the study area include toluene in one background sample; and acetone in one background sample and one sample from Site 16--however, detection of these two compounds may be a laboratory artifact. Pesticides detected in soil at the Submarine Base include two degradates of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT): 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (4,4'-DDD) in one background sample, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethene (4,4'-DDE) in one background sample and one sample from Site 16; and dibenzofuran in one sample from Site 16. BNAs were detected in one background sample and in two samples from Site 16. Hypothesis testing, using the Wilcoxon rank-sum test (also known as the Mann-Whitney test), indicates no statistical difference between ground-water constituent concentrations from Sites 5 and 16, and background concentrations. Hypothesis testing, however, indicates the concentration of barium in background ground-water samples is greater than in ground-water samples collected at Site 16.

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

Fresquez, Philip R.

Field mice are effective indicators of contaminant presence. This paper reports the concentrations of various radionuclides, heavy metals, polychlorinated biphenyls, high explosives, perchlorate, and dioxin/furans in field mice (mostly deer mice) collected from regional background areas in northern New Mexico. These data, represented as the regional statistical reference level (the mean plus three standard deviations = 99% confidence level), are used to compare with data from field mice collected from areas potentially impacted by Laboratory operations, as per the Environmental Surveillance Program at Los Alamos National Laboratory.

Direct Deposition of Metal (DDM) as a Repair Process for Metallic Military Parts

DTIC Science & Technology

2013-01-20

metal powder has properties metallurgically compatible with the substrate material. As the laser beam advances along a predefined tool path in a layer...Methodology Background During the DDM process, the energy of a high power industrial laser beam and a concentric stream of metallic alloy powder ...compatible with the substrate material. As the laser beam advances along a predefined tool path in a layer by layer fashion, metal powder is deposited

Per- and poly-fluoroalkyl substances (PFASs) in the urban, industrial, and background atmosphere of Northeastern China coast around the Bohai Sea: Occurrence, partitioning, and seasonal variation

NASA Astrophysics Data System (ADS)

Yao, Yiming; Chang, Shuai; Zhao, Yangyang; Tang, Jianhui; Sun, Hongwen; Xie, Zhiyong

2017-10-01

Air samples were collected using high-volume samplers at two coastal towns on the Bohai Sea in China, 320 km apart, and at a background site (North Huangcheng Island) in the Bohai Sea, 50 km from the coast. A suite of neutral and ionic per- and poly-fluoroalkyl substances (PFASs) was investigated. Urban activity was related to high levels of neutral PFASs at Tianjin while perfluorooctanoic carboxylic acid (PFOA) was dominant in the atmosphere at Weifang, possibly due to industrial sources. Polyfluoroalkyl phosphoric acid diesters (diPAPs) occurred in the particle phase only, with a total concentration range of 0.02-6.72 pg m-3. The dominant homologue was 6:2 diPAP. PFASs profiles at NHI suggested direct atmospheric transport of neutral and ionic PFASs from source regions. Temperature-dependent partitioning of fluorotelomer alcohols (FTOHs) was observed in winter, when total concentrations and particle-phase fractions of FTOHs were significantly higher as compared to those in summer. Correlation analyses suggested more active gas-phase degradation of FTOHs in summer and likely heterogeneous degradation in both seasons. Overall, it is necessary to account for ionic PFASs in both gas and particle phases and particulate matter was important for atmospheric transport and for determining the fate of PFASs, especially in areas close to a source region.

The geochemistry of Seine River Basin particulate matter: Distribution of an integrated metal pollution index

USGS Publications Warehouse

Meybeck, Michel; Horowitz, A.J.; Grosbois, C.

2004-01-01

Spatial analysis (1994-2001) and temporal trends (1980-2000) for particulate-associated metals at key stations in the Seine River Basin have been determined using a new metal pollution index (MPI). The MPI is based on the concentrations of Cd, Cu, Hg, Pb and Zn, normalized to calculated background levels estimated for each particulate matter samples for four fractions (clays and other aluminosilicates, carbonates, organic matter, and quartz). Background levels ascribed to each fraction were determined from a specific set of samples collected from relatively pristine areas in the upper Seine basin and validated on prehistoric samples. The unitless MPI is designed to vary between 0 for pristine samples to 100 for the ones extremely impacted by human activities and to assess the trends of general metal contamination and its mapping. Throughout the Seine basin, MPI currently range from 1 to 40, but values exceeding 100 have been found in periurban streams and the Eure tributary. Based on the MPI spatial distribution, the Seine River Basin displays a wide range of anthropogenic impacts linked to variations in population density, stream order, wastewater discharges and industrial activities. Correlations between the MPI and other trace elements indicate that anthropogenic impacts also strongly affect the concentrations of Ag, Sb, and P, marginally affect the concentrations of Ba, Ni, and Cr, and appear to have little effect on the concentrations of Li, Be, V, Co, and the major elements. Temporal MPI trends can also be reconstituted from past regulatory surveys. In the early 1980s, MPI were 2-5 times higher than nowadays at most locations, particularly downstream of Greater Paris where it reached levels as high as 250 (now 40), a value characteristic of present Paris urban sewage. The exceptional contamination of the Seine basin is gradually improving over the last 20 years but remains very high. ?? 2004 Elsevier B.V. All rights reserved.

Growth of soybean at future tropospheric ozone concentrations decreases canopy evapotranspiration and soil water depletion.

PubMed

Bernacchi, Carl J; Leakey, Andrew D B; Kimball, Bruce A; Ort, Donald R

2011-06-01

Tropospheric ozone is increasing in many agricultural regions resulting in decreased stomatal conductance and overall biomass of sensitive crop species. These physiological effects of ozone forecast changes in evapotranspiration and thus in the terrestrial hydrological cycle, particularly in intercontinental interiors. Soybean plots were fumigated with ozone to achieve concentrations above ambient levels over five growing seasons in open-air field conditions. Mean season increases in ozone concentrations ([O₃]) varied between growing seasons from 22 to 37% above background concentrations. The objective of this experiment was to examine the effects of future [O₃] on crop ecosystem energy fluxes and water use. Elevated [O₃] caused decreases in canopy evapotranspiration resulting in decreased water use by as much as 15% in high ozone years and decreased soil water removal. In addition, ozone treatment resulted in increased sensible heat flux in all years indicative of day-time increase in canopy temperature of up to 0.7 °C. Published by Elsevier Ltd.

Measurement of radon concentration in super-Kamiokande's buffer gas

NASA Astrophysics Data System (ADS)

Nakano, Y.; Sekiya, H.; Tasaka, S.; Takeuchi, Y.; Wendell, R. A.; Matsubara, M.; Nakahata, M.

2017-09-01

To precisely measure radon concentrations in purified air supplied to the Super-Kamiokande detector as a buffer gas, we have developed a highly sensitive radon detector with an intrinsic background as low as 0 . 33 ± 0 . 07 mBq /m3. In this article, we discuss the construction and calibration of this detector as well as results of its application to the measurement and monitoring of the buffer gas layer above Super-Kamiokande. In March 2013, the chilled activated charcoal system used to remove radon in the input buffer gas was upgraded. After this improvement, a dramatic reduction in the radon concentration of the supply gas down to 0 . 08 ± 0 . 07 mBq /m3. Additionally, the Rn concentration of the in-situ buffer gas has been measured 28 . 8 ± 1 . 7 mBq /m3 using the new radon detector. Based on these measurements we have determined that the dominant source of Rn in the buffer gas arises from contamination from the Super-Kamiokande tank itself.

Interannual heavy element and nutrient concentration trends in the top sediments of Venice Lagoon (Italy).

PubMed

Masiol, Mauro; Facca, Chiara; Visin, Flavia; Sfriso, Adriano; Pavoni, Bruno

2014-12-15

The elemental composition of surficial sediments of Venice Lagoon (Italy) in 1987, 1993, 1998 and 2003 were investigated. Zn and Cr concentrations resulted in higher than background levels, but only Cd and Hg were higher than legal quality standards (Italian Decree 2010/260 and Water Framework Directive 2000/60/EC). Contaminants with similar spatial distribution are sorted into three groups by means of correlation analysis: (i) As, Co, Cd, Cu, Fe, Pb, Zn; (ii) Ni, Cr; (iii) Hg. Interannual concentrations are compared by applying a factor analysis to the matrix of differences between subsequent samplings. A general decrease of heavy metal levels is observed from 1987 to 1993, whereas particularly high concentrations of Ni and Cr are recorded in 1998 as a consequence of intense clam fishing, subsequently mitigated by better prevention of illegal harvesting. Due to the major role played by anthropogenic sediment resuspension, bathymetric variations are also considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

Aerosol Observability and Predictability: From Research to Operations for Chemical Weather Forecasting. Lagrangian Displacement Ensembles for Aerosol Data Assimilation

NASA Technical Reports Server (NTRS)

da Silva, Arlindo

2010-01-01

A challenge common to many constituent data assimilation applications is the fact that one observes a much smaller fraction of the phase space that one wishes to estimate. For example, remotely sensed estimates of the column average concentrations are available, while one is faced with the problem of estimating 3D concentrations for initializing a prognostic model. This problem is exacerbated in the case of aerosols because the observable Aerosol Optical Depth (AOD) is not only a column integrated quantity, but it also sums over a large number of species (dust, sea-salt, carbonaceous and sulfate aerosols. An aerosol transport model when driven by high-resolution, state-of-the-art analysis of meteorological fields and realistic emissions can produce skillful forecasts even when no aerosol data is assimilated. The main task of aerosol data assimilation is to address the bias arising from inaccurate emissions, and Lagrangian misplacement of plumes induced by errors in the driving meteorological fields. As long as one decouples the meteorological and aerosol assimilation as we do here, the classic baroclinic growth of error is no longer the main order of business. We will describe an aerosol data assimilation scheme in which the analysis update step is conducted in observation space, using an adaptive maximum-likelihood scheme for estimating background errors in AOD space. This scheme includes e explicit sequential bias estimation as in Dee and da Silva. Unlikely existing aerosol data assimilation schemes we do not obtain analysis increments of the 3D concentrations by scaling the background profiles. Instead we explore the Lagrangian characteristics of the problem for generating local displacement ensembles. These high-resolution state-dependent ensembles are then used to parameterize the background errors and generate 3D aerosol increments. The algorithm has computational complexity running at a resolution of 1/4 degree, globally. We will present the result of assimilating AOD retrievals from MODIS (on both Aqua and TERRA satellites) from AERONET for validation. The impact on the GEOS-5 Aerosol Forecasting will be fully documented.

Chemical Source Localization Fusing Concentration Information in the Presence of Chemical Background Noise.

PubMed

Pomareda, Víctor; Magrans, Rudys; Jiménez-Soto, Juan M; Martínez, Dani; Tresánchez, Marcel; Burgués, Javier; Palacín, Jordi; Marco, Santiago

2017-04-20

We present the estimation of a likelihood map for the location of the source of a chemical plume dispersed under atmospheric turbulence under uniform wind conditions. The main contribution of this work is to extend previous proposals based on Bayesian inference with binary detections to the use of concentration information while at the same time being robust against the presence of background chemical noise. For that, the algorithm builds a background model with robust statistics measurements to assess the posterior probability that a given chemical concentration reading comes from the background or from a source emitting at a distance with a specific release rate. In addition, our algorithm allows multiple mobile gas sensors to be used. Ten realistic simulations and ten real data experiments are used for evaluation purposes. For the simulations, we have supposed that sensors are mounted on cars which do not have among its main tasks navigating toward the source. To collect the real dataset, a special arena with induced wind is built, and an autonomous vehicle equipped with several sensors, including a photo ionization detector (PID) for sensing chemical concentration, is used. Simulation results show that our algorithm, provides a better estimation of the source location even for a low background level that benefits the performance of binary version. The improvement is clear for the synthetic data while for real data the estimation is only slightly better, probably because our exploration arena is not able to provide uniform wind conditions. Finally, an estimation of the computational cost of the algorithmic proposal is presented.

Search for Ultra-High-Energy Neutrinos with AMANDA-II

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

Ackermann, M.; Bernardini, E.; Adams, J.

2008-03-10

A search for diffuse neutrinos with energies in excess of 10{sup 5} GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 10{sup 7} GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra-high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrinomore » flux of E{sup 2}{phi}{sub 90%CL} < 2.7 x 10{sup -7} GeV cm{sup -2} s{sup -1} sr{sup -1} valid over the energy range of 2 x 10{sup 5} to 10{sup 9} GeV. A number of models that predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.« less

Search for Ultra High-Energy Neutrinos with AMANDA-II

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

IceCube Collaboration; Klein, Spencer; Ackermann, M.

2007-11-19

A search for diffuse neutrinos with energies in excess of 10{sup 5} GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 10{sup 7} GeV, the Earth is essentially opaque to neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavormore » neutrino flux of E{sup 2} {Phi}{sub 90%CL} < 2.7 x 10{sup -7} GeV cm{sup -2}s{sup -1} sr{sup -1} valid over the energy range of 2 x 10{sup 5} GeV to 10{sup 9} GeV. A number of models which predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.« less

Amorphous lithium lanthanum titanate for solid-state microbatteries

DOE PAGES

Lee, Jungwoo Z.; Wang, Ziying; Xin, Huolin L.; ...

2016-12-16

Lithium lanthanum titanate (LLTO) is a promising solid state electrolyte for solid state batteries due to its demonstrated high bulk ionic conductivity. However, crystalline LLTO has a relatively low grain boundary conductivity, limiting the overall material conductivity. In this work, we investigate amorphous LLTO (a-LLTO) thin films grown by pulsed laser deposition (PLD). By controlling the background pressure and temperature we are able to optimize the ionic conductivity to 3 × 10 –4 S/cm and electronic conductivity to 5 × 10 –11 S/cm. XRD, TEM, and STEM/EELS analysis confirm that the films are amorphous and indicate that oxygen background gasmore » is necessary during the PLD process to decrease the oxygen vacancy concentration, decreasing the electrical conductivity. Amorphous LLTO is deposited onto high voltage LiNi 0.5Mn 1.5O 4 (LNMO) spinel cathode thin films and cycled up to 4.8 V vs. Li showing excellent capacity retention. Finally, these results demonstrate that a-LLTO has the potential to be integrated into high voltage thin film batteries.« less

What do correlations tell us about anthropogenic-biogenic interactions and SOA formation in the Sacramento plume during CARES?

NASA Astrophysics Data System (ADS)

Kleinman, L.; Kuang, C.; Sedlacek, A.; Senum, G.; Springston, S.; Wang, J.; Zhang, Q.; Jayne, J.; Fast, J.; Hubbe, J.; Shilling, J.; Zaveri, R.

2016-02-01

During the Carbonaceous Aerosols and Radiative Effects Study (CARES) the US Department of Energy (DOE) G-1 aircraft was used to sample aerosol and gas phase compounds in the Sacramento, CA, plume and surrounding region. We present data from 66 plume transects obtained during 13 flights in which southwesterly winds transported the plume towards the foothills of the Sierra Nevada. Plume transport occurred partly over land with high isoprene emission rates. Our objective is to empirically determine whether organic aerosol (OA) can be attributed to anthropogenic or biogenic sources, and to determine whether there is a synergistic effect whereby OA concentrations are enhanced by the simultaneous presence of high concentrations of carbon monoxide (CO) and either isoprene, MVK + MACR (sum of methyl vinyl ketone and methacrolein), or methanol, which are taken as tracers of anthropogenic and biogenic emissions, respectively. Linear and bilinear correlations between OA, CO, and each of three biogenic tracers, "Bio", for individual plume transects indicate that most of the variance in OA over short timescales and distance scales can be explained by CO. For each transect and species a plume perturbation, (i.e., ΔOA, defined as the difference between 90th and 10th percentiles) was defined and regressions done amongst Δ values in order to probe day-to-day and location-dependent variability. Species that predicted the largest fraction of the variance in ΔOA were ΔO3 and ΔCO. Background OA was highly correlated with background methanol and poorly correlated with other tracers. Because background OA was ˜ 60 % of peak OA in the urban plume, peak OA should be primarily biogenic and therefore non-fossil, even though the day-to-day and spatial variability of plume OA is best described by an anthropogenic tracer, CO. Transects were split into subsets according to the percentile rankings of ΔCO and ΔBio, similar to an approach used by Setyan et al. (2012) and Shilling et al. (2013) to determine if anthropogenic-biogenic (A-B) interactions enhance OA production. As found earlier, ΔOA in the data subset having high ΔCO and high ΔBio was several-fold greater than in other subsets. Part of this difference is consistent with a synergistic interaction between anthropogenic and biogenic precursors and part to an independent linear dependence of ΔOA on precursors. The highest values of ΔO3, along with high temperatures, clear skies, and poor ventilation, also occurred in the high ΔCO-high ΔBio data set. A complicated mix of A-B interactions can result. After taking into account linear effects as predicted from low concentration data, an A-B enhancement of OA by a factor of 1.2 to 1.5 is estimated.

Spatial & temporal variations of PM10 and particle number concentrations in urban air.

PubMed

Johansson, Christer; Norman, Michael; Gidhagen, Lars

2007-04-01

The size of particles in urban air varies over four orders of magnitude (from 0.001 microm to 10 microm in diameter). In many cities only particle mass concentrations (PM10, i.e. particles <10 microm diameter) is measured. In this paper we analyze how differences in emissions, background concentrations and meteorology affect the temporal and spatial distribution of PM10 and total particle number concentrations (PNC) based on measurements and dispersion modeling in Stockholm, Sweden. PNC at densely trafficked kerbside locations are dominated by ultrafine particles (<0.1 microm diameter) due to vehicle exhaust emissions as verified by high correlation with NOx. But PNC contribute only marginally to PM10, due to the small size of exhaust particles. Instead wear of the road surface is an important factor for the highest PM10 concentrations observed. In Stockholm, road wear increases drastically due to the use of studded tires and traction sand on streets during winter; up to 90% of the locally emitted PM10 may be due to road abrasion. PM10 emissions and concentrations, but not PNC, at kerbside are controlled by road moisture. Annual mean urban background PM10 levels are relatively uniformly distributed over the city, due to the importance of long range transport. For PNC local sources often dominate the concentrations resulting in large temporal and spatial gradients in the concentrations. Despite these differences in the origin of PM10 and PNC, the spatial gradients of annual mean concentrations due to local sources are of equal magnitude due to the common source, namely traffic. Thus, people in different areas experiencing a factor of 2 different annual PM10 exposure due to local sources will also experience a factor of 2 different exposure in terms of PNC. This implies that health impact studies based solely on spatial differences in annual exposure to PM10 may not separate differences in health effects due to ultrafine and coarse particles. On the other hand, health effect assessments based on time series exposure analysis of PM10 and PNC, should be able to observe differences in health effects of ultrafine particles versus coarse particles.

Spatial and temporal variation in endotoxin and PM10 concentrations in ambient air in a livestock dense area.

PubMed

de Rooij, Myrna M T; Heederik, Dick J J; Borlée, Floor; Hoek, Gerard; Wouters, Inge M

2017-02-01

Several studies have reported associations between farming and respiratory health in neighboring residents. Health effects are possibly linked to fine dust and endotoxin emissions from livestock farms. Little is known about levels of these air pollutants in ambient air in livestock dense areas. We aimed to explore temporal and spatial variation of PM10 and endotoxin concentrations, and the association with livestock-related spatial and meteorological temporal determinants. From March till September 2011, one week average PM10 samples were collected using Harvard Impactors at eight sites (residential gardens) representing a variety of nearby livestock-related characteristics. A background site was included in the study area, situated at least 500m away from the nearest farm. PM10 mass was determined by gravimetric analysis and endotoxin level by means of Limulus-Amebocyte-Lysate assay. Data were analyzed using mixed models. The range between sites of geometric mean concentrations was for PM10 19.8-22.3µg/m 3 and for endotoxin 0.46-0.66EU/m 3 . PM10 concentrations and spatial variation were very similar for all sites, while endotoxin concentrations displayed a more variable pattern over time with larger differences between sites. Nonetheless, the temporal pattern at the background location was highly comparable to the sites mean temporal pattern both for PM10 and endotoxin (Pearson correlation: 0.92, 0.62). Spatial variation was larger for endotoxin than for PM10 (within/between site variance ratio: 0.63, 2.03). Spatial livestock-related characteristics of the surroundings were more strongly related to endotoxin concentrations, while temporal determinants were more strongly related to PM10 concentrations. The effect of local livestock-related sources on PM10 concentration was limited in this study carried out in a livestock dense area. The effect on endotoxin concentrations was more profound. To gain more insight in the effect of livestock-related sources on ambient levels of PM10 and endotoxin, measurements should be based on a broader set of locations. Copyright © 2016. Published by Elsevier Inc.

Number concentration, size distribution and horizontal mass flux of Asian dust particles collected over free troposphere of Chinese desert region in calm weather condition using balloon borne measurements.

NASA Astrophysics Data System (ADS)

Habib, A.; Chen, B.

2017-12-01

Balloon borne measurements were carried out during calm weather conditions in Taklamakan Desert, which is considered as one of the major source areas of Asian dust (KOSA) particles. Vertical distribution of aerosols number concentration, size distribution, mass concentration and horizontal mass flux due to westerly wind was investigated .Vertical distribution of aerosol number concentration and size distribution at Dunhuang (40 °00'N, 94°30'E) China were observed by optical particle counter (OPC) on August 17, 2001, October 17, 2011, January 11, 2002, April 30, 2002. Five channels (0.3, 0.5, 0.8, 1.2 and 3.6 µm) were used in OPC for particle sizing measurements. Aerosol number concentration in winter season (January 11, 2002) at 3-5 km was very high. Variation of free tropospheric aerosols in April 30, 2002 was noticeable. Many inversions of temperature and aerosol concentration change are found at these inversion points. Super micron range was noticeable in size distribution of all balloon borne measurements. High values of estimated mass concentration of aerosols were observed at the ground atmosphere (1-2 km), and interestingly relatively high concentrations were frequently detected above about 2 km. Wind pattern observed by ERA-interim data sets at 500 and 850 hPa, shows that westerly winds were dominated in Taklamakan Desert during balloon borne observation period. Average horizontal mass flux of background Asian dust due to westerly wind was about in the range of 1219-58.5 μg/m³ tons/km2/day. Most of the profiles showed active transport of aerosols in the westerly dominated region, while, fluxes were found to be very low on January 11, 2002, compared with the other seasons. Vertical profiles of aerosols number concentration showed that significant transport of aerosols was dominated in westerly region (4-7 km). Low horizontal mass flux of aerosols was found in winter season

Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

PubMed Central

2012-01-01

Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic fermentation performance for sustainable bio-ethanol production. PMID:22839110

The optimisation of electrokinetic remediation for heavy metals and radioactivity contamination on Holyrood-Lunas soil (acrisol species) in Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia.

PubMed

Mohamed Johar, S; Embong, Z

2015-11-01

The optimisation of electrokinetic remediation of an alluvial soil, locally named as Holyrood-Lunas from Sri Gading Industrial Area, Batu Pahat, Johor, Malaysia, had been conducted in this research. This particular soil was chosen due to its relatively high level of background radiation in a range between 139.2 and 539.4 nGy h(-1). As the background radiation is correlated to the amount of parent nuclides, (238)U and (232)Th, hence, a remediation technique, such as electrokinetic, is very useful in reducing these particular concentrations of heavy metal and radionuclides in soils. Several series of electrokinetics experiments were performed in laboratory scale in order to study the influence of certain electrokinetic parameters in soil. The concentration before (pre-electrokinetic) and after the experiment (post-electrokinetic) was determined via X-ray fluorescence (XRF) analysis technique. The best electrokinetic parameter that contributed to the highest achievable concentration removal of heavy metals and radionuclides on each experimental series was incorporated into a final electrokinetic experiment. Here, High Pure Germanium (HPGe) was used for radioactivity elemental analysis. The XRF results suggested that the most optimised electrokinetic parameters for Cr, Ni, Zn, As, Pb, Th and U were 3.0 h, 90 volts, 22.0 cm, plate-shaped electrode by 8 × 8 cm and in 1-D configuration order whereas the selected optimised electrokinetic parameters gave very low reduction of (238)U and (232)Th at 0.23 ± 2.64 and 2.74 ± 23.78 ppm, respectively. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A biological indicator of inorganic arsenic exposure using the sum of urinary inorganic arsenic and monomethylarsonic acid concentrations

PubMed Central

Hata, Akihisa; Kurosawa, Hidetoshi; Endo, Yoko; Yamanaka, Kenzo; Fujitani, Noboru; Endo, Ginji

2016-01-01

Objectives: The sum of urinary inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) concentrations is used for the biological monitoring of occupational iAs exposure. Although DMA is a major metabolite of iAs, it is an inadequate index because high DMA levels are present in urine after seafood consumption. We estimated the urinary iAs+MMA concentration corresponding to iAs exposure. Methods: We used data from two arsenic speciation analyses of urine samples from 330 Bangladeshi with oral iAs exposure and 172 Japanese workers without occupational iAs exposure using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Results: iAs, MMA, and DMA, but not arsenobetaine (AsBe), were detected in the urine of the Bangladeshi subjects. The correlation between iAs+MMA+DMA and iAs+MMA was obtained as log (iAs+MMA) = 1.038 log (iAs+MMA+DMA) -0.658. Using the regression formula, the iAs+MMA value was calculated as 2.15 and 7.5 μg As/l, corresponding to 3 and 10 μg As/m3 of exposures, respectively. In the urine of the Japanese workers, arsenic was mostly excreted as AsBe. We used the 95th percentile of iAs+MMA (12.6 μg As/l) as the background value. The sum of the calculated and background values can be used as a biological indicator of iAs exposure. Conclusion: We propose 14.8 and 20.1 μg As/l of urinary iAs+MMA as the biological indicators of 3 and 10 μg As/m3 iAs exposure, respectively. PMID:27010090

Multivariate characterization of elements accumulated in King Bolete Boletus edulis mushroom at lowland and high mountain regions.

PubMed

Falandysz, J; Kunito, T; Kubota, R; Bielawski, L; Frankowska, A; Falandysz, Justyna J; Tanabe, S

2008-12-01

Based on ICP-MS, ICP-OES, HG-AAS, CV-AAS and elementary instrumental analysis of King Bolete collected from four sites of different soil bedrock geochemistry considered could be as mushroom abundant in certain elements. King's Bolete fruiting bodies are very rich in K (> 20 mg/g dry weight), rich in Ca, Mg, Na, Rb and Zn (> 100 microg/g dw), and relatively also rich in Ag, Cd, Cs, Cu, Fe, Mn and Se (> 10 microg/g dw). The caps of King Bolete when compared to stipes around two-to three-fold more abundant are in Ag, Cd, Cs, Cu, Hg, K, Mg, Mo, N, Rb, Se and Zn. King Bolete collected at the lowland and mountain sites showed Ag, Ba, Co, Cr, Hg, K, Mg, Mn, Mo and Na in caps in comparable concentrations, and specimens from the mountain areas accumulated more Cd and Sb. Elements such as Al, Pb and Rb occurred at relatively elevated concentration in King Bolete picked up at the metal ores-rich region of the Sudety Mountains. Because of high bioconcentration potential King Bolete at the background sites accumulate in fruiting bodies great concentrations of problematic elements such as Cd, Pb and Hg, i.e. up to nearly 20, 3 and 5 microg/g dw, on the average, respectively. The interdependence among determined mineral elements examined were using the principal components analysis (PCA) method. The PCA explained 56% of the total variance. The metals tend to cluster together (Ba, Cd, Cs, Cr, Ga, Rb, Se, Sr and V; K and Mg; Cu and Mo). The results provided useful environmental and nutritional background level information on 26 minerals as the composition of King Bolete from the sites of different bedrock soil geochemistry.

Role of Background in the CERCLA Cleanup Program

EPA Pesticide Factsheets

This document clarifies the U.S. Environmental Protection Agency (EPA) preferred approach for the consideration of background constituent concentrations of hazardous substances, pollutants, and contaminants in certain steps of the remedy selection process

Background considerations in the analysis of PIXE spectra by Artificial Neural Systems.

NASA Astrophysics Data System (ADS)

Correa, R.; Morales, J. R.; Requena, I.; Miranda, J.; Barrera, V. A.

2016-05-01

In order to study the importance of background in PIXE spectra to determine elemental concentrations in atmospheric aerosols using artificial neural systems ANS, two independently trained ANS were constructed, one which considered as input the net number of counts in the peak, and another which included the background. In the training and validation phases thirty eight spectra of aerosols collected in Santiago, Chile, were used. In both cases the elemental concentration values were similar. This fact was due to the intrinsic characteristic of ANS operating with normalized values of the net and total number of counts under the peaks, something that was verified in the analysis of 172 spectra obtained from aerosols collected in Mexico city. Therefore, networks operating under the mode which include background can reduce time and cost when dealing with large number of samples.

Distribution of trace metals at Hopewell Furnace National Historic Site, Berks and Chester Counties, Pennsylvania

USGS Publications Warehouse

Sloto, Ronald A.; Reif, Andrew G.

2011-01-01

Hopewell Furnace, located approximately 50 miles northwest of Philadelphia, was a cold-blast, charcoal iron furnace that operated for 113 years (1771 to 1883). The purpose of this study by the U.S. Geological Survey, in cooperation with the National Park Service, was to determine the distribution of trace metals released to the environment from an historical iron smelter at Hopewell Furnace National Historic Site (NHS). Hopewell Furnace used iron ore from local mines that contained abundant magnetite and accessory sulfide minerals enriched in arsenic, cobalt, copper, and other metals. Ore, slag, cast iron furnace products, soil, groundwater, stream base flow, streambed sediment, and benthic macroinvertebrates were sampled for this study. Soil samples analyzed in the laboratory had concentrations of trace metals low enough to meet Pennsylvania Department of Environmental Protection standards for non-residential use. Groundwater samples from the supply well met U.S. Environmental Protection Agency drinking-water regulations. Concentrations of metals in surface-water base flow at the five stream sampling sites were below continuous concentration criteria for protection of aquatic organisms. Concentrations of metals in sediment at the five stream sites were below probable effects level guidelines for protection of aquatic organisms except for copper at site HF-3. Arsenic, copper, lead, zinc, and possibly cobalt were incorporated into the cast iron produced by Hopewell Furnace. Manganese was concentrated in slag along with iron, nickel, and zinc. The soil near the furnace has elevated concentrations of chromium, copper, iron, lead, and zinc compared to background soil concentrations. Concentrations of toxic elements were not present at concentrations of concern in water, soil, or stream sediments, despite being elevated in ore, slag, and cast iron furnace products. The base-flow surface-water samples indicated good overall quality. The five sampled sites generally had low concentrations of nutrients and major ions but had elevated concentrations of iron, manganese, and strontium when compared to sites sampled in adjacent watersheds. The background site on Baptism Creek generally had the lowest concentrations and yields of constituents. Low concentrations of nutrients and major ions at all five sites indicate that measured concentrations can be attributed to general land use and geology and not to point sources. Streambed-sediment sampling results indicated higher concentrations of all metals except nickel at sites on French Creek compared to the background site on Baptism Creek. Concentrations of aluminum, cadmium, and nickel were highest in sediment from the sampling site upstream from Hopewell Furnace. The highest concentrations of arsenic, boron, cobalt, copper, iron, lead, manganese, mercury, and zinc were detected at the site just below Hopewell Furnace, which indicates that the source of these metals may be in Hopewell Furnace NHS. The invertebrate community at the background site on Baptism Creek was dominated by pollution sensitive taxa indicating a healthy, diverse benthic-macroinvertebrate community. Benthic-macroinvertebrate communities at sampling sites on French Creek indicated disturbed communities when compared to the background site on Baptism Creek and that the overall stream quality immediately above and below Hopewell Furnace NHS is degraded. The benthic-macroinvertebrate communities were dominated by pollution-tolerant taxa, and taxa were less diverse than at the background site. Habitat conditions at the upstream site on French Creek were good but were degraded at downstream sites on French Creek. The major habitat issues at these sites were related to a lack of stable substrate, erosion, and deposition. Water quality and streambed-sediment quality do not indicate that the degraded benthic-macroinvertebrate communities are the result of poor water quality. Habitat conditions (erosion and sedimentation) and physical alterations (water temperature) from the outfall of Hopewell Lake are the most likely causes of the impaired communities.

Development of ytterbium-doped oxyfluoride glasses for laser cooling applications.

PubMed

Krishnaiah, Kummara Venkata; de Lima Filho, Elton Soares; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

2016-02-26

Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb(3+)) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb(3+) concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb(3+): glass and decreases with increasing Yb(3+) concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm(3+) and Er(3+) ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb(3+): (2)F5/2 → (2)F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb(3+) with increasing Yb(3+) concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed.

Development of ytterbium-doped oxyfluoride glasses for laser cooling applications

PubMed Central

Krishnaiah, Kummara Venkata; Soares de Lima Filho, Elton; Ledemi, Yannick; Nemova, Galina; Messaddeq, Younes; Kashyap, Raman

2016-01-01

Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb3+) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb3+ concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb3+: glass and decreases with increasing Yb3+ concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm3+ and Er3+ ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb3+: 2F5/2 → 2F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb3+ with increasing Yb3+ concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed. PMID:26915817

Ongoing advances in quantitative PpIX fluorescence guided intracranial tumor resection (Conference Presentation)

NASA Astrophysics Data System (ADS)

Olson, Jonathan D.; Kanick, Stephen C.; Bravo, Jaime J.; Roberts, David W.; Paulsen, Keith D.

2016-03-01

Aminolevulinc-acid induced protoporphyrin IX (ALA-PpIX) is being investigated as a biomarker to guide neurosurgical resection of brain tumors. ALA-PpIX fluorescence can be observed visually in the surgical field; however, raw fluorescence emissions can be distorted by factors other than the fluorophore concentration. Specifically, fluorescence emissions are mixed with autofluorescence and attenuated by background absorption and scattering properties of the tissue. Recent work at Dartmouth has developed advanced fluorescence detection approaches that return quantitative assessments of PpIX concentration, which are independent of background optical properties. The quantitative fluorescence imaging (qFI) approach has increased sensitivity to residual disease within the resection cavity at the end of surgery that was not visible to the naked eye through the operating microscope. This presentation outlines clinical observations made during an ongoing investigation of ALA-PpIX based guidance of tumor resection. PpIX fluorescence measurements made in a wide-field hyperspectral imaging approach are co-registered with point-assessment using a fiber optic probe. Data show variations in the measured PpIX accumulation among different clinical tumor grades (i.e. high grade glioma, low grade glioma), types (i.e. primary tumors. metastases) and normal structures of interest (e.g. normal cortex, hippocampus). These results highlight the contrast enhancement and underscore the potential clinical benefit offered from quantitative measurements of PpIX concentration during resection of intracranial tumors.

Perfluoroalkyl substances during pregnancy and validated preeclampsia among nulliparous women in the Norwegian Mother and Child Cohort Study.

PubMed

Starling, Anne P; Engel, Stephanie M; Richardson, David B; Baird, Donna D; Haug, Line S; Stuebe, Alison M; Klungsøyr, Kari; Harmon, Quaker; Becher, Georg; Thomsen, Cathrine; Sabaredzovic, Azemira; Eggesbø, Merete; Hoppin, Jane A; Travlos, Gregory S; Wilson, Ralph E; Trogstad, Lill I; Magnus, Per; Longnecker, Matthew P

2014-04-01

Perfluoroalkyl substances (PFAS) are persistent and ubiquitous environmental contaminants, and human exposure to these substances may be related to preeclampsia, a common pregnancy complication. Previous studies have found serum concentrations of PFAS to be positively associated with pregnancy-induced hypertension and preeclampsia in a population with high levels of exposure to perfluorooctanoate. Whether this association exists among pregnant women with background levels of PFAS exposure is unknown. Using data from the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health, we carried out a study of nulliparous pregnant women enrolled in 2003-2007 (466 cases, 510 noncases) to estimate associations between PFAS concentrations and an independently validated diagnosis of preeclampsia. We measured levels of 9 PFAS in maternal plasma extracted midpregnancy; statistical analyses were restricted to 7 PFAS that were quantifiable in more than 50% of samples. In proportional hazards models adjusted for maternal age, prepregnancy body mass index (weight (kg)/height (m)(2)), educational level, and smoking status, we observed no strongly positive associations between PFAS levels and preeclampsia. We found an inverse association between preeclampsia and the highest quartile of perfluoroundecanoic acid concentration relative to the lowest quartile (hazard ratio = 0.55, 95% confidence interval: 0.38, 0.81). Overall, our findings do not support an increased risk of preeclampsia among nulliparous Norwegian women with background levels of PFAS exposure.

Identification and characterisation of local aerosol sources using high temporal resolution measurements.

PubMed

Contini, D; Donateo, A; Cesari, D; Belosi, F; Francioso, S

2010-09-01

Aerosol and gaseous pollution measurements were carried out at an urban background site in the south of Italy located near an industrial complex. Collection of 24 h samples of PM10 and PM2.5 and successive chemical quantification of metals were performed. Data were compared with measurements taken at a suburban background site, located at 25 km distance. The comparison showed the presence of an industrial contribution with a well defined chemical emission profile, similar, in terms of metals content, to urban emissions. As this made difficult the quantitative characterisation of the contribution of the two sources to atmospheric PM, a statistical method based on the treatment of data arising from high temporal resolution measurements was developed. Data were taken with a micrometeorological station based on an integrating nephelometer (Mie pDR-1200) for optical detection of PM2.5 concentration, with successive evaluation of vertical turbulent fluxes using the eddy-correlation method. Results show that the contribution from the two sources (urban emissions and industrial releases) have a very different behaviour, with the industrial contribution being present at high wind velocity with short concentration peaks (average duration 4 min) associated to strong positive and negative vertical fluxes. The estimated contribution to PM2.5 is 2.3% over long-term averages. The urban emissions are mainly present at low wind velocity, with longer concentration peaks in the morning and late evening hours, generally associated to small positive vertical fluxes. The characterisation of the contribution was performed using deposition velocity V(d) that is on average -3.5 mm s(-1) and has a diurnal pattern, with negligible values during the night and a minimum value of around -9 mm s(-1) late in the afternoon. Results show a correlation between V(d), friction velocity and wind velocity that could be the basis for a parameterisation of V(d) to be used in dispersion codes.

Contribution of dust storms to PM10 levels in an urban arid environment.

PubMed

Krasnov, Helena; Katra, Itzhak; Koutrakis, Petros; Friger, Michael D

2014-01-01

Quantitative information on the contribution of dust storms to atmospheric PM10 (particulate matter with an aerodynamic diameter < or = 10 microm) levels is still lacking, especially in urban environments with close proximity to dust sources. The main objective of this study was to quantify the contribution of dust storms to PM10 concentrations in a desert urban center, the city of Beer-Sheva, Negev, Israel, during the period of 2001-2012. Toward this end, a background value based on the "dust-free" season was used as a threshold value to identify potentially "dust days." Subsequently, the net contribution of dust storms to PM10 was assessed. During the study period, daily PM10 concentrations ranged from 6 to over 2000 microg/m3. In each year, over 10% of the daily concentrations exceeded the calculated threshold (BVt) of 71 microg/m3. An average daily net contribution of dust to PM10 of 122 microg/m3 was calculated for the entire study period based on this background value. Furthermore, a dust storm intensity parameter (Ai) was used to analyze several storms with very high PM10 contributions (hourly averages of 1000-5197 microg/m3). This analysis revealed that the strongest storms occurred mainly in the last 3 yr of the study. Finally, these findings indicate that this arid urban environment experiences high PM10 levels whose origin lies in both local and regional dust events. The findings indicate that over time, the urban arid environment experiences high PM10 levels whose origin lies in local and regional dust events. It was noticed that the strongest storms have occurred mainly in the last 3 yr. It is believed that environmental changes such as global warming and desertification may lead to an increased air pollution and risk exposure to human health.

Positron emission mammography (PEM): Effect of activity concentration, object size, and object contrast on phantom lesion detection

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

MacDonald, Lawrence R.; Wang, Carolyn L.; Eissa, Marna

2012-10-15

Purpose: To characterize the relationship between lesion detection sensitivity and injected activity as a function of lesion size and contrast on the PEM (positron emission mammography) Flex Solo II scanner using phantom experiments. Methods: Phantom lesions (spheres 4, 8, 12, 16, and 20 mm diameter) were randomly located in uniform background. Sphere activity concentrations were 3 to 21 times the background activity concentration (BGc). BGc was a surrogate for injected activity; BGc ranged from 0.44-4.1 kBq/mL, corresponding to 46-400 MBq injections. Seven radiologists read 108 images containing zero, one, or two spheres. Readers used a 5-point confidence scale to scoremore » the presence of spheres. Results: Sensitivity was 100% for lesions {>=}12 mm under all conditions except for one 12 mm sphere with the lowest contrast and lowest BGc (60% sensitivity). Sensitivity was 100% for 8 mm spheres when either contrast or BGc was high, and 100% for 4 mm spheres only when both contrast and BGc were highest. Sphere contrast recovery coefficients (CRC) were 49%, 34%, 26%, 14%, and 2.8% for the largest to smallest spheres. Cumulative specificity was 98%. Conclusions: Phantom lesion detection sensitivity depends more on sphere size and contrast than on BGc. Detection sensitivity remained {>=}90% for injected activities as low as 100 MBq, for lesions {>=}8 mm. Low CRC in 4 mm objects results in moderate detection sensitivity even for 400 MBq injected activity, making it impractical to optimize injected activity for such lesions. Low CRC indicates that when lesions <8 mm are observed on PEM images they are highly tracer avid with greater potential of clinical significance. High specificity (98%) suggests that image statistical noise does not lead to false positive findings. These results apply to the 85 mm thick object used to obtain them; lesion detectability should be better (worse) for thinner (thicker) objects based on the reduced (increased) influence of photon attenuation.« less

Ion transport in a pH-regulated nanopore.

PubMed

Yeh, Li-Hsien; Zhang, Mingkan; Qian, Shizhi

2013-08-06

Fundamental understanding of ion transport phenomena in nanopores is crucial for designing the next-generation nanofluidic devices. Due to surface reactions of dissociable functional groups on the nanopore wall, the surface charge density highly depends upon the proton concentration on the nanopore wall, which in turn affects the electrokinetic transport of ions, fluid, and particles within the nanopore. Electrokinetic ion transport in a pH-regulated nanopore, taking into account both multiple ionic species and charge regulation on the nanopore wall, is theoretically investigated for the first time. The model is verified by the experimental data of nanopore conductance available in the literature. The results demonstrate that the spatial distribution of the surface charge density at the nanopore wall and the resulting ion transport phenomena, such as ion concentration polarization (ICP), ion selectivity, and conductance, are significantly affected by the background solution properties, such as the pH and salt concentration.

Ships' Ballast Water Treatment by Chlorination Can Generate Toxic Trihalomethanes.

PubMed

Hernandez, Marco R; Ismail, Nargis; Drouillard, Ken G; MacIsaac, Hugh J

2017-08-01

The International Maritime Organization (IMO) will enforce a new abundance-based performance standard for ballast water in September, 2017. Strong oxidants, like chlorine, have been proposed as a method for achieving this standard. However chlorine treatment of ballast water can produce hazardous trihalomethanes. We assessed maximum trihalomethane production from one chlorine dose for three types of ballast water (fresh, brackish and marine) and three levels of total organic carbon (TOC) concentration (natural, filtered, enhanced). While the current standard test considers a 5 day voyage, there is a high possibility of shorter trips and sudden change of plans that will release treated waters in the environment. Water source and TOC significantly affected trihalomethane production, with the highest amounts generated in brackish waters and enhanced TOC concentration. The concentration of brominated trihalomethanes increased from background levels and was highest in brackish water, followed by marine and fresh water.

Magnetic Modeling of a Rotating Flux Concentrator System Designed to Mitigate Noise in Large Magnetic Sensors

DTIC Science & Technology

2010-09-01

region were defined as a background. The flux concentrators were drawn as solid pieces and assigned the material properties of permalloy ( NiFe ), with...assigning properties (coercivity, permeability, etc.) to the objects, assigning boundaries or sources, seeding the objects and creating a mesh, and then...a permeability of 5000 as that is a value readily achieved in this material. The material properties assigned to this background are those of a

Background subtraction for fluorescence EXAFS data of a very dilute dopant Z in Z + 1 host.

PubMed

Medling, Scott; Bridges, Frank

2011-07-01

When conducting EXAFS at the Cu K-edge for ZnS:Cu with very low Cu concentration (<0.04% Cu), a large background was present that increased with energy. This background arises from a Zn X-ray Raman peak, which moves through the Cu fluorescence window, plus the tail of the Zn fluorescence peak. This large background distorts the EXAFS and must be removed separately before reducing the data. A simple means to remove this background is described.

Development of a strontium chronic effects benchmark for aquatic life in freshwater.

PubMed

McPherson, Cathy A; Lawrence, Gary S; Elphick, James R; Chapman, Peter M

2014-11-01

There are no national water-quality guidelines for strontium for the protection of freshwater aquatic life in North America or elsewhere. Available data on the acute and chronic toxicity of strontium to freshwater aquatic life were compiled and reviewed. Acute toxicity was reported to occur at concentrations ranging from 75 mg/L to 15 000 mg/L. The majority of chronic effects occurred at concentrations above 11 mg/L; however, calculation of a representative benchmark was confounded by results from 4 studies indicating that chronic effects occurred at lower concentrations than all other studies, in 2 cases below background concentrations reported for US and European streams. Two of these studies, including 1 reporting effects below background concentrations, were repeated and found not to be reproducible; chronic effects occurred at considerably higher strontium concentrations than in the original studies. Studies with narrow-mouthed toad and goldfish were not repeated; both studies reported chronic effects below background concentrations, and both studies had been conducted by the authors of 1 of the 2 studies that were repeated and shown to be nonreproducible. Studies by these authors (3 of the 4 confounding studies), conducted over 30 yr ago, lacked detail in reporting of methods and results. It is thus likely that repeating the toad and goldfish studies would also have resulted in a higher strontium effects concentration. A strontium chronic effects benchmark of 10.7 mg/L that incorporates the results of additional testing summarized in the present study is proposed for freshwater environments. © 2014 SETAC.

Of the necessity of knowledge of the natural pedo-geochemical background content in the evaluation of the contamination of soils by trace elements.

PubMed

Baize, D; Sterckeman, T

2001-01-08

In order to evaluate the contamination of the Dornach (Switzerland) site within the framework of the CEEM-Soil project, each participating team was allowed to take a maximum of 15 samples. The French team's sampling was organized in such a way as to answer the following questions: (i) what is the natural concentration of the soils at this site (local pedo-geochemical background content)?; (ii) what are the levels of Cd, Cu, Pb and Zn contamination of the soil?; (iii) what is the depth reached by the surface contamination that is derived from atmospheric fallout?; (iv) how is the contamination spread along the longest axis of the area under study? The relationships between total Fe and the trace metals have allowed local variations in the natural pedo-geochemical background content to be detected and thus permitted the anthropogenic contamination to be estimated. There would appear to be a low level of Pb contamination over all the site investigated (an increase of the order of 5-10 mg kg(-1) on the background level), limited to the surface humus-bearing layers. There is also a significant contamination by Cu over all of the site (an increase of the order of 30-40 mg kg(-1)). This contamination has remained in the surface horizons (0-20 cm). Very high Zn and Cd concentrations have been found in the four surface (0-4 cm) and deep horizons (15-70 cm) taken under the forest and very much lower values in the samples taken from cultivated soils. The most likely explanation is an unequal inheritance between the upper part of the site (wooded with thinner very clayey soils) and the lower cultivated part of the site (with thicker less clayey soils developed in a loamy material). For various reasons, it seems unlikely that a contamination of the wooded part should be so much higher than the cultivated part due to the interception of atmospheric dust by the trees. The local pedo-geochemical background Cd and Zn content of the upper wooded part proved to be clearly higher than that which would be encountered in most soils of Switzerland and France. Given this evaluation of the background content, it seems that only the surface horizons have been affected by Zn contamination (an addition of approx. 60-100 mg kg(-1)). In the case of Cd, the increase in concentrations is only 0.5-1 mg kg(-1) for the ploughed horizons, as well as the for the A horizons.

Developing noninvasive diagnosis for single-gene disorders: the role of digital PCR.

PubMed

Barrett, Angela N; Chitty, Lyn S

2014-01-01

Cell-free fetal DNA constitutes approximately 10 % of the cell-free DNA found in maternal plasma and can be used as a reliable source of fetal genetic material for noninvasive prenatal diagnosis (NIPD) from early pregnancy. The relatively high levels of maternal background can make detection of paternally inherited point mutations challenging. Diagnosis of inheritance of autosomal recessive disorders using qPCR is even more challenging due to the high background of mutant maternal allele. Digital PCR is a very sensitive modified method of quantitative real-time PCR (qPCR), allowing absolute quantitation and rare allele detection without the need for standards or normalization. Samples are diluted and then partitioned into a large number of small qPCR reactions, some of which contain the target molecule and some which do not; the proportion of positive reactions can be used to calculate the concentration of targets in the initial sample. Here we discuss the use of digital PCR as an accurate approach to NIPD for single-gene disorders.

A G-quadruplex-based Label-free Fluorometric Aptasensor for Adenosine Triphosphate Detection.

PubMed

Li, Li Juan; Tian, Xue; Kong, Xiang Juan; Chu, Xia

2015-01-01

A G-quadruplex-based, label-free fluorescence assay was demonstrated for the detection of adenosine triphosphate (ATP). A double-stranded DNA (dsDNA), hybridized by ATP-aptamer and its complementary sequence, was employed as a substrate for ATP binding. SYBR Green I (SG I) was a fluorescent probe and exonuclease III (Exo III) was a nuclease to digest the dsDNA. Consequently, in the absence of ATP, the dsDNA was inset with SG I and was digested by Exo III, resulting in a low background signal. In the presence of ATP, the aptamer in dsDNA folded into a G-quadruplex structure that resisted the digestion of Exo III. SG I was inserted into the structure, showing high fluorescence. Owing to a decrease of the background noise, a high signal-to-noise ratio could be obtained. This sensor can detect ATP with a concentration ranging from 50 μM to 5 mM, and possesses a capacity for the sensitive determination of other targets.

Sub-chronic inhalation of high concentrations of manganese sulfate induces lower airway pathology in rhesus monkeys

PubMed Central

Dorman, David C; Struve, Melanie F; Gross, Elizabeth A; Wong, Brian A; Howroyd, Paul C

2005-01-01

Background Neurotoxicity and pulmonary dysfunction are well-recognized problems associated with prolonged human exposure to high concentrations of airborne manganese. Surprisingly, histological characterization of pulmonary responses induced by manganese remains incomplete. The primary objective of this study was to characterize histologic changes in the monkey respiratory tract following manganese inhalation. Methods Subchronic (6 hr/day, 5 days/week) inhalation exposure of young male rhesus monkeys to manganese sulfate was performed. One cohort of monkeys (n = 4–6 animals/exposure concentration) was exposed to air or manganese sulfate at 0.06, 0.3, or 1.5 mg Mn/m3 for 65 exposure days. Another eight monkeys were exposed to manganese sulfate at 1.5 mg Mn/m3 for 65 exposure days and held for 45 or 90 days before evaluation. A second cohort (n = 4 monkeys per time point) was exposed to manganese sulfate at 1.5 mg Mn/m3 and evaluated after 15 or 33 exposure days. Evaluations included measurement of lung manganese concentrations and evaluation of respiratory histologic changes. Tissue manganese concentrations were compared for the exposure and control groups by tests for homogeneity of variance, analysis of variance, followed by Dunnett's multiple comparison. Histopathological findings were evaluated using a Pearson's Chi-Square test. Results Animals exposed to manganese sulfate at ≥0.3 mg Mn/m3 for 65 days had increased lung manganese concentrations. Exposure to manganese sulfate at 1.5 mg Mn/m3 for ≥15 exposure days resulted in increased lung manganese concentrations, mild subacute bronchiolitis, alveolar duct inflammation, and proliferation of bronchus-associated lymphoid tissue. Bronchiolitis and alveolar duct inflammatory changes were absent 45 days post-exposure, suggesting that these lesions are reversible upon cessation of subchronic high-dose manganese exposure. Conclusion High-dose subchronic manganese sulfate inhalation is associated with increased lung manganese concentrations and small airway inflammatory changes in the absence of observable clinical signs. Subchronic exposure to manganese sulfate at exposure concentrations (≤0.3 mg Mn/m3) similar to the current 8-hr occupational threshold limit value established for inhaled manganese was not associated with pulmonary pathology. PMID:16242036

Issue Paper on Metal Exposure Assessment

EPA Pesticide Factsheets

This paper explores the best approaches for characterizing exposure pathways and routes, estimating the most relevant exposure concentrations, linking exposure to dose, and coping with natural or background concentrations.

Mercury Contamination in Costa Rica

NASA Astrophysics Data System (ADS)

Varekamp, J. C.; Haynes, A.; Balcom, P. H.

2012-12-01

Recent measurements of Hg in air in the central valley of Costa Rica produced some remarkably high values (up to 700 ng Hg/m3;Castillo et al., 2011), raising concerns for public health. We made a broad assessment of Hg as an environmental contaminant in Costa Rica, and sampled and analyzed lake and wetland sediment and soils to derive atmospheric Hg deposition rates. We also measured Hg(0) in air in three locations, and sampled local fish that were analyzed for Hg. We set up a sampling program of Hg in hair of Costa Ricans, sampling hair from a broad crossection of the population, in combination with dietary and personal information. The lake sediments had Hg concentrations between 34 and 316 ppb Hg, with several lakes at common natural background concentrations (20-100 ppb Hg). Some lakes showed a Hg contamination component with concentrations well above simple background values. These sediments also were very rich in organic matter, and the high Hg concentrations may be a result of Hg focusing from the watersheds into the lake depositional environments. Deduced atmospheric deposition rates of Hg range from 0.16-0.25 ng Hg/cm2 per year, which is at the low end of the global range of measured wet atmospheric deposition rates. The observed Hg concentrations in sediment and soils thus can be characterized as natural background to mildly contaminated, but nothing that would indicate Hg inventories as expected from the reported high Hg air burdens. Some of our Hg(0) in air measurements were done at the same locations as those done earlier and yielded values between 0.6-4.2 ng Hg/m3; these values are similar to the low range measurements of Castillo et al. (their night time values), but we found no evidence in 2011 for their high daytime values. The range of a few ng Hg/m3 in air is compatible with global Hg dispersion modeling. Fish tissue of Trout and Tilapia gave a range of 68-112 ppb Hg (wet weight base), well below the 300 ppb Hg EPA alert level. Overall, these data do not point to a major local source of environmental Hg in Costa Rica, which would be most likely geothermal or volcanic in origin. We sampled hair from 53 people in San Jose, Heredia, and surrounding villages. The Hg(hair) contents ranged from 97-13,840 ppb Hg, with >50% of the subjects sampled above the USEPA alert level of 1000 ppb Hg. Three individuals had Hg> 8000 ppb Hg, which is a matter of concern. From the dietary information we calculated that 76% of the subjects sampled had an Hg intake above the USEPA recommended level of 0.1 microgram/kg bodyweight per day, largely from large marine fish such as tuna, swordfish, and shark. Many of the fish are imported and the local marine fish probably obtained their Hg burden outside the Costa Rica coastal region. In conclusion, there does not seem to be a direct large natural volcanic/geothermal Hg source in Costa Rica that may create public health concerns. However, the Costa Rican people studied by us have overall high Hg(hair) which seems to be related to their level of large marine fish consumption, which in several cases may be a matter of health concern.

Functionalized vertical GaN micro pillar arrays with high signal-to-background ratio for detection and analysis of proteins secreted from breast tumor cells.

PubMed

Choi, Mun-Ki; Kim, Gil-Sung; Jeong, Jin-Tak; Lim, Jung-Taek; Lee, Won-Yong; Umar, Ahmad; Lee, Sang-Kwon

2017-11-02

The detection of cancer biomarkers has recently attracted significant attention as a means of determining the correct course of treatment with targeted therapeutics. However, because the concentration of these biomarkers in blood is usually relatively low, highly sensitive biosensors for fluorescence imaging and precise detection are needed. In this study, we have successfully developed vertical GaN micropillar (MP) based biosensors for fluorescence sensing and quantitative measurement of CA15-3 antigens. The highly ordered vertical GaN MP arrays result in the successful immobilization of CA15-3 antigens on each feature of the arrays, thereby allowing the detection of an individual fluorescence signal from the top surface of the arrays owing to the high regularity of fluorophore-tagged MP spots and relatively low background signal. Therefore, our fluorescence-labeled and CA15-3 functionalized vertical GaN-MP-based biosensor is suitable for the selective quantitative analysis of secreted CA15-3 antigens from MCF-7 cell lines, and helps in the early diagnosis and prognosis of serious diseases as well as the monitoring of the therapeutic response of breast cancer patients.

Photosynthetic capacity is negatively correlated with the concentration of leaf phenolic compounds across a range of different species

PubMed Central

Sumbele, Sally; Fotelli, Mariangela N.; Nikolopoulos, Dimosthenis; Tooulakou, Georgia; Liakoura, Vally; Liakopoulos, Georgios; Bresta, Panagiota; Dotsika, Elissavet; Adams, Mark A.; Karabourniotis, George

2012-01-01

Background and aims Phenolic compounds are the most commonly studied of all secondary metabolites because of their significant protective–defensive roles and their significant concentration in plant tissues. However, there has been little study on relationships between gas exchange parameters and the concentration of leaf phenolic compounds (total phenolics (TP) and condensed tannins (CT)) across a range of species. Therefore, we addressed the question: is there any correlation between photosynthetic capacity (Amax) and TP and CT across species from different ecosystems in different continents? Methodology A plethora of functional and structural parameters were measured in 49 plant species following different growth strategies from five sampling sites located in Greece and Australia. The relationships between several leaf traits were analysed by means of regression and principal component analysis. Principal results The results revealed a negative relationship between TP and CT and Amax among the different plant species, growth strategies and sampling sites, irrespective of expression (with respect to mass, area or nitrogen content). Principal component analysis showed that high concentrations of TP and CT are associated with thick, dense leaves with low nitrogen. This leaf type is characterized by low growth, Amax and transpiration rates, and is common in environments with low water and nutrient availability, high temperatures and high light intensities. Therefore, the high TP and CT in such leaves are compatible with the protective and defensive functions ascribed to them. Conclusions Our results indicate a functional integration between carbon gain and the concentration of leaf phenolic compounds that reflects the trade-off between growth and defence/protection demands, depending on the growth strategy adopted by each species. PMID:23050073

The Impact of the Internet on Health Consultation Market Concentration: An Econometric Analysis of Secondary Data

PubMed Central

2016-01-01

Background Many markets have traditionally been dominated by a few best-selling products, and this is also the case for the health care industry. However, we do not know whether the market will be more or less concentrated when health care services are delivered online (known as E-consultation), nor do we know how to reduce the concentration of the E-consultation market. Objective The aim of this study was to investigate the concentration of the E-consultation market and how to reduce its concentration through information disclosure mechanisms (online reputation and self-representation). Methods We employed a secondary data econometric analysis using transaction data obtained from an E-consultation Website (haodf.com) for three diseases (infantile pneumonia, diabetes, and pancreatic cancer) from 2008 to 2015. We included 2439 doctors in the analysis. Results The E-consultation market largely follows the 20/80 principle, namely that approximately 80% of orders are fulfilled by nearly 20% of doctors. This is much higher than the offline health care market. Meanwhile, the market served by doctors with strong online reputations (beta=0.207, P<.001) or strong online self-representation (beta=0.386, P<.001) is less concentrated. Conclusions When health care services are delivered online, the market will be more concentrated (known as the “Superstar” effect), indicating poor service efficiency for society as a whole. To reduce market concentration, E-consultation websites should provide important design elements such as ratings of doctors (user feedback), articles contributed by doctors, and free consultation services (online representation). A possible and important way to reduce the market concentration of the E-consultation market is to accumulate enough highly rated or highly self-represented doctors. PMID:27793793

Alpha Hemolysin Induces an Increase of Erythrocytes Calcium: A FLIM 2-Photon Phasor Analysis Approach

PubMed Central

Sanchez, Susana; Bakás, Laura; Gratton, Enrico; Herlax, Vanesa

2011-01-01

α-hemolysin (HlyA) from Escherichia coli is considered as the prototype of a family of toxins called RTX (repeat in toxin), a group of proteins that share genetic and structural features. HlyA is an important virulence factor in E. coli extraintestinal infections, such as meningitis, septicemia and urinary infections. High concentrations of the toxin cause the lysis of several cells such as erythrocytes, granulocytes, monocytes, endothelial and renal epithelial cells of different species. At low concentrations it induces the production of cytokines and apoptosis. Since many of the subcytolytic effects in other cells have been reported to be triggered by the increase of intracellular calcium, we followed the calcium concentration inside the erythrocytes while incubating with sublytic concentrations of HlyA. Calcium concentration was monitored using the calcium indicator Green 1, 2-photon excitation, and fluorescence lifetime imaging microscopy (FLIM). Data were analyzed using the phasor representation. In this report, we present evidence that, at sublytic concentrations, HlyA induces an increase of calcium concentration in rabbit erythrocytes in the first 10 s. Results are discussed in relation to the difficulties of measuring calcium concentrations in erythrocytes where hemoglobin is present, the contribution of the background and the heterogeneity of the response observed in individual cells. PMID:21698153

Indoor birch pollen concentrations differ with ventilation scheme, room location, and meteorological factors.

PubMed

Menzel, A; Matiu, M; Michaelis, R; Jochner, S

2017-05-01

Indoor pollen concentrations are an underestimated human health issue. In this study, we measured hourly indoor birch pollen concentrations on 8 days in April 2015 with portable pollen traps in five rooms of a university building at Freising, Germany. These data were compared to the respective outdoor values right in front of the rooms and to background pollen data. The rooms were characterized by different aspects and window ventilation schemes. Meteorological data were equally measured directly in front of the windows. Outdoor concentration could be partly explained with phenological data of 56 birches in the surrounding showing concurrent high numbers of trees attaining flowering stages. Indoor pollen concentrations were lower than outdoor concentrations: mean indoor/outdoor (I/O) ratio was highest in a room with fully opened window and additional mechanical ventilation (.75), followed by rooms with fully opened windows (.35, .12) and lowest in neighboring rooms with tilted window (.19) or windows only opened for short ventilation (.07). Hourly I/O ratios depended on meteorology and increased with outside temperature and wind speed oriented perpendicular to the window opening. Indoor concentrations additionally depended on the previously measured concentrations, indicating accumulation of pollen inside the rooms even after the full flowering period. © 2016 The Authors. Indoor Air Published by John Wiley & Sons Ltd.

Probiotics modify tight-junction proteins in an animal model of nonalcoholic fatty liver disease

PubMed Central

Briskey, David; Heritage, Mandy; Jaskowski, Lesley-Anne; Peake, Jonathan; Gobe, Glenda; Subramaniam, V. Nathan; Crawford, Darrell; Campbell, Catherine; Vitetta, Luis

2016-01-01

Background: We have investigated the effects of a multispecies probiotic preparation containing a combination of probiotic bacterial genera that included Bifidobacteria, Lactobacilli and a Streptococcus in a mouse model of high-fat diet or obesity-induced liver steatosis. Methods: Three groups of C57B1/6J mice were fed either a standard chow or a high-fat diet for 20 weeks, while a third group was fed a high-fat diet for 10 weeks and then concomitantly administered probiotics for a further 10 weeks. Serum, liver and large bowel samples were collected for analysis. Results: The expression of the tight-junction proteins ZO-1 and ZO-2 was reduced (p < 0.05) in high-fat diet-fed mice compared to chow-fed mice. Probiotic supplementation helped to maintain tight ZO-1 and ZO-2 expression compared with the high-fat diet group (p < 0.05), but did not restore ZO-1 or ZO-2 expression compared with chow-fed mice. Mice fed a high-fat diet ± probiotics had significant steatosis development compared with chow-fed mice (p < 0.05); steatosis was less severe in the probiotics group compared with the high-fat diet group. Hepatic triglyceride concentration was higher in mice fed a high-fat diet ± probiotics compared with the chow group (p < 0.05), and was lower in the probiotics group compared with the high-fat diet group (p < 0.05). Compared with chow-fed mice, serum glucose, cholesterol concentration and the activity of alanine transaminase were higher (p < 0.05), whereas serum triglyceride concentration was lower (p < 0.05) in mice fed a high-fat diet ± probiotics. Conclusions: Supplementation with a multispecies probiotic formulation helped to maintain tight-junction proteins ZO-1 and ZO-2, and reduced hepatic triglyceride concentration compared with a high-fat diet alone. PMID:27366215

In-Situ Characterization of Cloud Condensation Nuclei, Interstitial, and background Particles using Single Particle Mass Spectrometer, SPLAT II

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

Zelenyuk, Alla; Imre, D.; Earle, Michael

2010-10-01

Aerosol indirect effect remains the most uncertain aspect of climate change modeling because proper test requires knowledge of individual particles sizes and compositions with high spatial and temporal resolution. We present the first deployment of a single particle mass spectrometer (SPLAT II) that is operated in a dual data acquisition mode to measure all the required individual particle properties with sufficient temporal resolution to definitively resolve the aerosol-cloud interaction in this exemplary case. We measured particle number concentrations, asphericity, and individual particle size, composition, and density with better than 60 seconds resolution. SPLAT II measured particle number concentrations between 70more » particles cm-3and 300 particles cm-3, an average particle density of 1.4 g cm-3. Found that most particles are composed of oxygenated organics, many of which are mixed with sulfates. Biomass burn particles some with sulfates were prevalent, particularly at higher altitudes, and processed sea-salt was observed over the ocean. Analysis of cloud residuals shows that with time cloud droplets acquire sulfate by the reaction of peroxide with SO2. Based on the particle mass spectra and densities we find that the compositions of cloud condensation nuclei are similar to those of background aerosol but, contain on average ~7% more sulfate, and do not include dust and metallic particles. A comparison between the size distributions of background, activated, and interstitial particles shows that while nearly none of the activated particles is smaller than 115 nm, more than 80% of interstitial particles are smaller than 115 nm. We conclude that for this cloud the most important difference between CCN and background aerosol is particle size although having more sulfate also helps.« less