40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting under...

40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting under...

40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting under...

40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting under...

Green manure plants for remediation of soils polluted by metals and metalloids: ecotoxicity and human bioavailability assessment.

PubMed

Foucault, Y; Lévêque, T; Xiong, T; Schreck, E; Austruy, A; Shahid, M; Dumat, C

2013-10-01

Borage, white mustard and phacelia, green manure plants currently used in agriculture to improve soil properties were cultivated for 10 wk on various polluted soils with metal(loid) concentrations representative of urban brownfields or polluted kitchen gardens. Metal(loid) bioavailability and ecotoxicity were measured in relation to soil characteristics before and after treatment. All the plants efficiently grow on the various polluted soils. But borage and mustard only are able to modify the soil characteristics and metal(loid) impact: soil respiration increased while ecotoxicity, bioaccessible lead and total metal(loid) quantities in soils can be decreased respectively by phytostabilization and phytoextraction mechanisms. These two plants could therefore be used for urban polluted soil refunctionalization. However, plant efficiency to improve soil quality strongly depends on soil characteristics. Copyright © 2013. Published by Elsevier Ltd.

Transport routes of metalloids into and out of the cell: a review of the current knowledge.

PubMed

Zangi, Ronen; Filella, Montserrat

2012-04-15

Except for their extra- and intra-cellular interfaces, cell membranes are hydrophobic and inhibit the transport of hydrophilic molecules. Metalloids in aqueous solutions form chemical species with oxygen and hydroxyl groups and, therefore, exist as hydrophilic neutral polar solutes or as hydrophilic anions. This characteristic of metalloids introduces a large barrier for their passage through the cell membrane via unaided diffusion. The necessity for an uptake mechanism for metalloids arises from the requirement of these species for the maintenance of life, such as the need of boron for plant cells. Conversely, the transport of these species out of the cell is necessary because some metalloids are toxic, such as arsenic and antimony, and their entrance into the cell is undesirable. The undesired uptake of these toxic species is possible via pathways designed for the uptake of other structurally and chemically similar essential compounds. Therefore, the extrusion of arsenic and antimony out of the cell is an example of a detoxification mechanism. As a consequence of the hydrophobic character of the cell membrane in all living systems, the main route for the uptake and efflux of metalloids is facilitated by transmembrane proteins, driven either by concentration gradients or by energy-fueled pumps. However, metalloids forming or embedded in nano-sized particles escape the need to cross the cell membrane because these particles can be taken into the cell by endocytosis. Here, we review the uptake and efflux pathways of boron, silicon, arsenic, and antimony through the cell membranes of different organisms and the protein channels involved in these processes. In particular, passive diffusion via aquaglyceroporins, active transport via primary and secondary ion pumps, extrusion into vacuoles of metalloid-thiol conjugates via ATP-binding cassette, the efflux of methylated metalloids, and endocytosis are summarized. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Viability of a nanoremediation  process in single or multi-metal(loid) contaminated soils.

PubMed

Gil-Díaz, M; Pinilla, P; Alonso, J; Lobo, M C

2017-01-05

The effectiveness of single- and multi-metal(loid) immobilization of As, Cd, Cr, Pb and Zn using different doses of nanoscale zero-valent iron (nZVI) was evaluated and compared in two different soils, a calcareous and an acidic one. The effectiveness of nZVI to immobilize metal(loid)s in soil strongly depended on the metal characteristics, soil properties, dose of nZVI and presence of other metal(loid)s. In the case of single contamination, this nanoremediation strategy was effective for all of the metal(loid)s studied except for Cd. When comparing the two soils, anionic metal(loid)s (As and Cr) were more easily retained in acidic soil, whereas cationic metal(loid)s (Cd, Pb and Zn), were immobilized more in calcareous soil. In multi-metal(loid) contaminated soils, the presence of several metal(loid)s affected their immobilization, which was probably due to the competitive phenomenon between metal(loid) ions, which can reduce their sorption or produce synergistic effects. At 10% of nZVI, As, Cr and Pb availability decreased more than 82%, for Zn it ranged between 31 and 75% and for Cd between 13 and 42%. Thus, the application of nZVI can be a useful strategy to immobilize As, Cr, Pb and Zn in calcareous or acidic soils in both single- or multi-metal(loid) contamination conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Distribution of heavy metals and metalloids in bulk and particle size fractions of soils from coal-mine brownfield and implications on human health.

PubMed

Li, Hongxia; Ji, Hongbing; Shi, Chunjing; Gao, Yang; Zhang, Yan; Xu, Xiangyu; Ding, Huaijian; Tang, Lei; Xing, Yuxin

2017-04-01

Heavy metals (HMs) and metalloids migrate into their surroundings, thus increasing environmental risks and threatening human health. Current studies on coal-mine brownfields, however, have not thoroughly investigated soil-associated HMs and metalloids produced by coal mining. Therefore, this study explored the spatial and particle fraction distribution and human health implications of HMs and metalloids. The soil-associated HMs and metalloids are Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Nickel (Ni), Lead (Pb), Scandium (Sc), Titanium (Ti) and Zinc (Zn). Results showed that Cd, Cu, Pb, and Ni were enriched in bulk soils. Cadmium, Cu and Pb from anthropogenic source were mainly found at entrance roadsides and in sites closest to coal mines. HMs and metalloids primarily accumulated in fine fractions (<1, 1-5, and 5-10 μm). Moreover, HM and metalloid loadings substantially accumulated in the 75-250 μm and 250-1000 μm fractions. Most fine soil fractions showed moderate to strong potential ecological risks, whereas all the coarse particle fractions (50-75, 75-250, and 250-1000 μm) presented slight potential ecological risk. Exposure to soil-associated HMs and metalloids mainly occurred via ingestion. The total non-carcinogenic risks to children and adults fell below the safe level of 1, whereas the total carcinogenic risks to these individuals were higher than that of the maximum acceptable level set by the United States Environmental Protection Agency (USEPA, 1 × 10 -4 ). The total carcinogenic risk was mainly contributed by Cd and Ni through ingestion and dermal access. Therefore, hygiene and food security in areas should be emphasized. Copyright © 2017 Elsevier Ltd. All rights reserved.

Informal E-waste recycling in developing countries: review of metal(loid)s pollution, environmental impacts and transport pathways.

PubMed

Ackah, Michael

2017-11-01

Crude or primitive recycling practices are often adopted in material resource recovery from E-waste in developing nations. Significant human health and environmental impacts may occur because of such practices. Literature on metal(loid)s pollution during E-waste processing is fragmented. Here, I review the health and environmental impacts of E-waste recycling operations and transport pathways of metal(loid)s, dispersed during operations. This paper is organised into five sections. Section 1 relates to the background of global E-waste generation and legal/illegal trade, citing specific cases from Ghana and other developing nations. Section 2 provides a brief information on sources of metal(loid)s in E-waste. Section 3 describes characteristics of informal E-waste recycling operations in developing nations. Section 4 examines the health and environmental impacts in E-waste recycling while section 5 evaluates major transport pathways of metal(loid)s contaminants.

LiGe(SiMe₃)₃: A New Substituent for the Synthesis of Metalloid Tin Clusters from Metastable Sn(I) Halide Solutions.

PubMed

Binder, Mareike; Schrenk, Claudio; Block, Theresa; Pöttgen, Rainer; Schnepf, Andreas

2018-04-26

The most fruitful synthetic route to metalloid tin clusters applies the disproportionation reaction of metastable Sn(I) halide solutions, whereby Si(SiMe₃)₃ is mostly used as the stabilizing substituent. Here, we describe the synthesis and application of the slightly modified substituent Ge(SiMe₃)₃, which can be used for the synthesis of metalloid tin clusters to give the neutral cluster Sn 10 [Ge(SiMe₃)₃]₆ as well as the charged clusters {Sn 10 [Ge(SiMe₃)₃]₅} − and {Sn 10 [Ge(SiMe₃)₃]₄} 2− . The obtained metalloid clusters are structurally similar to their Si(SiMe₃)₃ derivatives. However, differences with respect to the stability in solution are observed. Additionally, a different electronic situation for the tin atoms is realized as shown by 119m Sn Mössbauer spectroscopy, giving further insight into the different kinds of tin atoms within the metalloid cluster {Sn 10 [Ge(SiMe₃)₃]₄} 2− . The synthesis of diverse derivatives gives the opportunity to check the influence of the substituent for further investigations of metalloid tin cluster compounds.

Arsenic and Antimony Transporters in Eukaryotes

PubMed Central

Maciaszczyk-Dziubinska, Ewa; Wawrzycka, Donata; Wysocki, Robert

2012-01-01

Arsenic and antimony are toxic metalloids, naturally present in the environment and all organisms have developed pathways for their detoxification. The most effective metalloid tolerance systems in eukaryotes include downregulation of metalloid uptake, efflux out of the cell, and complexation with phytochelatin or glutathione followed by sequestration into the vacuole. Understanding of arsenic and antimony transport system is of high importance due to the increasing usage of arsenic-based drugs in the treatment of certain types of cancer and diseases caused by protozoan parasites as well as for the development of bio- and phytoremediation strategies for metalloid polluted areas. However, in contrast to prokaryotes, the knowledge about specific transporters of arsenic and antimony and the mechanisms of metalloid transport in eukaryotes has been very limited for a long time. Here, we review the recent advances in understanding of arsenic and antimony transport pathways in eukaryotes, including a dual role of aquaglyceroporins in uptake and efflux of metalloids, elucidation of arsenic transport mechanism by the yeast Acr3 transporter and its role in arsenic hyperaccumulation in ferns, identification of vacuolar transporters of arsenic-phytochelatin complexes in plants and forms of arsenic substrates recognized by mammalian ABC transporters. PMID:22489166

Arsenic and antimony transporters in eukaryotes.

PubMed

Maciaszczyk-Dziubinska, Ewa; Wawrzycka, Donata; Wysocki, Robert

2012-01-01

Arsenic and antimony are toxic metalloids, naturally present in the environment and all organisms have developed pathways for their detoxification. The most effective metalloid tolerance systems in eukaryotes include downregulation of metalloid uptake, efflux out of the cell, and complexation with phytochelatin or glutathione followed by sequestration into the vacuole. Understanding of arsenic and antimony transport system is of high importance due to the increasing usage of arsenic-based drugs in the treatment of certain types of cancer and diseases caused by protozoan parasites as well as for the development of bio- and phytoremediation strategies for metalloid polluted areas. However, in contrast to prokaryotes, the knowledge about specific transporters of arsenic and antimony and the mechanisms of metalloid transport in eukaryotes has been very limited for a long time. Here, we review the recent advances in understanding of arsenic and antimony transport pathways in eukaryotes, including a dual role of aquaglyceroporins in uptake and efflux of metalloids, elucidation of arsenic transport mechanism by the yeast Acr3 transporter and its role in arsenic hyperaccumulation in ferns, identification of vacuolar transporters of arsenic-phytochelatin complexes in plants and forms of arsenic substrates recognized by mammalian ABC transporters.

Heavy metal(loid)s and organic contaminants in groundwater in the Pearl River Delta that has undergone three decades of urbanization and industrialization: Distributions, sources, and driving forces.

PubMed

Huang, Guanxing; Zhang, Ming; Liu, Chunyan; Li, Liangping; Chen, Zongyu

2018-09-01

Urbanization and industrialization have increased groundwater resource demands, and may drive the change of heavy metal(loid)s and organic chemicals in groundwater in the Pearl River Delta (PRD), southern China. Thus, a comprehensive understanding of the distributions, sources, and driving forces of heavy metal(loid)s and organic chemicals in groundwater in the PRD is vital for water resource management in this region. In this study, eight heavy metal(loid)s and fifty-five organic chemicals in groundwater across the PRD were investigated. The results show that undrinkable groundwater related to heavy metal(loid)s was mainly due to high concentrations of Fe (19.3%) and As (6.8%). Eighteen organic contaminants were detected in groundwater in the PRD, where the most frequently detected organic contaminant was naphthalene, and its detection rate was 2.51%. In 5.3% of all groundwater samples, one or more organic contaminants were found. All detected organic contaminants, except ones without allowable limits, in groundwater were at concentrations below allowable limits of China. The mean concentrations of heavy metal(loid)s in granular aquifers were higher than those in fissured and karst aquifers, especially for Fe and As. Except Se, the mean concentrations of other heavy metal(loid)s and the frequency of detection of organic contaminants in groundwater in urbanized and peri-urban areas were higher than those in non-urbanized areas, especially for Hg, Co, and organic contaminants. Fe, As, and Se in groundwater mainly originated from the release of Fe/As/Se rich sediments. The former two were driven by reduction reactions, while the latter was driven by oxidation resulting from the infiltration of NO 3 - . In contrast, other five heavy metal(loid)s and organic contaminants in groundwater mainly originated from the anthropogenic sources, such as the infiltration of industrial sewage. It is evident that urbanization and industrialization are two powerful driving forces for heavy metal(loid)s and organic contaminants in groundwater in the PRD. Copyright © 2018 Elsevier B.V. All rights reserved.

Functional characterisation of metal(loid) processes in planta through the integration of synchrotron techniques and plant molecular biology

PubMed Central

Donner, Erica; Punshon, Tracy; Guerinot, Mary Lou; Lombi, Enzo

2013-01-01

Functional characterisation of the genes regulating metal(loid) homeostasis in plants is a major focus of crop biofortification, phytoremediation, and food security research. This paper focuses on the potential for advancing plant metal(loid) research by combining molecular biology and synchrotron-based techniques. Recent advances in x-ray focussing optics and fluorescence detection have greatly improved the potential of synchrotron techniques for plant science research, allowing metal(loids) to be imaged in vivo in hydrated plant tissues at sub-micron resolution. Laterally resolved metal(loid) speciation can also be determined. By using molecular techniques to probe the location of gene expression and protein localisation and combining it with this synchrotron-derived data, functional information can be effectively and efficiently assigned to specific genes. This paper provides a review of the state of the art in this field, and provides examples as to how synchrotron-based methods can be combined with molecular techniques to facilitate functional characterisation of genes in planta. PMID:22200921

Semi-continuous detection of mercury in gases

DOEpatents

Granite, Evan J [Wexford, PA; Pennline, Henry W [Bethel Park, PA

2011-12-06

A new method for the semi-continuous detection of heavy metals and metalloids including mercury in gaseous streams. The method entails mass measurement of heavy metal oxides and metalloid oxides with a surface acoustic wave (SAW) sensor having an uncoated substrate. An array of surface acoustic wave (SAW) sensors can be used where each sensor is for the semi-continuous emission monitoring of a particular heavy metal or metalloid.

Evaluation of the Possible Sources and Controlling Factors of Toxic Metals/Metalloids in the Florida Everglades and Their Potential Risk of Exposure.

PubMed

Li, Yanbin; Duan, Zhiwei; Liu, Guangliang; Kalla, Peter; Scheidt, Daniel; Cai, Yong

2015-08-18

The Florida Everglades is an environmentally sensitive wetland ecosystem with a number of threatened and endangered fauna species susceptible to the deterioration of water quality. Several potential toxic metal sources exist in the Everglades, including farming, atmospheric deposition, and human activities in urban areas, causing concerns of potential metal exposure risks. However, little is known about the pollution status of toxic metals/metalloids of potential concern, except for Hg. In this study, eight toxic metals/metalloids (Cd, Cr, Pb, Ni, Cu, Zn, As, and Hg) in Everglades soils were investigated in both dry and wet seasons. Pb, Cr, As, Cu, Cd, and Ni were identified to be above Florida SQGs (sediment quality guidelines) at a number of sampling sites, particularly Pb, which had a level of potential risk to organisms similar to that of Hg. In addition, a method was developed for quantitative source identification and controlling factor elucidation of toxic metals/metalloids by introducing an index, enrichment factor (EF), in the conventional multiple regression analysis. EFs represent the effects of anthropogenic sources on metals/metalloids in soils. Multiple regression analysis showed that Cr and Ni were mainly controlled by anthropogenic loading, whereas soil characteristics, in particular natural organic matter (NOM), played a more important role for Hg, As, Cd, and Zn. NOM may control the distribution of these toxic metals/metalloids by affecting their mobility in soils. For Cu and Pb, the effects of EFs and environmental factors are comparable, suggesting combined effects of loading and soil characteristics. This study is the first comprehensive research with a vast amount of sampling sites on the distribution and potential risks of toxic metals/metalloids in the Everglades. The finding suggests that in addition to Hg other metals/metalloids could also potentially be an environmental problem in this wetland ecosystem.

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) from the karstic Croatian river Krka.

PubMed

Dragun, Zrinka; Filipović Marijić, Vlatka; Krasnići, Nesrete; Ivanković, Dušica; Valić, Damir; Žunić, Jakov; Kapetanović, Damir; Smrzlić, Irena Vardić; Redžović, Zuzana; Grgić, Ivana; Erk, Marijana

2018-01-01

Total and cytosolic concentrations of twenty metals/metalloids in the liver of brown trout Salmo trutta (Linnaeus, 1758) were studied in the period from April 2015 to May 2016 at two sampling sites on Croatian river Krka, to establish if river water contamination with metals/metalloids downstream of Knin town has influenced metal bioaccumulation in S. trutta liver. Differences were observed between two sites, with higher concentrations of several elements (Ag, As, Ca, Co, Na, Se, Sr, V) found downstream of Knin town, whereas few others (Cd, Cs, Mo, Tl) were, unexpectedly, increased at the Krka River spring. However, total metal/metalloid concentrations in the liver of S. trutta from both sites of the Krka River were still mainly below previously reported levels for pristine freshwaters worldwide. The analysis of seasonal changes of metal/metalloid concentrations in S. trutta liver and their association with fish sex and size mostly indicated their independence of fish physiology, making them good indicators of water contamination and exposure level. Metal/metalloid concentrations in the metabolically available hepatic cytosolic fractions reported in this study are the first data of that kind for S. trutta liver, and the majority of analyzed elements were present in the cytosol in the quantity higher than 50% of their total concentrations, thus indicating their possible availability for toxic effects. However, the special attention should be directed to As, Cd, Cs, and Tl, which under the conditions of increased exposure tended to accumulate more within the cytosol. Although metal/metalloid concentrations in S. trutta liver were still rather low, monitoring of the Krka River water quality and of the health status of its biota is essential due to a trend of higher metal/metalloid bioaccumulation downstream of Knin town, especially taking into consideration the proximity of National Park Krka and the need for its conservation. Copyright © 2017 Elsevier Inc. All rights reserved.

Resolving colocalization of bacteria and metal(loid)s on plant root surfaces by combining fluorescence in situ hybridization (FISH) with multiple-energy micro-focused X-ray fluorescence (ME μXRF).

PubMed

Honeker, Linnea K; Root, Robert A; Chorover, Jon; Maier, Raina M

2016-12-01

Metal(loid)-contamination of the environment due to anthropogenic activities is a global problem. Understanding the fate of contaminants requires elucidation of biotic and abiotic factors that influence metal(loid) speciation from molecular to field scales. Improved methods are needed to assess micro-scale processes, such as those occurring at biogeochemical interfaces between plant tissues, microbial cells, and metal(loid)s. Here we present an advanced method that combines fluorescence in situ hybridization (FISH) with synchrotron-based multiple-energy micro-focused X-ray fluorescence microprobe imaging (ME μXRF) to examine colocalization of bacteria and metal(loid)s on root surfaces of plants used to phytostabilize metalliferous mine tailings. Bacteria were visualized on a small root section using SytoBC nucleic acid stain and FISH probes targeting the domain Bacteria and a specific group (Alphaproteobacteria, Gammaproteobacteria, or Actinobacteria). The same root region was then analyzed for elemental distribution and metal(loid) speciation of As and Fe using ME μXRF. The FISH and ME μXRF images were aligned using ImageJ software to correlate microbiological and geochemical results. Results from quantitative analysis of colocalization show a significantly higher fraction of As colocalized with Fe-oxide plaques on the root surfaces (fraction of overlap 0.49±0.19) than to bacteria (0.072±0.052) (p<0.05). Of the bacteria that colocalized with metal(loid)s, Actinobacteria, known for their metal tolerance, had a higher correlation with both As and Fe than Alphaproteobacteria or Gammaproteobacteria. This method demonstrates how coupling these micro-techniques can expand our understanding of micro-scale interactions between roots, metal(loid)s and microbes, information that should lead to improved mechanistic models of metal(loid) speciation and fate. Copyright © 2016 Elsevier B.V. All rights reserved.

Metal(loid) allocation and nutrient retranslocation in Pinus halepensis trees growing on semiarid mine tailings.

PubMed

Parraga-Aguado, Isabel; Querejeta, Jose-Ignacio; González-Alcaraz, María Nazaret; Conesa, Hector M

2014-07-01

The goal of this study was to evaluate internal metal(loid) cycling and the risk of metal(loid) accumulation in litter from Pinus halepensis trees growing at a mine tailing disposal site in semiarid Southeast Spain. Internal nutrient retranslocation was also evaluated in order to gain insight into the ability of pine trees to cope with the low-fertility soil conditions at the tailings. We measured metal(loid) concentrations in the foliage (young and old needles), woody stems and fresh leaf litter of pine trees growing on tailings. The nutrient status and stable isotope composition of pine foliage (δ(13)C, δ(15)N, δ(18)O as indicators of photosynthesis and water use efficiency) were also analyzed. Tailing soil properties in vegetation patches and in adjacent bare soil patches were characterized as well. Significant amounts of metal(loid)s such us Cd, Cu, Pb and Sb were immobilized in the woody stems of Pinus halepensis trees growing on tailings. Leaf litterfall showed high concentrations of As, Cd, Sb, Pb and Zn, which thereby return to the soil. However, water extractable metal(loid) concentrations in tailing soils were similar between vegetation patches (mineral soil under the litter layer) and bare soil patches. The pines growing on mine tailings showed very low foliar P concentrations in all leaf age classes, which suggests severe P deficiency. Young (current year) needles showed lower accumulation of metal(loid)s, higher nutrient concentrations (P and K), and higher water use efficiency (as indicated by and δ(13)C and δ(18)O data) than older needles. Substantial nutrient resorption occurred before leaf litterfall, with 46% retranslocation efficiency for P and 89% for K. In conclusion, phytostabilization of semiarid mine tailings with Pinus halepensis is feasible but would require careful monitoring of the trace elements released from litterfall, in order to assess the long term risk of metal(loid) transfer to the food chain. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of Organic Matter - Mineral Interfacial Reactions on Metal(loid) Speciation and Bioaccessibility

NASA Astrophysics Data System (ADS)

Chorover, J.; Kong, S.; Root, R. A.; Thomas, A.

2015-12-01

Bioaccessibility of contaminant metals in geomedia is often measured on the basis of kinetic release to solution during in vitro reaction with biofluid simulants. We postulate that development of a predictive-mechanistic understanding of bioaccessibility requires knowledge of metal(loid) molecular speciation upon sample introduction, as well as its change over the course of the in vitro reaction. Our results - including data from batch, column, mesocosm and field studies pertaining to arsenic, lead, and zinc contaminated materials - indicate the strong influence of organic matter and associated biological activity on metal(loid) speciation in mine tailings and related model systems. Furthermore, presence/absence of organic matter during bioassays affects the kinetics of metal(loid) release into biofluid simulants through multiple mechanisms.

Characterizing metal(loid) solubility in airborne PM10, PM2.5 and PM1 in Frankfurt, Germany using simulated lung fluids

NASA Astrophysics Data System (ADS)

Wiseman, Clare L. S.; Zereini, Fathi

2014-06-01

The purpose of this study is to assess the solubility of traffic-related metal(loid)s associated with airborne PM of human health concern, employing a physiologically-based extraction test with simulated lung fluids (artificial lysosomal fluid (ALF) and Gamble's solution). Airborne PM (PM10, PM2.5 and PM1) samples were collected in Frankfurt am Main, Germany, using a high volume sampler. Following extraction of the soluble metal(loid) fractions, sample filters were digested with a high pressure asher. Metal(loid) concentrations (As, Ce, Co, Cr, Cu, Mn, Ni, Pb, Sb, Ti and V) were determined in extracts and digests per ICP-Q-MS. All metal(loid)s occurred at detectable concentrations in the three airborne PM fractions. Copper was the most abundant element in mass terms, with mean concentrations of 105 and 53 ng/m3 in PM10 and PM2.5, respectively. Many of the metal(loid)s were observed to be soluble in simulated lung fluids, with Cu, As, V and Sb demonstrating the highest overall mobility in airborne PM. For instance, all four elements associated with PM10 had a solubility of >80% in ALF (24 h). Clearly, solubility is strongly pH dependent, as reflected by the higher relative mobility of samples extracted with the acidic ALF. Given their demonstrated solubility, this study provides indirect evidence that a number of toxic metal(loid)s are likely to possess an enhanced pulmonary toxic potential upon their inhalation. The co-presence of many toxic elements of concern in airborne PM suggests an assessment of health risk must consider the possible interactive impacts of multi-element exposures.

Metals and metalloids in precipitation collected during CHINARE campaign from Shanghai, China, to Zhongshan Station, Antarctica: Spatial variability and source identification

NASA Astrophysics Data System (ADS)

Shi, G.; Teng, J.; Ma, H.; Li, Y.; Sun, B.

2015-06-01

Metals and metalloids in continental precipitation have been widely observed, but the data over open oceans are still very limited. Investigation of metals and metalloids in marine precipitation is of great significance to understand global transport of these elements in the atmosphere and their input fluxes to the oceans. So shipboard sampling of precipitation was conducted during a Chinese National Antarctic Research Expedition campaign from Shanghai, China, to Zhongshan Station, East Antarctica, and 22 samples (including 17 rainfall and 5 snowfall events) were collected and analyzed for concentrations of Pb, Ni, Cr, Cu, Co, Hg, As, Cd, Sb, Se, Zn, Mn, and Ti. Results show that concentrations of both metals and metalloids vary considerably along the cruise, with higher concentrations at coastal sites and lower values on the south Indian Ocean. Although only soluble fractions were determined for elements, concentrations in this study are generally comparable to the reported values of marine rain. Enrichment factor analysis shows that most of metals and metalloids are enriched versus crustal sources, even in the samples collected from remote south Indian Ocean. In addition, metals and metalloids in precipitation are also very enriched above sea-salt abundance, indicating that impacts of sea-salt aerosols on their concentrations are negligible. Main sources of metals and metalloids were explored with the aid of multivariate statistical analyses. The results show that human emissions have far-reaching distribution, which may exert an important influence on the solubility of elements in precipitation. This investigation provides valuable information on spatial variation and possible sources of trace elements in precipitation over the open oceans corresponding to understudied region.

Health risks of children's cumulative and aggregative exposure to metals and metalloids in a typical urban environment in China.

PubMed

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Chen, Yiting; Wang, Beibei; Sun, Chengye; Zheng, Binghui; Wei, Fusheng

2016-03-01

Rapid development of industrialization and urbanization results in serious environmental contamination by metal(loid)s, which would consequently cause deleterious health effects to the exposed people through multi-pathways. Therefore, total health risk assessment for the population in urban environment is very important. Unfortunately, few studies to date investigate the cumulative health risks of metal(loid)s through aggregative pathways in Children who are often susceptible population. 12 metal(loid)s including Lead(Pb), Cadmium(Cd), Arsenic(As), Chromium(Cr), Zinc(Zn), Copper(Cu), Nickel(Ni), Manganese(Mn), Cobalt(Co), Selenium(Se), Antimony(Se) and Vanadium(V), were analyzed in PM10, drinking water, food, soil and indoor dust in this study. The cumulative and aggregative risks of these metal(loid)s among the local children were then evaluated on a field sampling and questionnaire-survey basis. The results showed that the environments were heavily polluted by metal(loid)s. For most metal(loid)s, food ingestion accounted for more than 80% of the total daily exposure dose. The non-cancer risks were up to 30 times higher than the acceptable level due to the food ingestion via Pb, Cr, Cu, Zn, As, Se, Cd and Sb, and the PM10 inhalation via Cr and Mn. While, the cancer risks were mainly attributed to Cr via food ingestion and As via food and dust ingestion, and approximately 100 times of the maximum acceptable level of 1.0 × 10(-4). The study highlights the cumulative and aggregative exposure assessment, instead of pollutant investigation to evaluate the potential health risks and emphasizes concerns to improve indoor hygienic and environmental quality and to decrease the potential harmful health effects of children living in urban area. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ecological and human health risks associated with abandoned gold mine tailings contaminated soil.

PubMed

Ngole-Jeme, Veronica Mpode; Fantke, Peter

2017-01-01

Gold mining is a major source of metal and metalloid emissions into the environment. Studies were carried out in Krugersdorp, South Africa, to evaluate the ecological and human health risks associated with exposure to metals and metalloids in mine tailings contaminated soils. Concentrations of arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) in soil samples from the area varied with the highest contamination factors (expressed as ratio of metal or metalloid concentration in the tailings contaminated soil to that of the control site) observed for As (3.5x102), Co (2.8x102) and Ni (1.1x102). Potential ecological risk index values for metals and metalloids determined from soil metal and metalloid concentrations and their respective risk factors were correspondingly highest for As (3.5x103) and Co (1.4x103), whereas Mn (0.6) presented the lowest ecological risk. Human health risk was assessed using Hazard Quotient (HQ), Chronic Hazard Index (CHI) and carcinogenic risk levels, where values of HQ > 1, CHI > 1 and carcinogenic risk values > 1×10-4 represent elevated risks. Values for HQ indicated high exposure-related risk for As (53.7), Cr (14.8), Ni (2.2), Zn (2.64) and Mn (1.67). Children were more at risk from heavy metal and metalloid exposure than adults. Cancer-related risks associated with metal and metalloid exposure among children were also higher than in adults with cancer risk values of 3×10-2 and 4×10-2 for As and Ni respectively among children, and 5×10-3 and 4×10-3 for As and Ni respectively among adults. There is significant potential ecological and human health risk associated with metal and metalloid exposure from contaminated soils around gold mine tailings dumps. This could be a potential contributing factor to a setback in the health of residents in informal settlements dominating this mining area as the immune systems of some of these residents are already compromised by high HIV prevalence.

Ecological and human health risks associated with abandoned gold mine tailings contaminated soil

PubMed Central

Ngole-Jeme, Veronica Mpode; Fantke, Peter

2017-01-01

Gold mining is a major source of metal and metalloid emissions into the environment. Studies were carried out in Krugersdorp, South Africa, to evaluate the ecological and human health risks associated with exposure to metals and metalloids in mine tailings contaminated soils. Concentrations of arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) in soil samples from the area varied with the highest contamination factors (expressed as ratio of metal or metalloid concentration in the tailings contaminated soil to that of the control site) observed for As (3.5x102), Co (2.8x102) and Ni (1.1x102). Potential ecological risk index values for metals and metalloids determined from soil metal and metalloid concentrations and their respective risk factors were correspondingly highest for As (3.5x103) and Co (1.4x103), whereas Mn (0.6) presented the lowest ecological risk. Human health risk was assessed using Hazard Quotient (HQ), Chronic Hazard Index (CHI) and carcinogenic risk levels, where values of HQ > 1, CHI > 1 and carcinogenic risk values > 1×10−4 represent elevated risks. Values for HQ indicated high exposure-related risk for As (53.7), Cr (14.8), Ni (2.2), Zn (2.64) and Mn (1.67). Children were more at risk from heavy metal and metalloid exposure than adults. Cancer-related risks associated with metal and metalloid exposure among children were also higher than in adults with cancer risk values of 3×10−2 and 4×10−2 for As and Ni respectively among children, and 5×10−3 and 4×10−3 for As and Ni respectively among adults. There is significant potential ecological and human health risk associated with metal and metalloid exposure from contaminated soils around gold mine tailings dumps. This could be a potential contributing factor to a setback in the health of residents in informal settlements dominating this mining area as the immune systems of some of these residents are already compromised by high HIV prevalence. PMID:28222184

Polymers for metal extractions in carbon dioxide

DOEpatents

DeSimone, Joseph M.; Tumas, William; Powell, Kimberly R.; McCleskey, T. Mark; Romack, Timothy J.; McClain, James B.; Birnbaum, Eva R.

2001-01-01

A composition useful for the extraction of metals and metalloids comprises (a) carbon dioxide fluid (preferably liquid or supercritical carbon dioxide); and (b) a polymer in the carbon dioxide, the polymer having bound thereto a ligand that binds the metal or metalloid; with the ligand bound to the polymer at a plurality of locations along the chain length thereof (i.e., a plurality of ligands are bound at a plurality of locations along the chain length of the polymer). The polymer is preferably a copolymer, and the polymer is preferably a fluoropolymer such as a fluoroacrylate polymer. The extraction method comprises the steps of contacting a first composition containing a metal or metalloid to be extracted with a second composition, the second composition being as described above; and then extracting the metal or metalloid from the first composition into the second composition.

Evolution of Metal(Loid) Binding Sites in Transcriptional Regulators

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

Ordonez, E.; Thiyagarajan, S.; Cook, J.D.

2009-05-22

Expression of the genes for resistance to heavy metals and metalloids is transcriptionally regulated by the toxic ions themselves. Members of the ArsR/SmtB family of small metalloregulatory proteins respond to transition metals, heavy metals, and metalloids, including As(III), Sb(III), Cd(II), Pb(II), Zn(II), Co(II), and Ni(II). These homodimeric repressors bind to DNA in the absence of inducing metal(loid) ion and dissociate from the DNA when inducer is bound. The regulatory sites are often three- or four-coordinate metal binding sites composed of cysteine thiolates. Surprisingly, in two different As(III)-responsive regulators, the metalloid binding sites were in different locations in the repressor, andmore » the Cd(II) binding sites were in two different locations in two Cd(II)-responsive regulators. We hypothesize that ArsR/SmtB repressors have a common backbone structure, that of a winged helix DNA-binding protein, but have considerable plasticity in the location of inducer binding sites. Here we show that an As(III)-responsive member of the family, CgArsR1 from Corynebacterium glutamicum, binds As(III) to a cysteine triad composed of Cys{sup 15}, Cys{sup 16}, and Cys{sup 55}. This binding site is clearly unrelated to the binding sites of other characterized ArsR/SmtB family members. This is consistent with our hypothesis that metal(loid) binding sites in DNA binding proteins evolve convergently in response to persistent environmental pressures.« less

Methodological factors influencing inhalation bioaccessibility of metal(loid)s in PM2.5 using simulated lung fluid.

PubMed

Kastury, Farzana; Smith, E; Karna, Ranju R; Scheckel, Kirk G; Juhasz, A L

2018-06-07

In this study, methodological factors influencing the dissolution of metal(loid)s in simulated lung fluid (SLF) was assessed in order to develop a standardised method for the assessment of inhalation bioaccessibility in PM 2.5 . To achieve this aim, the effects of solid to liquid (S/L) ratio (1:100 to 1:5000), agitation (magnetic agitation, occasional shaking, orbital and end-over-end rotation), composition of SLF (artificial lysosomal fluid: ALF; phagolysosomal simulant fluid: PSF) and extraction time (1-120 h) on metal(loid) bioaccessibility were investigated using PM 2.5 from three Australian mining/smelting impacted soils and a certified reference material. The results highlighted that SLF composition significantly (p < 0.001) influenced metal(loid) bioaccessibility and that when a S/L ratio of 1:5000 and end-over-end rotation was used, metal(loid) solubility plateaued after approximately 24 h. Additionally, in order to assess the exposure of metal(loid)s via incidental ingestion of surface dust, PM 2.5 was subjected to simulated gastro-intestinal tract (GIT) solutions and the results were compared to extraction using SLF. Although As bioaccessibility in SLF (24 h) was significantly lower than in simulated GIT solutions (p < 0.05), Pb bioaccessibility was equal to or significantly higher than that extracted using simulated GIT solutions (p < 0.05). Copyright © 2018 Elsevier Ltd. All rights reserved.

Data on metals (Zn, Al, Sr, and Co) and metalloid (As) concentration levels of ballast water in commercial ships entering Bushehr port, along the Persian Gulf.

PubMed

Soleimani, Farshid; Dobaradaran, Sina; Hayati, Abdolreza; Khorsand, Maryam; Keshtkar, Mozhgan

2016-12-01

In this article, we determined the concentration levels of metals including Zn, Al, Sr, and Co and metalloid of As of ballast water in commercial ships entering Bushehr port, along the Persian Gulf. Ballast water samples were taken from commercial ships entering Bushehr port from 34 ports around the world during 15 February and 25 August 2016. The concentration levels of metals and metalloid were determined by using a graphite furnace absorption spectrometer (AAS).

Glucose-6-phosphate dehydrogenase and Trypanothione reductase interaction protects Leishmania donovani from metalloid mediated oxidative stress.

PubMed

Ghosh, Ayan Kumar; Saini, Savita; Das, Sushmita; Mandal, Abhishek; Sardar, Abul Hasan; Ansari, Md Yousuf; Abhishek, Kumar; Kumar, Ajay; Singh, Ruby; Verma, Sudha; Equbal, Asif; Ali, Vahab; Das, Pradeep

2017-05-01

Exploration of metabolons as viable drug target is rare in kinetoplastid biology. Here we present a novel protein-protein interaction among Glucose-6-phosphate dehydrogenase (LdG6PDH) and Trypanothione reductase (LdTryR) of Leishmania donovani displaying interconnection between central glucose metabolism and thiol metabolism of this parasite. Digitonin fractionation patterns observed through immunoblotting indicated localisation of both LdG6PDH and LdTryR in cytosol. In-silico and in-vitro interaction observed by size exclusion chromatography, co-purification, pull-down assay and spectrofluorimetric analysis revealed LdG6PDH and LdTryR physically interact with each other in a NADPH dependent manner. Coupled enzymatic assay displayed that NADPH generation was severely impaired by addition of Sb III , As III and Te IV extraneously, which hint towards metalloid driven structural changes of the interacting proteins. Co-purification patterns and pull-down assays also depicted that metalloids (Sb III , As III and Te IV ) hinder the in-vitro interaction of these two enzymes. Surprisingly, metalloids at sub-lethal concentrations induced the in-vivo interaction of LdG6PDH and LdTryR, as analyzed by pull-down assays and fluorescence microscopy signifying protection against metalloid mediated ROS. Inhibition of LdTryR by thioridazine in LdG6PDH -/- parasites resulted in metalloid induced apoptotic death of the parasites due to abrupt fall in reduced thiol content, disrupted NADPH/NADP + homeostasis and lethal oxidative stress. Interestingly, clinical isolates of L.donovani resistant to SAG exhibited enhanced interaction between LdG6PDH and LdTryR and showed cross resistivity towards As III and Te IV . Thus, our findings propose the metabolon of LdG6PDH and LdTryR as an alternate therapeutic target and provide mechanistic insight about metalloid resistance in Visceral Leishmaniasis. Copyright © 2017. Published by Elsevier Inc.

Generalized Slater--Pauling curve and the role of metalloids in Fe-based amorphous alloys

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

Sostarich, M.

1990-05-01

A modification of the generalized Slater--Pauling curve so as to consider the concentration dependence of the number of majority-spin {ital sp} electrons per average atom is proposed for amorphous iron-metalloid alloys. In this way an improved matching of the measured magnetic moment dependence on composition is achieved for Fe alloys with B and/or P as metalloids. Comparison of theory with experiment shows that amorphous Fe-P alloys tend to be magnetically rather strong, whereas their Fe-B counterparts are weak itinerant ferromagnets in almost the entire range of compositions.

Investigation of biomethylation of arsenic and tellurium during composting.

PubMed

Diaz-Bone, Roland A; Raabe, Maren; Awissus, Simone; Keuter, Bianca; Menzel, Bernd; Küppers, Klaus; Widmann, Renatus; Hirner, Alfred V

2011-05-30

Though the process of composting features a high microbiological activity, its potential to methylate metals and metalloids has been little investigated so far in spite of the high impact of this process on metal(loid) toxicity and mobility. Here, we studied the biotransformation of arsenic, tellurium, antimony, tin and germanium during composting. Time resolved investigation revealed a highly dynamic process during self-heated composting with markedly differing time patterns for arsenic and tellurium species. Extraordinary high concentrations of up to 150 mg kg(-1) methylated arsenic species as well as conversion rates up to 50% for arsenic and 5% for tellurium were observed. In contrast, little to no conversion was observed for antimony, tin and germanium. In addition to experiments with metal(loid) salts, composting of arsenic hyperaccumulating ferns Pteris vittata and P. cretica grown on As-amended soils was studied. Arsenic accumulated in the fronds was efficiently methylated resulting in up to 8 mg kg(-1) methylated arsenic species. Overall, these studies indicate that metal(loid)s can undergo intensive biomethylation during composting. Due to the high mobility of methylated species this process needs to be considered in organic waste treatment of metal(loid) contaminated waste materials. Copyright © 2010 Elsevier B.V. All rights reserved.

VOLATILE ORGANO-METALLOIDS IN BIO-SOLID MATERIALS: ANALYSIS BY VACUUM DISTILLATION-GC/MS

EPA Science Inventory

An analytical method based on vacuum distillation-gas chromatography-mass spectrometry (VD-GC-MS)

was developed for determining volatile organo-metalloid contaminants in bio-solid materials. Method

performance was evaluated for dimethylselenide (DMSe), dimethyldisel...

In-Situ Analysis Of Metal(loid)s In Plants: State Of The Art And Artefacts

EPA Science Inventory

Metals and metalloids play important roles in plant function and metabolism. Likewise, plants subsequently introduce vital dietary nutrition to people and animals. Understanding the transport, localisation and speciation of these elements is critical for understanding availabil...

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.

The Sequential Application of Macroalgal Biosorbents for the Bioremediation of a Complex Industrial Effluent

PubMed Central

Kidgell, Joel T.; de Nys, Rocky; Paul, Nicholas A.; Roberts, David A.

2014-01-01

Fe-treated biochar and raw biochar produced from macroalgae are effective biosorbents of metalloids and metals, respectively. However, the treatment of complex effluents that contain both metalloid and metal contaminants presents a challenging scenario. We test a multiple-biosorbent approach to bioremediation using Fe-biochar and biochar to remediate both metalloids and metals from the effluent from a coal-fired power station. First, a model was derived from published data for this effluent to predict the biosorption of 21 elements by Fe-biochar and biochar. The modelled outputs were then used to design biosorption experiments using Fe-biochar and biochar, both simultaneously and in sequence, to treat effluent containing multiple contaminants in excess of water quality criteria. The waste water was produced during ash disposal at an Australian coal-fired power station. The application of Fe-biochar and biochar, either simultaneously or sequentially, resulted in a more comprehensive remediation of metalloids and metals compared to either biosorbent used individually. The most effective treatment was the sequential use of Fe-biochar to remove metalloids from the waste water, followed by biochar to remove metals. Al, Cd, Cr, Cu, Mn, Ni, Pb, Zn were reduced to the lowest concentration following the sequential application of the two biosorbents, and their final concentrations were predicted by the model. Overall, 17 of the 21 elements measured were remediated to, or below, the concentrations that were predicted by the model. Both metalloids and metals can be remediated from complex effluent using biosorbents with different characteristics but derived from a single feedstock. Furthermore, the extent of remediation can be predicted for similar effluents using additive models. PMID:25061756

Bioaccumulation trends of arsenic and antimony in a freshwater ecosystem affected by mine drainage

USGS Publications Warehouse

Dovick, Meghan A.; Kulp, Thomas R.; Arkle, Robert .; Pilliod, David S.

2015-01-01

We compared As and Sb bioaccumulation and biomagnification when these metalloids co-occurred at varying environmental concentrations in a stream and wetlands near a contaminated mine site in Idaho (USA). We measured As and Sb concentrations in water and substrate samples, and in tissues of organisms representing several trophic levels. Bioaccumulation of both As and Sb was observed in stream organisms with the following trend of bio-diminution with increasing trophic level: primary producers > tadpoles > macroinvertebrates > trout. We also note reductions in metalloid concentrations in one of two stream remediation reaches engineered within the past 17 years to ameliorate metalloid contamination in the stream. Several wetlands contained thick microbial mats and were highly populated with boreal toad tadpoles that fed on them. The mats were extremely contaminated (up to 76 564 mg kg–1 As and 675 mg kg–1 Sb) with amorphous As- and Sb-bearing minerals that we interpret as biogenic precipitates from geomicrobiological As- and Sb-cycling. Ingested mat material provided a direct source of metalloids to tadpoles, and concentrations of 3867 mg kg–1 (As) and 375 mg kg–1 (Sb) reported here represent the highest whole body As and Sb levels ever reported in living tadpoles. The bulk of tadpole metalloid burden remained in the gut despite attempts to purge the tadpoles prior to analysis. This study adds to a number of recent investigations reporting bioaccumulation, but not biomagnification, of As and Sb in food webs. Moreover, our results suggest that tadpoles, in particular, may be more resistant to metalloid contamination than previously assumed.

Stabilization of metal(loid)s in two contaminated agricultural soils: Comparing biochar to its non-pyrolysed source material.

PubMed

Trakal, Lukáš; Raya-Moreno, Irene; Mitchell, Kerry; Beesley, Luke

2017-08-01

Two metal(loid) contaminated agricultural soils were amended with grape stalk (wine production by-product)-derived biochar as well as its pre-pyrolysed origin material, to investigate their geochemical impacts on As, Cr, Cu and Zn. Detailed physico-chemical evaluation combined with a column leaching test determined the retention of metal(loid)s from soil solution by each amendments. A pot experiment measured metal(loid)s in soil pore water and their uptake to ryegrass when the amendments were mixed into soils at 1 and 5% (w/w). Total Cr and Zn concentrations were reduced furthest in column leachates by the addition of raw material and biochar respectively, compared to the untreated soil; Cr(III) was the predominant specie initially due to rapid acidification of leachates and organic complexation resulting from raw material addition. Loadings of metal(loid)s to the amendments recovered from the post-leached columns were in the order Cu » Zn > Cr ≈ As. In the pot test ryegrass Cr uptake was initiated by the addition of both amendments, compared to the untreated soil, whereas only biochar addition resulted in significant increases in Zn uptake, explained by its significant enhancement of ryegrass biomass yield, especially at 5% dosage; raw material addition significantly decreased biomass yields. Inconsistent relationships between pore water parameters and ryegrass uptake were common to both soils investigated. Therefore, whilst both amendments modified soil metal(loid) geochemistry, their effects differed fundamentally; in environmental risk management terms these results highlight the need to investigate the detailed geochemical response of contaminated soils to diverse organic amendment additions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mobility of engineered inorganic nanoparticles in porous media

NASA Astrophysics Data System (ADS)

Metreveli, George; Heidmann, Ilona; Schaumann, Gabriele Ellen

2013-04-01

Besides the excellent properties and great potential for various industrial, medical, pharmaceutical, cosmetic, and life science applications, engineered inorganic nanoparticles (EINP) can show also disadvantages concerning increasing risk potential with increasing application, if they are released in the environmental systems. EINP can influence microbial activity and can show toxic effects (Fabrega et al., 2009). Similar to the inorganic natural colloids, EINP can be transported in soil and groundwater systems (Metreveli et al., 2005). Furthermore, due to the large surface area and high sorption and complex formation capacity, EINP can facilitate transport of different contaminants. In this study the mobility behaviour of EINP and their effect on the transport of different metal(loid) species in water saturated porous media was investigated. For these experiments laboratory column system was used. The column was filled with quartz sand. The interactions between EINP and metal(loid)s were characterised by coupling of asymmetrical flow field flow fractionation (AF4) with inductively coupled plasma mass spectrometer (ICP-MS). As EINP laponite (synthetic three layer clay mineral), and as metal(loid)s Cu, Pb, Zn, Pt and As were used. In AF4 experiments sorption of metal(loid)s on the surface of EINP could be observed. The extent of interactions was influenced by pH value and was different for different metal(loid)s. Laboratory column experiments showed high mobility of EINP, which facilitated transport of most of metal(loid)s in water saturated porous media. Furthermore the migration of synthetic silver nanoparticles in natural soil columns was determined in leaching experiments. Acknowledgement Financial support by German Research Council (DFG) and Max-Buchner-Research Foundation (MBFSt) is gratefully acknowledged. We thank Karlsruhe Institute of Technology (KIT) for the opportunity to perform the column and AF4 experiments. References: Fabrega, J., Fawcett, S. R., Renshaw, J. C. Lead, J. R. 2009. Silver nanoparticle impact on bacterial growth: Effect of pH, concentration, and organic matter. Environ. Sci. Technol. 43 (19): 7285-7290 Metreveli, G., Kaulisch, E.-M., Frimmel, F. H. 2005. Coupling of a column system with ICP-MS for the characterisation of colloid mediated metal(loid) transport in porous media. Acta Hydrochim. Hydrobiol. 33 (4): 337-345

An inhalation-ingestion bioaccessibility assay (IIBA) for the assessment of exposure to metal(loid)s in PM10

EPA Science Inventory

Although metal(loid) bioaccessibility of ambient particulate matter, with an aerodynamic diameter of <10 μm (PM10), has recently received increasing attention, limited research exists into standardising in-vitro methodologies using simulated lung fluid (SLF). Contradictions...

Toxic metal(loid) speciation during weathering of iron sulfide mine tailings under semi-arid climate

PubMed Central

Root, Robert A.; Hayes, Sarah M.; Hammond, Corin M.; Maier, Raina M.; Chorover, Jon

2015-01-01

Toxic metalliferous mine-tailings pose a significant health risk to ecosystems and neighboring communities from wind and water dispersion of particulates containing high concentrations of toxic metal(loid)s (e.g., Pb, As, Zn). Tailings are particularly vulnerable to erosion before vegetative cover can be reestablished, i.e., decades or longer in semi-arid environments without intervention. Metal(loid) speciation, linked directly to bioaccessibility and lability, is controlled by mineral weathering and is a key consideration when assessing human and environmental health risks associated with mine sites. At the semi-arid Iron King Mine and Humboldt Smelter Superfund site in central Arizona, the mineral assemblage of the top 2 m of tailings has been previously characterized. A distinct redox gradient was observed in the top 0.5 m of the tailings and the mineral assemblage indicates progressive transformation of ferrous iron sulfides to ferrihydrite and gypsum, which, in turn weather to form schwertmannite and then jarosite accompanied by a progressive decrease in pH (7.3 to 2.3). Within the geochemical context of this reaction front, we examined enriched toxic metal(loid)s As, Pb, and Zn with surficial concentrations 41.1, 10.7, 39.3 mM kg-1 (3080, 2200, and 2570 mg kg-1), respectively. The highest bulk concentrations of As and Zn occur at the redox boundary representing a 1.7 and 4.2 fold enrichment relative to surficial concentrations, respectively, indicating the translocation of toxic elements from the gossan zone to either the underlying redox boundary or the surface crust. Metal speciation was also examined as a function of depth using X-ray absorption spectroscopy (XAS). The deepest sample (180 cm) contains sulfides (e.g., pyrite, arsenopyrite, galena, and sphalerite). Samples from the redox transition zone (25-54 cm) contain a mixture of sulfides, carbonates (siderite, ankerite, cerrusite, and smithsonite) and metal(loid)s sorbed to neoformed secondary Fe phases, principally ferrihydrite. In surface samples (0-35 cm), metal(loid)s are found as sorbed species or incorporated into secondary Fe hydroxysulfate phases, such as schwertmannite and jarosites. Metal-bearing efflorescent salts (e.g., ZnSO4·nH2O) were detected in the surficial sample. Taken together, these data suggest the bioaccessibility and lability of metal(loid)s are altered by mineral weathering, which results in both the downward migration of metal(loid)s to the redox boundary, as well as the precipitation of metal salts at the surface. PMID:26549929

Correlations in metal release profiles following sorption by Lemna minor.

PubMed

Üçüncü Tunca, Esra; Ölmez, Tolga T; Özkan, Alper D; Altındağ, Ahmet; Tunca, Evren; Tekinay, Turgay

2016-08-02

Following the rapid uptake of contaminants in the first few hours of exposure, plants typically attempt to cope with the toxic burden by releasing part of the sorbed material back into the environment. The present study investigates the general trends in the release profiles of different metal(loid)s in the aquatic macrophyte Lemna minor and details the correlations that exist between the release of metal(loid) species. Water samples with distinct contamination profiles were taken from Nilüfer River (Bursa, Turkey), Yeniçağa Lake (Bolu, Turkey), and Beyşehir Lake (Konya, Turkey) and used for release studies; 36 samples were tested in total. Accumulation and release profiles were monitored over five days for 11 metals and a metalloid ((208)Pb, (111)Cd, (52)Cr,(53)Cr,(60)Ni,(63)Cu,(65)Cu,(75)As,(55)Mn, (137)Ba, (27)Al, (57)Fe, (66)Zn,(68)Zn) and correlation, cluster and principal component analyses were employed to determine the factors that affect the release of these elements. Release profiles of the tested metal(loid)s were largely observed to be distinct; however, strong correlations have been observed between certain metal pairs (Cr/Ni, Cr/Cu, Zn/Ni) and principal component analysis was able to separate the metal(loid)s into three well-resolved groups based on their release.

Determination of the long-term release of metal(loid)s from construction materials using DGTs.

PubMed

Schmukat, A; Duester, L; Ecker, D; Heininger, P; Ternes, T A

2013-09-15

Long-term leaching experiments are crucial to estimate the potential release of dangerous substances from construction materials. The application of Diffuse Gradients in Thin film (DGT) in static-batch experiments was tested to study the long-term release of metal(loid)s from construction materials for hydraulic engineering, for half a year. Long-term release experiments are essential to improve calculations of the life-time release for this materials. DGTs in batch experiments were found to be a space and labour efficient application, which enabled (i) to study, in a non-invasive manner, the total release of nine metal(loid)s for half a year, (ii) to differentiate between release mechanisms and (iii) to study mechanisms which were contrary to the release or caused experimental artefacts in the batch experiments. For copper slag (test material) it was found that eight metal(loid)s were released over the whole time period of 184 d. Cu, Ni and Pb were found to be released, predominantly caused by (the) weathering of sulphide minerals. Only for Zn a surface depletion mechanism was identified. The results from the long-term batch experiments deliver new information on the release of metal(loid)s during the life cycle of construction materials with regard to river basin management objectives. Copyright © 2013 Elsevier B.V. All rights reserved.

Catalyst activator

DOEpatents

McAdon, Mark H.; Nickias, Peter N.; Marks, Tobin J.; Schwartz, David J.

2001-01-01

A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

Spatial clustering of metal and metalloid mixtures in unregulated water sources on the Navajo Nation - Arizona, New Mexico, and Utah, USA.

PubMed

Hoover, Joseph H; Coker, Eric; Barney, Yolanda; Shuey, Chris; Lewis, Johnnye

2018-08-15

Contaminant mixtures are identified regularly in public and private drinking water supplies throughout the United States; however, the complex and often correlated nature of mixtures makes identification of relevant combinations challenging. This study employed a Bayesian clustering method to identify subgroups of water sources with similar metal and metalloid profiles. Additionally, a spatial scan statistic assessed spatial clustering of these subgroups and a human health metric was applied to investigate potential for human toxicity. These methods were applied to a dataset comprised of metal and metalloid measurements from unregulated water sources located on the Navajo Nation, in the southwest United States. Results indicated distinct subgroups of water sources with similar contaminant profiles and that some of these subgroups were spatially clustered. Several profiles had metal and metalloid concentrations that may have potential for human toxicity including arsenic, uranium, lead, manganese, and selenium. This approach may be useful for identifying mixtures in water sources, spatially evaluating the clusters, and help inform toxicological research investigating mixtures. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Modulating the sensing properties of Escherichia coli-based bioreporters for cadmium and mercury.

PubMed

Kang, Yerin; Lee, Woonwoo; Jang, Geupil; Kim, Bong-Gyu; Yoon, Youngdae

2018-06-01

Despite the large number of bioreporters developed to date, the ability to detect heavy metal(loid)s with bioreporters has thus far been limited owing to the lack of appropriate genetic systems. We here present a novel approach to modulate the selectivity and sensitivity of microbial whole-cell bioreporters (WCBs) for sensing metal(loid)s via the znt-operon from Escherichia coli, which were applied to quantify the bioavailability of these contaminants in environmental samples. The WCB harboring the fusion gene zntAp::egfp was used as a microbial metal(loid) sensor, which was turned on by the interaction between ZntR and metal(loid) ions. This design makes it possible to modulate the selectivity and sensitivity to metal(loid)s simply by changing the metal-binding property of ZntR and by disrupting the metal efflux system of E. coli, respectively. In fact, the E. coli cell-based bioreporter harboring zntAp::egfp showed multi-target responses to Cd(II), Hg(II), and Zn(II). However, the WCBs showed responses toward only Cd(II) and Hg(II) when the amino acid sequence of the metal-binding loop of ZntR was changed to CNHEPGTVCPIC and CPGDDSADC, respectively. Moreover, the sensitivity toward both Cd(II) and Hg(II) was enhanced when copA, which is known to export copper and silver, was deleted. Thus, our findings provide a strong foundation for expanding the target of WCBs from the currently limited number of genetic systems available.

Relationships between seminal plasma metals/metalloids and semen quality, sperm apoptosis and DNA integrity.

PubMed

Wang, Yi-Xin; Wang, Peng; Feng, Wei; Liu, Chong; Yang, Pan; Chen, Ying-Jun; Sun, Li; Sun, Yang; Yue, Jing; Gu, Long-Jie; Zeng, Qiang; Lu, Wen-Qing

2017-05-01

This study aimed to investigate the relationships between environmental exposure to metals/metalloids and semen quality, sperm apoptosis and DNA integrity using the metal/metalloids levels in seminal plasma as biomarkers. We determined 18 metals/metalloids in seminal plasma using an inductively coupled plasma-mass spectrometry among 746 men recruited from a reproductive medicine center. Associations of these metals/metalloids with semen quality (n = 746), sperm apoptosis (n = 331) and DNA integrity (n = 404) were evaluated using multivariate linear and logistic regression models. After accounting for multiple comparisons and confounders, seminal plasma arsenic (As) quartiles were negatively associated with progressive and total sperm motility using multivariable linear regression analysis, which were in accordance with the trends for increased odds ratios (ORs) for below-reference semen quality parameters in the logistic models. We also found inverse correlations between cadmium (Cd) quartiles and progressive and total sperm motility, whereas positive correlations between zinc (Zn) quartiles and sperm concentration, between copper (Cu) and As quartiles and the percentage of tail DNA, between As and selenium (Se) quartiles and tail extent and tail distributed moment, and between tin (Sn) categories and the percentage of necrotic spermatozoa (all P trend <0.05). These relationships remained after the simultaneous consideration of various elements. Our results indicate that environmental exposure to As, Cd, Cu, Se and Sn may impair male reproductive health, whereas Zn may be beneficial to sperm concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anthropogenic accumulation of metals and metalloids in carbonate-rich sediments: Insights from the ancient harbor setting of Tyre (Lebanon)

NASA Astrophysics Data System (ADS)

Elmaleh, A.; Galy, A.; Allard, T.; Dairon, R.; Day, J. A.; Michel, F.; Marriner, N.; Morhange, C.; Couffignal, F.

2012-04-01

The Antique and Byzantine sediments of the northern harbor of Tyre (Lebanon) store high amounts of metals and metalloids as the result of a millennial anthropogenic contamination as well as of efficient trapping and immobilization processes. Geochemical and mineralogical analyses reveal the contrasted patterns for the accumulation of trace metal(loid)s in the sedimentary sequence recovered by coring the inner part, now emerged, of the ancient harbor. Lead, Sn, Cu and Ag concentrations can be as high as 3000, 150, 1000, and 1.2 μg/g, respectively. Enrichment factors were calculated with respect to (1) Th and (2) the chemistry of the substratum and appear to be driven by anthropogenic inputs. Indeed, a drastic change in both excess concentrations and concentration ratios is observed through Roman and Byzantine times, pointing to major intensification of the trade and use of metals in Tyre, coherent with historical data. Good preservation of the archeological signal, despite (1) sediment disturbances that have caused age depth inversions, and (2) the large time lapse since the time of deposition of anthropogenic trace metal(loid)s is probably due to the reducing character of the sediments. Tyre's sedimentary sequence provides an interesting analog for modern carbonate-rich harbor environments, in which a millenary accumulation of trace metal(loid)s has been overall well preserved and suggests a restricted mobility of anthropogenic contamination for a period of time in excess of 1500 years.

Comparison Study on the Estimation of the Spatial Distribution of Regional Soil Metal(loid)s Pollution Based on Kriging Interpolation and BP Neural Network.

PubMed

Jia, Zhenyi; Zhou, Shenglu; Su, Quanlong; Yi, Haomin; Wang, Junxiao

2017-12-26

Soil pollution by metal(loid)s resulting from rapid economic development is a major concern. Accurately estimating the spatial distribution of soil metal(loid) pollution has great significance in preventing and controlling soil pollution. In this study, 126 topsoil samples were collected in Kunshan City and the geo-accumulation index was selected as a pollution index. We used Kriging interpolation and BP neural network methods to estimate the spatial distribution of arsenic (As) and cadmium (Cd) pollution in the study area. Additionally, we introduced a cross-validation method to measure the errors of the estimation results by the two interpolation methods and discussed the accuracy of the information contained in the estimation results. The conclusions are as follows: data distribution characteristics, spatial variability, and mean square errors (MSE) of the different methods showed large differences. Estimation results from BP neural network models have a higher accuracy, the MSE of As and Cd are 0.0661 and 0.1743, respectively. However, the interpolation results show significant skewed distribution, and spatial autocorrelation is strong. Using Kriging interpolation, the MSE of As and Cd are 0.0804 and 0.2983, respectively. The estimation results have poorer accuracy. Combining the two methods can improve the accuracy of the Kriging interpolation and more comprehensively represent the spatial distribution characteristics of metal(loid)s in regional soil. The study may provide a scientific basis and technical support for the regulation of soil metal(loid) pollution.

Preliminary investigation of metal and metalloid contamination of homeopathic products marketed in Croatia.

PubMed

Tumir, Hrvoje; Bosnir, Jasna; Vedrina-Dragojević, Irena; Dragun, Zrinka; Tomić, Sinisa; Puntarić, Dinko

2010-07-01

Due to their popularity as a complementary therapy in many diseases, homeopathic products of animal, vegetable, mineral and chemical origin should be tested for the presence of contaminants to prevent eventual toxic effects. Thirty samples of homeopathic products were analyzed to estimate possible contamination with potentially toxic elements: Pb, Cd, As, Hg, Cr, Ni and Zn, and to assess human exposure to these metals/metalloid as a consequence of their consumption. Atomic absorption spectrometry was used to determine metal and metalloid concentrations. Most tested products had very low metal/metalloid levels (below the limit of quantification of the method), but the metal/metalloid levels in the remaining products were in the following ranges (in microg g(-1)): Pb 0.33-1.29 (6 samples), Cd 2.78 (1 sample), As 0.22 (1 sample), Hg 0.02-0.12 (24 samples), Cr 0.40-10.27 (10 samples), Ni 0.43-55.00 (19 samples), and Zn 2.20-27.80 (11 samples). In the absence of regulatory standards for homeopathic products, the obtained results were compared to maximum allowable levels (MALs) as proposed by USP Ad Hoc Advisory Panel. Some analyzed preparations had metal levels above MALs (Pb: 2 samples; Cd: 1 sample; Ni: 2 samples). However, estimated cumulative daily intakes from tested homeopathic products were in all cases lower than permitted daily exposures for all dosage forms. The risk of bioaccumulation of metals/metalloid from the homeopathic medicines seems to be rather low, due to small quantities of those products prescribed to be applied per day, as well as insignificant metal contamination of the majority of tested products. However, the fact that particular formulations were contaminated by metals above MALs indicates potential risk and points to the necessity of regular monitoring of homeopathic products for metal contamination, due to their frequent and mostly unsupervised use. 2010 Elsevier Ltd. All rights reserved.

Metal(loid) bioaccessibility and inhalation risk assessment: A comparison between an urban and an industrial area.

PubMed

Hernández-Pellón, A; Nischkauer, W; Limbeck, A; Fernández-Olmo, I

2018-04-25

The content of metal(loid)s in particulate matter (PM) is of special concern due to their contribution to overall (PM) toxicity. In this study, the bioaccessibility and human health risk of potentially toxic metal(loid)s associated with PM 10 were investigated in two areas of the Cantabrian region (northern Spain) with different levels of exposure: an industrial area mainly influenced by a ferromanganese alloy plant; and an urban area consisting mainly of residential and commercial activities, but also affected, albeit to a lesser extent by the ferroalloy plant. Total content and bioaccessible fractions in simulated lung fluids (SLFs) of Fe, Mn, Zn, Ni, Cu, Sb, Mo, Cd and Pb were determined by ICP-MS. Gamble's solution and artificial lysosomal fluid (ALF) were used to mimic different conditions inside the human respiratory system. A health risk assessment was performed based on the United States Environmental Protection Agency's (USEPA) methodology. Most metal(loid)s showed moderate and high bioaccessibility in Gamble's solution and ALF, respectively. Despite the high variability between the samples, metal(loid) bioaccessibility was found to be higher on average at the industrial site, suggesting a greater hazard to human health in the proximity of the main metal(loid) sources. Based on the results of the risk assessment, the non-carcinogenic risk associated with Mn exposure was above the safe limit (HQ> 1) under all the studied scenarios at the industrial site and under some specific scenarios at the urban location. The estimated carcinogenic inhalation risk for Cd exposure at the industrial site was found to be within the range between 1.0 × 10 -6 to 1.0 × 10 -4 (uncertainty range) under some scenarios. The results obtained in this study indicate that Mn and Cd inhalation exposure occurring in the vicinities of the studied areas may pose a human health risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Mobility and toxicity of heavy metal(loid)s arising from contaminated wood ash application to a pasture grassland soil.

PubMed

Mollon, L C; Norton, G J; Trakal, L; Moreno-Jimenez, E; Elouali, F Z; Hough, R L; Beesley, L

2016-11-01

Heavy metal(loid) rich ash (≤10,000 mg kg -1 total As, Cr, Cu and Zn) originating from the combustion of contaminated wood was subjected to several experimental procedures involving its incorporation into an upland pasture soil. Ash was added to soil that had been prior amended with local cattle manure, replicating practices employed at the farm scale. Metal(loid) concentrations were measured in soil pore water and ryegrass grown on soil/manure plus ash mixtures (0.1-3.0% vol. ash) in a pot experiment; toxicity evaluation was performed on the same pore water samples by means of a bacterial luminescence biosensor assay. Thereafter a sequential extraction procedure was carried out on selected soil, manure and ash mixtures to elucidate the geochemical association of ash derived metal(loid)s with soil constituents. Predictive modelling was applied to selected data from the pot experiment to determine the risk of transfer of As to meat and milk products in cattle grazing pasture amended with ash. The inclusion of manure to soils receiving ash reduced phyto-toxicity and increased ryegrass biomass yields, compared to soil with ash, but without manure. Elevated As and Cu concentrations in pore water and ryegrass tissue resulting from ash additions were reduced furthest by the inclusion of manure due to an increase in their geochemical association with organic matter. Zinc was the only measured metal(loid) to remain uniformly soluble and bioavailable regardless of the addition of ash and manure. Risk modelling on pot experimental data highlighted that an ash addition of >1% (vol.) to this pasture soil could result in As concentrations in milk and meat products exceeding acceptable limits. The results of this study therefore suggest that even singular low doses of ash applied to soil increase the risk of leaching of metal(loid)s and intensify the risk of As transfer in the food chain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison Study on the Estimation of the Spatial Distribution of Regional Soil Metal(loid)s Pollution Based on Kriging Interpolation and BP Neural Network

PubMed Central

Zhou, Shenglu; Su, Quanlong; Yi, Haomin

2017-01-01

Soil pollution by metal(loid)s resulting from rapid economic development is a major concern. Accurately estimating the spatial distribution of soil metal(loid) pollution has great significance in preventing and controlling soil pollution. In this study, 126 topsoil samples were collected in Kunshan City and the geo-accumulation index was selected as a pollution index. We used Kriging interpolation and BP neural network methods to estimate the spatial distribution of arsenic (As) and cadmium (Cd) pollution in the study area. Additionally, we introduced a cross-validation method to measure the errors of the estimation results by the two interpolation methods and discussed the accuracy of the information contained in the estimation results. The conclusions are as follows: data distribution characteristics, spatial variability, and mean square errors (MSE) of the different methods showed large differences. Estimation results from BP neural network models have a higher accuracy, the MSE of As and Cd are 0.0661 and 0.1743, respectively. However, the interpolation results show significant skewed distribution, and spatial autocorrelation is strong. Using Kriging interpolation, the MSE of As and Cd are 0.0804 and 0.2983, respectively. The estimation results have poorer accuracy. Combining the two methods can improve the accuracy of the Kriging interpolation and more comprehensively represent the spatial distribution characteristics of metal(loid)s in regional soil. The study may provide a scientific basis and technical support for the regulation of soil metal(loid) pollution. PMID:29278363

Contamination level, distribution and health risk assessment of heavy and toxic metallic and metalloid elements in a cultivated mushroom Pleurotus florida (Mont.) singer.

PubMed

Khani, Rouhollah; Moudi, Maryam; Khojeh, Vahid

2017-02-01

There are great concentrations of toxic metallic and metalloid elements such as lead, arsenic, mercury, cadmium or silver in many species of mushrooms comparative to other fruits and vegetables. In this study, contamination with heavy and toxic metallic and metalloid elements in the cultivated mushroom of (Pleurotus florida (Mont.) Singer) is investigated. P. florida was cultivated on different substrates; wheat straw (as blank), wheat straw + pine cone, wheat straw + soybean straw and wheat straw + urea and the effects of these substrates on contamination levels of Mn, Fe, Cu, Zn, As, Cd, and Pb were analyzed. The results showed that the concentrations of essential elements (Mn, Fe, Cu, and Zn) in the target mushroom are at the typical levels. The estimated daily intakes of studied metallic and metalloid elements were below their oral reference dosage mentioned by the international regulatory bodies. Health risk index (HRI) was calculated to evaluate the consumer's health risk assessment from the metal intake that contaminated in the cultivated mushroom of P. florida on the different nutrient sources. In this study, the individual HRIs were less than 1, which indicates insignificant potential health risk associated with the consumption of target mushroom from the studied substrates. Based on the HRIs values among the toxic metallic and metalloid elements, As in the target mushroom in the substrate of the wheat straw + pine cone is the main sources of risk, and it may cause severe health problems. Thus, this study suggests that the concentrations of heavy and toxic elements should be periodically monitored in cultivated mushrooms.

Spin-exchange interaction between transition metals and metalloids in soft-ferromagnetic metallic glasses

NASA Astrophysics Data System (ADS)

Das, Santanu; Choudhary, Kamal; Chernatynskiy, Aleksandr; Choi Yim, Haein; Bandyopadhyay, Asis K.; Mukherjee, Sundeep

2016-06-01

High-performance magnetic materials have immense industrial and scientific importance in wide-ranging electronic, electromechanical, and medical device technologies. Metallic glasses with a fully amorphous structure are particularly suited for advanced soft-magnetic applications. However, fundamental scientific understanding is lacking for the spin-exchange interaction between metal and metalloid atoms, which typically constitute a metallic glass. Using an integrated experimental and molecular dynamics approach, we demonstrate the mechanism of electron interaction between transition metals and metalloids. Spin-exchange interactions were investigated for a Fe-Co metallic glass system of composition [(Co1-x Fe x )0.75B0.2Si0.05]96Cr4. The saturation magnetization increased with higher Fe concentration, but the trend significantly deviated from simple rule of mixtures. Ab initio molecular dynamics simulation was used to identify the ferromagnetic/anti-ferromagnetic interaction between the transition metals and metalloids. The overlapping band-structure and density of states represent ‘Stoner type’ magnetization for the amorphous alloys in contrast to ‘Heisenberg type’ in crystalline iron. The enhancement of magnetization by increasing iron was attributed to the interaction between Fe 3d and B 2p bands, which was further validated by valence-band study.

Use of Lead Isotopes to Identify Sources of Metal and Metalloid Contaminants in Atmospheric Aerosol from Mining Operations

PubMed Central

Félix, Omar I.; Csavina, Janae; Field, Jason; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.

2014-01-01

Mining operations are a potential source of metal and metalloid contamination by atmospheric particulate generated from smelting activities, as well as from erosion of mine tailings. In this work, we show how lead isotopes can be used for source apportionment of metal and metalloid contaminants from the site of an active copper mine. Analysis of atmospheric aerosol shows two distinct isotopic signatures: one prevalent in fine particles (< 1 μm aerodynamic diameter) while the other corresponds to coarse particles as well as particles in all size ranges from a nearby urban environment. The lead isotopic ratios found in the fine particles are equal to those of the mine that provides the ore to the smelter. Topsoil samples at the mining site show concentrations of Pb and As decreasing with distance from the smelter. Isotopic ratios for the sample closest to the smelter (650 m) and from topsoil at all sample locations, extending to more than 1 km from the smelter, were similar to those found in fine particles in atmospheric dust. The results validate the use of lead isotope signatures for source apportionment of metal and metalloid contaminants transported by atmospheric particulate. PMID:25496740

Contamination of soils with heavy metals and metalloids and its ecological hazard (analytic review)

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.

2013-07-01

According to the present-day ecotoxicologic data, hazardous heavy metals/metalloids form the following sequence in the soil: Se > Tl > Sb > Cd > V > Hg > Ni > Cu > Cr > As > Ba. This sequence differs from the well-known series of the hazardous heavy elements, in which the danger of Pb and Zn is exaggerated, whereas that of V, Sb, and Ba, is underestimated. Tl also should be included in the list of hazardous elements in the soil. At present, the stress is made on the investigation of heavy metals/metalloids in agricultural soils rather than in urban soils, as the former produce contaminated products poisoning both animals and humans. The main sources of soil contamination with heavy metals are the following: aerial deposition from stationary and moving sources; hydrogenic contamination from the industrial sewage discharging into water bodies; sewage sediments; organic and mineral fertilizers and chemicals for plant protection, tailing dumps of ash, slag, ores, and sludge. In addition to the impact on plants and groundwater, heavy metals/metalloids exert a negative effect on the soil proper. Soil microorganisms appear to be very sensitive to the influence of heavy elements.

Metalloid compounds as drugs

PubMed Central

Sekhon, B. S.

2013-01-01

The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O’-)tellurate (AS101) may be a promising agent for the treatment of Parkinson’s disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

Spatiotemporal assessment (quarter century) of pulp mill metal(loid) contaminated sediment to inform remediation decisions.

PubMed

Hoffman, Emma; Lyons, James; Boxall, James; Robertson, Cam; Lake, Craig B; Walker, Tony R

2017-06-01

A bleached kraft pulp mill in Nova Scotia has discharged effluent wastewater into Boat Harbour, a former tidal estuary within Pictou Landing First Nation since 1967. Fifty years of effluent discharge into Boat Harbour has created >170,000 m 3 of unconsolidated sediment, impacted by inorganic and organic contaminants, including metal[loid]s, polycyclic aromatic hydrocarbons (PAHs), dioxins, and furans. This study aimed to characterize metal(loid)-impacted sediments to inform decisions for a $89 million CAD sediment remediation program. The remediation goals are to return this impacted aquatic site to pre-mill tidal conditions. To understand historical sediment characteristics, spatiotemporal variation covering ~quarter century, of metal(loid) sediment concentrations across 103 Boat Harbour samples from 81 stations and four reference locations, were assessed by reviewing secondary data from 1992 to 2015. Metal(loid) sediment concentrations were compared to current Canadian freshwater and marine sediment quality guidelines (SQGs). Seven metal(loid)s, As, Cd, Cr, Cu, Pb, Hg, and Zn, exceeded low effect freshwater and marine SQGs; six, As, Cd, Cr, Pb, Hg, and Zn, exceeded severe effect freshwater SQGs; and four, Cd, Cu, Hg, and Zn, exceeded severe effect marine SQGs. Metal(loid) concentrations varied widely across three distinct temporal periods. Significantly higher Cd, Cu, Pb, Hg, and Zn concentrations were measured between 1998 and 2000, compared to earlier, 1992-1996 and more recent 2003-2015 data. Most samples, 69%, were shallow (0-15 cm), leaving deeper horizons under-characterized. Geographic information system (GIS) techniques also revealed inadequate spatial coverage, presenting challenges for remedy decisions regarding vertical and horizontal delineation of contaminants. Review of historical monitoring data revealed that gaps still exist in our understanding of sediment characteristics in Boat Harbour, including spatial, vertical and horizontal, and temporal variation of sediment contamination. To help return Boat Harbour to a tidal estuary, more detailed sampling is required to better characterize these sediments and to establish appropriate reference (background) concentrations to help develop cost-effective remediation approaches for this decades-old problem.

Development of an accelerated leaching method for incineration bottom ash correlated to toxicity characteristic leaching protocol.

PubMed

Lin, Shengxuan; Zhou, Xuedong; Ge, Liya; Ng, Sum Huan; Zhou, Xiaodong; Chang, Victor Wei-Chung

2016-10-01

Heavy metals and some metalloids are the most significant inorganic contaminants specified in toxicity characteristic leaching procedure (TCLP) in determining the safety of landfills or further utilization. As a consequence, a great deal of efforts had been made on the development of miniaturized analytical devices, such as Microchip Electrophoresis (ME) and μTAS for on-site testing of heavy metals and metalloids to prevent spreading of those pollutants or decrease the reutilization period of waste materials such as incineration bottom ash. However, the bottleneck lied in the long and tedious conventional TCLP that requires 18 h of leaching. Without accelerating the TCLP process, the on-site testing of the waste material leachates was impossible. In this study, therefore, a new accelerated leaching method (ALM) combining ultrasonic assisted leaching with tumbling was developed to reduce the total leaching time from 18 h to 30 min. After leaching, the concentrations of heavy metals and metalloids were determined with ICP-MS or ICP-optical emission spectroscopy. No statistical significance between ALM and TCLP was observed for most heavy metals (i.e., cobalt, manganese, mercury, molybdenum, nickel, silver, strontium, and tin) and metalloids (i.e., arsenic and selenium). For the heavy metals with statistical significance, correlation factors derived between ALM and TCLP were 0.56, 0.20, 0.037, and 0.019 for barium, cadmium, chromium, and lead, respectively. Combined with appropriate analytical techniques (e.g., ME), the ALM can be applied to rapidly prepare the incineration bottom ash samples as well as other environmental samples for on-site determination of heavy metals and metalloids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assisted phytostabilization of a multicontaminated mine technosol using biochar amendment: Early stage evaluation of biochar feedstock and particle size effects on As and Pb accumulation of two Salicaceae species (Salix viminalis and Populus euramericana).

PubMed

Lebrun, Manhattan; Miard, Florie; Nandillon, Romain; Léger, Jean-Christophe; Hattab-Hambli, Nour; Scippa, Gabriella S; Bourgerie, Sylvain; Morabito, Domenico

2018-03-01

Soil contamination by metal(loid)s is one of the most important environmental problem. It leads to loss of environment biodiversity and soil functions and can have harmful effects on human health. Therefore, contaminated soils could be remediated, using phytoremediation. Indeed, plant growth will improve soil conditions while accumulating metal(loid)s and modifying their mobility. However, due to the poor fertility and high metal(loid)s levels of these soils, amendments, like biochar, has to be applied. This study was performed on a former mine technosol contaminated by As and Pb and aimed to study (i) the effect of biochar on soil physico-chemical properties and plant phytostabilization potential (ii) biochar feedstock and particle size effects. In this goal, a mesocosm experiment was set up using four different biochars, obtained from two feedstocks (lightwood and pinewood) and harboring two particle sizes (inf. 0.1 mm and 0.2-0.4 mm) and two Salicaceae species. Soil and soil pore water physico-chemical properties as well as plant growth and metal(loid)s distribution were assessed. The results showed that biochar was efficient in improving soil physico-chemical properties and reducing Pb soil pore water concentrations. This amelioration allowed plant growth and increased dry weight production of both species. Regarding metal(loid)s distribution, willow and poplar showed an As and Pb accumulation in roots and low translocation towards edible parts, i.e stems and leaves, which shows a phytostabilization potential. Finally, the 2 biochar parameters, feedstock and particle size, only affected soil and soil pore water physico-chemical properties while having no effect on plant growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Variation and distribution of metals and metalloids in soil/ash mixtures from Agbogbloshie e-waste recycling site in Accra, Ghana.

PubMed

Itai, Takaaki; Otsuka, Masanari; Asante, Kwadwo Ansong; Muto, Mamoru; Opoku-Ankomah, Yaw; Ansa-Asare, Osmund Duodu; Tanabe, Shinsuke

2014-02-01

Illegal import and improper recycling of electronic waste (e-waste) are an environmental issue in developing countries around the world. African countries are no exception to this problem and the Agbogbloshie market in Accra, Ghana is a well-known e-waste recycling site. We have studied the levels of metal(loid)s in the mixtures of residual ash, formed by the burning of e-waste, and the cover soil, obtained using a portable X-ray fluorescence spectrometer (P-XRF) coupled with determination of the 1M HCl-extractable fraction by an inductively coupled plasma mass spectrometer. The accuracy and precision of the P-XRF measurements were evaluated by measuring 18 standard reference materials; this indicated the acceptable but limited quality of this method as a screening tool. The HCl-extractable levels of Al, Co, Cu, Zn, Cd, In, Sb, Ba, and Pb in 10 soil/ash mixtures varied by more than one order of magnitude. The levels of these metal(loid)s were found to be correlated with the color (i.e., soil/ash ratio), suggesting that they are being released from disposed e-waste via open burning. The source of rare elements could be constrained using correlation to the predominant metals. Human hazard quotient values based on ingestion of soil/ash mixtures exceeded unity for Pb, As, Sb, and Cu in a high-exposure scenario. This study showed that along with common metals, rare metal(loid)s are also enriched in the e-waste burning site. We suggest that risk assessment considering exposure to multiple metal(loid)s should be addressed in studies of e-waste recycling sites. © 2013. Published by Elsevier B.V. All rights reserved.

Characterization of PAHs and metals in indoor/outdoor PM10/PM2.5/PM1 in a retirement home and a school dormitory.

PubMed

Hassanvand, Mohammad Sadegh; Naddafi, Kazem; Faridi, Sasan; Nabizadeh, Ramin; Sowlat, Mohammad Hossein; Momeniha, Fatemeh; Gholampour, Akbar; Arhami, Mohammad; Kashani, Homa; Zare, Ahad; Niazi, Sadegh; Rastkari, Noushin; Nazmara, Shahrokh; Ghani, Maryam; Yunesian, Masud

2015-09-15

In the present work, we investigated the characteristics of polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s in indoor/outdoor PM10, PM2.5, and PM1 in a retirement home and a school dormitory in Tehran from May 2012 to May 2013. The results indicated that the annual levels of indoor and outdoor PM10 and PM2.5 were much higher than the guidelines issued by the World Health Organization (WHO). The most abundant detected metal(loid)s in PM were Si, Fe, Zn, Al, and Pb. We found higher percentages of metal(loid)s in smaller size fractions of PM. Additionally, the results showed that the total PAHs (ƩPAHs) bound to PM were predominantly (83-88%) found in PM2.5, which can penetrate deep into the alveolar regions of the lungs. In general, carcinogenic PAHs accounted for 40-47% of the total PAHs concentrations; furthermore, the smaller the particle size, the higher the percentage of carcinogenic PAHs. The percentages of trace metal(loid)s and carcinogenic PAHs in PM2.5 mass were almost twice as high as those in PM10. This can most likely be responsible for the fact that PM2.5 can cause more adverse health effects than PM10 can. The average BaP-equivalent carcinogenic (BaP-TEQ) levels both indoors and outdoors considerably exceeded the maximum permissible risk level of 1 ng/m(3) of BaP. The enrichment factors and diagnostic ratios indicated that combustion-related anthropogenic sources, such as gasoline- and diesel-fueled vehicles as well as natural gas combustion, were the major sources of PAHs and trace metal(loid)s bound to PM. Copyright © 2015 Elsevier B.V. All rights reserved.

Heavy metals and metalloids in the surface sediments of the Xiangjiang River, Hunan, China: distribution, contamination, and ecological risk assessment.

PubMed

Chai, Liyuan; Li, Huan; Yang, Zhihui; Min, Xiaobo; Liao, Qi; Liu, Yi; Men, Shuhui; Yan, Yanan; Xu, Jixin

2017-01-01

Here, we aim to determine the distribution, ecological risk and sources of heavy metals and metalloids in the surface sediments of the Xiangjiang River, Hunan Province, China. Sixty-four surface sediment samples were collected in 16 sites of the Xiangjiang River, and the concentrations of ten heavy metals and metalloids (Mn, Zn, Cr, V, Pb, Cu, As, Ni, Co, and Cd) in the sediment samples were investigated using an inductively coupled plasma mass spectrometer (ICP-MS) and an atomic fluorescence spectrophotometer (AFS), respectively. The results showed that the mean concentrations of the ten heavy metals and metalloids in the sediment samples followed the order Mn > Zn > Cr > V > Pb > Cu > As ≈ Ni >Co > Cd. The geoaccumulation index (I geo ), enrichment factor (EF), modified degree of contamination (mC d ), and potential ecological risk index (RI) revealed that Cd, followed by Pb, Zn, and Cu, caused severely contaminated and posed very highly potential ecological risk in the Xiangjiang River, especially in Shuikoushan of Hengyang, Xiawan of Zhuzhou, and Yijiawan of Xiangtan. The Pearson's correlation coefficient (PCC) analysis, principal component analysis (PCA), and hierarchical cluster analysis (HCA) indicated that the ten heavy metals and metalloids in the sampling sediments of the Xiangjiang River were classified into three groups: (1) Cd, Pb, Zn, and Cu which possibly originated from Shuikoushan, Xiawan, and Yijiawan clustering Pb-Zn mining and smelting industries; (2) Co, V, Ni, Cr, and Al from natural resources; and (3) Mn and As. Therefore, our results suggest that anthropogenic activities, especially mining and smelting, have caused severe contamination of Cd, Pb, Zn, and Cu and posed very high potential ecological risk in the Xiangjiang River.

Geospatial distribution of metal(loid)s and human health risk assessment due to intake of contaminated groundwater around an industrial hub of northern India.

PubMed

Kashyap, Rachit; Verma, K S; Uniyal, Sanjay Kr; Bhardwaj, S K

2018-02-12

The study focused on analyzing concentrations of metal(loid)s, their geospatial distribution in groundwater around an industrial hub of northern India. Human health risk posed due to the intake of contaminated groundwater was also evaluated. For this, 240 samples were assayed using inductively coupled plasma emission spectrophotometer. For risk assessment, the methodology proposed by US Environmental Protection Agency was adopted. Geometric mean of Al, As, Mo, Cd, Co, Cr, Fe, Mn, Ni, Pb, Se, and Zn was 193.13, 27.35, 4.22, 2.85, 92.81, 14.97, 271.78, 25.76, 54.75, 19.50, 16.94, and 1830.27 μg/l, respectively. Levels of Al (84%), As (63%), Ni (63%), Pb (49%), and Se (41%) exceeded the Bureau of Indian Standards (BIS). Principal component analysis is accounted for ~ 88% of the total variance and reflected pollution loads of Al, As, Mo, Cr, Fe, Se, and Pb in the groundwater. Based on it, four sources of metal(loid)s, namely geogenic (34.55%), mixed (industrial and agricultural, 26.76%), waste dumping (15.31%), and industrial (11.25%) were identified. Semi-variogram mapping model demonstrated significant geospatial variations of the metal(loid)s. Hazard index (HI) suggested potential non-carcinogenic risks to the inhabitants due to As, Al, Ni, Se, and Pb, which were the largest contributors. Based on maximum concentrations of metal(loid)s, HI for child and adult was above unity. Arsenic was identified as the most hazardous pollutant that may have chronic carcinogenic health implications. At western side of study area, carcinogenic health risks exceeded critical threshold of 1 × 10 -4 , indicating that As posed health risks to residents by intake of groundwater.

Bioaccessibility, release kinetics, and molecular speciation of arsenic and lead in geo-dusts from the Iron King Mine Federal Superfund site in Humboldt, Arizona.

PubMed

Menka, Nazune; Root, Rob; Chorover, Jon

2014-01-01

Mine tailings contain multiple toxic metal(loid)s that pose a threat to human health via inhalation and ingestion. The goals of this research include understanding the speciation and molecular environment of these toxic metal(loid)s (arsenic and lead) as well as the impacts particle size and residence time have on their bioaccessibilty in simulated gastric and lung fluid. Additionally, future work will include smaller size fractions (PM10 and PM2.5) of surface mine tailings, with the goal of increasing our understanding of multi-metal release from contaminated geo-dusts in simulated bio-fluids. This research is important to environmental human health risk assessment as it increases the accuracy of exposure estimations to toxic metal(loid)s.

The use of red mud as an immobiliser for metal/metalloid-contaminated soil: A review.

PubMed

Hua, Yumei; Heal, Kate V; Friesl-Hanl, Wolfgang

2017-03-05

This review focuses on the applicability of red mud as an amendment for metal/metalloid-contaminated soil. The varying properties of red muds from different sources are presented as they influence the potentially toxic element (PTE) concentration in amended soil. Experiments conducted worldwide from the laboratory to the field scale are screened and the influencing parameters and processes in soils are highlighted. Overall red mud amendment is likely to contribute to lowering the PTE availability in contaminated soil. This is attributed to the high pH, Fe and Al oxide/oxyhydroxide content of red mud, especially hematite, boehmite, gibbsite and cancrinite phases involved in immobilising metals/metalloids. In most cases red mud amendment resulted in a lowering of metal concentrations in plants. Bacterial activity was intensified in red mud-amended contaminated soil, suggesting the toxicity from PTEs was reduced by red mud, as well as indirect effects due to changes in soil properties. Besides positive effects of red mud amendment, negative effects may also appear (e.g. increased mobility of As, Cu) which require site-specific risk assessments. Red mud remediation of metal/metalloid contaminated sites has the potential benefit of reducing red mud storage and associated problems. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of nutrient and lime additions in mine site rehabilitation strategies on the accumulation of antimony and arsenic by native Australian plants.

PubMed

Wilson, Susan C; Leech, Calvin D; Butler, Leo; Lisle, Leanne; Ashley, Paul M; Lockwood, Peter V

2013-10-15

The effects of nutrient and lime additions on antimony (Sb) and arsenic (As) accumulation by native Australian and naturalised plants growing in two contaminated mine site soils (2,735 mg kg(-1) and 4,517 mg kg(-1) Sb; 826 mg kg(-1) and 1606 As mgkg(-1)) was investigated using a glasshouse pot experiment. The results indicated an increase in soil solution concentrations with nutrient addition in both soils and also with nutrient+lime addition for Sb in one soil. Metalloid concentrations in plant roots were significantly greater than concentrations in above ground plant parts. The metalloid transfer to above ground plant parts from the roots and from the soil was, however, low (ratio of leaf concentration/soil concentration≪1) for all species studied. Eucalyptus michaeliana was the most successful at colonisation with lowest metalloid transfer to above ground plant parts. Addition of nutrients and nutrients+lime to soils, in general, increased plant metalloid accumulation. Relative As accumulation was greater than that of Sb. All the plant species studied were suitable for consideration in the mine soil phytostabilisation strategies but lime additions should be limited and longer term trials also recommended. Copyright © 2013 Elsevier B.V. All rights reserved.

Metals and metalloids treatment in contaminated neutral effluents using modified materials.

PubMed

Calugaru, Iuliana Laura; Neculita, Carmen Mihaela; Genty, Thomas; Zagury, Gérald J

2018-04-15

Circumneutral surface water and groundwater can contain hazardous concentrations of metals and metalloids that can threaten organisms in surrounding ecosystems. Extensive research has been conducted over the past two decades to prevent, limit, and treat water pollution. Among the currently available treatment options is the use of natural and residual materials, which is generally regarded as effective and inexpensive. The modification of such materials enhances the removal capacity of metals and metalloids, as well as the physical and chemical stability of the materials and resulting sludge (after treatment). This paper reviews several modified materials that have produced and evaluated in the past twenty years to treat various contaminants in water under specific conditions. Important factors on performance improvement following the modifications are emphasized. Sorption capacity and kinetics, and element removal mechanisms are also discussed. Element recovery, material regeneration, water reuse, evaluation of treatment efficiency for real effluents are also considered, as well as the applicability of these materials in both active and passive treatment systems. Modified natural and residual materials are a promising option for the treatment of metals and metalloids in circumneutral contaminated waters. However, further research is necessary to evaluate their field-scale performance and to properly assess treatment costs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

DOEpatents

Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

2015-02-10

Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

The Little Penguin (Eudyptula minor) as an indicator of coastal trace metal pollution.

PubMed

Finger, Annett; Lavers, Jennifer L; Dann, Peter; Nugegoda, Dayanthi; Orbell, John D; Robertson, Bruce; Scarpaci, Carol

2015-10-01

Monitoring trace metal and metalloid concentrations in marine animals is important for their conservation and could also reliably reflect pollution levels in their marine ecosystems. Concentrations vary across tissue types, with implications for reliable monitoring. We sampled blood and moulted feathers of the Little Penguin (Eudyptula minor) from three distinct colonies, which are subject to varying levels of anthropogenic impact. Non-essential trace metal and metalloid concentrations in Little Penguins were clearly linked to the level of industrialisation adjacent to the respective foraging zones. This trend was more distinct in blood than in moulted feathers, although we found a clear correlation between blood and feathers for mercury, lead and iron. This study represents the first reported examination of trace metals and metalloids in the blood of any penguin species and demonstrates that this high trophic feeder is an effective bioindicator of coastal pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Source identification and potential ecological hazards assessment of trace metalloid/heavy metals in the soil of Tianshan Mountains, Xinjiang, China].

PubMed

Zhang, Zhao-Yong; Jilili, Abuduwailil; Jiang, Feng-Qing

2014-11-01

In this study, the contents of ten metalloid/heavy metals (As, Pb, Ni, Cd, Co, Hg, Cu, Mn, Zn and Cr) in soil samples collected from three sections including the central Urumqi-Akesu, eastern Blikun-Yiwu and western Zhaosu-Tekesi in Tianshan Mountains were determined, and their sources were identified by using typical statistical and multivariate statistical methods. The potential ecological risks of these heavy metals were assessed by employing pollution index method, potential ecological risk index and the background values of Tianshan Mountains, and Xinjiang, and also the Second National Standard of the Soil Qualities of China. The results showed that the contents of the heavy metals (Pb, Ni, Cd, Co, Hg, Cu, Mn Zn and Cr) and metalloid As were all higher than the soil background values of the Tianshan Mountain or Xinjiang, and their variation co- efficients belonged to the medium variation. In general, the contents of the ten metalloid/heavy metals in the soil of Tianshan Mountains were low. Principal component analysis showed that the ten metalloid/heavy metals could be identified as two principal components, among which PC1 (Cd, Pb, Hg, Mn and Zn) could be seen as 'human influence sources factor', PC2 (Cu, Ni, Cr, Co and As) as 'natural sources factor'. Mn and As had larger loads both in PC1 and PC2, and they could be co-influenced by human and natural sources. The pollution assessment showed that Hg and Cd in central Urumuqi-Akesu section and As in western Zhaosu-Tekesi section were all at alert level, while the other heavy metals in other sections were all at security level. From the comprehensive pollution indices (P(z)) of heavy metals, it was found that the ten metalloid/heavy metals in the soils of central Urumqi-Akesu section were at low pollution level, but those in the other two sections were at clean level. The potential ecological risk assessment showed that the potential ecological risk coefficient (E(i)r) and the ecological damage index (RI) of Hg and Cd in central Urumqi-Akesu section and that of As in western Zhaosu-Tekesi section were relatively high.

Toxicology of metals and metalloids: Promising issues for future studies in environmental health and toxicology.

PubMed

Barbosa, Fernando

2017-01-01

The function and behavior of chemical elements in ecosystems and in human health probably comprise one of the most studied issues and a theme of great interest and fascination in science. Hot topics are emerging on an annual basis in this field. Bearing this in mind, some promising themes to explore in the field of metals and metalloids in the environment and in toxicology are highlighted and briefly discussed herein.

The use of atomic spectroscopy in the pharmaceutical industry for the determination of trace elements in pharmaceuticals.

PubMed

Lewen, Nancy

2011-06-25

The subject of the analysis of various elements, including metals and metalloids, in the pharmaceutical industry has seen increasing importance in the last 10-15 years, as modern analytical instrumentation has afforded analysts with the opportunity to provide element-specific, accurate and meaningful information related to pharmaceutical products. Armed with toxicological data, compendial and regulatory agencies have revisited traditional approaches to the testing of pharmaceuticals for metals and metalloids, and analysts have begun to employ the techniques of atomic spectroscopy, such as flame- and graphite furnace atomic absorption spectroscopy (FAAS, Flame AA or FAA and GFAAS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS), to meet their analytical needs. Newer techniques, such as laser-induced breakdown spectroscopy (LIBS) and Laser Ablation ICP-MS (LAICP-MS) are also beginning to see wider applications in the analysis of elements in the pharmaceutical industry.This article will provide a perspective regarding the various applications of atomic spectroscopy in the analysis of metals and metalloids in drug products, active pharmaceutical ingredients (API's), raw materials and intermediates. The application of atomic spectroscopy in the analysis of metals and metalloids in clinical samples, nutraceutical, metabolism and pharmacokinetic samples will not be addressed in this work. Copyright © 2010 Elsevier B.V. All rights reserved.

Health risk assessment of heavy metals and metalloid in drinking water from communities near gold mines in Tarkwa, Ghana.

PubMed

Bortey-Sam, Nesta; Nakayama, Shouta M M; Ikenaka, Yoshinori; Akoto, Osei; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-07-01

Concentrations of heavy metals and metalloid in borehole drinking water from 18 communities in Tarkwa, Ghana, were measured to assess the health risk associated with its consumption. Mean concentrations of heavy metals (μg/L) exceeded recommended values in some communities. If we take into consideration the additive effect of heavy metals and metalloid, then oral hazard index (HI) results raise concerns about the noncarcinogenic adverse health effects of drinking groundwater in Huniso. According to the US Environmental Protection Agency's (USEPA) guidelines, HI values indicating noncarcinogenic health risk for adults and children in Huniso were 0.781 (low risk) and 1.08 (medium risk), respectively. The cancer risk due to cadmium (Cd) exposure in adults and children in the sampled communities was very low. However, the average risk values of arsenic (As) for adults and children through drinking borehole water in the communities indicated medium cancer risk, but high cancer risk in some communities such as Samahu and Mile 7. Based on the USEPA assessment, the average cancer risk values of As for adults (3.65E-05) and children (5.08E-05) indicated three (adults) and five (children) cases of neoplasm in a hundred thousand inhabitants. The results of this study showed that residents in Tarkwa who use and drink water from boreholes could be at serious risk from exposure to these heavy metals and metalloid.

Oxygen vacancy induces self-doping effect and metalloid LSPR in non-stoichiometric tungsten suboxide synergistically contributing to the enhanced photoelectrocatalytic performance of WO3-x/TiO2-x heterojunction.

PubMed

Huang, Weicheng; Wang, Jinxin; Bian, Lang; Zhao, Chaoyue; Liu, Danqing; Guo, Chongshen; Yang, Bin; Cao, Wenwu

2018-06-27

A WO3-x/TiO2-x nanotube array (NTA) heterojunction photoanode was strategically designed to improve photoelectrocatalytic (PEC) performance by establishing a synergistic vacancy-induced self-doping effect and localized surface plasmon resonance (LSPR) effect of metalloid non-stoichiometric tungsten suboxide. The WO3-x/TiO2-x NTA heterojunction photoanode was synthesized through a successive process of anodic oxidation to form TiO2 nanotube arrays, magnetron sputtering to deposit metalloid WO3-x, and post-hydrogen reduction to engender oxygen vacancy in TiO2-x as well as crystallization. On the merits of such a synergistic effect, WO3-x/TiO2-x shows higher light-harvesting ability, stronger photocurrent response, and resultant improved photoelectrocatalytic performance than the contrast of WO3-x/TiO2, WO3/TiO2 and TiO2, confirming the importance of oxygen vacancies in improving PEC performance. Theoretical calculation based on density functional theory was applied to investigate the electronic structural features of samples and reveal how the oxygen vacancy determines the optical property. The carrier density tuning mechanism and charge transfer model were considered to be associated with the synergistic effect of self-doping and metalloid LSPR effect in the WO3-x/TiO2-x NTA.

Assessment of Phytostabilization Success in Metalliferous Acid Mine Tailings

NASA Astrophysics Data System (ADS)

Wang, Y.; Root, R. A.; Hammond, C.; Amistadi, M. K.; Maier, R. M.; Chorover, J.

2014-12-01

Legacy mine tailings are a significant source of metal(loid)s due to wind and water erosion, especially in the arid southwest, and exposure to fugative dusts presents a health risk to surrounding populations. Compost assisted phytostabilization has been implemented to reduce off site emissions at the Iron King Mine U.S. Superfund Site in central Arizona, concurrent with a greenhouse mesocosm study for detailed study of subsurface mechanisms. Quantification of plant available toxic metal(loid)s in the amended tailings was accessed with a targeted single extraction of diethylenetriaminepentaactic acid (DTPA). Greenhouse mesocosms (1m dia, 0.4 m deep), run in triplicate, mimicked field treatments with: i) tailings only control (TO), ii) tailings plus 15 wt% compost (TC), iii) TC + quailbush seeds (TCA), and iv) TC + buffalo grass seeds (TCB). Core samples collected at 3-month intervals for 1 year were dissected by depth (10 cm each) for analysis. DTPA results indicated that compost treated samples decreased plant availability of Al, As, Cd, Cu, Fe, and Pb but increased Mn and Zn compared with TO. TCB decreased plant available metal(loid)s at all depths, whereas TCA plant available Al, As, Cd, Cu, Fe, Mn and Zn increased in the deeper 20-30cm and 30-40 cm relative to TCB. Samples from the greenhouse were compared to tailings from both the field site and tailings impacted soils used to grow vegetables. Mineral transformations and metal complexation, in the pre- and post-extracted tailings were analyzed by synchrotron transmission XRD and FTIR spectroscopy. The temporal change in plant available metal(loid)s in response to phytostabilization indicates mineralogical alteration that improves soil quality by reducing plant available metal(loid)s. These results will aid in the understanding and efficacy of phytostabilization as a means of remediating and reducing toxicity on mine tailings as well as providing information on health risk management in the region.

Metals removal and recovery in bioelectrochemical systems: A review.

PubMed

Nancharaiah, Y V; Venkata Mohan, S; Lens, P N L

2015-11-01

Metal laden wastes and contamination pose a threat to ecosystem well being and human health. Metal containing waste streams are also a valuable resource for recovery of precious and scarce elements. Although biological methods are inexpensive and effective for treating metal wastewaters and in situ bioremediation of metal(loid) contamination, little progress has been made towards metal(loid) recovery. Bioelectrochemical systems are emerging as a new technology platform for removal and recovery of metal ions from metallurgical wastes, process streams and wastewaters. Biodegradation of organic matter by electroactive biofilms at the anode has been successfully coupled to cathodic reduction of metal ions. Until now, leaching of Co(II) from LiCoO2 particles, and removal of metal ions i.e. Co(III/II), Cr(VI), Cu(II), Hg(II), Ag(I), Se(IV), and Cd(II) from aqueous solutions has been demonstrated. This article reviews the state of art research of bioelectrochemical systems for removal and recovery of metal(loid) ions and pertaining removal mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low-level Environmental Metals and Metalloids and Incident Pregnancy Loss

PubMed Central

Buck Louis, Germaine M.; Smarr, Melissa M.; Sundaram, Rajeshwari; Steuerwald, Amy J.; Sapra, Katherine J.; Lu, Zhaohui; Parsons, Patrick J.

2017-01-01

Environmental exposure to metals and metalloids is associated with pregnancy loss in some but not all studies. We assessed arsenic, cadmium, mercury, and lead concentrations in 501 couples upon trying for pregnancy and followed them throughout pregnancy to estimate the risk of incident pregnancy loss. Using Cox proportional hazard models, we estimated hazard ratios (HR) and 95% confidence intervals (CIs) for pregnancy loss after covariate adjustment for each partner modeled individually then we jointly modeled both partners’ concentrations. Incidence of pregnancy loss was 28%. In individual partner models, the highest adjusted HRs were observed for female and male blood cadmium (HR=1.08; CI 0.81, 1.44; HR=1.09; 95% CI 0.84, 1.41, respectively). In couple based models, neither partner’s blood cadmium concentrations were associated with loss (HR=1.01; 95% CI 0.75, 1.37; HR=0.92; CI 0.68, 1.25, respectively). We observed no evidence of a significant relation between metal(loids) at environmentally relevant concentrations and pregnancy loss. PMID:28163209

Low-level environmental metals and metalloids and incident pregnancy loss.

PubMed

Buck Louis, Germaine M; Smarr, Melissa M; Sundaram, Rajeshwari; Steuerwald, Amy J; Sapra, Katherine J; Lu, Zhaohui; Parsons, Patrick J

2017-04-01

Environmental exposure to metals and metalloids is associated with pregnancy loss in some but not all studies. We assessed arsenic, cadmium, mercury, and lead concentrations in 501 couples upon trying for pregnancy and followed them throughout pregnancy to estimate the risk of incident pregnancy loss. Using Cox proportional hazard models, we estimated hazard ratios (HR) and 95% confidence intervals (CIs) for pregnancy loss after covariate adjustment for each partner modeled individually then we jointly modeled both partners' concentrations. Incidence of pregnancy loss was 28%. In individual partner models, the highest adjusted HRs were observed for female and male blood cadmium (HR=1.08; CI 0.81, 1.44; HR=1.09; 95% CI 0.84, 1.41, respectively). In couple based models, neither partner's blood cadmium concentrations were associated with loss (HR=1.01; 95% CI 0.75, 1.37; HR=0.92; CI 0.68, 1.25, respectively). We observed no evidence of a significant relation between metal(loids) at these environmentally relevant concentrations and pregnancy loss. Published by Elsevier Inc.

Mobility of multiple heavy metalloids in contaminated soil under various redox conditions: Effects of iron sulfide presence and phosphate competition.

PubMed

Park, Ji-Hyun; Kim, So-Jeong; Ahn, Joo Sung; Lim, Dong-Hee; Han, Young-Soo

2018-04-01

The mobility of heavy metalloids including As, Sb, Mo, W, and Cr in soil was investigated under both reducing and oxidizing conditions. The effects of soil mineralogy and the presence of competitive anions were studied as important factors affecting the mobility of these contaminants. Batch experiments conducted with the addition of oxidized and fresh FeS exhibited enhanced sorption rates for As and W under oxidizing conditions, and for Mo under reducing conditions. The inhibitory effect of phosphate on the sorption rates was most apparent for As and Mo under both oxidizing and reducing conditions, while only a small phosphate effect was observed for Sb and W. For Sb and W mobility, pH was determined to be the most important controlling factor. The results of long-term batch experiments revealed that differences in the mobility of metalloids, particularly As, were also influenced by microbial activity in the oxidizing and reducing conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

AMOchar: Amorphous manganese oxide coating of biochar improves its efficiency at removing metal(loid)s from aqueous solutions.

PubMed

Trakal, Lukáš; Michálková, Zuzana; Beesley, Luke; Vítková, Martina; Ouředníček, Petr; Barceló, Andreu Piqueras; Ettler, Vojtěch; Číhalová, Sylva; Komárek, Michael

2018-06-01

A novel sorbent made from biochar modified with an amorphous Mn oxide (AMOchar) was compared with pure biochar, pure AMO, AMO+biochar mixtures and biochar+birnessite composite for the removal of various metal(loid)s from aqueous solutions using adsorption and solid-state analyses. In comparison with the pristine biochar, both Mn oxide-biochar composites were able to remove significantly greater quantities of various metal(loid)s from the aqueous solutions, especially at a ratio 2:1 (AMO:biochar). The AMOchar proved most efficient, removing almost 99, 91 and 51% of Pb, As and Cd, respectively. Additionally, AMOchar and AMO+biochar mixture exhibited reduced Mn leaching, compared to pure AMO. Therefore, it is concluded that the synthesis of AMO and biochar is able to produce a double acting sorbent ('dorbent') of enhanced efficiency, compared with the individual deployment of their component materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Interactions and accumulation differences of metal(loid)s in three sea cucumber species collected from the Northern Mediterranean Sea.

PubMed

Tunca, Evren; Aydın, Mehmet; Şahin, ÜlküAlver

2016-10-01

This study was conducted on Holothuria polii, Holothuria tubulosa, and Holothuria mammata collected from five stations with different depths in the Northern Mediterranean Sea. The body walls and guts of these holothurians were examined in terms of interactions of 10 metals (iron (Fe), copper (Cu), manganese (Mn), zinc (Zn), chromium (Cr), cobalt (Co), vanadium (V), nickel (Ni), cadmium (Cd), and lead (Pb)) and one metalloid (arsenic (As)) using a multivariate analysis, and interspecies differences were determined. The multivariate analysis of variance (MANOVA) revealed significant differences between the species in terms of metal(loid) accumulations. The principal component analysis (PCA) showed a more association between H. tubulosa and H. polii with regard to the accumulation. The cluster analysis (CA) located Pb concentrations of the guts to the farthest place from all elements regardless of the species. A correlation analysis displayed that the element concentrations of the guts were more closely related to each other compared with those of the walls. The most inconsistent element in terms of correlations was the gut Fe contents. Accordingly, while Fe concentrations of H. mammata and H. tubulosa were correlated with all elements (except Pb) in divalent metal transporter 1 (DMT1) (divalent cation transporter 1 (DCT1) or natural resistance-associated macrophage protein 2 (NRAMP2)) belonging to the NRAM protein family, this was not the case in H. polii. Consequently, significant relationships between accumulated metal(loid)s that changed by tissues and sea cucumber species were observed.

Continuous leaching modifies the surface properties and metal(loid) sorption of sludge-derived biochar.

PubMed

Feng, Mingyu; Zhang, Weihua; Wu, Xueyong; Jia, Yanming; Jiang, Chixiao; Wei, Hang; Qiu, Rongliang; Tsang, Daniel C W

2018-06-01

After the application of sludge derived biochar (SDBC) for soil stabilization, it is subjected to continuous leaching that may change its surface properties and metal(loid) immobilization performance. This study simulated the continuous leaching through the fresh SDBC sample in columns with unsaturated and saturated zones under flushing with 0.01M NaNO 3 solution (pH5.5) and acidic solution (pH adjusted to 3.2 by HNO 3 :H 2 SO 4 =1:2), respectively. The resultant changes were assessed in terms of the SDBC surface characteristics and metal(loid) sorption capacities. Continuous leaching was found to gradually decrease the density of basic functional groups and increase the density of carboxyl groups as well as cation exchange capacity on the SDBC surface. It was attributed to the surface acidification and oxidation process by the leaching process, yet it occurred to a lesser extent than the atmospheric exposure. Continuous leaching increased Pb(II), Cr(VI), and As(III) sorption capacity of the SDBC, probably because the increase in carboxyl groups promoted inner-sphere complexation and Fe oxidation as revealed by spectroscopic analysis. It was noteworthy that the SDBC in the unsaturated and saturated zones under continuous leaching displayed distinctive effects on metal(loid) sorption capacity than the atmospheric exposure. Future investigations are needed for understanding the fate and interactions of the SDBC under varying redox conditions and intermittent leaching process. Copyright © 2017. Published by Elsevier B.V.

Ecological and human health risks from metal(loid)s in peri-urban soil in Nanjing, China.

PubMed

Ding, Zhuhong; Hu, Xin

2014-06-01

In order to investigate the ecological and human health risks of metal(loid)s (Cu, Pb, Zn, Ni, Cd, Mn, Cr, and As) in peri-urban soils, 43 surface soil samples were collected from the peri-urban area around Nanjing, a megacity in China. The average contents were 1.19, 67.8, 37.6, 105, 167, 44.6, 722, and 50.8 mg kg(-1) for Cd, Cr, Ni, Pb, Zn, Cu, Mn, and As, respectively. A significant positive correlation was found between Cu, Pb, Zn, Cd, Mn, and As (p < 0.01), and Cr had a significant positive correlation with Ni (p < 0.01). Geoaccumulation indices indicate the presence of Cd and As contamination in all of the peri-urban soil samples. Potential ecological risk indices show that the metal(loid)s in the soil could result in higher ecological risks. Cd is the main contributor to the risk, followed by As. The levels of Cu, Pb, Zn, Cd, Mn, and As in stomach and intestinal phases show a positive linear correlation with their total contents. Mn, Zn, Ni, Cd, and Pb in stomach phase showed higher bioaccessibility, while in intestinal phase, Cu, Cr, and As had the higher bioaccessibility. The carcinogenic risk in children and adults posed by As, Pb, and Cr via ingestion was deemed acceptable. The non-carcinogenic risks posed by these metal(loid)s via ingestion to children are higher than to adults and mainly result from As.

Ge(14)[Ge(SiMe(3))(3)](5)Li(3)(THF)(6): the largest metalloid cluster compound of germanium: on the way to fullerene-like compounds?

PubMed

Schenk, Christian; Schnepf, Andreas

2008-10-14

The reaction of GeBr with LiGe(SiMe(3))(3) yields the largest metalloid cluster compound of germanium Ge(14)[Ge(SiMe(3))(3)](5)Li(3)(THF)(6), in which 14 germanium atoms are arranged as a hollow sphere in the cluster core, showing that in the case of germanium also fullerene-like compounds might be present in the borderland between the molecular and solid states.

Response of spontaneous plants from an ex-mining site of Elba island (Tuscany, Italy) to metal(loid) contamination.

PubMed

Pistelli, Laura; D'Angiolillo, Francesca; Morelli, Elisabetta; Basso, Barbara; Rosellini, Irene; Posarelli, Mauro; Barbafieri, Meri

2017-03-01

The release of large amounts of toxic metals in the neighboring sites of abandoned mine areas represents an important environmental risk for the ecosystem, because it adversely affects soil, water, and plant growth. The aim of the present study was to investigate the metal(loid) (As, Cr, Cu, Ni, Pb, and Zn) contents of native Mediterranean plants grown on the ex-mining area of Elba island (Italy), with the prospective of its recovery by further phytoremediation technology. Soil samples were collected and characterized for metal(loid) content in total and potentially available (EDTA-extractable) fractions. Arsenic was particularly high, being 338 and 2.1 mg kg -1 as total and available fractions, respectively. Predominant native species, namely Dittrichia viscosa L. Greuter, Cistus salviifolius L., Lavandula stoechas L., and Bituminaria bituminosa L., were analyzed for metal content in the different plant organs. D. viscosa exhibited the highest metal(loid) content in the leaves and the singular behavior of translocating arsenic to the leaves (transfer factor about 2.06 and mean bioconcentration factor about 12.48). To assess the healthy status of D. viscosa plants, the leaves were investigated further. The activities of the main antioxidant enzymes and the levels of secondary metabolites linked to oxidative stress in plants from the ex-mining area were not significantly different from those of control plants, except for a lower content of carotenoids, indicating that native plants were adapted to grow in these polluted soils. These results indicate that D. viscosa can be suitable for the revegetation of highly metal-contaminated areas.

Magnetic phase diagrams of amorphous (Ni100-xFex)-metalloid alloys: The key role of the electronic density of states at the Fermi level for the onset of magnetic order

NASA Astrophysics Data System (ADS)

Kiss, L. F.; Bakonyi, I.

2017-11-01

There have been extended studies on the appearance of ferromagnetism in transition-metal-metalloid (MD) glasses. In particular, the paramagnetic (PM) to ferromagnetic (FM) transition has been investigated on numerous (Ni100-xFex)-MD alloys upon the introduction of Fe where MD can represent a combination of various metalloid elements, while keeping the metal/metalloid ratio constant. It has been reported that adding a sufficient amount of Fe to a Pauli PM Ni-MD alloy matrix first induces a spin-glass (SG) state at low temperatures which goes over to a PM state at higher temperatures. Beyond a certain Fe content, xc, the SG state transforms to a FM state upon increasing the temperature. By plotting the characteristic transition temperatures as a function of the Fe content, a magnetic phase diagram can be constructed for each Ni-Fe-MD system which has a multicritical point (MCP) at xc. By using the reported magnetic phase diagrams of various Ni-Fe-MD alloy systems, it is shown that the critical Fe content, xc scales inversely with the density of states at the Fermi level, N(EF), of the parent Ni-MD matrix. This means that the higher the N(EF), the lower the critical Fe content to induce ferromagnetism in the Ni-MD matrix. This is then discussed in terms of the Stoner enhancement factor, S, which characterizes the tendency of the matrix to become ferromagnetic.

Transport and attenuation of metal(loid)s in mine tailings amended with organic carbon: Column experiments

NASA Astrophysics Data System (ADS)

Lindsay, Matthew B. J.; Blowes, David W.; Ptacek, Carol J.; Condon, Peter D.

2011-07-01

A laboratory-scale column experiment was conducted to evaluate the effect of organic carbon amendments on the mobility of As, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Tl and Zn in mine tailings. Three columns were packed with sulfide- and carbonate-rich tailings, which were amended with a 1:1 (vol.) mixture of peat and spent brewing grain at proportions of 0, 2 and 5 vol. %. A simulated input solution characterized by circumneutral pH and elevated concentrations of SO 4 and S 2O 3 was passed through the columns for 540 days. The input solution contained low concentrations of metal(loid)s during the initial 300 days and elevated concentrations thereafter. Decreases in mass transport of S 2O 3 were observed in all columns; with increased attenuation observed at 5 vol. % organic carbon content. Removal of Mn, Ni, Cu, Sb and Mo was observed in all columns during the initial 300 days. However, during this time, mobilization of Fe, As, Zn and Pb was observed, with the greatest increases in concentration observed at the higher organic carbon content. During the final 240 days, S 2O 3 removal was enhanced in columns containing organic carbon, and Fe, Mn, Ni, Tl, As and Sb removal also was observed. This study demonstrates the influence of organic carbon amendments on metal(loid) mobility in mine tailings. Decreases in mass discharge of metal(loid)s may be achieved using this technique; however, site-specific geochemical conditions must be considered before field-scale implementation.

Monitoring and assessment of heavy metal/metalloid concentration by inductively coupled plasma mass spectroscopy (ICP-MS) method in Gonyeli Lake, Cyprus.

PubMed

Alkas, Fehmi Burak; Shaban, Jehad Abdullah; Sukuroglu, Ayca Aktas; Kurt, Mehmet Ali; Battal, Dilek; Saygi, Sahan

2017-09-22

The presence of heavy metals/metalloids in the ecosystem has been an increasing ecological and global public health concern due to their potential to cause adverse health effects. For this reason, the accumulation of some heavy metals such as Cr, Mn, Ni, Cu, As, Cd, Pb was assessed by way of ICP-MS in water, sediment and fish (Cyprinus carpio) sampled from Gonyeli Lake, North Cyprus. The results showed that these metals/metalloids are found widespread throughout the study area. In water, most concentrated element was manganese with 92.1 ppb and least concentrated was lead with 0.914 ppb. In sediment, copper had the highest concentration with 613 ppm, and cadmium the lowest with 1.57 ppm. In fish tissues (muscle and gills), the most concentrated element was manganese with 12.5 ppm and the least concentrated cadmium with 0.017 ppm. These results indicate that future remediation efforts are indispensable for the rehabilitation of the lake.

The potential of genetic engineering of plants for the remediation of soils contaminated with heavy metals.

PubMed

Fasani, Elisa; Manara, Anna; Martini, Flavio; Furini, Antonella; DalCorso, Giovanni

2018-05-01

The genetic engineering of plants to facilitate the reclamation of soils and waters contaminated with inorganic pollutants is a relatively new and evolving field, benefiting from the heterologous expression of genes that increase the capacity of plants to mobilize, stabilize and/or accumulate metals. The efficiency of phytoremediation relies on the mechanisms underlying metal accumulation and tolerance, such as metal uptake, translocation and detoxification. The transfer of genes involved in any of these processes into fast-growing, high-biomass crops may improve their reclamation potential. The successful phytoextraction of metals/metalloids and their accumulation in aerial organs have been achieved by expressing metal ligands or transporters, enzymes involved in sulfur metabolism, enzymes that alter the chemical form or redox state of metals/metalloids and even the components of primary metabolism. This review article considers the potential of genetic engineering as a strategy to improve the phytoremediation capacity of plants in the context of heavy metals and metalloids, using recent case studies to demonstrate the practical application of this approach in the field. © 2017 John Wiley & Sons Ltd.

Dietary compounds as modulators of metals and metalloids toxicity.

PubMed

Jadán-Piedra, Carlos; Chiocchetti, Gabriela Matuoka; Clemente, María Jesús; Vélez, Dinoraz; Devesa, Vicenta

2017-07-07

A large part of the population is exposed to metals and metalloids through the diet. Most of the in vivo studies on its toxicokinetics and toxicity are conducted by means of exposure through drinking water or by intragastric or intraperitoneal administration of aqueous standards, and therefore they do not consider the effect of the food matrix on the exposure. Numerous studies show that some components of the diet can modulate the toxicity of these food contaminants, reducing their effect on a systemic level. Part of this protective role may be due to a reduction of intestinal absorption and subsequent tissue accumulation of the toxic element, although it may also be a consequence of their ability to counteract the toxicity directly by their antioxidant and/or anti-inflammatory activity, among other factors. The present review provides a compilation of existing information about the effect that certain components of the diet have on the toxicokinetics and toxicity of the metals and metalloids of greatest toxicological importance that are present in food (arsenic, cadmium, lead, and mercury), and of their most toxic chemical species.

Assessing ecotoxicity and uptake of metals and metalloids in relation to two different earthworm species (Eiseina hortensis and Lumbricus terrestris).

PubMed

Leveque, Thibaut; Capowiez, Yvan; Schreck, Eva; Mazzia, Christophe; Auffan, Mélanie; Foucault, Yann; Austruy, Annabelle; Dumat, Camille

2013-08-01

Due to diffuse atmospheric fallouts of process particles enriched by metals and metalloids, polluted soils concern large areas at the global scale. Useful tools to assess ecotoxicity induced by these polluted soils are therefore needed. Earthworms are currently used as biotest, however the influence of specie and earthworm behaviour, soil characteristics are poorly highlighted. Our aim was therefore to assess the toxicity of various polluted soils with process particles enriches by metals and metalloids (Pb, Cd, Cu, Zn, As and Sb) collected from a lead recycling facility on two earthworm species belonging to different ecological types and thus likely to have contrasted behavioural responses (Eiseina hortensis and Lumbricus terrestris). The combination of behavioural factors measurements (cast production and biomass) and physico-chemical parameters such as metal absorption, bioaccumulation by earthworms and their localization in invertebrate tissues provided a valuable indication of pollutant bioavailability and ecotoxicity. Soil characteristics influenced ecotoxicity and metal uptake by earthworms, as well as their soil bioturbation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultra-stiff metallic glasses through bond energy density design.

PubMed

Schnabel, Volker; Köhler, Mathias; Music, Denis; Bednarcik, Jozef; Clegg, William J; Raabe, Dierk; Schneider, Jochen M

2017-07-05

The elastic properties of crystalline metals scale with their valence electron density. Similar observations have been made for metallic glasses. However, for metallic glasses where covalent bonding predominates, such as metalloid metallic glasses, this relationship appears to break down. At present, the reasons for this are not understood. Using high energy x-ray diffraction analysis of melt spun and thin film metallic glasses combined with density functional theory based molecular dynamics simulations, we show that the physical origin of the ultrahigh stiffness in both metalloid and non-metalloid metallic glasses is best understood in terms of the bond energy density. Using the bond energy density as novel materials design criterion for ultra-stiff metallic glasses, we are able to predict a Co 33.0 Ta 3.5 B 63.5 short range ordered material by density functional theory based molecular dynamics simulations with a high bond energy density of 0.94 eV Å -3 and a bulk modulus of 263 GPa, which is 17% greater than the stiffest Co-B based metallic glasses reported in literature.

Method for applying a diffusion barrier interlayer for high temperature components

DOEpatents

Wei, Ronghua; Cheruvu, Narayana S.

2016-03-08

A coated substrate and a method of forming a diffusion barrier coating system between a substrate and a MCrAl coating, including a diffusion barrier coating deposited onto at least a portion of a substrate surface, wherein the diffusion barrier coating comprises a nitride, oxide or carbide of one or more transition metals and/or metalloids and a MCrAl coating, wherein M includes a transition metal or a metalloid, deposited on at least a portion of the diffusion barrier coating, wherein the diffusion barrier coating restricts the inward diffusion of aluminum of the MCrAl coating into the substrate.

Immunological alterations in individuals exposed to metal(loid)s in the Panasqueira mining area, Central Portugal.

PubMed

Coelho, Patrícia; García-Lestón, Julia; Costa, Solange; Costa, Carla; Silva, Susana; Fuchs, Dietmar; Geisler, Simon; Dall'Armi, Valentina; Zoffoli, Roberto; Bonassi, Stefano; Pásaro, Eduardo; Laffon, Blanca; Teixeira, João Paulo

2014-03-15

Environmental studies performed in Panasqueira mine area (central Portugal) identified high concentrations of several metal(loid)s in environmental media, and individuals environmentally and occupationally exposed showed higher levels of As, Cr, Mg, Mn, Mo, Pb and Zn in blood, urine, hair and nails when compared to unexposed controls. To evaluate the presence of immunological alterations attributable to environmental contamination, we quantified neopterin, kynurenine, tryptophan, and nitrite concentrations in plasma, and analysed the percentage of several lymphocytes subsets, namely CD3(+), CD4(+) and CD8(+) T-cells, CD19(+) B-cells, and CD16(+)56(+) natural killer (NK) cells in a group of individuals previously tested for metal(loid) levels in different biological matrices. The environmentally exposed group had significantly lower levels of %CD8(+) and higher CD4(+)/CD8(+) ratios, whereas the occupationally exposed individuals showed significant decreases in %CD3(+) and %CD4(+), and significant increases in %CD16(+)56(+), when compared to controls. Analysed biomarkers were found to be influenced by age, particularly neopterin, kynurenine and kynurenine to tryptophan ratio (Kyn/Trp) with significantly higher levels in older individuals, and %CD3(+), %CD8(+) and %CD19(+) with significantly lower values in older individuals. Males environmentally exposed showed significantly lower values of %CD19(+) when compared to control females. The concentration of Pb in toenails was associated to the level of neopterin, kynurenine and Kyn/Trp ratio (all direct), and the concentration of Mn in blood to the level of %CD8(+), %CD19(+) (both inverse) and CD4(+)/CD8(+) ratio (direct). Overall our results show that the metal(loid) contamination in Panasqueira mine area induced immunotoxic effects in exposed populations, possibly increasing susceptibility to diseases. Copyright © 2013 Elsevier B.V. All rights reserved.

Genotoxic effect of exposure to metal(loid)s. A molecular epidemiology survey of populations living and working in Panasqueira mine area, Portugal.

PubMed

Coelho, Patrícia; García-Lestón, Julia; Costa, Solange; Costa, Carla; Silva, Susana; Dall'Armi, Valentina; Zoffoli, Roberto; Bonassi, Stefano; de Lima, João Pereira; Gaspar, Jorge Francisco; Pásaro, Eduardo; Laffon, Blanca; Teixeira, João Paulo

2013-10-01

Previous studies investigating the exposure to metal(loid)s of populations living in the Panasqueira mine area of central Portugal found a higher internal dose of elements such as arsenic, chromium, lead, manganese, molybdenum and zinc in exposed individuals. The aims of the present study were to evaluate the extent of genotoxic damage caused by environmental and occupational exposure in individuals previously tested for metal(loid) levels in different biological matrices, and the possible modulating role of genetic polymorphisms involved in metabolism and DNA repair. T-cell receptor mutation assay, comet assay, micronucleus (MN) test and chromosomal aberrations (CA) were performed in a group of 122 subjects working in the Panasqueira mine or living in the same region. The modifying effect of polymorphisms in GSTA2, GSTM1, GSTP1, GSTT1, XRCC1, APEX1, MPG, MUTYH, OGG1, PARP1, PARP4, ERCC1, ERCC4, and ERCC5 genes was investigated. Significant increases in the frequency of all biomarkers investigated were found in exposed groups, however those environmentally exposed were generally higher. Significant influences of polymorphisms were observed for GSTM1 deletion and OGG1 rs1052133 on CA frequencies, APEX1 rs1130409 on DNA damage, ERCC1 rs3212986 on DNA damage and CA frequency, and ERCC4 rs1800067 on MN and CA frequencies. Our results show that the metal(loid) contamination in the Panasqueira mine area induced genotoxic damage both in individuals working in the mine or living in the area. The observed effects are closely associated to the internal exposure dose, and are more evident in susceptible genotypes. The urgent intervention of authorities is required to protect exposed populations. © 2013.

Potential impact of acid precipitation on arsenic and selenium.

PubMed Central

Mushak, P

1985-01-01

The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling. PMID:4076075

Potential impact of acid precipitation on arsenic and selenium.

PubMed

Mushak, P

1985-11-01

The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling.

Ultrasonochemically conjugated metalloid/triblock copolymer nanocomposite and subsequent thin solid laminate growth for surface and interface studies.

PubMed

Veerapandian, Murugan; Yun, KyuSik

2010-09-07

Polymer and metalloid nanoparticles can be conjugated in a symphonized manner using ultrasonochemical force to obtain hybrid nanocomposites. The process is demonstrated using polymer poly(ethylene glycol) (PEG), metalloid SiO(2)@Ag, and triblock copolymer ABA. The acoustic microstreaming and cavitation force from the ultrasonics are crucial parameters that determine the harmonized PEG stabilization and ABA blending of the metalloid nanocomposites that are obtained. Surface plasmon resonance in the resulting hybrid systems are examined by UV-vis absorbance spectroscopy. The resulting PEG-stabilized SiO(2)-Ag conjugated with a triblock copolymer poly(p-dioxanone-co-caprolactone)-block-poly(ethylene oxide)-block-poly(p-dioxanone-co-caprolactone) (PPDO-co-PCL-b-PEG-b-PPDO-co-PCL/ABA) (PEG-SiO(2)@Ag/ABA) shows a red shift of 20 nm (410 nm) from its initial resonance at 390 nm (PEG-SiO(2)@Ag). Nanocomposite particles were then spin-coated on a glass substrate to obtain the growth of thin solid laminates (thickness 27 microm). Structural functionality was studied by FT-IR, (1)H NMR, and FT-Raman spectroscopy. Morphological properties were ensured from FE-SEM, HRTEM, AFM, and FIB-SEM. Identity and crystallinity of the prepared nanocomposite were confirmed by XRD analysis. A very low weight percentile loss of the fabricated nanocomposites ensures its high thermal stability. Fabricated nanocomposite laminate might have a role in coating, reinforcement, and resistance and as substrate additives for a variety of surface and interface studies. Further, the ultrasonochemical approach utilized here could also be a smart system to fabricate other heteronanostructures in a single platform.

X-ray elemental mapping techniques for elucidating the ecophysiology of hyperaccumulator plants.

PubMed

van der Ent, Antony; Przybyłowicz, Wojciech J; de Jonge, Martin D; Harris, Hugh H; Ryan, Chris G; Tylko, Grzegorz; Paterson, David J; Barnabas, Alban D; Kopittke, Peter M; Mesjasz-Przybyłowicz, Jolanta

2018-04-01

Contents Summary 432 I. Introduction 433 II. Preparation of plant samples for X-ray micro-analysis 433 III. X-ray elemental mapping techniques 438 IV. X-ray data analysis 442 V. Case studies 443 VI. Conclusions 446 Acknowledgements 449 Author contributions 449 References 449 SUMMARY: Hyperaccumulators are attractive models for studying metal(loid) homeostasis, and probing the spatial distribution and coordination chemistry of metal(loid)s in their tissues is important for advancing our understanding of their ecophysiology. X-ray elemental mapping techniques are unique in providing in situ information, and with appropriate sample preparation offer results true to biological conditions of the living plant. The common platform of these techniques is a reliance on characteristic X-rays of elements present in a sample, excited either by electrons (scanning/transmission electron microscopy), protons (proton-induced X-ray emission) or X-rays (X-ray fluorescence microscopy). Elucidating the cellular and tissue-level distribution of metal(loid)s is inherently challenging and accurate X-ray analysis places strict demands on sample collection, preparation and analytical conditions, to avoid elemental redistribution, chemical modification or ultrastructural alterations. We compare the merits and limitations of the individual techniques, and focus on the optimal field of applications for inferring ecophysiological processes in hyperaccumulator plants. X-ray elemental mapping techniques can play a key role in answering questions at every level of metal(loid) homeostasis in plants, from the rhizosphere interface, to uptake pathways in the roots and shoots. Further improvements in technological capabilities offer exciting perspectives for the study of hyperaccumulator plants into the future. © 2017 University of Queensland. New Phytologist © 2017 New Phytologist Trust.

Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

NASA Astrophysics Data System (ADS)

Prabhakar, Gouri; Sorooshian, Armin; Toffol, Emily; Arellano, Avelino F.; Betterton, Eric A.

2014-08-01

A statistical analysis of data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of aerosol samplers has been used to study the spatial and temporal concentration trends in airborne particulate metals and metalloids for southern Arizona. The study region is a rapidly growing area in southwestern North America characterized by high fine soil concentrations (among the highest in the United States), anthropogenic emissions from an area within the fastest growing region in the United States, and a high density of active and abandoned mining sites. Crustal tracers in the region are most abundant in the summer (April-June) followed by fall (October-November) as a result of dry meteorological conditions which favor dust emissions from natural and anthropogenic activity. A distinct day-of-week cycle is evident for crustal tracer mass concentrations, with the greatest amplitude evident in urban areas. There have been significant reductions since 1988 in the concentrations of toxic species that are typically associated with smelting and mining. Periods with high fine soil concentrations coincide with higher concentrations of metals and metalloids in the atmosphere, with the enhancement being higher at urban sites.

Distribution of metals and metalloids in dried seaweeds and health risk to population in southeastern China.

PubMed

Chen, Qing; Pan, Xiao-Dong; Huang, Bai-Fen; Han, Jian-Long

2018-02-23

Concern about metals and metalloids, especially heavy metals in seaweeds has risen due to potential health risk. This study investigated the distribution of 10 metals and metalloids in 295 dried seaweeds (brown and red) and estimated the possible health risk via hazard index (HI). Elements in seaweeds can be sequenced in descending order by mean values: Al > Mn > As > Cu > Cr > Ni > Cd > Se > Pb > Hg. The levels of Cd, Cu, Mn and Ni in red seaweeds were significantly higher than those in brown seaweeds (P < 0.01). Correlation analysis showed contents of Ni-Cr (r = 0.59, P < 0.01) in seaweeds had moderate positive correlations. Seaweeds from different geographical origins had diverse element distribution. Risk assessment showed that HI at mean level was less than the threshold of 1. It indicates that for the general people there is low health risk to these elements by the intake of seaweeds. Furthermore, in terms of the confirmative toxicity of some metals, such as Cd, Pb and Hg, surveillance of metals in seaweeds should be performed continuously.

Distribution of metal and metalloid elements in human scalp hair in Taiyuan, China.

PubMed

Zhu, Yuen; Wang, Yuzhe; Meng, Fanjian; Li, Lifen; Wu, Shan; Mei, Xiaohui; Li, Hua; Zhang, Guixiang; Wu, Daishe

2018-02-01

This study investigated the levels of metal and metalloid elements (As, Ca, Cd, Cr, Cu, Fe, Hg, Mg, Ni, Pb, and Zn) in scalp hair samples collected from 161 people of different age and gender groups living in the six districts of Taiyuan, an industrial city with rich coal reserve in Shanxi province in China. Levels of most elements in the hair were high in the 26-40 age groups and increased with the length of residence. Calcium, Cr, Mg, Ni and Zn levels in the females' hair were significantly higher than those in the males' (p < 0.05). Element levels in the hair didn't have significantly differences between industrial and non-industrial districts because most of industry factories are in the upper wind position in Taiyuan, and contamination is prone to spread to non-industrial districts. The principal component analysis indicates that the main sources of these elements are mining activities, the neighboring stainless steel industry, and coal combustion. These results indicate that the industrial activities primarily contribute to the metal and metalloid pollution in Taiyuan, whereas numerous factors caused the metals accumulation in hair. Copyright © 2017 Elsevier Inc. All rights reserved.

Nature's refineries — Metals and metalloids in arc volcanoes

USGS Publications Warehouse

Henley, R.W.; Berger, Byron R.

2013-01-01

Chemical data for fumaroles and for atmospheric gas and ash plumes from active arc volcanoes provide glimpses of the rates of release of metal and metalloids, such as Tl and Cd, from shallow and mid-crust magmas. Data from copper deposits formed in ancient volcanoes at depths of up to about 1500 m in the fractures below paleo-fumaroles, and at around 2000–4000 m in association with sub-volcanic intrusions (porphyry copper deposits) provide evidence of sub-surface deposition of Cu–Au–Ag–Mo and a range of other minor elements including Te, Se, As and Sb. These deposits, or ‘sinks’, of metals consistently record sustained histories of magmatic gas streaming through volcanic systems interspersed by continuing intrusive and eruptive activity. Here we integrate data from ancient and modern volcanic systems and show that the fluxes of metals and metalloids are controlled by a) the maintenance of fracture permeability in the stressed crust below volcanoes and b) the chemical processes that are triggered as magmatic gas, initially undersaturated with metals and metalloids, expands from lithostatic to very low pressure conditions through fracture arrays. The recognition of gas streaming may also account for the phenomenon of ‘excess degassing’, and defines an integral, but generally understated, component of active volcanic systems – a volcanic gas core – that is likely to be integral to the progression of eruptions to Plinean state.Destabilization of solvated molecular metal and metalloid species in magmatic gas mixtures and changes in their redox state are triggered, as it expands to the surface by abrupt pressure drops, or throttles' in the fracture array that guides expansion to the surface. The electronically harder, low electronegativity metals, such as copper and iron, deposit rapidly in response to expansion followed more slowly by arsenic with antimony as sulfosalts. Heavy, large radius, softer elements such as bismuth, lead, and thallium along with cadmium are strongly fractionated along the way, eventually venting their excess along with SO2, CO2, and other components of the carrier gas, into the atmosphere. These elements, many of which are toxic, may also be dispersed by mixing with groundwater in the permeable crust below volcanoes and generate potential health risks due to Hg, As, and Se contamination of drinking water resources.

Applicability of drinking water treatment residue for lake restoration in relation to metal/metalloid risk assessment

PubMed Central

Yuan, Nannan; Wang, Changhui; Pei, Yuansheng; Jiang, Helong

2016-01-01

Drinking water treatment residue (DWTR), a byproduct generated during potable water production, exhibits a high potential for recycling to control eutrophication. However, this beneficial recycling is hampered by unclear metal/metalloid pollution risks related to DWTR. In this study, the pollution risks of Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn due to DWTR application were first evaluated for lake water based on human health risk assessment models and comparison of regulatory standards. The risks of DWTR were also evaluated for sediments on the basis of toxicity characteristics leaching procedure and fractionation in relation to risk assessment code. Variations in the biological behaviors of metal/metalloid in sediments caused by DWTR were assessed using Chironomus plumosus larvae and Hydrilla verticillata. Kinetic luminescent bacteria test (using Aliivibrio fischeri) was conducted to analyze the possibility of acute and chronic detrimental effects of sediment with DWTR application. According to the obtained results, we identify a potential undesirable effect of DWTR related to Fe and Mn (typically under anaerobic conditions); roughly present a dosage threshold calculation model; and recommend a procedure for DWTR prescreening to ensure safe application. Overall, managed DWTR application is necessary for successful eutrophication control. PMID:27929083

Applicability of drinking water treatment residue for lake restoration in relation to metal/metalloid risk assessment

NASA Astrophysics Data System (ADS)

Yuan, Nannan; Wang, Changhui; Pei, Yuansheng; Jiang, Helong

2016-12-01

Drinking water treatment residue (DWTR), a byproduct generated during potable water production, exhibits a high potential for recycling to control eutrophication. However, this beneficial recycling is hampered by unclear metal/metalloid pollution risks related to DWTR. In this study, the pollution risks of Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn due to DWTR application were first evaluated for lake water based on human health risk assessment models and comparison of regulatory standards. The risks of DWTR were also evaluated for sediments on the basis of toxicity characteristics leaching procedure and fractionation in relation to risk assessment code. Variations in the biological behaviors of metal/metalloid in sediments caused by DWTR were assessed using Chironomus plumosus larvae and Hydrilla verticillata. Kinetic luminescent bacteria test (using Aliivibrio fischeri) was conducted to analyze the possibility of acute and chronic detrimental effects of sediment with DWTR application. According to the obtained results, we identify a potential undesirable effect of DWTR related to Fe and Mn (typically under anaerobic conditions); roughly present a dosage threshold calculation model; and recommend a procedure for DWTR prescreening to ensure safe application. Overall, managed DWTR application is necessary for successful eutrophication control.

Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

PubMed Central

2014-01-01

Background Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. Results A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. Conclusions C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction. PMID:25098921

Quantitative analysis of some important metals and metalloids in tobacco products by inductively coupled plasma-mass spectrometry (ICP-MS)

PubMed Central

2012-01-01

Background Large scale usage of tobacco causes a lot of health troubles in human. Various formulations of tobacco are extensively used by the people particularly in developing world. Besides several toxic tobacco constituents some metals and metalloids are also believed to pose health risks. This paper describes inductively coupled plasma-mass spectrometric (ICP-MS) quantification of some important metals and metalloids in various brands of smoked, sniffed, dipped and chewed tobacco products. Results A microwave-assisted digestion method was used for sample preparation. The method was validated by analyzing a certified reference material. Percentage relative standard deviation (% R.S.D.) between recovered and certified values was < 5.8. Linearity value for calibration curve of each metal was 1 > r > 0.999. Improved limits of detection (LODs) were in range of ng/L for all elements. Fe, Al and Mn were found to be in the highest concentration in all types of tobacco products, while Zn, Cu, Ni and Cr were below the average concentration of 40 μg/g, and Pb, Co, As, Se and Cd were below 5 μg/g. All elements, apart from Pb, were high in concentration in dipping tobacco in comparison to other tobacco products. Generally, the order of all elemental concentration can be expressed in different tobacco products as chewing < smoked < sniffing < dipping. However, smoked and sniffing will interchange their position in the case of Mn, Cu, Se and Cd. Multivariate statistical analyses were also performed to evaluate the correlation and variations among tobacco products. Conclusions The present study highlights the quantification of some important metals and metalloids in a wide spectrum of tobacco formulations. The outcome of this study would be beneficial for health authorities and individuals. PMID:22709464

Contaminations, Sources, and Health Risks of Trace Metal(loid)s in Street Dust of a Small City Impacted by Artisanal Zn Smelting Activities

PubMed Central

Wu, Tingting; Bi, Xiangyang; Sun, Guangyi; Feng, Xinbin; Shang, Lihai; Zhang, Hua; He, Tianrong; Chen, Ji

2017-01-01

To investigate the impact of artisanal zinc smelting activities (AZSA) on the distribution and enrichment of trace metal(loid)s in street dust of a small city in Guizhou province, SW China, street dust samples were collected and analyzed for 10 trace metal(loid)s (Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Pb, and Hg). Meanwhile, the health risks of local resident exposed to street dust were assessed. The result showed that the average concentrations of 10 elements were Zn (1039 mg kg−1), Pb (423 mg kg−1), Cr (119 mg kg−1), Cu (99 mg kg−1), As (55 mg kg−1), Ni (39 mg kg−1), Co (18 mg kg−1), Sb (7.6 mg kg−1), Cd (2.6 mg kg−1), and Hg (0.22 mg kg−1). Except Ni, Co, and Cr, other elements in street dust were obviously elevated compared to the provincial soil background. Pb, Zn, Cd, Sb, and Cu were at heavy to moderate contamination status, especially Pb and Zn, with maximums of 1723 and 708 mg kg−1, respectively; As and Hg were slightly contaminated; while Cr, Ni, and Co were at un-contaminated levels. Multivariate statistical analysis revealed AZSA contributed to the increase of Pb, Zn, Cd, Sb, As, and Hg, while, natural sources introduced Ni, Co, Cr, and Cu. The health risk assessment disclosed that children had higher non-carcinogenic risk than those found in adults, and As has hazardous index (HI) higher than 1 both for children and adults, while Pb and Cr only had HIs higher than 1 for children, other elements were relatively safe. For carcinogenic risks, the major concern was As, then a lesser concern for Cr. The study showed that although the scale of AZSA was small, the contamination of heavy metal(loid)s in street dust and associated health risks were severe. PMID:28841170

Composition and fate of mine- and smelter-derived particulates in soils from humid subtropical and semiarid areas

NASA Astrophysics Data System (ADS)

Ettler, Vojtech; Kribek, Bohdan; Mihaljevic, Martin; Vanek, Ales; Penizek, Vit; Sracek, Ondra; Mapani, Ben; Kamona, Fred; Nyambe, Imasiku

2017-04-01

Soils in the vicinity of non-ferrous metal smelters are often highly polluted by inorganic contaminants released from particulate emissions, which undergo weathering processes and release contaminants when deposited in soils. We studied the heavy mineral fraction, separated from mining- and smelter-affected topsoils, from both a humid subtropical area in the Zambian Copperbelt and a hot semi-arid area in the northern Namibia. High concentrations of metal(loid)s were detected in the studied soils: up to 1450 ppm As, 8980 ppm Cu, 4640 ppm Pb, 2620 ppm Zn. A combination of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM/EDS), and electron probe microanalysis (EPMA) helped to identify the phases forming individual metal(loid)-bearing particles. Whereas spherical particles originate from the smelting and flue gas cleaning processes, angular particles either have geogenic origins or they are windblown from the mining operations and mine waste disposal sites. Sulphides from ores and mine tailings often exhibit weathering rims in contrast to smelter-derived high-temperature sulphides (chalcocite [Cu2S], digenite [Cu9S5], covellite [CuS], non-stoichiometric quenched Cu-Fe-S phases). Soils from humid subtropical areas exhibit higher available concentrations of metal(loids), and higher frequencies of weathering features (especially for copper-bearing oxides such as delafossite [CuFeO2]) are observed. In contrast, metal(loid)s are efficiently retained in semi-arid soils, where a high proportion of non-weathered smelter slag particles and low-solubility Ca-Cu-Pb arsenates occur. Our results indicate that compared to semi-arid areas (where inorganic contaminants were rather immobile in soils despite their high concentrations) a higher potential risk exists for agriculture in mine- and smelter-affected humid subtropical areas (where metal(loid) contaminants can be highly available for the uptake by crops). This study was supported by the Czech Science Foundation projects (GACR 13-17501S and 16-13142S).

Metals and Breast Cancer

PubMed Central

Byrne, Celia; Divekar, Shailaja D.; Storchan, Geoffrey B.; Parodi, Daniela A.; Martin, Mary Beth

2014-01-01

Metalloestrogens are metals that activate the estrogen receptor in the absence of estradiol. The metalloestrogens fall into two subclasses: metal/metalloid anions and bivalent cationic metals. The metal/metalloid anions include compounds such as arsenite, nitrite, selenite, and vanadate while the bivalent cations include metals such as cadmium, calcium, cobalt, copper, nickel, chromium, lead, mercury, and tin. The best studied metalloestrogen is cadmium. It is a heavy metal and a prevalent environmental contaminant with no known physiological function. This review addresses our current understanding of the mechanism by which cadmium and the bivalent cationic metals activate estrogen receptor-α. The review also summarizes the in vitro and in vivo evidence that cadmium functions as an estrogen and the potential role of cadmium in breast cancer. PMID:23338949

Friction Modifier Using Adherent Metallic Multilayered or Mixed Element Layer Conversion Coatings

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor); Defalco, Francis G. (Inventor); Starks, Lloyd L., Sr. (Inventor)

2013-01-01

A process for creating conversion coatings and spin, drawing, and extrusion finishes for surfaces, wherein the conversion coatings and spin, drawing, and extrusion finishes contain potassium, phosphorus, nitrogen, and one or more non-alkaline metals and/or one or more metalloids. The process comprises forming an aqueous solution of water, phosphoric acid or sulfuric acid, ammonium hydroxide, an alkali metal hydroxide, and one or more non-alkaline metals and/or one or more metalloids. The aqueous solution forms an anti-friction multilayer conversion and/or mixed element coating or a spin, drawing, and extrusion finish on a surface when applied to the surface, either directly without the use of applied external electromotive force, or as an additive in lubricating fluids.

Conversion of direct process high-boiling residue to monosilanes

DOEpatents

Brinson, Jonathan Ashley; Crum, Bruce Robert; Jarvis, Jr., Robert Frank

2000-01-01

A process for the production of monosilanes from the high-boiling residue resulting from the reaction of hydrogen chloride with silicon metalloid in a process typically referred to as the "direct process." The process comprises contacting a high-boiling residue resulting from the reaction of hydrogen chloride and silicon metalloid, with hydrogen gas in the presence of a catalytic amount of aluminum trichloride effective in promoting conversion of the high-boiling residue to monosilanes. The present process results in conversion of the high-boiling residue to monosilanes. At least a portion of the aluminum trichloride catalyst required for conduct of the process may be formed in situ during conduct of the direct process and isolation of the high-boiling residue.

Current role of ICP-MS in clinical toxicology and forensic toxicology: a metallic profile.

PubMed

Goullé, Jean-Pierre; Saussereau, Elodie; Mahieu, Loïc; Guerbet, Michel

2014-08-01

As metal/metalloid exposure is inevitable owing to its omnipresence, it may exert toxicity in humans. Recent advances in metal/metalloid analysis have been made moving from flame atomic absorption spectrometry and electrothermal atomic absorption spectrometry to the multi-elemental inductively coupled plasma (ICP) techniques as ICP atomic emission spectrometry and ICP-MS. ICP-MS has now emerged as a major technique in inorganic analytical chemistry owing to its flexibility, high sensitivity and good reproducibility. This in depth review explores the ICP-MS metallic profile in human toxicology. It is now routinely used and of great importance, in clinical toxicology and forensic toxicology to explore biological matrices, specifically whole blood, plasma, urine, hair, nail, biopsy samples and tissues.

Inhalable desert dust, urban emissions, and potentially biotoxic metals in urban Saharan-Sahelian air

USGS Publications Warehouse

Garrison, Virginia H.; Majewski, Michael S.; Konde, Lassana; Wolf, Ruth E.; Otto, Richard D.; Tsuneoka, Yutaka

2014-01-01

Saharan dust incursions and particulates emitted from human activities degrade air quality throughout West Africa, especially in the rapidly expanding urban centers in the region. Particulate matter (PM) that can be inhaled is strongly associated with increased incidence of and mortality from cardiovascular and respiratory diseases and cancer. Air samples collected in the capital of a Saharan–Sahelian country (Bamako, Mali) between September 2012 and July 2013 were found to contain inhalable PM concentrations that exceeded World Health Organization (WHO) and US Environmental Protection Agency (USEPA) PM2.5 and PM10 24-h limits 58 – 98% of days and European Union (EU) PM10 24-h limit 98% of days. Mean concentrations were 1.2-to-4.5 fold greater than existing limits. Inhalable PM was enriched in transition metals, known to produce reactive oxygen species and initiate the inflammatory response, and other potentially bioactive and biotoxic metals/metalloids. Eroded mineral dust composed the bulk of inhalable PM, whereas most enriched metals/metalloids were likely emitted from oil combustion, biomass burning, refuse incineration, vehicle traffic, and mining activities. Human exposure to inhalable PM and associated metals/metalloids over 24-h was estimated. The findings indicate that inhalable PM in the Sahara–Sahel region may present a threat to human health, especially in urban areas with greater inhalable PM and transition metal exposure.

Probing the distribution and contamination levels of 10 trace metal/metalloids in soils near a Pb/Zn smelter in Middle China.

PubMed

Li, Zhonggen; Feng, Xinbin; Bi, Xiangyang; Li, Guanghui; Lin, Yan; Sun, Guangyi

2014-03-01

The horizontal and vertical distribution patterns and contamination status of ten trace metal/metalloids (Ag, Bi, Co, Cr, Ge, In, Ni, Sb, Sn, Tl) in soils around one of the largest Chinese Pb-Zn smelter in Zhuzhou City, Central China, were revealed. Different soil samples were collected from 11 areas, including ten agricultural areas and one city park area, with a total of 83 surface soil samples and six soil cores obtained. Trace metal/metalloids were determined by inductively coupled plasma-mass spectrometry after digestion by an acid mixture of HF and HNO3. The results showed that Ag, Bi, In, Sb, Sn, and Tl contents decreased both with the distance to the Pb-Zn smelter as well as the soil depth, hinting that these elements were mainly originated from the Pb-Zn smelting operations and were introduced into soils through atmospheric deposition. Soil Ge was influenced by the smelter at a less extent, while the distributions of Co, Cr, and Ni were roughly even among most sampling sites and soil depths, suggesting that they were primarily derived from natural sources. The contamination status, as revealed by the geo-accumulation index (I geo), indicated that In and Ag were the most enriched elements, followed by Sb, Bi, and Sn. In general, Cr, Tl, Co, Ni, and Ge were of an uncontaminated status.

Bioaccumulation of metals and metalloids in medicinal plant Ipomoea pes-caprae from areas impacted by tsunami.

PubMed

Kozak, Lidia; Kokociński, Mikołaj; Niedzielski, Przemysław; Lorenc, Stanisław

2015-02-01

Tsunami events may have an enormous impact on the functioning of aquatic and terrestrial ecosystems by altering various relationships with biotic components. Concentrations of acid-leachable fractions of heavy metals and metalloids in soils and plant samples from areas affected by the December 2004 tsunami in Thailand were determined. Ipomoea pes-caprae, a common plant species growing along the seashore of this region, and frequently used in folk medicine, was selected to assess the presence of selected elements. Elevated amounts of Cd, Pb, Zn, and As in soil samples, and Pb, Zn, As, Se, Cr, and Ni in plant samples were determined from the tsunami-impacted regions for comparison with reference locations. The flowers of Ipomoea pes-caprae contained the highest amounts of these metals, followed by its leaves, and stems. In addition, its bioaccumulation factor (BAF) supports this capability of high metal uptake by Ipomoea pes-caprae from the areas affected by the tsunami in comparison with a reference site. This uptake was followed by the translocation of these elements to the various plant components. The presence of these toxic metals in Ipomoea pes-caprae growing in contaminated soils should be a concern of those who use this plant for medicinal purposes. Further studies on the content of heavy metals and metalloids in this plant in relation to human health concerns are recommended. © 2014 SETAC.

Inhalable desert dust, urban emissions, and potentially biotoxic metals in urban Saharan-Sahelian air.

PubMed

Garrison, V H; Majewski, M S; Konde, L; Wolf, R E; Otto, R D; Tsuneoka, Y

2014-12-01

Saharan dust incursions and particulates emitted from human activities degrade air quality throughout West Africa, especially in the rapidly expanding urban centers in the region. Particulate matter (PM) that can be inhaled is strongly associated with increased incidence of and mortality from cardiovascular and respiratory diseases and cancer. Air samples collected in the capital of a Saharan-Sahelian country (Bamako, Mali) between September 2012 and July 2013 were found to contain inhalable PM concentrations that exceeded World Health Organization (WHO) and US Environmental Protection Agency (USEPA) PM2.5 and PM10 24-h limits 58 - 98% of days and European Union (EU) PM10 24-h limit 98% of days. Mean concentrations were 1.2-to-4.5 fold greater than existing limits. Inhalable PM was enriched in transition metals, known to produce reactive oxygen species and initiate the inflammatory response, and other potentially bioactive and biotoxic metals/metalloids. Eroded mineral dust composed the bulk of inhalable PM, whereas most enriched metals/metalloids were likely emitted from oil combustion, biomass burning, refuse incineration, vehicle traffic, and mining activities. Human exposure to inhalable PM and associated metals/metalloids over 24-h was estimated. The findings indicate that inhalable PM in the Sahara-Sahel region may present a threat to human health, especially in urban areas with greater inhalable PM and transition metal exposure. Published by Elsevier B.V.

The formal combination of three singlet biradicaloid entities to a singlet hexaradicaloid metalloid Ge14[Si(SiMe3)3]5[Li(THF)2]3 cluster.

PubMed

Schenk, Christian; Kracke, Andreas; Fink, Karin; Kubas, Adam; Klopper, Wim; Neumaier, Marco; Schnöckel, Hansgeorg; Schnepf, Andreas

2011-03-02

The reaction of GeBr with LiSi(SiMe(3))(3) leads to the metalloid cluster compound [(THF)(2)Li](3)Ge(14)[Si(SiMe(3))(3)](5) (1). After the introduction of a first cluster of this type, in which 14 germanium atoms form an empty polyhedron, [(THF)(2)Li](3)Ge(14)[Ge(SiMe(3))(3)](5) (2), we present here further investigations on 1 to obtain preliminary insight into its chemical and bonding properties. The molecular structure of 1 is determined via X-ray crystal structure solution using synchrotron radiation. The electronic structure of the Ge(14) polyhedron is further examined by quantum chemical calculations, which indicate that three singlet biradicaloid entities formally combine to yield the singlet hexaradicaloid character of 1. Moreover, the initial reactions of 1 after elimination of the [Li(THF)(2)](+) groups by chelating ligands (e.g., TMEDA or 12-crown-4) are presented. Collision induced dissociation experiments in the gas phase, employing FT-ICR mass spectrometry, lead to the elimination of the singlet biradicaloid Ge(5)H(2)[Si(SiMe(3))(3)](2) cluster. The unique multiradicaloid bonding character of the metalloid cluster 1 might be used as a model for reactions and properties in the field of surface science and nanotechnology.

Reconstructing the history of mining and remediation in the Coeur d'Alene, Idaho Mining District using lake sediments.

PubMed

Morra, Matthew J; Carter, Meghan M; Rember, William C; Kaste, James M

2015-09-01

Mining that began in the late 1800s intensified during World War II contaminating Lake Coeur d'Alene sediments with potentially toxic elements. We used 80y of the sediment record to reconstruct metal(loid) loadings to the lake and quantitatively evaluate the effectiveness of tailings management. Sediment core analysis for pollen, chronological markers, and metal(loid)s permitted stratigraphic reconstruction showing that contaminant loading decreased after tailings pond construction, but that most metal(loid) concentrations exceed recommended limits. Arsenic concentrations (250-450 mg kg(-)(1)) at the sediment-water interface are potentially toxic; however, low P concentrations in recent sediments (1.0-1.4 mg kg(-)(1)) inhibit eutrophication and the concomitant release of soluble As. Zinc (3 g kg(-)(1)), Cd (10 mg kg(-)(1)), Ag (10 mg kg(-)(1)), and Cu (90 mg kg(-)(1)) concentrations are now lower than in sediments deposited during active mining, but remain an environmental concern. Sedimentary Cr and Pb concentrations have not changed in the last 50y, because tailings continue to enter the lake. Although modern Cr concentrations (40 mg kg(-)(1)) are unlikely to cause toxicity, current Pb concentrations (4 g kg(-)(1)) exceed acceptable limits, creating challenges for remediation. Strategies to manage other mining-contaminated watersheds should include consideration of elemental differences when evaluating remediation effectiveness. Copyright © 2015 Elsevier Ltd. All rights reserved.

The associations between metals/metalloids concentrations in blood plasma of Hong Kong residents and their seafood diet, smoking habit, body mass index and age.

PubMed

Qin, Yan Yan; Leung, Clement Kai Man; Lin, Che Kit; Wong, Ming Hung

2015-09-01

The concentrations of metals/metalloids in blood plasma collected from 111 healthy residents (51 female, 60 male) in Hong Kong (obtained from the Hong Kong Red Cross Blood Transfusion Service, from March to April 2008) were quantified by means of a double-focusing sector field inductively coupled plasma optical emission spectrometer (ICP-OES). Results showed that concentrations of these toxic metals such as Hg, Cd, and Pb in Hong Kong residents were not serious when compared with other countries. Males accumulated significantly higher (p < 0.05 or 0.01) Fe (female 0.92 mg/L; male 1.28), Sn (0.44 μg/L; 0.60), Cr (0.77; 0.90), Hg (1.01; 1.73), and Pb (23.4; 31.6) than females. Smokers accumulated significantly higher (p < 0.05) Cd (smoker 0.27 μg/L; nonsmoker 0.17) and Pb (32.8; 17.6) than nonsmokers. Positive correlations were found between concentrations of As, Cd, Pb, and Hg, with respect to seafood diet habit, body mass index (BMI), and age. More intensive studies involving more samples are needed before a more definite conclusion can be drawn, especially on the causal relationships between concentrations of metals/metalloids with dietary preference and lifestyle of the general public.

The interaction of heavy metals and metalloids in the soil-plant system in the São Domingos mining area (Iberian Pyrite Belt, Portugal).

PubMed

Andráš, Peter; Matos, João Xavier; Turisová, Ingrid; Batista, Maria João; Kanianska, Radoslava; Kharbish, Sherif

2018-05-11

São Domingos belongs among the most important historic Iberian Pyrite Belt Cu mines. The anthrosoil is contaminated by a very high content of heavy metals and metalloids. The study was focused on evaluating the interaction of some chemical elements (Ca, Mg, Fe, Mn, Cu, Pb, Zn, Ag, Cd, Ni, Co, As, Sb) in the system soil vs. five autochthonous dominant plant species: Pinus pinaster Aiton, Quercus rotundifolia Lam., Agrostis sp., Juncus conglomeratus L. and Juncus effusus L. The plants are heavily contaminated by Cu, Pb, As and Zn. The bioconcentration factor proved that they exhibit features of metal tolerant excluders. The trees are accumulators of Ag, whereas the graminoids are hyper-accumulators of Ag and Juncus effusus of Co. The translocation factor confirmed that the selected elements are immobilised in the roots except for Mn and Zn in Pinus pinaster and Mn in Quercus rotundifolia and Juncus conglomeratus. The bioaccumulation of Mn, Zn and Cu at low pH increases. The increased content of Ca and Mg in the soil inhibits, in the case of some metals and metalloids, their intake to plants. Although the studied plants, despite their fitness and vitality at the contaminated sites, are not suitable for phytoextraction (except Co and Ag), they can be used for phytostabilisation at the mining habitats.

Bioaccumulation and phyto-translocation of arsenic, chromium and zinc by Jatropha curcas L.: impact of dairy sludge and biofertilizer.

PubMed

Yadav, Santosh Kumar; Juwarkar, Asha A; Kumar, G Phani; Thawale, Prashant R; Singh, Sanjeev K; Chakrabarti, Tapan

2009-10-01

The present study was planned to remediate the metalloid and metal contaminated soil by using non-edible and economic plant species Jatropha curcas L. The experiment was conducted on pots to improve the survival rate, metal tolerance and growth response of the plant on soil; having different concentrations of arsenic, chromium and zinc. The soil was amended with dairy sludge and bacterial inoculum (Azotobacter chroococcum) as biofertilizer. The results of the study showed that the bioaccumulation potential was increased with increase in metalloid and metal concentration in soil system. Application of dairy sludge significantly reduces the DTPA-extractable As, Cr and Zn concentration in soil. The application of organic amendment stabilizes the As, Cr and Zn and reduced their uptake in plant tissues.

Production of Volatile Derivatives of Metal(loid)s by Microflora Involved in Anaerobic Digestion of Sewage Sludge

PubMed Central

Michalke, K.; Wickenheiser, E. B.; Mehring, M.; Hirner, A. V.; Hensel, R.

2000-01-01

Gases released from anaerobic wastewater treatment facilities contain considerable amounts of volatile methyl and hydride derivatives of metals and metalloids, such as arsine (AsH3), monomethylarsine, dimethylarsine, trimethylarsine, trimethylbismuth (TMBi), elemental mercury (Hg0), trimethylstibine, dimethyltellurium, and tetramethyltin. Most of these compounds could be shown to be produced by pure cultures of microorganisms which are representatives of the anaerobic sewage sludge microflora, i.e., methanogenic archaea (Methanobacterium formicicum, Methanosarcina barkeri, Methanobacterium thermoautotrophicum), sulfate-reducing bacteria (Desulfovibrio vulgaris, D. gigas), and a peptolytic bacterium (Clostridium collagenovorans). Additionally, dimethylselenium and dimethyldiselenium could be detected in the headspace of most of the pure cultures. This is the first report of the production of TMBi, stibine, monomethylstibine, and dimethylstibine by a pure culture of M. formicicum. PMID:10877769

Blood and urinary levels of metals and metalloids in the general adult population of Northern France: The IMEPOGE study, 2008-2010.

PubMed

Nisse, Catherine; Tagne-Fotso, Romuald; Howsam, Mike; Richeval, Camille; Labat, Laurence; Leroyer, Ariane

2017-04-01

The assessment of human chemical risks related to occupational or environmental exposure to pollutants requires the use of both accurate exposure indicators and reference values. The objective of this study was to evaluate the blood and urinary levels of various metals and metalloids in a sample of adults aged 20-59 years of the general population of Northern France, a formerly heavily industrialised area that retains some industrial activity. A cross-sectional study was conducted between 2008 and 2010, enrolling 2000 residents of Northern France. The quota method was used to guarantee the representativeness of the participants on a sex, age, social category and smoking status basis, according to the census done by the French National Institute of Statistics and Economic Studies. The levels of 14 metals: aluminium (Al), antimony (Sb), total arsenic (As), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), thallium (Tl), vanadium (V) and zinc (Zn) were quantified by ICP-MS in urine and blood samples. A total of 982 men and 1018 women participated, allowing the analysis of 1992 blood and 1910 urine samples. Some metal(loid)s were detected in over 99% of the blood (Cd, Co, Mn, Ni, Pb) and urine (As, Co, Pb, Zn) samples and the remaining metals in 84-99% of the samples, with the exception of blood V (19%), blood Be (57%) and urine Be (58%). Mean blood levels of Pb and Zn were significantly higher in men, and Mn, Co and Cr in women. In urine, mean Pb, Tl and Sb concentrations were significantly higher in men, and Al and Co in women. Current smokers had significantly higher mean levels of blood Cd and Pb and lower blood Co, Mn and Hg. In urine (adjusted on urinary creatinine), the smokers had higher mean levels of Cd, Pb, V and Zn and lower mean levels of As, Co, and Hg. Overall, the mean urinary levels of most metal(loid)s found in the general population of Northern France were higher than those found in the French national survey for the same period except for urinary V. Mean blood lead level was markedly less than that of the French national population. This first biomonitoring survey of a large number of metal(loid)s in the general population of Northern France provides useful information on exposure levels to toxic elements and highlights the specificity of the regional environment. These data could be used, in complement to the national human biomonitoring reference values, for the interpretation of biomonitoring results. Copyright © 2016 Elsevier GmbH. All rights reserved.

Association between heavy metal and metalloid levels in topsoil and cancer mortality in Spain.

PubMed

Núñez, Olivier; Fernández-Navarro, Pablo; Martín-Méndez, Iván; Bel-Lan, Alejandro; Locutura Rupérez, Juan F; López-Abente, Gonzalo

2017-03-01

Spatio-temporal cancer mortality studies in Spain have revealed patterns for some tumours which display a distribution that is similar across the sexes and persists over time. Such characteristics would be common to tumours that shared risk factors, including the geochemical composition of the soil. The aim of this study was to assess the possible association between heavy metal and metalloid levels in topsoil (upper soil horizon) and cancer mortality in mainland Spain. Ecological cancer mortality study at a municipal level, covering 861,440 cancer deaths (27 different tumour locations) in 7917 Spanish mainland towns, from 1999 to 2008. The elements included in this analysis were Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Topsoil levels (partial extraction) were determined by ICP-MS at 13,317 sampling points. For the analysis, the data on the topsoil composition have been transformed by the centred logratio (clr-transformation). Principal factor analysis was performed to obtain independent latent factors for the transformed variables. To estimate the effect of heavy metal levels in topsoil composition on mortality, we fitted Besag, York and Mollié models, which included each town's factor scores as the explanatory variable. Integrated Nested Laplace Approximation (INLA) was used as a tool for Bayesian inference. All results were adjusted for sociodemographic variables. The results showed an association between trace contents of heavy metals and metalloids in topsoil and mortality due to tumours of the digestive system in mainland Spain. This association was observed in both sexes, something that would support the hypothesis that the incorporation of heavy metals into the trophic chain might be playing a role in the aetiology of some types of cancer. Topsoil composition and the presence of potentially toxic elements in trace concentrations might be an additional component in the aetiology of some types of cancer, and go some way to determine the ensuing geographic differences in mortality in Spain. The results support the interest of inclusion of heavy metal levels in topsoil as a hypothesis in analytical epidemiological studies using biological markers of exposure to heavy metals and metalloids.

Coordinated role of soluble and cell wall bound phenols is a key feature of the metabolic adjustment in a mining woody fleabane (Dittrichia viscosa L.) population under semi-arid conditions.

PubMed

López-Orenes, Antonio; Bueso, María C; Párraga-Aguado, Isabel M; Calderón, Antonio A; Ferrer, María A

2018-03-15

Environmental contamination by hazardous heavy metals/metalloids (metal(loid)s) is growing worldwide. To restrict the migration of toxic contaminants, the establishment of a self-sustainable plant cover is required. Plant growth in multi-polluted soils is a challenging issue not only by metal(loid) toxicities, but also by the co-occurrence of other stressors. Dittrichia viscosa is a pioneer Mediterranean species able to thrive in metal(loid)-enriched tailings in semi-arid areas. The aim of the present work was to examine the metabolic adjustments involved in the acclimation responses of this plant to conditions prevailing in mine-tailings during Mediterranean spring and summer. For this purpose, fully-expanded leaves, and rhizosphere soil of both mining and non-mining populations of D. viscosa grown spontaneously in south-eastern Spain were sampled in two consecutive years. Quantitative analysis of >50 biochemical, physiological and edaphic parameters were performed, including nutrient status, metal(loid) contents, leaf redox components, primary and secondary metabolites, salicylic acid levels, and soil physicochemical properties. Results showed that mining plants exhibited high foliar Zn/Pb co-accumulation capacity, without substantially affecting their photosynthetic metabolism or nutritional status even in the driest summer period. The comparison of the antioxidative/oxidative profile between mining and non-mining D. viscosa populations revealed no major seasonal changes in the content of primary antioxidants (ascorbate and GSH), or in the levels of ROS. Multivariate analysis showed that phenylalanine ammonia-lyase (PAL) and peroxidase (PRX) activities and soluble and cell wall-bound phenols were potential biomarkers for discriminating between both populations. During the dry season, a marked enhancement in the activity of both PAL and soluble PRX resulted in both a drop in the accumulation of soluble phenols and an increase of the strong metal chelator caffeic acid in the cell-wall fraction, supporting the view that the plasticity of phenylpropanoid metabolism provide an effective way to counteract the effects of stress combinations. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of lead, cadmium, arsenic, and mercury co-exposure on children's intelligence quotient in an industrialized area of southern China.

PubMed

Pan, Shangxia; Lin, Lifeng; Zeng, Fan; Zhang, Jianpeng; Dong, Guanghui; Yang, Boyi; Jing, You; Chen, Shejun; Zhang, Gan; Yu, Zhiqiang; Sheng, Guoying; Ma, Huimin

2018-04-01

Exposure to metal(loid)s can lead to adverse effects on nervous system in children. However, little is known about the possible interaction effects of simultaneous exposure to multiple metal(loid)s on children's intelligence. In addition, relationship between blood lead concentrations (<100 μg/L) and the intelligence of children over 5 years needs further epidemiological evidence. We recruited 530 children aged 9-11 years, including 266 living in a town near an industrialized area and 264 from another town in the same city in South China as a reference. The levels of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) in blood (BPb, BCd, BAs, BHg) and urine (UPb, UCd, UAs, UHg) were assessed, as well as children's intelligence quotient (IQ). A significant decrease in IQ scores was identified in children from the industrialized town (p < .05), who had statistically higher geometric mean concentrations of BPb, BCd, UPb, UCd and UHg (65.89, 1.93, 4.04, 1.43 and 0.37 μg/L, respectively) compared with children from the reference town (37.21, 1.07, 2.14, 1.02 and 0.30 μg/L, respectively, p < .05). After adjusting confounders, only BPb had a significant negative association with IQ (B = -0.10, 95% confidence interval: -0.15 to -0.05, p < .001), which indicated that IQ decreased 0.10 points when BPb increased 1 μg/L. Significant negative interactions between BAs and BHg, positive interaction between UPb and UCd on IQ were observed (p < .10), and BPb <100 μg/L still negatively affected IQ (p < .05). Our findings suggest that although only BPb causes a decline in children's IQ when simultaneously exposed to these four metal(loid)s at relatively low levels, interactions between metal(loid)s on children's IQ should be paid special attention, and the reference standard in China of 100 μg/L BPb for children above 5 years old should be revised. Copyright © 2017 Elsevier Ltd. All rights reserved.

Risk Assessment and Source Identification of 17 Metals and Metalloids on Soils from the Half-Century Old Tungsten Mining Areas in Lianhuashan, Southern China.

PubMed

Guo, Li; Zhao, Weituo; Gu, Xiaowen; Zhao, Xinyun; Chen, Juan; Cheng, Shenggao

2017-11-29

Background: Mining activities always emit metal(loid)s into the surrounding environment, where their accumulation in the soil may pose risks and hazards to humans and ecosystems. Objective : This paper aims to determine of the type, source, chemical form, fate and transport, and accurate risk assessment of 17 metal(loid) contaminants including As, Cd, Cu, Ni, Pb, Zn, Cr, Ag, B, Bi, Co, Mo, Sb, Ti, V, W and Sn in the soils collected from an abandoned tungsten mining area, and to guide the implementing of appropriate remediation strategies. Methods : Contamination factors ( CFs ) and integrated pollution indexes ( IPIs ) and enrichment factors ( EFs ) were used to assess their ecological risk and the sources were identified by using multivariate statistics analysis, spatial distribution investigation and correlation matrix. Results : The IPI and EF values indicated the soils in the mine site and the closest downstream one were extremely disturbed by metal(loid)s such as As, Bi, W, B, Cu, Pb and Sn, which were emitted from the mining wastes and acid drainages and delivered by the runoff and human activities. Arsenic contamination was detected in nine sites with the highest CF values at 24.70 next to the mining site. The Cd contamination scattered in the paddy soils around the resident areas with higher fraction of bioavailable forms, primarily associated with intense application of phosphorus fertilizer. The lithogenic elements V, Ti, Ag, Ni, Sb, Mo exhibit low contamination in all sampling points and their distribution were depended on the soil texture and pedogenesis process. Conclusions : The long term historical mining activities have caused severe As contamination and higher enrichment of the other elements of orebody in the local soils. The appropriate remediation treatment approach should be proposed to reduce the bioavailability of Cd in the paddy soils and to immobilize As to reclaim the soils around the mining site. Furthermore, alternative fertilizing way and irrigating water sources are urgencies to reduce the input of Cd and As into the local soils effectively.

Risk Assessment and Source Identification of 17 Metals and Metalloids on Soils from the Half-Century Old Tungsten Mining Areas in Lianhuashan, Southern China

PubMed Central

Guo, Li; Zhao, Weituo; Gu, Xiaowen; Zhao, Xinyun; Chen, Juan; Cheng, Shenggao

2017-01-01

Background: Mining activities always emit metal(loid)s into the surrounding environment, where their accumulation in the soil may pose risks and hazards to humans and ecosystems. Objective: This paper aims to determine of the type, source, chemical form, fate and transport, and accurate risk assessment of 17 metal(loid) contaminants including As, Cd, Cu, Ni, Pb, Zn, Cr, Ag, B, Bi, Co, Mo, Sb, Ti, V, W and Sn in the soils collected from an abandoned tungsten mining area, and to guide the implementing of appropriate remediation strategies. Methods: Contamination factors (CFs) and integrated pollution indexes (IPIs) and enrichment factors (EFs) were used to assess their ecological risk and the sources were identified by using multivariate statistics analysis, spatial distribution investigation and correlation matrix. Results: The IPI and EF values indicated the soils in the mine site and the closest downstream one were extremely disturbed by metal(loid)s such as As, Bi, W, B, Cu, Pb and Sn, which were emitted from the mining wastes and acid drainages and delivered by the runoff and human activities. Arsenic contamination was detected in nine sites with the highest CF values at 24.70 next to the mining site. The Cd contamination scattered in the paddy soils around the resident areas with higher fraction of bioavailable forms, primarily associated with intense application of phosphorus fertilizer. The lithogenic elements V, Ti, Ag, Ni, Sb, Mo exhibit low contamination in all sampling points and their distribution were depended on the soil texture and pedogenesis process. Conclusions: The long term historical mining activities have caused severe As contamination and higher enrichment of the other elements of orebody in the local soils. The appropriate remediation treatment approach should be proposed to reduce the bioavailability of Cd in the paddy soils and to immobilize As to reclaim the soils around the mining site. Furthermore, alternative fertilizing way and irrigating water sources are urgencies to reduce the input of Cd and As into the local soils effectively. PMID:29186069

Arsenic Methyltransferase

EPA Science Inventory

The metalloid arsenic enters the environment by natural processes (volcanic activity, weathering of rocks) and by human activity (mining, smelting, herbicides and pesticides). Although arsenic has been exploited for homicidal and suicidal purposes since antiquity, its significan...

Extraction of metals and/or metalloids from acidic media using supercritical fluids and salts

DOEpatents

Wai, Chien M.; Smart, Neil G.; Lin, Yuehe

1998-01-01

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent is described. The chelating agent forms chelates that are soluble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent comprises a trialkyl phosphate, a triaryl phosphate, a trialkylphosphine oxide, a triarylphosphine oxide, or mixtures thereof. The method provides an environmentally benign process for removing contaminants from industrial waste. The method is particularly useful for extracting actinides from acidic solutions, and the process can be aided by the addition of nitrate salts. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Physiological impacts of soil pollution and arsenic uptake in three plant species: Agrostis capillaris, Solanum nigrum and Vicia faba.

PubMed

Austruy, A; Wanat, N; Moussard, C; Vernay, P; Joussein, E; Ledoigt, G; Hitmi, A

2013-04-01

In order to revegetate an industrial soil polluted by trace metals and metalloids (As, Pb, Cu, Cd, Sb), the impact of pollution on three plant species, Solanum nigrum and Agrostis capillaris, both native species in an industrial site, and Vicia faba, a plant model species, is studied. Following the study of soil pollution from the industrial wasteland of Auzon, it appears that the As is the principal pollutant. Particular attention is given to this metalloid, both in its content and its speciation in the soil that the level of its accumulation in plants. In V. faba and A. capillaris, the trace metals and metalloids inhibit the biomass production and involve a lipid peroxidation in the leaves. Furthermore, these pollutants cause a photosynthesis perturbation by stomatal limitations and a dysfunction of photosystem II. Whatever the plant, the As content is less than 0.1 percent of dry matter, the majority of As absorbed is stored in the roots which play the role of trap organ. In parallel, the culture of S. nigrum decreases significantly the exchangeable and weakly adsorbed fraction of As in rhizospheric soil. This study has highlighted the ability of tolerance to trace metals of S. nigrum and to a lesser extent A. capillaris. Our data indicate that V. faba is not tolerant to soil pollution and is not a metallophyte species. Copyright © 2012 Elsevier Inc. All rights reserved.

High mobilization of arsenic, metals and rare earth elements in seepage waters driven by respiration of old allochthonous organic carbon.

PubMed

Weiske, Arndt; Schaller, Jörg; Hegewald, Tilo; Machill, Susanne; Werner, Ingo; Dudel, E Gert

2013-12-01

Metal and metalloid mobilization processes within seepage water are of major concern in a range of water reservoir systems. The mobilization process of arsenic and heavy metals within a dam and sediments of a drinking water reservoir was investigated. Principle component analysis (PCA) on time series data of seepage water showed a clear positive correlation of arsenic with iron and DOC (dissolved organic carbon), and a negative correlation with nitrate due to respiratory processes. A relationship of reductive metal and metalloid mobilization with respiration of old carbon was shown. The system is influenced by sediment layers as well as a recent DOC input from degraded ombrotrophic peatbogs in the catchment area. The isotopic composition ((12)C, (13)C and (14)C) of DOC is altered along the path from basin to seepage water, but no significant changes in structural parameters (LC-OCD-OND, FT-IR) could be seen. DIC (dissolved inorganic carbon) in seepage water partly originates from respiratory processes, and a higher relationship of it with sediment carbon than with the DOC inventory of infiltrating water was found. This study revealed the interaction of respiratory processes with metal and metalloid mobilization in sediment water flows. In contrast to the presumption that emerging DOC via respiratory processes mainly controls arsenic and metal mobilization it could be shown that the presence of aged carbon compounds is essential. The findings emphasize the importance of aged organic carbon for DOC, DIC, arsenic and metal turnover.

Higher trophic level affects nutrient, silicon, metal(loid), and radionuclide mobilization from freshwater sediments

NASA Astrophysics Data System (ADS)

Schaller, Jörg; Planer-Friedrich, Britta

2017-04-01

Organic sediments in aquatic ecosystems are well known sinks for nutrients, silicon, and metal(loid)s. Organic matter-decomposing organisms like invertebrate shredders, grazers, bioturbators, and filter feeder are key-species for the carbon and energy turnover within the decomposer community. We could show that invertebrate shredders and grazer affect element fixation or remobilization by changing binding properties of organic sediments and the attached biofilm. Bioturbators affect element fixation or remobilization by changing redox conditions within the uppermost sediment layer. Last but not least filter feeders, like the zebra mussel Dreissena polymorpha, an invasive organism in North American and European freshwater ecosystems significantly contributed to element mobilization of silicon, iron, phosphorus, arsenic, and copper and to immobilization of uranium (p<0.001), probably driven by redox conditions, microbial activity within the gut system, or active control of element homeostasis. Except of the filter feeder D. polymorpha, the invertebrates are able to minimize the accumulation of non-nutrient elements due to specific strategies, which is an important strategy for species living in systems tending to element accumulation. However, D. polymorpha revealed a significant uptake and accumulation of arsenic, copper, iron, and especially uranium both into the soft body tissues and the seashell. This accumulation by D. polymorpha is in line with previous observations of metal(loid) accumulation from biomonitoring studies. In summary, higher trophic level strongly contributes to element fixation or remobilization in aquatic systems.

Assessment of edibility and effect of arbuscular mycorrhizal fungi on Solanum melongena L. grown under heavy metal(loid) contaminated soil.

PubMed

Chaturvedi, Ritu; Favas, Paulo; Pratas, João; Varun, Mayank; Paul, Manoj S

2018-02-01

Arbuscular mycorrhizal fungi (AMF) aids in plant establishment at heavy metal(loid) (HM) contaminated soils, strengthening plant defense system along with promoting growth. A pot experiment was carried out to evaluate the effect of AMF on eggplants grown under HM stress. Further, the potential health risks of HM exposure to the humans via dietary intake of eggplant were also estimated. Results showed that AMF application improved growth, biomass and antioxidative defense response of plants against HM stress. Significant difference (p ≤ 0.001) in parameters under study was found on increasing metal dose and on application of AMF. Among metal(loid)s maximum uptake was recorded for Pb (29.64mgkg - 1 in roots; 23.08mgkg - 1 in shoot) followed by As (3.84mgkg - 1 in roots; 8.20mgkg - 1 in shoot) and, Cd (0.96mgkg - 1 in roots; 2.12mgkg - 1 in shoot). Based on the accumulation of HM in edible part, Hazard Quotient (HQ) was calculated. HQ was found to be > 1 for Pb, which highlights the risks associated with consumption of Eggplants grown on Pb contaminated soil. However this potential, which was further enhanced by application of AMF, can be harnessed for on-site remediation of Pb contaminated soils. The content of Cd and As in the edible part was found to be within safe limits (HQ < 1) when compared to chronic reference dose stated by USEPA. Copyright © 2017 Elsevier Inc. All rights reserved.

Particle-size dependence on metal(loid) distributions in mine wastes: Implications for water contamination and human exposure

USGS Publications Warehouse

Kim, C.S.; Wilson, K.M.; Rytuba, J.J.

2011-01-01

The mining and processing of metal-bearing ores has resulted in contamination issues where waste materials from abandoned mines remain in piles of untreated and unconsolidated material, posing the potential for waterborne and airborne transport of toxic elements. This study presents a systematic method of particle size separation, mass distribution, and bulk chemical analysis for mine tailings and adjacent background soil samples from the Rand historic mining district, California, in order to assess particle size distribution and related trends in metal(loid) concentration as a function of particle size. Mine tailings produced through stamp milling and leaching processes were found to have both a narrower and finer particle size distribution than background samples, with significant fractions of particles available in a size range (???250 ??m) that could be incidentally ingested. In both tailings and background samples, the majority of trace metal(loid)s display an inverse relationship between concentration and particle size, resulting in higher proportions of As, Cr, Cu, Pb and Zn in finer-sized fractions which are more susceptible to both water- and wind-borne transport as well as ingestion and/or inhalation. Established regulatory screening levels for such elements may, therefore, significantly underestimate potential exposure risk if relying solely on bulk sample concentrations to guide remediation decisions. Correlations in elemental concentration trends (such as between As and Fe) indicate relationships between elements that may be relevant to their chemical speciation. ?? 2011 Elsevier Ltd.

Characterization of iron and manganese minerals and their associated microbiota in different mine sites to reveal the potential interactions of microbiota with mineral formation.

PubMed

Park, Jin Hee; Kim, Bong-Soo; Chon, Chul-Min

2018-01-01

Different environmental conditions such as pH and dissolved elements of mine stream induce precipitation of different minerals and their associated microbial community may vary. Therefore, mine precipitates from various environmental conditions were collected and their associated microbiota were analyzed through metagenomic DNA sequencing. Various Fe and Mn minerals including ferrihydrite, schwertmannite, goethite, birnessite, and Mn-substituted δ-FeOOH (δ-(Fe 1-x , Mn x )OOH) were found in the different environmental conditions. The Fe and Mn minerals were enriched with toxic metal(loid)s including As, Cd, Ni and Zn, indicating they can act as scavengers of toxic metal(loid)s in mine streams. Under acidic conditions, Acidobacteria was dominant phylum and Gallionella (Fe oxidizing bacteria) was the predominant genus in these Fe rich environments. Manganese oxidizing bacteria, Hyphomicrobium, was found in birnessite forming environments. Leptolyngbya within Cyanobacteria was found in Fe and Mn oxidizing environments, and might contribute to Fe and Mn oxidation through the production of molecular oxygen. The potential interaction of microbial community with minerals in mine sites can be traced by analysis of microbial community in different Fe and Mn mineral forming environments. Iron and Mn minerals contribute to the removal of toxic metal(loid)s from mine water. Therefore, the understanding characteristics of mine precipitates and their associated microbes helps to develop strategies for the management of contaminated mine water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geochemical and mineralogical characterization of a neutral, low-sulfide/high-carbonate tailings impoundment, Markušovce, eastern Slovakia.

PubMed

Hiller, Edgar; Petrák, Marián; Tóth, Roman; Lalinská-Voleková, Bronislava; Jurkovič, L'ubomír; Kučerová, Gabriela; Radková, Anežka; Sottník, Peter; Vozár, Jaroslav

2013-11-01

Tailings deposits generated from mining activities represent a potential risk for the aquatic environment through the release of potentially toxic metals and metalloids occurring in a variety of minerals present in the tailings. Physicochemical and mineralogical characteristics of tailings such as total concentrations of chemical elements, pH, ratio of acid-producing to acid-neutralizing minerals, and primary and secondary mineral phases are very important factors that control the actual release of potentially toxic metals and metalloids from the tailings to the environment. The aims of this study are the determination of geochemical and mineralogical characteristics of tailings deposited in voluminous impoundment situated near the village of Markušovce (eastern Slovakia) and identification of the processes controlling the mobility of selected toxic metals (Cu, Hg) and metalloids (As, Sb). The studied tailings have unique features in comparison with the other tailings investigated previously because of the specific mineral assemblage primarily consisting of barite, siderite, quartz, and minor sulfides. To meet the aims, samples of the tailings were collected from 3 boreholes and 15 excavated pits and subjected to bulk geochemical analyses (i.e., determination of chemical composition, pH, Eh, acid generation, and neutralization potentials) combined with detailed mineralogical characterization using optical microscopy, X-ray diffraction (XRD), electron microprobe analysis (EMPA), and micro-X-ray diffraction (μ-XRD). Additionally, the geochemical and mineralogical factors controlling the transfer of potentially toxic elements from tailings to waters were also determined using short-term batch test (European norm EN 12457), sampling of drainage waters and speciation-equilibrium calculations performed with PHREEQC. The tailings mineral assemblage consists of siderite, barite, quartz, and dolomite. Sulfide minerals constitute only a minor proportion of the tailings mineral assemblage and their occurrence follows the order: chalcopyrite > pyrite > tetrahedrite>arsenopyrite. The mineralogical composition of the tailings corresponds well to the primary mineralization mined. The neutralization capacity of the tailings is high, as confirmed by the values of neutralization potential to acid generation potential ratio, ranging from 6.7 to 63.9, and neutral to slightly alkaline pH of the tailings (paste pH 7.16-8.12) and the waters (pH 7.00-8.52). This is explained by abundant occurrence of carbonate minerals in the tailings, which readily neutralize the acidity generated by sulfide oxidation. The total solid-phase concentrations of metal(loid)s decrease as Cu>Sb>Hg>As and reflect the proportions of sulfides present in the tailings. Sulfide oxidation generally extends to a depth of 2 m. μ-XRD and EMPA were used to study secondary products developed on the surface of sulfide minerals and within the tailings. The main secondary minerals identified are goethite and X-ray amorphous Fe oxyhydroxides and their occurrence decreases with increasing tailings depth. Secondary Fe phases are found as mineral coatings or individual grains and retain relatively high amounts of metal(loid)s (up to 57.6 wt% Cu, 1.60 wt% Hg, 23.8 wt% As, and 2.37 wt% Sb). Based on batch leaching tests and lysimeter results, the mobility of potentially toxic elements in the tailings is low. The limited mobility of metals and metalloids is due to their retention by Fe oxyhydroxides and low solubilities of metal(loid)-bearing sulfides. The observations are consistent with PHREEQC calculations, which predict the precipitation of Fe oxyhydroxides as the main solubility-controlling mineral phases for As, Cu, Hg, and Sb. Waters discharging from tailings impoundment are characterized by a neutral to slightly alkaline pH (7.52-7.96) and low concentrations of dissolved metal(loid)s (<5-7.0 μg/L Cu, <0.1-0.3 μg/L Hg, 5.0-16 μg/L As, and 5.0-43 μg/L Sb). Primary factors influencing aqueous chemistry at the site are mutual processes of sulfide oxidation and carbonate dissolution as well as precipitation reactions and sorption onto hydrous ferric oxides abundantly present at the discharge of the impoundment waters. The results of the study show that, presently, there are no threats of acid mine drainage formation at the site and significant contamination of natural aquatic ecosystem in the close vicinity of the tailings impoundment.

Periodic Table of Elements: Los Alamos National Laboratory

Science.gov Websites

Highlighted in Huffington Post 12/6/17 Quantum dots amplify light with electrical pumping 11/20/17 Josh Smith Actinides Transition metals Nonmetals Post-transition metals Halogens Metalloid Noble gases Contact

Effect of rhizobacteria on arsenic uptake by macrophyte Eichhornia crassipes (Mart.) Solms.

PubMed

Kaur, Parvinder; Singh, Simranjeet; Kumar, Vivek; Singh, Nasib; Singh, Joginder

2018-01-28

Wastewater flowing in streams and nallahs across India carries several trace metals, including metalloid arsenic (As), which are considered serious environmental contaminants due to their toxicity, and recalcitrant nature. In this study, we determined the phytoremediation of As by Eichhornia crassipes (Mart.) Solms either alone or in association with plant growth-promoting rhizobacteria. Pseudomonas and Azotobacter inoculation to E. crassipes resulted in enhanced As removal compared to uninoculated control. Co-inoculation with a consortium of Pseudomonas, Azotobacter, Azospirillum, Actinomyces, and Bacillus resulted in a higher As (p < 0.05) phytoaccumulation efficiency. P. aeruginosa strain jogii was found particularly effective in augmenting As removal by E. crassipes. Our findings indicate that the synergistic association of E. crassipes and various rhizobacteria is an effective strategy to enhance removal of As and thus may be utilized as an efficient biological alternative for the removal of this metalloid from wastewaters.

Fluid extraction using carbon dioxide and organophosphorus chelating agents

DOEpatents

Smart, N.G.; Wai, C.M.; Lin, Y.; Kwang, Y.H.

1998-11-24

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO{sub 2}, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO{sub 2} and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process. 1 fig.

Extraction of metals and/or metalloids from acidic media using supercritical fluids and salts

DOEpatents

Wai, C.M.; Smart, N.G.; Lin, Y.

1998-06-23

A method is described for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent. The chelating agent forms chelates that are soluble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent comprises a trialkyl phosphate, a triaryl phosphate, a trialkylphosphine oxide, a triarylphosphine oxide, or mixtures thereof. The method provides an environmentally benign process for removing contaminants from industrial waste. The method is particularly useful for extracting actinides from acidic solutions, and the process can be aided by the addition of nitrate salts. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

Fluid extraction using carbon dioxide and organophosphorus chelating agents

DOEpatents

Smart, Neil G.; Wai, Chien M.; Lin, Yuehe; Kwang, Yak Hwa

1998-01-01

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

Precision synthesis of colloidal inorganic nanocrystals using metal and metalloid amides

NASA Astrophysics Data System (ADS)

Yarema, Maksym; Caputo, Riccarda; Kovalenko, Maksym V.

2013-08-01

Rational selection of molecular precursors is the key consideration in the synthesis of inorganic nanocrystals and nanoparticles. This review highlights the state-of-the-art and future potential of metal amides as precursors in the solution-phase synthesis of monodisperse colloidal nanocrystals of metals and metal alloys, as well as metal oxides and chalcogenides. We exclusively focus on homoleptic metal and metalloid alkylamides M(NR2)n and silylamides M[N(SiMe3)2]n as predominant choice of element-nitrogen bonded precursors, which are often advantageous to commonly used metal-oxygen and metal-carbon bonded counterparts. In particular, these amides are highly reactive in oxidation, reduction and metathesis reactions; they are oxygen-free, easy-to-make and/or commercially available. A comprehensive literature review is complemented by our theoretical studies on the thermal stability of metal silylamides using molecular dynamics simulations.

Polymer functionalized nanocomposites for metals removal from water and wastewater: An overview.

PubMed

Lofrano, Giusy; Carotenuto, Maurizio; Libralato, Giovanni; Domingos, Rute F; Markus, Arjen; Dini, Luciana; Gautam, Ravindra Kumar; Baldantoni, Daniela; Rossi, Marco; Sharma, Sanjay K; Chattopadhyaya, Mahesh Chandra; Giugni, Maurizio; Meric, Sureyya

2016-04-01

Pollution by metal and metalloid ions is one of the most widespread environmental concerns. They are non-biodegradable, and, generally, present high water solubility facilitating their environmental mobilisation interacting with abiotic and biotic components such as adsorption onto natural colloids or even accumulation by living organisms, thus, threatening human health and ecosystems. Therefore, there is a high demand for effective removal treatments of heavy metals, making the application of adsorption materials such as polymer-functionalized nanocomposites (PFNCs), increasingly attractive. PFNCs retain the inherent remarkable surface properties of nanoparticles, while the polymeric support materials provide high stability and processability. These nanoparticle-matrix materials are of great interest for metals and metalloids removal thanks to the functional groups of the polymeric matrixes that provide specific bindings to target pollutants. This review discusses PFNCs synthesis, characterization and performance in adsorption processes as well as the potential environmental risks and perspectives. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth

PubMed Central

Bentley, Ronald; Chasteen, Thomas G.

2002-01-01

A significant 19th century public health problem was that the inhabitants of many houses containing wallpaper decorated with green arsenical pigments experienced illness and death. The problem was caused by certain fungi that grew in the presence of inorganic arsenic to form a toxic, garlic-odored gas. The garlic odor was actually put to use in a very delicate microbiological test for arsenic. In 1933, the gas was shown to be trimethylarsine. It was not until 1971 that arsenic methylation by bacteria was demonstrated. Further research in biomethylation has been facilitated by the development of delicate techniques for the determination of arsenic species. As described in this review, many microorganisms (bacteria, fungi, and yeasts) and animals are now known to biomethylate arsenic, forming both volatile (e.g., methylarsines) and nonvolatile (e.g., methylarsonic acid and dimethylarsinic acid) compounds. The enzymatic mechanisms for this biomethylation are discussed. The microbial conversion of sodium arsenate to trimethylarsine proceeds by alternate reduction and methylation steps, with S-adenosylmethionine as the usual methyl donor. Thiols have important roles in the reductions. In anaerobic bacteria, methylcobalamin may be the donor. The other metalloid elements of the periodic table group 15, antimony and bismuth, also undergo biomethylation to some extent. Trimethylstibine formation by microorganisms is now well established, but this process apparently does not occur in animals. Formation of trimethylbismuth by microorganisms has been reported in a few cases. Microbial methylation plays important roles in the biogeochemical cycling of these metalloid elements and possibly in their detoxification. The wheel has come full circle, and public health considerations are again important. PMID:12040126

In situ trapping of As, Sb and Se hydrides on nanometer-sized ceria-coated iron oxide-silica and slurry suspension introduction to ICP-OES.

PubMed

Dados, A; Kartsiouli, E; Chatzimitakos, Th; Papastephanou, C; Stalikas, C D

2014-12-01

A procedure is developed for the analysis of sub-μg L(-1) levels of arsenic, antimony and selenium after preconcentration of their hydrides. The study highlights the capability of an aqueous suspension of a nanometer-sized magnetic ceria, in the presence of iodide, to function as a sorbent for the in situ trapping and preconcentration of the hydrides of certain metalloids. After extraction, the material is magnetically separated from the trapping solution and analyzed. A slurry suspension sampling approach with inductively coupled plasma-optical emission spectrometry (ICP-OES) is employed for measurements, as the quantitative elution of the adsorbed metalloids is not feasible. The whole analytical procedure consists of five steps: (i) pre-reduction of As, Sb and Se, (ii) generation of the hydrides AsH3, SbH3 and SeH2, (iii) in situ collection in the trapping suspension of magnetic ceria, (iv) isolation of the particles by applying a magnetic field, and (v) measurement of As, Sb and Se concentrations using ICP-OES. Under the established experimental conditions, the efficiency of trapping accounted for 94 ± 2%, 89 ± 2% and 98 ± 3% for As, Sb and Se, respectively, signifying the effective implementation of the overall procedure. The applicability of the procedure has been demonstrated by analyzing tap and lake water and a reference material (soft drinking water). The obtained analytical figures of merit were satisfactory for the analysis of the above metalloids in natural waters by ICP-OES. Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation of As-tolerant bacteria and their potentials of reducing As and Cd accumulation of edible tissues of vegetables in metal(loid)-contaminated soils.

PubMed

Wang, Xiaohan; Nie, Zongwei; He, Linyan; Wang, Qi; Sheng, Xiafang

2017-02-01

In this study, three As-tolerant bacteria Ralstonia eutropha Q2-8, Rhizobium tropici Q2-13, and Exiguobacterium aurantiacum Q3-11 were isolated from the rhizosphere and bulk soils of Chinese cabbage. The strains were characterized for their production of indole-3-acetic acid (IAA) and siderophores, their effects on soil metal(loid) bioavailability and organic matter content, and their effects on the edible tissue growth and metal(loid) accumulation of Chinese cabbage and radish in the metal(loid)-contaminated soil. The strains produced IAA and siderophores and increased the edible tissue biomass (ranging from 74% to 124%) of the vegetables compared to the controls. Furthermore, strain Q2-8 reduced As contents (ranging from 22% to 50%), while strains Q2-13 and Q3-11 decreased Cd contents (ranging from 21% to 53%) of the edible tissues of the vegetables compared to the controls. Strains Q2-8, Q2-13, and Q3-11 decreased the DTPA-extractable Cd contents (ranging from 16% to 41%) and increased the organic matter contents of the rhizosphere soils compared to the controls. The results showed the effects of the strains on the increased edible tissue growth and reduced As and Cd uptake of the edible tissues and highlighted the possibility to develop a new bacterial-assisted technique for reduced metal(loid) uptake of vegetables in the metal(loid)-contaminated soils. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessment of status of three water bodies in Serbia based on tissue metal and metalloid concentration (ICP-OES) and genotoxicity (comet assay).

PubMed

Sunjog, Karolina; Kolarević, Stoimir; Kračun-Kolarević, Margareta; Višnjić-Jeftić, Željka; Skorić, Stefan; Gačić, Zoran; Lenhardt, Mirjana; Vasić, Nebojša; Vuković-Gačić, Branka

2016-06-01

Metals and metalloids are natural components of the biosphere, which are not produced per se by human beings, but whose form and distribution can be affected by human activities. Like all substances, they are a contaminant if present in excess compared to background levels and/or in a form that would not normally occur in the environment. Samples of liver, gills, gonads and muscle from European chub, Squalius cephalus, were analyzed for Al, As, B, Ba, Cr, Cu, Fe, Hg, Mn, Mo, Sr and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) to highlight the importance of tissue selection in monitoring research. The comet assay or single cell gel electrophoresis (SCGE) was selected as an in vivo genotoxicity assay, a rapid and sensitive method for measuring genotoxic effects in blood, liver and gills of the European chub. Microscopic images of comets were scored using Comet IV Computer Software (Perceptive Instruments, UK). The objective of our study was to investigate two reservoirs, Zlatar and Garasi, and one river, Pestan by: (i) determining and comparing metal and metalloid concentrations in sediment, water and tissues of European chub: liver, gills, muscle and gonads (ii) comparing these findings with genotoxicity of water expressed through DNA damage of fish tissues. A clear link between the level of metals in water, sediment and tissues and between metal and genotoxicity levels at examined sites was not found. This suggests that other xenobiotics (possibly the organic compounds), contribute to DNA damage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Aquaglyceroporins: ancient channels for metalloids

PubMed Central

Bhattacharjee, Hiranmoy; Mukhopadhyay, Rita; Thiyagarajan, Saravanamuthu; Rosen, Barry P

2008-01-01

The identification of aquaglyceroporins as uptake channels for arsenic and antimony shows how these toxic elements can enter the food chain, and suggests that food plants could be genetically modified to exclude arsenic while still accumulating boron and silicon. PMID:19014407

Biogeochemical Barriers: Redox Behavior of Metals and Metalloids

EPA Science Inventory

Redox conditions and pH are arguably the most important geochemical parameters that control contaminant transport and fate in groundwater systems. Oxidation-reduction (redox) reactions mediate the chemical behavior of both inorganic and organic chemical constituents by affecting...

Evaluating the Long-Term Stability of Metals Precipitated In-Situ

EPA Science Inventory

Because metals (including metals and metalloids) cannot be destroyed, unlike organic contaminants, in-situ approaches for their removal from groundwater necessarily involves fixation/immobilization in the solid aquifer matrix. Consequently, the success of precipitation based in...

Linking Arsenic Metabolism and Toxic Effects

EPA Science Inventory

Although arsenic has been long recognized as a toxicant and a carcinogen, the molecular basis for few of its adverse effects are well understood. Like other metalloids, arsenic undergoes extensive metabolism involving oxidation state changes and formation of methyl-arsenic bonds ...

Nuclear magnetic resonance data of C36H30Br2OSb2

NASA Astrophysics Data System (ADS)

Mikhova, B. M.

This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

Nuclear magnetic resonance data of C36H30Cl2OSb2

NASA Astrophysics Data System (ADS)

Mikhova, B. M.

This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

Selenium Treatment Technologies

EPA Science Inventory

Selenium (Se) is a metalloid that is a dietary requirement in small quantities, but toxic at higher quantities. It also is known to bioaccumulate. In oxic environments, it exists as selenate (+6) and selenite (+4), both of which are soluble. Selenite will sorb more strongly to...

Trace Element Speciation and Distribution Study at Shewanella oneidensis MR-1 Biofilm/Mineral/Water Interfaces

NASA Astrophysics Data System (ADS)

Gelabert, A.; Wang, Y.; Gescher, J.; Ha, J.; Cordova, C. D.; Singer, D. M.; Spormann, A. M.; Trainor, T. P.; Eng, P. J.; Brown, G. E.

2006-12-01

Fe- and Al-(oxyhydr)oxides are among the most reactive mineral surfaces contacted by surface and ground waters, and thus they constitute important sorbents for heavy metal and metalloid ions. As microbial biofilms may be present as coatings on these minerals, they are likely to induce major changes in surface charges and sorption capacities for metal(loid) ions compared to biofilm-free mineral surfaces. In addition, the micro- environments in biofilms can be quite different from those in bulk solutions, which can enhance (or inhibit) metal adsorption on mineral surfaces and produce biominerals that are not predicted by equilibrium thermodynamics based on the bulk solution values. In order to provide a more quantitative understanding of these effects, we have carried out a study of the interaction of Zn(II), Pb(II), and As(V) with Shewanella oneidensis (wild type, EPS-deficient mutant, and ppx- and ppk-deficient mutants) grown on highly polished and oriented single crystal surfaces of α-Al2O3 (1-102) and α-Fe2O3 (0001). This gram-negative bacterium commonly found in soil and sediments can use a wide range of electron donors and terminal electron acceptors including Fe(III) and Mn(IV) oxides under anaerobic conditions. In-situ ATR-FTIR analyses and potentiometric titrations of S. oneidensis biofilm collected from a glass bead-filled column inoculated with S. oneidensis were conducted in order to determine the nature of functional groups present on the bacterial surfaces, to quantify the site densities and protonation constants for these groups, and to determine the electrostatic parameters for S. oneidensis surfaces. GI-XAFS analyses performed on BL 11-2 at SSRL, together with macroscopic metal adsorption experiments as a function of pH (2 to 6.5), metal concentration (10-3 to 10-7 M), and ionic strength (10-1 to 10-3 M), were used to determine ion speciation and local coordination environments in the biofilm and to develop a surface complexation model describing the interactions among biofilm, metal(loid)s, and mineral surfaces. The long-period X-ray Standing Wave- fluorescent yield (XSW-FY) method, performed on BL ID-13-C at the APS, was used to obtain quantitative in situ information on the partitioning of Zn(II), Pb(II), and As(V) at these interfaces as a function of pH and ion concentration. XSW-FY results show that S. oneidensis biofilms do not block reactive sites on the hematite or alumina surfaces under our experimental conditions, which is consistent with the conclusion of our previous studies on trace element distributions at Burkholderia cepacia/mineral/water interfaces. Comparison of the observed trace element partitioning measured by XSW-FY with theoretical predictions of partitioning through thermodynamic models (using binding constants of metal(loid)s with the biofilm determined in this study and published binding constants of metal(loid)s with mineral substrates) allows us to describe biofilm local microenvironments and to understand how the biofilm coatings affect the reactivity of mineral surfaces.

TOXIC TRACE METALS IN MAMMALIAN HAIR AND NAILS

EPA Science Inventory

Data have been compiled from the available world literature on the accumulation and bioconcentration of selected toxic trace metals in human hair and nails and other mammalian hair, fur, nails, claws, and hoofs. The toxic trace metals and metalloids include antimony, arsenic, bor...

MINERALOGICAL PRESERVATION OF SOLID SAMPLES COLLECTED FROM ANOXIC SUBSURFACE ENVIRONMENTS

EPA Science Inventory

Remedial technologies utilized at hazardous waste sites for the treatment of metal and metalloid contaminants often take advantage of reduction-oxidation (redox) processes to reach ground water clean up goals. This is because redox reactions, in many cases, govern the biogeochem...

Plasma deposition of amorphous metal alloys

DOEpatents

Hays, Auda K.

1986-01-01

Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

Plasma deposition of amorphous metal alloys

DOEpatents

Hays, A.K.

1979-07-18

Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

Disposition and Mechanisms of Toxicities of Metals and Metalloids

EPA Science Inventory

Dr. Hughes will provide a concise overview of general disposition (e.g., absorption) and mechanisms of toxicity of metal toxicity (e.g., direct interaction with functional groups of critical proteins, generation of reactive oxygen species, and alteration of cell signaling pathway...

Chapter4: Toxicology and Epidemiology of Arsenic and its Compounds

EPA Science Inventory

Arsenic poses numerous environmental challenges, especially in the groundwater of Bangladesh and other developing nations. As a metalloid, arsenic has the properties of both a metal and a nonmetal. In organisms, metabolism of arsenic consists ofcomplex and multiple reduction and ...

Toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus changes under a global warming perspective: Variations in air temperature and soil moisture content.

PubMed

González-Alcaraz, M Nazaret; van Gestel, Cornelis A M

2016-12-15

This study aimed to assess how the current global warming perspective, with increasing air temperature (20°C vs. 25°C) and decreasing soil moisture content (50% vs. 30% of the soil water holding capacity, WHC), affected the toxicity of a metal(loid)-polluted agricultural soil to Enchytraeus crypticus. Enchytraeids were exposed for 21d to a dilution series of the agricultural soil with Lufa 2.2 control soil under four climate situations: 20°C+50% WHC (standard conditions), 20°C+30% WHC, 25°C+50% WHC, and 25°C+30% WHC. Survival, reproduction and bioaccumulation of As, Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn were obtained as endpoints. Reproduction was more sensitive to both climate factors and metal(loid) pollution. High soil salinity (electrical conductivity~3dSm -1 ) and clay texture, even without the presence of high metal(loid) concentrations, affected enchytraeid performance especially at drier conditions (≥80% reduction in reproduction). The toxicity of the agricultural soil increased at drier conditions (10% reduction in EC10 and EC50 values for the effect on enchytraeid reproduction). Changes in enchytraeid performance were accompanied by changes in As, Fe, Mn, Pb and Zn bioaccumulation, with lower body concentrations at drier conditions probably due to greater competition with soluble salts in the case of Fe, Mn, Pb and Zn. This study shows that apart from high metal(loid) concentrations other soil properties (e.g. salinity and texture) may be partially responsible for the toxicity of metal(loid)-polluted soils to soil invertebrates, especially under changing climate conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Acid mine drainage pollution in the Tinto and Odiel rivers (Iberian Pyrite Belt, SW Spain) and bioavailability of the transported metals to the Huelva Estuary.

PubMed

Nieto, José Miguel; Sarmiento, Aguasanta M; Olías, Manuel; Canovas, Carlos R; Riba, Inmaculada; Kalman, Judit; Delvalls, T Angel

2007-05-01

The Tinto and Odiel rivers are seriously affected by acid mine drainage (AMD) from the long-term mining activities in Iberian Pyrite Belt (IPB). As a consequence, the Huelva estuary is heavily contaminated by metals and metalloids. This study presents an estimation of the seasonal variation, and the dissolved contaminant load transported by both rivers from February 2002 to September 2004. Besides, toxicity and bioaccumulation tests with the sediments of the estuary have been conducted in order to measure the mobility of the toxic metals. Results show that the Tinto and Odiel rivers transport enormous quantities of dissolved metals to the estuary: 7900 t yr(-1) of Iron (Fe), 5800 t yr(-1) Aluminium (Al), 3500 t yr(-1) Zinc (Zn), 1700 t yr(-1) Copper (Cu), 1600 t yr(-1) Manganese (Mn) and minor quantities of other metals and metalloids. These values represent 37% of the global gross flux of dissolved Zn transported by rivers in to the ocean, and 15% of the global gross flux of dissolved Cu. These metals and metalloids usually sink in the estuarine sediments due to pH and salinity changes. The increase of salinity in the estuary favours the adsorption and trapping of metals. For this reason, the mobility and bioavailability of metals such as Zn, Cd and Cu is higher in sediments located in the area of fresh water influence that in sediments located in the marine influenced area of the estuary, showing a higher percentage of fractionation and bioaccumulation of these metals in the station influenced by the fresh water environment.

A review on the importance of metals and metalloids in atmospheric dust and aerosol from mining operations.

PubMed

Csavina, Janae; Field, Jason; Taylor, Mark P; Gao, Song; Landázuri, Andrea; Betterton, Eric A; Sáez, A Eduardo

2012-09-01

Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport. Copyright © 2012 Elsevier B.V. All rights reserved.

Metal and Nutrient Distribution and Fractionation in Managed Urban Watersheds Across the US Southwest

NASA Astrophysics Data System (ADS)

Papelis, C.; Williams, A. C.; Boettcher, T. M.

2008-12-01

Metals, metalloids, and nutrients are common contaminants of concern in arid and semi-arid watersheds in the Southwestern U.S. Because of the dramatic population growth in this part of the U.S., the potential for contamination of urban watersheds has also increased over the last few decades. Streams in urban watersheds receive storm water, urban runoff, shallow groundwater, and treated wastewater, among other sources. In addition, urban watersheds are often heavily managed to mitigate flood events and sediment- related impacts. Sediment transport can have a profound effect on the water quality of affected bodies of water. However, differences in geology, hydrogeology, and land use may have dramatic effects on the distribution of nutrients and metals in different urban watersheds. To test these effects, aqueous and sediment samples were collected above and below erosion control and other structures along two heavily managed urban watersheds, namely the Las Vegas Wash in the Las Vegas Valley Watershed, Nevada, and the Rio Salado (Salt River) in the Phoenix Metropolitan Area, Arizona. The construction of such control structures has the potential to alter the distribution of metals and metalloids in bodies of water used by wildlife. In this study, all sediments were characterized by particle size distribution, specific surface area, mineralogical composition, and scanning electron microscopy. The results of total arsenic, boron, and phosphorus extractions will be discussed, as a function of sediment characteristics. Significant differences exist between the two U.S. Southwest watersheds studied, including land use, water sources, sediment characteristics, nutrient and metal distribution, and overall system complexity. These differences lead to significant variations in metalloid and nutrient distributions in the two watersheds. Differences and similarities in the two systems will be explained as a function of sediment characteristics and watershed properties.

Pollution and health risk assessment of industrial and residential area based on metal and metalloids contents in soil and sediment samples from and around the petrochemical industry, Serbia

NASA Astrophysics Data System (ADS)

Relic, Dubravka; Sakan, Sanja; Andjelkovic, Ivan; Djordjevic, Dragana

2017-04-01

Within this study the investigation of pollution state of metal and metalloids contamination in soils and sediments samples of the petrochemical and nearby residential area is present. The pseudo-total concentrations of Ba, Cd, Co, Cu, Cr, Mn, Ni, Pb, V, Zn, As, Hg, and Se were monitored with ICP/OES. The pollution indices applied in this work, such as the enrichment factor, the pollution load index, the total enrichment factor, and the ecological risk index showed that some of the soil and sediment samples were highly polluted by Hg, Ba, Pb, Cd, Cr Cu and Zn. The highest pollution indices were calculated for Hg in samples from the petrochemical area: chloralkali plant, electrolysis factory, mercury disposal area, and in samples from the waste channel. The pollution indices of the samples from the residential area indicated that this area is not polluted by investigated elements. Besides the pollution indices, the metal and metalloids concentrations were used in the equations for calculating the health risk criteria. We calculate no carcinogenic and carcinogenic risks for the composite worker and residential people by usage adequate equations. In analyzed samples, the no carcinogenic risks were lower than 1. The highest values of carcinogenic risk were obtained in sediment samples from the waste channel within the petrochemical industry and the metal that mostly contributes to the highest carcinogenic risk is Cr. Correlation analysis of pollution indices and carcinogenic risks calculated from the residential area samples showed good correlations while this is not the case for an industrial area.

Arsenic tolerance in Arabidopsis is mediated by two ABCC-type phytochelatin transporters

PubMed Central

Song, Won-Yong; Park, Jiyoung; Mendoza-Cózatl, David G.; Suter-Grotemeyer, Marianne; Shim, Donghwan; Hörtensteiner, Stefan; Geisler, Markus; Weder, Barbara; Rea, Philip A.; Rentsch, Doris; Schroeder, Julian I.; Lee, Youngsook; Martinoia, Enrico

2010-01-01

Arsenic is an extremely toxic metalloid causing serious health problems. In Southeast Asia, aquifers providing drinking and agricultural water for tens of millions of people are contaminated with arsenic. To reduce nutritional arsenic intake through the consumption of contaminated plants, identification of the mechanisms for arsenic accumulation and detoxification in plants is a prerequisite. Phytochelatins (PCs) are glutathione-derived peptides that chelate heavy metals and metalloids such as arsenic, thereby functioning as the first step in their detoxification. Plant vacuoles act as final detoxification stores for heavy metals and arsenic. The essential PC–metal(loid) transporters that sequester toxic metal(loid)s in plant vacuoles have long been sought but remain unidentified in plants. Here we show that in the absence of two ABCC-type transporters, AtABCC1 and AtABCC2, Arabidopsis thaliana is extremely sensitive to arsenic and arsenic-based herbicides. Heterologous expression of these ABCC transporters in phytochelatin-producing Saccharomyces cerevisiae enhanced arsenic tolerance and accumulation. Furthermore, membrane vesicles isolated from these yeasts exhibited a pronounced arsenite [As(III)]–PC2 transport activity. Vacuoles isolated from atabcc1 atabcc2 double knockout plants exhibited a very low residual As(III)–PC2 transport activity, and interestingly, less PC was produced in mutant plants when exposed to arsenic. Overexpression of AtPCS1 and AtABCC1 resulted in plants exhibiting increased arsenic tolerance. Our findings demonstrate that AtABCC1 and AtABCC2 are the long-sought and major vacuolar PC transporters. Modulation of vacuolar PC transporters in other plants may allow engineering of plants suited either for phytoremediation or reduced accumulation of arsenic in edible organs. PMID:21078981

Response of key soil parameters during compost-assisted phytostabilization in extremely acidic tailings: effect of plant species.

PubMed

Solís-Dominguez, Fernando A; White, Scott A; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A; Chorover, Jon; Maier, Raina M

2012-01-17

Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ∼ 2.5) metalliferous (As, Pb, Zn: 2000-3000 mg kg(-1)) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites.

A Review on the Importance of Metals and Metalloids in Atmospheric Dust and Aerosol from Mining Operations

PubMed Central

Csavina, Janae; Field, Jason; Taylor, Mark P.; Gao, Song; Landázuri, Andrea; Betterton, Eric A.; Sáez, A. Eduardo

2012-01-01

Contaminants can be transported rapidly and over relatively long distances by atmospheric dust and aerosol relative to other media such as water, soil and biota; yet few studies have explicitly evaluated the environmental implications of this pathway, making it a fundamental but understudied transport mechanism. Although there are numerous natural and anthropogenic activities that can increase dust and aerosol emissions and contaminant levels in the environment, mining operations are notable with respect to the quantity of particulates generated, the global extent of area impacted, and the toxicity of contaminants associated with the emissions. Here we review (i) the environmental fate and transport of metals and metalloids in dust and aerosol from mining operations, (ii) current methodologies used to assess contaminant concentrations and particulate emissions, and (iii) the potential health and environmental risks associated with airborne contaminants from mining operations. The review evaluates future research priorities based on the available literature and suggest that there is a particular need to measure and understand the generation, fate and transport of airborne particulates from mining operations, specifically the finer particle fraction. More generally, our findings suggest that mining operations play an important but underappreciated role in the generation of contaminated atmospheric dust and aerosol and the transport of metal and metalloid contaminants, and highlight the need for further research in this area. The role of mining activities in the fate and transport of environmental contaminants may become increasingly important in the coming decades, as climate change and land use are projected to intensify, both of which can substantially increase the potential for dust emissions and transport. PMID:22766428

Assessment of metal exposure, ecological status and required water quality monitoring strategies in small- to medium-size temperate rivers.

PubMed

Marijić, Vlatka Filipović; Perić, Mirela Sertić; Kepčija, Renata Matoničkin; Dragun, Zrinka; Kovarik, Ivana; Gulin, Vesna; Erk, Marijana

2016-01-01

The present study was undertaken to obtain a better understanding of the seasonal variability of total dissolved metal/metalloid levels and physicochemical parameters within small- to medium-size freshwater ecosystems in temperate climate region. The research was conducted in four seasons in the Sutla River, medium-size polluted, and the Črnomerec Stream, small-size unpolluted watercourse in Croatia. In the Sutla River, characterized by the rural/industrial catchment, physicochemical parameters and total dissolved metal concentrations of 21 trace and 4 macro elements were analysed downstream of the point source of pollution, the glass production facility, indicating for the first time their variability across four seasons. Based on dissolved oxygen, total dissolved solids, nutrient concentrations, conductivity and total chemical oxygen demand, quality status of the Sutla River was good, but moderate to poor during summer, what was additionally confirmed by the highest levels of the most of 25 measured metals/metalloids in summer. Comparison with the reference small-size watercourse, the Črnomerec Stream, indicated significant anthropogenic impact on the Sutla River, most evident for Fe, Mn, Mo, Ni, Pb, Rb and Tl levels (3-70-fold higher in the Sutla River across all seasons). Generally, presented results indicated significant decrease of the water quality in the anthropogenically impacted small- to medium-size watercourses in summer, regarding physicochemical water parameters and total dissolved metal/metalloid concentrations, and pointed to significant seasonality of these parameters. Confirmed seasonality of river ecological status indicates that seasonal assessment represents a prerequisite for proper classification of the water quality in small- to medium-size temperate rivers.

Response of Key Soil Parameters During Compost-Assisted Phytostabilization in Extremely Acidic Tailings: Effect of Plant Species

PubMed Central

Solís-Dominguez, Fernando A.; White, Scott A.; Hutter, Travis Borrillo; Amistadi, Mary Kay; Root, Robert A.; Chorover, Jon; Maier, Raina M.

2012-01-01

Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ~ 2.5) metalliferous (As, Pb, Zn: 2000–3000 mg kg−1) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites. PMID:22191663

The filter feeder Dreissena polymorpha affects nutrient, silicon, and metal(loid) mobilization from freshwater sediments.

PubMed

Schaller, Jörg; Planer-Friedrich, Britta

2017-05-01

Organic sediments in aquatic ecosystems are well known sinks for nutrients, silicon, and metal(loid)s. Organic matter-consuming organisms like invertebrate shredders, grazers, and bioturbators significantly affect element fixation or remobilization by changing redox conditions or binding properties of organic sediments. Little is known about the effect of filter feeders, like the zebra mussel Dreissena polymorpha, an invasive organism in North American and European freshwater ecosystems. A laboratory batch experiment exposing D. polymorpha (∼1200 organisms per m 2 ) to organic sediment from a site contaminated with arsenic, copper, lead, and uranium revealed a significant uptake and accumulation of arsenic, copper, iron, and especially uranium both into the soft body tissues and the seashell. This is in line with previous observations of metal(loid) accumulation from biomonitoring studies. Regarding its environmental impact, D. polymorpha significantly contributed to mobilization of silicon, iron, phosphorus, arsenic, and copper and to immobilization of uranium (p < 0.001), probably driven by redox conditions, microbial activity within the gut system, or active control of element homeostasis. No net mobilization or immobilization was observed for zinc and lead, because of their low mobility at the prevailing pH of 7.5-8.5. The present results suggest that D. polymorpha can both ameliorate (nutrient mobilization, immobilization of toxicants mobile under oxic conditions) or aggravate negative effects (mobilization of toxicants mobile under reducing conditions) in ecosystems. Relating the results of the present study to observed population densities in natural freshwater ecosystems suggests a significant influence of D. polymorpha on element cycling and needs to be considered in future studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advances In Assessing Bioavailability Of Metal(Loid)s In Contaminated Soils

EPA Science Inventory

The term bioavailability has many different meanings across various disciplines of toxicology and pharmacology. Often bioavailability is concerned with human health aspects such as in the case of lead (Pb) ingestion by children. However, some of the most contaminated sites are ...

Review of Phosphate in soils: Interaction with micronutrients, radionuclides, and heavy metals

USDA-ARS?s Scientific Manuscript database

Phosphate-phosphorus present in the vadose zone of soil as native, added, or residual fertilizer influences the retention, transport, and bioavailability of heavy metals, metalloids, or metallic radionuclides to aboveground vegetation, soil microorganisms, and fauna that browse that vegetation, or d...

SELENIUM MODIFIES THE METABOLISM AND TOXICITY OF ARSENIC IN PRIMARY RAT HEPATOCYTES

EPA Science Inventory

ABSTRACT
Selenium Modifies the Metabolism and Toxicity of Arsenic in Primary Rat Hepatocytes. Miroslav Styblo, David J. Thomas (2000) Toxicol. Appl. Pharmacol.
Arsenic and selenium are metalloids with similar chemical properties and metabolic fates. Inorganic arsenic (iAs...

ASSESSING SOIL ARSENIC BIOAVAILABILITY IN THE LABORATORY MOUSE

EPA Science Inventory

Variation among soils in the bioavailability of arsenic can be a critical determinant of the risk posed by exposure to these soils. Although in vitro techniques can provide vital data on aspects of bioavailability of metals and metalloids from soils, these results must be valida...

Mechanical contact induced transformation from the amorphous to the crystalline state in metallic glass

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Buckley, D. H.

1984-01-01

Friction and wear tests were conducted with 3.2- and 6.4-millimeter-diameter aluminum oxide spheres sliding, in reciprocating motion, on a Fe67Co18B14Si1 metallic foil. Crystallites with a size range of 10 to 150 nanometers were produced on the wear surface of the amorphous alloy. A strong interaction between transition metals and metalloids such as silicon and boron results in strong segregation during repeated sliding, provides preferential transition metal-metalloid clustering in the amorphous alloy, and subsequently produces the diffused honeycomb structure formed by dark grey bands and primary crystals, that is, alpha-Fe in the matrix. Large plastic flow occurs on an amorphous alloy surface with sliding and the flow film of the alloy transfers to the aluminum oxide pin surface. Multiple slip bands due to shear deformation are observed on the side of the wear track. Two distinct types of wear debris were observed as a result of sliding: an alloy wear debris, and/or powdery-whiskery oxide debris.

Seasonal variation and annual trends of metals and metalloids in the blood of the Little Penguin (Eudyptula minor).

PubMed

Finger, Annett; Lavers, Jennifer L; Orbell, John D; Dann, Peter; Nugegoda, Dayanthi; Scarpaci, Carol

2016-09-15

Little Penguins (Eudyptula minor) are high-trophic coastal feeders and are effective indicators of bioavailable pollutants in their foraging zones. Here, we present concentrations of metals and metalloids in blood of 157 Little Penguins, collected over three years and during three distinct seasons (breeding, moulting and non-breeding) at two locations: the urban St Kilda colony and the semi-rural colony at Phillip Island, Victoria, Australia. Penguin metal concentrations were foremostly influenced by location (St Kilda>Phillip Island for non-essential elements) and differed among years and seasons at both locations, reflecting differences in seasonal metal bioaccumulation or seasonal exposure through prey. Mean blood mercury concentrations showed an increasing annual trend and a negative correlation with flipper length at St Kilda. Notably, this study is the first to report on blood metal concentrations during the different stages of moult, showing the mechanism of non-essential metal mobilisation and detoxification. Copyright © 2016 Elsevier Ltd. All rights reserved.

The assessment of source attribution of soil pollution in a typical e-waste recycling town and its surrounding regions using the combined organic and inorganic dataset.

PubMed

Luo, Jie; Qi, Shihua; Xie, Xianming; Gu, X W Sophie; Wang, Jinji

2017-01-01

Guiyu is a well-known electronic waste dismantling and recycling town in south China. Concentrations and distribution of the 21 mineral elements and 16 polycyclic aromatic hydrocarbons (PAHs) collected there were evaluated. Principal component analyses (PCA) applied to the data matrix of PAHs in the soil extracted three major factors explaining 85.7% of the total variability identified as traffic emission, coal combustion, and an unidentified source. By using metallic or metalloid element concentrations as variables, five principal components (PCs) were identified and accounted for 70.4% of the information included in the initial data matrix, which can be denoted as e-waste dismantling-related contamination, two different geological origins, anthropogenic influenced source, and marine aerosols. Combining the 21 metallic and metalloid element datasets with the 16 PAH concentrations can narrow down the coarse source and decrease the unidentified contribution to soil in the present study and therefore effectively assists the source identification process.

The use of food waste-based diets and Napier grass to culture grass carp: growth performance and contaminants contained in cultured fish.

PubMed

Cheng, Zhang; Mo, Wing-Yin; Nie, Xiang-Ping; Li, Kai-Bing; Choi, Wai-Ming; Man, Yu-Bon; Wong, Ming-Hung

2016-04-01

The present study used commercial feeds, food waste feeds, Napier grass, and mixed feeds (food waste feed to Napier grass ratio, 1:10) to feed grass carp (Ctenopharyngodon idellus). The results indicated that grass carp fed with food waste feeds and mix feeds achieved growth performance (based on specific growth rate and feed conversion ratio) that was similar to commercial feeds (p > 0.05). Concentrations of metalloid/metals in food waste feeds and polycyclic aromatic hydrocarbons (PAHs) in Napier grass were relatively higher than other types of fish feeds (p < 0.05). However, most of the metalloid/metals and PAH levels in fish fed with four types of fish feeds were not significantly different (p > 0.05). These findings show that food waste feeds are suitable for using in the production of fish feed and Napier grass can be served as supplemental feeds for grass carp, and hence reducing the production cost.

Structural, chemical and biological aspects of antioxidants for strategies against metal and metalloid exposure

PubMed Central

2009-01-01

Oxidative stress contributes to the pathophysiology of exposure to heavy metals/metalloid. Beneficial renal effects of some medications, such as chelation therapy depend at least partially on the ability to alleviate oxidative stress. The administration of various natural or synthetic antioxidants has been shown to be of benefit in the prevention and attenuation of metal induced biochemical alterations. These include vitamins, N-acetylcysteine, α-lipoic acid, melatonin, dietary flavonoids and many others. Human studies are limited in this regard. Under certain conditions, surprisingly, the antioxidant supplements may exhibit pro-oxidant properties and even worsen metal induced toxic damage. To date, the evidence is insufficient to recommend antioxidant supplements in subject with exposure to metals. Prospective, controlled clinical trials on safety and effectiveness of different therapeutic antioxidant strategies either individually or in combination with chelating agent are indispensable. The present review focuses on structural, chemical and biological aspects of antioxidants particularly related to their chelating properties. PMID:20716905

Assessing Different Mechanisms of Toxicity in Mountaintop Removal/Valley Fill Coal Mining-Affected Watershed Samples Using Caenorhabditis elegans

PubMed Central

Turner, Elena A.; Kroeger, Gretchen L.; Arnold, Mariah C.; Thornton, B. Lila; Di Giulio, Richard T.; Meyer, Joel N.

2013-01-01

Mountaintop removal-valley fill coal mining has been associated with a variety of impacts on ecosystem and human health, in particular reductions in the biodiversity of receiving streams. However, effluents emerging from valley fills contain a complex mixture of chemicals including metals, metalloids, and salts, and it is not clear which of these are the most important drivers of toxicity. We found that streamwater and sediment samples collected from mine-impacted streams of the Upper Mud River in West Virginia inhibited the growth of the nematode Caenorhabditis elegans. Next, we took advantage of genetic and transgenic tools available in this model organism to test the hypotheses that the toxicity could be attributed to metals, selenium, oxidative stress, or osmotic stress. Our results indicate that in general, the toxicity of streamwater to C. elegans was attributable to osmotic stress, while the toxicity of sediments resulted mostly from metals or metalloids. PMID:24066176

Heavy metals, metalloids and other hazardous elements in marine plastic litter.

PubMed

Turner, Andrew

2016-10-15

Plastics, foams and ropes collected from beaches in SW England have been analysed for As, Ba, Br, Cd, Cl, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn and Zn by field-portable-x-ray fluorescence spectrometry. High concentrations of Cl in foams that were not PVC-based were attributed to the presence of chlorinated flame retardants. Likewise, high concentrations of Br among both foams and plastics were attributed to the presence of brominated flame retardants. Regarding heavy metals and metalloids, Cd and Pb were of greatest concern from an environmental perspective. Lead was encountered in plastics, foams and ropes and up to concentrations of 17,500μgg(-1) due to its historical use in stabilisers, colourants and catalysts in the plastics industry. Detectable Cd was restricted to plastics, where its concentration often exceeded 1000μgg(-1); its occurrence is attributed to the use of both Cd-based stabilisers and colourants in a variety of products. Copyright © 2016 Elsevier Ltd. All rights reserved.

The synthesis of ternary acetylides with tellurium: Li 2 TeC 2 and Na 2 TeC 2

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

Németh, Károly; Unni, Aditya K.; Kalnmals, Christopher

The synthesis of ternary acetylides Li 2TeC 2 and Na 2TeC 2 is presented as the first example of ternary acetylides with metalloid elements instead of transition metals. The synthesis was carried out by the direct reaction of the corresponding bialkali acetylides with tellurium powder in liquid ammonia. Alternatively, the synthesis of Na 2TeC 2 was also carried out by the direct reaction of tellurium powder and two equivalents of NaC 2H in liquid ammonia leading to Na 2TeC 2 and acetylene gas through an equilibrium containing the assumed NaTeC 2H molecules besides the reactants and the products. The resultingmore » disordered crystalline materials were characterized by X-ray diffraction and Raman spectroscopy. Implications of these new syntheses on the synthesis of other ternary acetylides with metalloid elements and transition metals are also discussed.« less

Assessment of influences of cooking on cadmium and arsenic bioaccessibility in rice, using an in vitro physiologically-based extraction test.

PubMed

Zhuang, Ping; Zhang, Chaosheng; Li, Yingwen; Zou, Bi; Mo, Hui; Wu, Kejun; Wu, Jingtao; Li, Zhian

2016-12-15

The health risks associated with rice consumption may decrease if consumers use cooking practices which can reduce the bioaccessibility of metal(loid)s. The effects of cooking on the Cd and As bioaccessibility, at three contamination levels of rice, were studied. Results indicated that cooking reduced bioaccessibility of Cd and As in rice. Cooking resulted in a significant increase (p<0.01) of Cd and As concentrations in the residual fraction. Low volume water-cooking of rice to dryness reduced total Cd by about 10% for rices A and B, while medium or high volume water-cooking had no effect on Cd bioaccessibility in all rice types. In contrast, low volume cooking did not remove As, but a significant decrease (p<0.05) was observed when cooking with higher volumes of water. This study provides information for a better understanding of more realistic estimation of metal(loid)s exposure from rice and the possible health risks. Copyright © 2016. Published by Elsevier Ltd.

History of Arsenic as a Poison and Medicinal

EPA Science Inventory

Since ancient times, human exposure to the metalloid arsenic has been both intentional and unintentional. The intentional exposure to arsenic has been to inflict harm on others as well as to be a curative agent for those who are ill. The unintentional exposure has either been f...

Advances in Assessing Bioavailability of Metal(loid)s in Contaminated Soils

USDA-ARS?s Scientific Manuscript database

The term bioavailability has many different meanings across various disciplines of toxicology and pharmacology. Often bioavailability is concerned with human health aspects such in the case of lead (Pb) ingestion by children. However, some of the most contaminated sites are found in non-public acc...

INVESTIGATIONS INTO THE MODE OF ACTION OF ARSENIC

EPA Science Inventory

Arsenic is a ubiquitous metalloid to which there is significant human exposure through the air, water, and food. That arsenic can induce cancer in humans has been known since the late 17th century, yet how arsenic induces cancer has been the subject of a myriad of scientific inve...

A COMPREHENSIVE APPROACH TO IDENTIFY AND QUANTIFY FUNDAMENTAL PARAMETERS THAT INFLUENCE METAL LEACHING CHEMISTRY IN LANDFILLS SYSTEMS (PRESENTATION)

EPA Science Inventory

Various anthropogenic activities generate hazardous solid wastes that are affluent in heavy metals, which can cause significant damage to the environment and human health. Heavy metals/metalloids can exist in multiple oxidation states, and can undergo oxidation or reduction when ...

A COMPREHENSIVE APPROACH TO IDENTIFY AND QUANTIFY FUNDAMENTAL PARAMETERS THAT INFLUENCE METAL LEACHING CHEMISTRY IN LANDFILLS SYSTEMS (ABSTRACT)

EPA Science Inventory

Various anthropogenic activities generate hazardous solid wastes that are affluent in heavy metals, which can cause significant damage to the environment and human health. Heavy metals/metalloids can exist in multiple oxidation states, and can undergo oxidation or reduction when ...

EFFECTS OF DIETARY COPPER, ZINC, LEAD, CADMIUM, AND ARSENIC ON GROWTH AND SURVIVAL OF JUVENILE FISH USING LIVE FOOD ORGANISMS

EPA Science Inventory

Except for certain organometallic compounds, dietary exposures of aquatic organisms to metal/metalloids have received little regulatory attention. However, various studies have suggested that dietary exposure could be important, especially in areas where current water column conc...

Arsenic Exposure and Toxicology: A Historical Perspective

EPA Science Inventory

The metalloid arsenic is a natural environmental contaminant to which humans are routinely exposed in food, water, air and soil. Arsenic has a long history of use as a homicidal agent, but in the past 100 years arsenic, in various forms, has also been used as a pesticide and a ch...

RECOMBINANT RAT CYT19, AN ARSENIC METHYLTRANSFERASE, EFFICIENTLY GENERATES TRIMETHYLARSINE OXIDE IN THE ABSENCE OF GLUTATHIONE

EPA Science Inventory

Chronic exposure to inorganic arsenic (iAs), a toxic metalloid sometimes present in drinking water, is associated with increased prevalences of various cancers and other disorders. Humans and many other species enzymatically convert iAs into methylated metabolites. The major meta...

Flexible Reactive Berm (FRBerm) for Removal of Heavy Metals from Runoff Water

DTIC Science & Technology

2016-10-01

contamination, runoff, variable terrain requirements, reactive filter barrier. Unclassified Unclassified UU UL 47 Dr. Steve Larson 601-634-3431 Page...Figure 1. Illustration of a Sediment Control Filter Sock ............................................................... 1 Figure 2. Conceptual...Design of the Flexible Reactive Filter Barriers to Remove Soluble and Sediment Bound Metal(loids) in Stormwater Runoff

Understanding the Role of a nano Ce Additive in the Size Distribution and Organic Composition of Diesel Emissions

EPA Science Inventory

A number of alkali, alkaline earth, transition, and metalloid elements are known to act as fuel catalysts to limit the formation of soot precursors or promote its oxidation. These have been used with varying success on a variety of stationary and mobile combustion sources. Iron...

LABORATORY EVALUATION OF ZERO-VALENT IRON TO TREAT WATER IMPACTED BY ACID MINE DRAINAGE

EPA Science Inventory

This study examines the applicability and limitations of granular zero-valent iron for the treatment of water impacted by mine wastes. Rates of acid neutralization and of metal (Cu, Cd, Ni, Zn, Hg, Al, and Mn) and metalloid (As) uptake were determined in batch systems using simu...

Phytoremediation and phytomining: Using plants to remediate contaminated or mineralized environments

USDA-ARS?s Scientific Manuscript database

One type of harsh environment for plants is metal and metalloid contaminated or mineralized soils which exist in most countries due to geological formations or to the history of mining and smelting. Depending on soil pH and fertility, metal-rich soils may be barren and eroding into wider areas. Some...

Rhizobium selenitireducens proteins involved in the reduction of selenite to elemental selenium

USDA-ARS?s Scientific Manuscript database

Microbial based bioremediation barriers can remove the metalloid selenite (SeO3–2) from flowing groundwater. The organisms associated with the process include microorganisms from within the bacterial and archaeal domains that can reduce soluble SeO3–2 to the insoluble and reddish-colored elemental ...

Role of complex organic arsenicals in food in aggregate exposure to arsenic

EPA Science Inventory

For much of the world’s population, food is the major source of exposure to arsenic. Exposure to this non-essential metalloid at relatively low levels has been linked to a wide range of adverse health effects. Thus, evaluating foods as sources of exposure to arsenic is important ...

Selenium and tellurium nanomaterials

NASA Astrophysics Data System (ADS)

Piacenza, Elena; Presentato, Alessandro; Zonaro, Emanuele; Lampis, Silvia; Vallini, Giovanni; Turner, Raymond J.

2018-04-01

Over the last 40 years, the rapid and exponential growth of nanotechnology led to the development of various synthesis methodologies to generate nanomaterials different in size, shape and composition to be applied in various fields. In particular, nanostructures composed of Selenium (Se) or Tellurium (Te) have attracted increasing interest, due to their intermediate nature between metallic and non-metallic elements, being defined as metalloids. Indeed, this key shared feature of Se and Te allows us the use of their compounds in a variety of applications fields, such as for manufacturing photocells, photographic exposure meters, piezoelectric devices, and thermoelectric materials, to name a few. Considering also that the chemical-physical properties of elements result to be much more emphasized when they are assembled at the nanoscale range, huge efforts have been made to develop highly effective synthesis methods to generate Se- or Te-nanomaterials. In this context, the present book chapter will explore the most used chemical and/or physical methods exploited to generate different morphologies of metalloid-nanostructures, focusing also the attention on the major advantages, drawbacks as well as the safety related to these synthetic procedures.

Determination of the oxidation states of metals and metalloids: An analytical review

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.

2013-12-01

The hazard of many heavy metals/metalloids in the soil depends on their oxidation state. The problem of determining the oxidation state has been solved due to the use of synchrotron radiation methods with the analysis of the X-ray absorption near-edge structure (XANES). The determination of the oxidation state is of special importance for some hazardous heavy elements (arsenic, antimony, selenium, chromium, uranium, and vanadium). The mobility and hazard of each of these elements depend on its oxidation state. The mobilities are higher at lower oxidation states of As, Cr, V, and Se and at higher oxidation states of Sb and U. The determination of the oxidation state of arsenic has allowed revealing its fixation features in the rhizosphere of hydrophytes. The known oxidation states of chromium and uranium are used for the retention of these elements on geochemical barriers. Different oxidation states have been established for vanadium displacing iron in goethite. The determination of the oxidation state of manganese in the rhizosphere and the photosynthetic apparatus of plants is of special importance for agricultural chemists.

Heavy metals and metalloid content in vegetables and soil collected from the gardens of Zagreb, Croatia.

PubMed

Puntarić, Dinko; Vidosavljević, Domagoj; Gvozdić, Vlatka; Puntarić, Eda; Puntarić, Ida; Mayer, Dijana; Bosnir, Jasna; Lasić, Dario; Jergović, Matijana; Klarić, Ivana; Vidosavljević, Marina; Krivdić, Ivancica

2013-09-01

Aim of this study was to determine concentration of Pb, Cd, As and Hg in green leafy vegetables and soil in the urban area of Zagreb, Croatia and to determine if there is a connection between the contamination of soil and vegetables. Green leafy vegetables and soil samples were taken from the gardens located in the outskirts of the city. Concentrations of Pb, Cd, As and Hg were determined by atomic absorption spectrometry; showing that average concentrations of metals and metalloids in vegetables and in soil, regardless of the location of sampling were below the maximum allowed concentration (MAC). The analysis determined that metal concentrations in only nine vegetable samples (9%) were above maximum allowed values prescribed by national and European legislation (three with higher concentrations of Pb, one with a higher concentration of Cd and five with higher concentrations of Hg). Concentrations of contaminants present in the analysed samples, in general, are lower than the ones published in similar studies. The final distribution and concentration of contaminants in vegetables of Zagreb, besides industry and traffic, is affected by the dominant wind direction.

RETROSPECTIVE STUDY OF METHYLMERCURY AND OTHER METAL(LOID)S IN MADAGASCAR UNPOLISHED RICE (Oryza sativa L.)

PubMed Central

Rothenberg, Sarah E.; Mgutshini, Noma L.; Bizimis, Michael; Johnson-Beebout, Sarah E.; Ramanantsoanirina, Alain

2014-01-01

The rice ingestion rate in Madagascar is among the highest globally; however studies concerning metal(loid) concentrations in Madagascar rice are lacking. For Madagascar unpolished rice (n=51 landraces), levels of toxic elements (e.g., total mercury, methylmercury, arsenic and cadmium) as well as essential micronutrients (e.g., zinc and selenium) were uniformly low, indicating potentially both positive and negative health effects. Aside from manganese (Wilcoxon rank sum, p<0.01), no significant differences in concentrations for all trace elements were observed between rice with red bran (n=20) and brown bran (n=31) (Wilcoxon rank sum, p=0.06–0.91). Compared to all elements in rice, rubidium (i.e., tracer for phloem transport) was most positively correlated with methylmercury (Pearson's r=0.33, p<0.05) and total mercury (r=0.44, p<0.05), while strontium (i.e., tracer for xylem transport) was least correlated with total mercury and methylmercury (r<0.01 for both), suggesting inorganic mercury and methylmercury were possibly more mobile in phloem compared to xylem. PMID:25463705

Functionalized graphene oxide for clinical glucose biosensing in urine and serum samples

PubMed Central

Veerapandian, Murugan; Seo, Yeong-Tai; Shin, Hyunkyung; Yun, Kyusik; Lee, Min-Ho

2012-01-01

A novel clinical glucose biosensor fabricated using functionalized metalloid-polymer (silver-silica coated with polyethylene glycol) hybrid nanoparticles on the surface of a graphene oxide nanosheet is reported. The cyclic voltammetric response of glucose oxidase modification on the surface of a functionalized graphene oxide electrode showed a surface-confined reaction and an effective redox potential near zero volts, with a wide linearity of 0.1–20 mM and a sensitivity of 7.66 μA mM−1 cm−2. The functionalized graphene oxide electrode showed a better electrocatalytic response toward oxidation of H2O2 and reduction of oxygen. The practical applicability of the functionalized graphene oxide electrode was demonstrated by measuring the peak current against multiple urine and serum samples from diabetic patients. This new hybrid nanoarchitecture combining a three-dimensional metalloid-polymer hybrid and two-dimensional graphene oxide provided a thin solid laminate on the electrode surface. The easy fabrication process and retention of bioactive immobilized enzymes on the functionalized graphene oxide electrode could potentially be extended to detection of other biomolecules, and have broad applications in electrochemical biosensing. PMID:23269871

Functionalized graphene oxide for clinical glucose biosensing in urine and serum samples.

PubMed

Veerapandian, Murugan; Seo, Yeong-Tai; Shin, Hyunkyung; Yun, Kyusik; Lee, Min-Ho

2012-01-01

A novel clinical glucose biosensor fabricated using functionalized metalloid-polymer (silver-silica coated with polyethylene glycol) hybrid nanoparticles on the surface of a graphene oxide nanosheet is reported. The cyclic voltammetric response of glucose oxidase modification on the surface of a functionalized graphene oxide electrode showed a surface-confined reaction and an effective redox potential near zero volts, with a wide linearity of 0.1-20 mM and a sensitivity of 7.66 μA mM(-1) cm(-2). The functionalized graphene oxide electrode showed a better electrocatalytic response toward oxidation of H(2)O(2) and reduction of oxygen. The practical applicability of the functionalized graphene oxide electrode was demonstrated by measuring the peak current against multiple urine and serum samples from diabetic patients. This new hybrid nanoarchitecture combining a three-dimensional metalloid-polymer hybrid and two-dimensional graphene oxide provided a thin solid laminate on the electrode surface. The easy fabrication process and retention of bioactive immobilized enzymes on the functionalized graphene oxide electrode could potentially be extended to detection of other biomolecules, and have broad applications in electrochemical biosensing.

Accumulation of Heavy Metals and Metalloid in Foodstuffs from Agricultural Soils around Tarkwa Area in Ghana, and Associated Human Health Risks.

PubMed

Bortey-Sam, Nesta; Nakayama, Shouta M M; Akoto, Osei; Ikenaka, Yoshinori; Fobil, Julius N; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-07-28

This study was carried out to assess the extent of heavy metals and metalloid accumulation from agricultural soils to foodstuffs (viz, M. esculenta (cassava) and Musa paradisiaca (plantain)) around thirteen neighboring communities within Tarkwa, Ghana; and to estimate the human health risk associated with consumption of these foodstuffs. Concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were measured with an inductively coupled plasma-mass spectrometer and mercury analysis was done using a mercury analyzer. From the results, 30% of cassava samples collected, contained higher concentrations of Pb when compared to Codex Alimentarius Commission standard values. Bioconcentration factor indicated that Ni had higher capacity of absorption into food crops from soil than the other heavy metals. For both children and adults, the target hazard quotient (THQ) of Pb in cassava in communities such as Techiman, Wangarakrom, Samahu, and Tebe (only children) were greater than 1, which is defined as an acceptable risk value. This indicated that residents could be exposed to significant health risks associated with cassava consumption.

Accumulation of Heavy Metals and Metalloid in Foodstuffs from Agricultural Soils around Tarkwa Area in Ghana, and Associated Human Health Risks

PubMed Central

Bortey-Sam, Nesta; Nakayama, Shouta M. M.; Akoto, Osei; Ikenaka, Yoshinori; Fobil, Julius N.; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-01-01

This study was carried out to assess the extent of heavy metals and metalloid accumulation from agricultural soils to foodstuffs (viz, M. esculenta (cassava) and Musa paradisiaca (plantain)) around thirteen neighboring communities within Tarkwa, Ghana; and to estimate the human health risk associated with consumption of these foodstuffs. Concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were measured with an inductively coupled plasma–mass spectrometer and mercury analysis was done using a mercury analyzer. From the results, 30% of cassava samples collected, contained higher concentrations of Pb when compared to Codex Alimentarius Commission standard values. Bioconcentration factor indicated that Ni had higher capacity of absorption into food crops from soil than the other heavy metals. For both children and adults, the target hazard quotient (THQ) of Pb in cassava in communities such as Techiman, Wangarakrom, Samahu, and Tebe (only children) were greater than 1, which is defined as an acceptable risk value. This indicated that residents could be exposed to significant health risks associated with cassava consumption. PMID:26225988

Metal and Metalloid Contaminants in Airborne Dust Associated with Mining Operations

NASA Astrophysics Data System (ADS)

Betterton, E. A.; Csavina, J. L.; Field, J. P.; Landázuri, A. C.; Felix Villar, O.; Rine, K. P.; Sáez, A.; Pence, J.; Shayan, H.; Russell, M.

2011-12-01

Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. In this work, we report the size-resolved chemical characterization of atmospheric aerosols sampled near an inactive Superfund site and at an active mining and smelting site in Arizona. Aerosols were characterized with 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactors (MOUDI), Dustrack monitors, and total suspended particulate (TSP) collectors. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm aerodynamic diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources.

Bimetallic strip for low temperature use. [4-300/sup 0/K

DOEpatents

Bussiee, J.F.; Welch, D.O.; Suenaga, M.

A class of mechanically pre-stressed structures is provided suitably bi-layer strips, consisting of a layer of group 5 transition metals in intimate contact with a layer of an intermetallic compound of transition metals with certain group 3A, 4A or 5A metals or metalloids such as Ga, In, Si, Ge, Sn, As or Sb. The changes of Young's modulus of these bi-layered combinations at temperatures in the region of somewhat above absolute zero provides a useful means of sensing temperature changes. Such bi-metallic strips may be used as control strips in thermostats, or in direct dial reading instruments. The structures are made by preparing a sandwich of a group 5B transition metal strip between the substantially thicker strips of an alloy between copper and a predetermined group 3A, 4A or 5A metal or metalloid, holding the three layers are heated, cooled the copper alloys and is removed. Removing one of the two formed interlayer alloys between the transition metal and the metal previously alloyed with copper remain.

Bimetallic strip for low temperature use

DOEpatents

Bussiere, Jean F.; Welch, David O.; Suenaga, Masaki

1981-01-01

There is provided a class of mechanically pre-stressed structures, suitably bi-layer strips comprising a layer of group 5 transition metals in intimate contact with a layer of an intermetallic compound of said transition metals with certain group 3A, 4A or 5A metals or metalloids suitably gallium, indium, silicon, germanium, tin, arsenic or antimony. The changes of Young's modulus of these bi-layered combinations at temperatures in the region of but somewhat above absolute zero provides a useful means of sensing temperature changes. Such bi-metallic strips may be used as control strips in thermostats, in direct dial reading instruments, or the like. The structures are made by preparing a sandwich of a group 5B transition metal strip between the substantially thicker strips of an alloy between copper and a predetermined group 3A, 4A or 5A metal or metalloid, holding the three layers of the sandwich in intimate contact heating the same, cooling the same and removing the copper alloy and then removing one of the two thus formed interlayer alloys between said transition metal and the metal previously alloyed with copper.

Geochemical and mineralogical controls on metal(loid) mobility in the oxide zone of the Prairie Creek Deposit, NWT

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

Stavinga, Drew; Jamieson, Heather; Layton-Matthews, Daniel

2017-02-01

Prairie Creek is an unmined high grade Zn-Pb-Ag deposit in the southern Mackenzie Mountains of the Northwest Territories, located in a 320 km2 enclave surrounded by the Nahanni National Park reserve. The upper portion of the quartz-carbonate-sulphide vein mineralization has undergone extensive oxidation, forming high grade zones, rich in smithsonite (ZnCO3) and cerussite (PbCO3). This weathered zone represents a significant resource and a potential component of mine waste material. This study is focused on characterizing the geochemical and mineralogical controls on metal(loid) mobility under mine waste conditions, with particular attention to the metal carbonates as a potential source of tracemore » elements to the environment. Analyses were conducted using a combination of microanalytical techniques (electron microprobe, scanning electron microscopy with automated mineralogy, laser-ablation inductively-coupled mass spectrometry, and synchrotron-based element mapping, micro-X-ray diffraction and micro-X-ray absorbance). The elements of interest included Zn, Pb, Ag, As, Cd, Cu, Hg, Sb and Se.« less

Jacks of metal/metalloid chelation trade in plants—an overview

PubMed Central

Anjum, Naser A.; Hasanuzzaman, Mirza; Hossain, Mohammad A.; Thangavel, Palaniswamy; Roychoudhury, Aryadeep; Gill, Sarvajeet S.; Rodrigo, Miguel A. Merlos; Adam, Vojtěch; Fujita, Masayuki; Kizek, Rene; Duarte, Armando C.; Pereira, Eduarda; Ahmad, Iqbal

2015-01-01

Varied environmental compartments including soils are being contaminated by a myriad toxic metal(loid)s (hereafter termed as “metal/s”) mainly through anthropogenic activities. These metals may contaminate food chain and bring irreparable consequences in human. Plant-based approach (phytoremediation) stands second to none among bioremediation technologies meant for sustainable cleanup of soils/sites with metal-contamination. In turn, the capacity of plants to tolerate potential consequences caused by the extracted/accumulated metals decides the effectiveness and success of phytoremediation system. Chelation is among the potential mechanisms that largely govern metal-tolerance in plant cells by maintaining low concentrations of free metals in cytoplasm. Metal-chelation can be performed by compounds of both thiol origin (such as GSH, glutathione; PCs, phytochelatins; MTs, metallothioneins) and non-thiol origin (such as histidine, nicotianamine, organic acids). This paper presents an appraisal of recent reports on both thiol and non-thiol compounds in an effort to shed light on the significance of these compounds in plant-metal tolerance, as well as to provide scientific clues for the advancement of metal-phytoextraction strategies. PMID:25883598

Biosorbents for Removing Hazardous Metals and Metalloids †

PubMed Central

Inoue, Katsutoshi; Parajuli, Durga; Ghimire, Kedar Nath; Biswas, Biplob Kumar; Kawakita, Hidetaka; Oshima, Tatsuya; Ohto, Keisuke

2017-01-01

Biosorbents for remediating aquatic environmental media polluted with hazardous heavy metals and metalloids such as Pb(II), Cr(VI), Sb(III and V), and As(III and V) were prepared from lignin waste, orange and apple juice residues, seaweed and persimmon and grape wastes using simple and cheap methods. A lignophenol gel such as lignocatechol gel was prepared by immobilizing the catechol functional groups onto lignin from sawdust, while lignosulfonate gel was prepared directly from waste liquor generated during pulp production. These gels effectively removed Pb(II). Orange and apple juice residues, which are rich in pectic acid, were easily converted using alkali (e.g., calcium hydroxide) into biosorbents that effectively removed Pb(II). These materials also effectively removed Sb(III and V) and As(III and V) when these were preloaded with multi-valent metal ions such as Zr(IV) and Fe(III). Similar biosorbents were prepared from seaweed waste, which is rich in alginic acid. Other biosorbents, which effectively removed Cr(VI), were prepared by simply treating persimmon and grape wastes with concentrated sulfuric acid. PMID:28773217

Potential Biotechnological Strategies for the Cleanup of Heavy Metals and Metalloids

PubMed Central

Mosa, Kareem A.; Saadoun, Ismail; Kumar, Kundan; Helmy, Mohamed; Dhankher, Om Parkash

2016-01-01

Global mechanization, urbanization, and various natural processes have led to the increased release of toxic compounds into the biosphere. These hazardous toxic pollutants include a variety of organic and inorganic compounds, which pose a serious threat to the ecosystem. The contamination of soil and water are the major environmental concerns in the present scenario. This leads to a greater need for remediation of contaminated soils and water with suitable approaches and mechanisms. The conventional remediation of contaminated sites commonly involves the physical removal of contaminants, and their disposition. Physical remediation strategies are expensive, non-specific and often make the soil unsuitable for agriculture and other uses by disturbing the microenvironment. Owing to these concerns, there has been increased interest in eco-friendly and sustainable approaches such as bioremediation, phytoremediation and rhizoremediation for the cleanup of contaminated sites. This review lays particular emphasis on biotechnological approaches and strategies for heavy metal and metalloid containment removal from the environment, highlighting the advances and implications of bioremediation and phytoremediation as well as their utilization in cleaning-up toxic pollutants from contaminated environments. PMID:27014323

Metal(loid)s behaviour in soils amended with nano zero-valent iron as a function of pH and time.

PubMed

Vítková, Martina; Rákosová, Simona; Michálková, Zuzana; Komárek, Michael

2017-01-15

Nano zero-valent iron (nZVI) is currently investigated as a stabilising amendment for contaminated soils. The effect of pH (4-8) and time (48 and 192 h) on the behaviour of nZVI-treated Pb-Zn and As-contaminated soil samples was assessed. Additionally, soil leachates were subsequently used to study the direct interaction between soil solution components and nZVI particles in terms of mineralogical changes and contaminant retention. A typical U-shaped leaching trend as a function of pH was observed for Cd, Pb and Zn, while As was released predominantly under alkaline conditions. Oxidising conditions prevailed, so pH was the key controlling parameter rather than redox conditions. Generally, longer contact time resulted in increased soluble concentrations of metal(loid)s. However, the stabilisation effect of nZVI was only observed after the direct soil leachate-nZVI interactions, showing enhanced redox and sorption processes for the studied metals. A significant decrease of dissolved As concentrations was observed for both experimental soils, but with different efficiencies depending on neutralisation capacity, organic matter content or solid fractionation of As related to the origin of the soils. Scorodite (FeAsO 4 ·2H 2 O) was predicted as a potential solubility-controlling mineral phase for As. Sorption of metal(loid)s onto secondary Fe- and Al-(oxyhydr)oxides (predicted to precipitate at pH > 5) represents an important scavenger mechanism. Moreover, transmission electron microscopy confirmed the retention of Zn and Pb under near-neutral and alkaline conditions by newly formed Fe oxides or aluminosilicates. This study shows that the efficiency of nZVI application strongly depends not only on soil pH-Eh conditions and contaminant type, but also on the presence of organic matter and other compounds such as Al/Fe/Mn oxyhydroxides and clay minerals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Accumulation patterns and risk assessment of metals and metalloid in muscle and offal of free-range chickens, cattle and goat in Benin City, Nigeria.

PubMed

Ogbomida, Emmanuel Temiotan; Nakayama, Shouta M M; Bortey-Sam, Nesta; Oroszlany, Balazs; Tongo, Isioma; Enuneku, Alex Ajeh; Ozekeke, Ogbeide; Ainerua, Martins Oshioriamhe; Fasipe, Iriagbonse Priscillia; Ezemonye, Lawrence Ikechukwu; Mizukawa, Hazuki; Ikenaka, Yoshinori; Ishizuka, Mayumi

2018-04-30

The use of free range animals for monitoring environmental health offers opportunities to detect exposure and assess the toxicological effects of pollutants in terrestrial ecosystems. Potential human health risk of dietary intake of metals and metalloid via consumption of offal and muscle of free range chicken, cattle and goats by the urban population in Benin City was evaluated. Muscle, gizzard, liver and kidney samples were analyzed for Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb concentrations using inductively coupled plasma mass spectrometer (ICP-MS) while Hg was determined using Hg analyzer. Mean concentrations of metals (mg/kg ww) varied significantly depending upon the tissues and animal species. Human health risk estimations for children and adults showed estimated daily intake (EDI) values of tissues below oral reference dose (RfD) threshold for non essential metals Cd, As, Pb and Hg thus strongly indicating no possible health risk via consumption of animal based food. Calculated Hazard quotient (THQ) was less than 1 (< 1) for all the metals analyzed for both adult and children. However, Cd and As had the highest value of THQ suggestive of possible health risk associated with continuous consumption of Cd and As contaminated animal based foods. Hazard Index (HI) for additive effect of metals was higher in chicken liver and gizzard for children and chicken liver for adults. Thus, HI indicated that chicken liver and gizzard may contribute significantly to adult and children dietary exposure to heavy metals. Principal component analysis (PCA) showed a clear species difference in metal accumulation between chickens and the ruminants. This study provides baseline data for future studies and also valuable evidence of anthropogenic impacts necessary to initiate national and international policies for control of heavy metal and metalloid content in food items. Copyright © 2017. Published by Elsevier Inc.

Selenium Distribution and Fractionation in a Managed Urban Watershed

NASA Astrophysics Data System (ADS)

Papelis, C.; Boettcher, T. M.; Harris-Burr, R. D.

2006-12-01

Metals, and metalloids, are common contaminants of concern in arid and semi-arid watersheds in the Southwestern U.S. Because of the dramatic population growth in this part of the U.S., the potential for contamination of urban watersheds has also increased over the last few decades. Streams in urban watersheds receive storm water, urban runoff, shallow groundwater, and treated wastewater. In addition, urban watersheds are often heavily managed to mitigate flood events and sediment-related impacts. Clearly, sediment transport can have a profound effect on the water quality of affected bodies of water, not only by affecting water clarity, but also by facilitating the transport of chemical constituents, as well as microbiological components. The Las Vegas Wash (Wash) is the lowest point in the Las Vegas Valley Watershed and receives storm water, urban runoff, and treated wastewater from the entire Las Vegas Valley. To minimize erosion, caused by the dramatic wastewater flow increase during the last few decades, several erosion control structures are being built. In addition, wetlands being constructed in the Wash area receive most of the water from the Wash. The construction of these ponds has the potential to alter the distribution of metals and metalloids in bodies of water used by wildlife. An element of particular concern is selenium, a metalloid commonly found at elevated concentrations in soils of the U.S. Southwest. To assess the potential adverse impact on water quality, sediment samples were collected along the Wash, upstream and downstream of erosion control structures, and around current and future constructed wetlands. The sediments were characterized by particle size distribution, specific surface area, mineralogical composition, organic carbon content, and scanning electron microscopy. The total selenium, as well as the percentages associated with exchangeable, organic, carbonate, and oxide sediment fractions were determined. The distribution of selenium as a function of sediment properties and the potential of selenium availability in this environment will be discussed.

Individual and cumulative effects of agriculture, forestry and metal mining activities on the metal and phosphorus content of fluvial fine-grained sediment; Quesnel River Basin, British Columbia, Canada.

PubMed

Smith, Tyler B; Owens, Philip N

2014-10-15

The impact of agriculture, forestry and metal mining on the quality of fine-grained sediment (<63 μm) was investigated in the Quesnel River Basin (QRB) (~11,500 km(2)) in British Columbia, Canada. Samples of fine-grained sediment were collected monthly during the snow-free season in 2008 using time-integrated samplers at replicate sites representative of agriculture, forestry and mining activities in the basin (i.e. "impacted" sites). Samples were also collected from replicate reference sites and also from the main stem of the Quesnel River at the downstream confluence with the Fraser River. Generally, metal(loid) and phosphorus (P) concentrations for "impacted" sites were greater than for reference sites. Furthermore, concentrations of copper (forestry and mining sites), manganese (agriculture and forestry sites) and selenium (agriculture, forestry and mining sites) exceeded upper sediment quality guideline (SQG) thresholds. These results suggest that agriculture, forestry and metal mining activities are having an influence on the concentrations of sediment-associated metal(loid)s and P in the Quesnel basin. Metal(loid) and P concentrations of sediment collected from the downstream site were not significantly greater than values for the reference sites, and were typically lower than the values for the impacted sites. This suggests that the cumulative effects of agriculture, forestry and mining activities in the QRB are presently not having a measureable effect at the river basin-scale. The lack of a cumulative effect at the basin-scale is thought to reflect: (i) the relatively recent occurrence of land use disturbances in this basin; (ii) the dominance of sediment contributions from natural forest and agriculture; and (iii) the potential for storage of contaminants on floodplains and other storage elements between the locations of disturbance activities and the downstream sampling site, which may be attenuating the disturbance signal. Copyright © 2014 Elsevier B.V. All rights reserved.

Potential ecological and human health risks of heavy metals in surface soils associated with iron ore mining in Pahang, Malaysia.

PubMed

Diami, Siti Merryan; Kusin, Faradiella Mohd; Madzin, Zafira

2016-10-01

The composition of heavy metals (and metalloid) in surface soils of iron ore mine-impacted areas has been evaluated of their potential ecological and human health risks. The mining areas included seven selected locations in the vicinity of active and abandoned iron ore-mining sites in Pahang, Malaysia. Heavy metals such as Fe, Mn, Cu, Zn, Co, Pb, Cr, Ni, and Cd and metalloid As were present in the mining soils of the studied area, while Cu was found exceeding the soil guideline value at all sampling locations. However, the assessment of the potential ecological risk index (RI) indicated low ecological risk (RI between 44 and 128) with respect to Cd, Pb, Cu, As, Zn, Co, and Ni in the surface soils. Contributions of potential ecological risk [Formula: see text]by metal elements to the total potential ecological RI were evident for Cd, As, Pb, and Cu. Contribution of Cu appears to be consistently greater in the abandoned mining area compared to active iron ore-mining site. For non-carcinogenic risk, no significant potential health risk was found to both children and adults as the hazard indices (HIs) were all below than 1. The lifetime cancer risk (LCR) indicated that As has greater potential carcinogenic risk compared to other metals that may induce carcinogenic effects such as Pb, Cr, and Cd, while the LCR of As for children fell within tolerable range for regulatory purposes. Irrespective of carcinogenic or non-carcinogenic risk, greater potential health risk was found among children (by an order of magnitude higher for most metals) compared to adults. The hazard quotient (HQ) and cancer risk indicated that the pathways for the risk to occur were found to be in the order of ingestion > dermal > inhalation. Overall, findings showed that some metals and metalloid were still present at comparable concentrations even long after cessation of the iron ore-mining activities.

Integrated phytobial remediation for sustainable management of arsenic in soil and water.

PubMed

Roy, Madhumita; Giri, Ashok K; Dutta, Sourav; Mukherjee, Pritam

2015-02-01

Arsenic (As), cited as the most hazardous substance by the U.S. Agency for Toxic Substance and Disease Registry (ATSDR, 2005), is an ubiquitous metalloid which when ingested for prolonged periods cause extensive health effects leading to ultimate untimely death. Plants and microbes can help mitigate soil and groundwater As problem since they have evolved elaborate detoxification machineries against this toxic metalloid as a result of their coexistence with this since the origin of life on earth. Utilization of the phytoremediation and bioremediation potential of the plants and microbes, respectively, is now regarded as two innovative tools that encompass biology, geology, biotechnology and allied sciences with cutting edge applications for sustainable mitigation of As epidemic. Discovery of As hyperaccumulating plants that uptake and concentrate large amounts of this toxic metalloid in their shoots or roots offered new hope to As phytoremediation, solar power based nature's own green remediation. This review focuses on how phytoremediation and bioremediation can be merged together to form an integrated phytobial remediation which could synergistically achieve the goal of large scale removal of As from soil, sediment and groundwater and overcome the drawbacks of the either processes alone. The review also points to the feasibility of the introduction of transgenic plants and microbes that bring new hope for more efficient treatment of As. The review identifies one critical research gap on the importance of remediation of As contaminated groundwater not only for drinking purpose but also for irrigation purpose and stresses that more research should be conducted on the use of constructed wetland, one of the most suitable areas of application of phytobial remediation. Finally the review has narrowed down on different phytoinvestigation and phytodisposal methods, which constitute the most essential and the most difficult part of pilot scale and field scale applications of phytoremediation programs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential human health risk by metal(loid)s, 234,238U and 210Po due to consumption of fish from the "Luis L. Leon" Reservoir (Northern México).

PubMed

Luna-Porres, Mayra Y; Rodríguez-Villa, Marco A; Herrera-Peraza, Eduardo F; Renteria-Villalobos, Marusia; Montero-Cabrera, María E

2014-06-25

Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007-0.014 and 0.01-0.02 Bq∙kg-1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16-3.26, 0.70-1.13 and 0.93-1.37 Bq∙kg-1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13-0.39, 0.005-0.126 and 0.009-0.08 mg∙kg-1 ww, respectively, while in gill samples they were 0.11-0.43, 0.002-0.039 and 0.02-0.26 mg∙kg-1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg-1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg-1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg-1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg-1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat.

Levels of PM2.5/PM10 and associated metal(loid)s in rural households of Henan Province, China.

PubMed

Wu, Fuyong; Wang, Wei; Man, Yu Bon; Chan, Chuen Yu; Liu, Wenxin; Tao, Shu; Wong, Ming Hung

2015-04-15

Although a majority of China's rural residents use solid fuels (biomass and coal) for household cooking and heating, clean energy such as electricity and liquid petroleum gas is becoming more popular in the rural area. Unfortunately, both solid fuels and clean energy could result in indoor air pollution. Daily respirable particulate matter (PM≤10 μm) and inhalable particulate matter (PM≤2.5 μm) were investigated in kitchens, sitting rooms and outdoor area in rural Henan during autumn (Sep to Oct 2012) and winter (Jan 2013). The results showed that PM (PM2.5 and PM10) and associated metal(loid)s varied among the two seasons and the four types of domestic energy used. Mean concentrations of PM2.5 and PM10 in kitchens during winter were 59.2-140.4% and 30.5-145.1% higher than those during autumn, respectively. Similar with the trends of PM2.5 and PM10, concentrations of As, Pb, Zn, Cd, Cu, Ni and Mn in household PM2.5 and PM10 were apparently higher in winter than those in autumn. The highest mean concentrations of PM2.5 and PM10 (368.5 and 588.7 μg m(-3)) were recorded in sitting rooms in Baofeng during winter, which were 5.7 and 3.9 times of corresponding health based guidelines for PM2.5 and PM10, respectively. Using coal can result in severe indoor air pollutants including PM and associated metal(loid)s compared with using crop residues, electricity and gas in rural Henan Province. Rural residents' exposure to PM2.5 and PM10 would be roughly reduced by 13.5-22.2% and 8.9-37.7% via replacing coal or crop residues with electricity. The present study suggested that increased use of electricity as domestic energy would effectively improve indoor air quality in rural China. Copyright © 2015 Elsevier B.V. All rights reserved.

Deriving site-specific soil clean-up values for metals and metalloids: Rationale for including protection of soil microbial processes

PubMed Central

Kuperman, Roman G; Siciliano, Steven D; Römbke, Jörg; Oorts, Koen

2014-01-01

Although it is widely recognized that microorganisms are essential for sustaining soil fertility, structure, nutrient cycling, groundwater purification, and other soil functions, soil microbial toxicity data were excluded from the derivation of Ecological Soil Screening Levels (Eco-SSL) in the United States. Among the reasons for such exclusion were claims that microbial toxicity tests were too difficult to interpret because of the high variability of microbial responses, uncertainty regarding the relevance of the various endpoints, and functional redundancy. Since the release of the first draft of the Eco-SSL Guidance document by the US Environmental Protection Agency in 2003, soil microbial toxicity testing and its use in ecological risk assessments have substantially improved. A wide range of standardized and nonstandardized methods became available for testing chemical toxicity to microbial functions in soil. Regulatory frameworks in the European Union and Australia have successfully incorporated microbial toxicity data into the derivation of soil threshold concentrations for ecological risk assessments. This article provides the 3-part rationale for including soil microbial processes in the development of soil clean-up values (SCVs): 1) presenting a brief overview of relevant test methods for assessing microbial functions in soil, 2) examining data sets for Cu, Ni, Zn, and Mo that incorporated soil microbial toxicity data into regulatory frameworks, and 3) offering recommendations on how to integrate the best available science into the method development for deriving site-specific SCVs that account for bioavailability of metals and metalloids in soil. Although the primary focus of this article is on the development of the approach for deriving SCVs for metals and metalloids in the United States, the recommendations provided in this article may also be applicable in other jurisdictions that aim at developing ecological soil threshold values for protection of microbial processes in contaminated soils. PMID:24376192

Potential Human Health Risk by Metal(loid)s, 234,238U and 210Po due to Consumption of Fish from the “Luis L. Leon” Reservoir (Northern México)

PubMed Central

Luna-Porres, Mayra Y.; Rodríguez-Villa, Marco A.; Herrera-Peraza, Eduardo F.; Renteria-Villalobos, Marusia; Montero-Cabrera, María E.

2014-01-01

Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007–0.014 and 0.01–0.02 Bq∙kg−1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16–3.26, 0.70–1.13 and 0.93–1.37 Bq∙kg−1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13–0.39, 0.005–0.126 and 0.009–0.08 mg∙kg−1 ww, respectively, while in gill samples they were 0.11–0.43, 0.002–0.039 and 0.02–0.26 mg∙kg−1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg−1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg−1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg−1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg−1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat. PMID:24968208

Sulfidization of Organic Freshwater Flocs from a Minerotrophic Peatland: Speciation Changes of Iron, Sulfur, and Arsenic.

PubMed

ThomasArrigo, Laurel K; Mikutta, Christian; Lohmayer, Regina; Planer-Friedrich, Britta; Kretzschmar, Ruben

2016-04-05

Iron-rich organic flocs are frequently observed in surface waters of wetlands and show a high affinity for trace metal(loid)s. Under low-flow stream conditions, flocs may settle, become buried, and eventually be subjected to reducing conditions facilitating trace metal(loid) release. In this study, we reacted freshwater flocs (704-1280 mg As/kg) from a minerotrophic peatland (Gola di Lago, Switzerland) with sulfide (5.2 mM, S(-II)spike/Fe = 0.75-1.62 mol/mol) at neutral pH and studied the speciation changes of Fe, S, and As at 25 ± 1 °C over 1 week through a combination of synchrotron X-ray techniques and wet-chemical analyses. Sulfidization of floc ferrihydrite and nanocrystalline lepidocrocite caused the rapid formation of mackinawite (52-81% of Fesolid at day 7) as well as solid-phase associated S(0) and polysulfides. Ferrihydrite was preferentially reduced over lepidocrocite, although neoformation of lepidocrocite from ferrihydrite could not be excluded. Sulfide-reacted flocs contained primarily arsenate (47-72%) which preferentially adsorbed to Fe(III)-(oxyhydr)oxides, despite abundant mackinawite precipitation. At higher S(-II)spike/Fe molar ratios (≥1.0), the formation of an orpiment-like phase accounted for up to 35% of solid-phase As. Despite Fe and As sulfide precipitation and the presence of residual Fe(III)-(oxyhydr)oxides, mobilization of As was recorded in all samples (Asaq = 0.45-7.0 μM at 7 days). Aqueous As speciation analyses documented the formation of thioarsenates contributing up to 33% of Asaq. Our findings show that freshwater flocs from the Gola di Lago peatland may become a source of As under sulfate-reducing conditions and emphasize the pivotal role Fe-rich organic freshwater flocs play in trace metal(loid) cycling in S-rich wetlands characterized by oscillating redox conditions.

Insights into the subsurface transport of As(V) and Se(VI) in produced water from hydraulic fracturing using soil samples from Qingshankou Formation, Songliao Basin, China.

PubMed

Chen, Season S; Sun, Yuqing; Tsang, Daniel C W; Graham, Nigel J D; Ok, Yong Sik; Feng, Yujie; Li, Xiang-Dong

2017-04-01

Produced water is a type of wastewater generated from hydraulic fracturing, which may pose a risk to the environment and humans due to its high ionic strength and the presence of elevated concentrations of metals/metalloids that exceed maximum contamination levels. The mobilization of As(V) and Se(VI) in produced water and selected soils from Qingshankou Formation in the Songliao Basin in China were investigated using column experiments and synthetic produced water whose quality was representative of waters arising at different times after well creation. Temporal effects of produced water on metal/metalloid transport and sorption/desorption were investigated by using HYDRUS-1D transport modelling. Rapid breakthrough and long tailings of As(V) and Se(VI) transport were observed in Day 1 and Day 14 solutions, but were reduced in Day 90 solution probably due to the elevated ionic strength. The influence of produced water on the hydrogeological conditions (i.e., change between equilibrium and non-equilibrium transport) was evidenced by the change of tracer breakthrough curves before and after the leaching of produced water. This possibly resulted from the sorption of polyacrylamide (PAM (-CH 2 CHCONH 2 -) n ) onto soil surfaces, through its use as a friction reducer in fracturing solutions. The sorption was found to be reversible in this study. Minimal amounts of sorbed As(V) were desorbed whereas the majority of sorbed Se(VI) was readily leached out, to an extent which varied with the composition of the produced water. These results showed that the mobilization of As(V) and Se(VI) in soil largely depended on the solution pH and ionic strength. Understanding the differences in metal/metalloid transport in produced water is important for proper risk management. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mercury, arsenic and selenium concentrations in water and fish from sub-Saharan semi-arid freshwater reservoirs (Burkina Faso).

PubMed

Ouédraogo, Ousséni; Amyot, Marc

2013-02-01

Despite intensive mining activities in Burkina Faso, little is known on the environmental impacts of metals and metalloids potentially released from these activities. Water samples and 334 fish from 10 reservoirs were taken in order to evaluate the extent of mercury (Hg), selenium (Se) and arsenic (As) contamination in aquatic systems and their potential health risk for humans and wildlife, taking into account their antagonistic interactions. Water and fish levels of these elements were relatively low and did not reveal an important impact of gold mining activities. Water temperature and conductivity were the key factors associated with higher levels of MeHg. Higher sulfate content was reported in sites with more particulate Hg, As and Se, suggesting anthropogenic origin of metal(loid) inputs in water reservoirs. Metal(loid) concentrations in fish were low and ranged from 0.002 to 0.607 μg/g wet weight (w.w.) for Hg, 0.023 to 0.672 for Se and 0.039 to 0.42 for As. These levels are similar or slightly higher than those reported in many other studies from Africa. Nevertheless, more than 70% of piscivore fish exceeded the threshold for wildlife protection for MeHg. Further, a traditional risk analysis performed ignoring Se antagonism indicated that these piscivores should be consumed by humans with caution. However, when taking into account the antagonistic effect of Se on Hg toxicity, up to 99% of all fish could be protected from Hg toxicity by their Se content. When considering both As/Se and Se/Hg antagonism, 83% instead the 99% of fish should be considered safe for consumption. Fish Se and As concentrations did not pose potential risk for both animals and humans. Overall, these reservoirs were relatively unaffected by As, Se and Hg contamination despite the rising gold mining activities. Further, considering antagonistic effects of As, Se and Hg may help refine consumption advisories. Copyright © 2012 Elsevier B.V. All rights reserved.

Superior Na-ion storage properties of high aspect ratio SnSe nanoplates prepared by a spray pyrolysis process

NASA Astrophysics Data System (ADS)

Park, Gi Dae; Lee, Jong-Heun; Kang, Yun Chan

2016-06-01

SnSe nanoplates with thin and uniform morphology are prepared by one-pot spray pyrolysis, and are examined as anode materials for Na-ion batteries. During the spray pyrolysis process, metallic Se and Sn are prepared from SeO2 and SnO2, respectively, under a reducing atmosphere. Metallic Sn and metalloid Se, with melting points of 232 and 221 °C, respectively, form a melted Sn-Se mixture, which reacts exothermally to form SnSe nanocrystals. Several of these nanocrystals are grown simultaneously forming a micron-sized powder. Complete elimination of the excess amount of metalloid Se, by forming H2Se gas, results in aggregation-free SnSe nanoplates. The aspect ratio of these nanoplates is as high as 11.3. The discharge capacities for the SnSe nanoplates, prepared from spray solutions containing 100, 400, and 800% of the stoichiometric SeO2 content needed to form SnSe, are 407, 558, and 211 mA h g-1, respectively, after 50 cycles at a constant current density of 0.3 A g-1 their capacity retentions calculated from the second cycle onwards are 77, 100, and 60%, respectively. The phase pure SnSe nanoplates with a high aspect ratio show good cycling and rate performances for Na-ion storage.SnSe nanoplates with thin and uniform morphology are prepared by one-pot spray pyrolysis, and are examined as anode materials for Na-ion batteries. During the spray pyrolysis process, metallic Se and Sn are prepared from SeO2 and SnO2, respectively, under a reducing atmosphere. Metallic Sn and metalloid Se, with melting points of 232 and 221 °C, respectively, form a melted Sn-Se mixture, which reacts exothermally to form SnSe nanocrystals. Several of these nanocrystals are grown simultaneously forming a micron-sized powder. Complete elimination of the excess amount of metalloid Se, by forming H2Se gas, results in aggregation-free SnSe nanoplates. The aspect ratio of these nanoplates is as high as 11.3. The discharge capacities for the SnSe nanoplates, prepared from spray solutions containing 100, 400, and 800% of the stoichiometric SeO2 content needed to form SnSe, are 407, 558, and 211 mA h g-1, respectively, after 50 cycles at a constant current density of 0.3 A g-1 their capacity retentions calculated from the second cycle onwards are 77, 100, and 60%, respectively. The phase pure SnSe nanoplates with a high aspect ratio show good cycling and rate performances for Na-ion storage. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02983c

Understanding the Role of a nano Ce Additive in the Size Distribution and Organic Composition of the Particulate Phase of Diesel Emissions

EPA Science Inventory

A number of alkali, alkaline earth, transition, and metalloid elements are known to act as fuel catalysts to limit the formation of soot precursors or promote its oxidation. These have been used with varying success on a variety of stationary and mobile combustion sources. Iron...

Metalloid Aluminum Clusters with Fluorine

DTIC Science & Technology

2016-12-01

molecular dynamics, binding energy , siesta code, density of states, projected density of states 15. NUMBER OF PAGES 69 16. PRICE CODE 17. SECURITY...high energy density compared to explosives, but typically release this energy slowly via diffusion-limited combustion. There is recent interest in using...examine the cluster binding energy and electronic structure. Partial fluorine substitution in a prototypical aluminum-cyclopentadienyl cluster results

In Situ Fixation of Metal(loid)s in Contaminated Soils: A Comparison of Conventional, Opportunistic, and Engineered Soil Amendments

EPA Science Inventory

This study aimed to assess and compare the in vitro and in vivo bioaccessibility/bioavailability of As and Pb in a mining contaminated soil (As 2267 mg kg^-1, Pb 1126 mg kg^-1), after the addition of conventional (phosphoric acid), opportunistic ...

State of the Science Review: Potential for Beneficial Use of Waste By-Products for In-situ Remediation of Metal-Contaminated Soil and Sediment

EPA Science Inventory

Metal and metalloid contamination of soil and sediment is a widespread problem both in urban and rural areas throughout the United States (U.S. EPA, 2014). Beneficial use of waste by-products as amendments to remediate metal-contaminated soils and sediments can provide major eco...

Proceedings: ISEA Bioavailability Symposium, Durham, North Carolina Use of InVitro Bioaccessibility/Relative Bioavailability Estimates for Metals in Regulatory Settings: What is Needed?

EPA Science Inventory

Oral ingestion of soil and dust is a key pathway for human exposures to metal and metalloid contaminants. It is widely recognized that the site-specific bioavailability of metals in soil and dust may be reduced relative to the metal bioavailability in media such as water and food...

Phytoremediation strategies for soils contaminated with heavy metals: Modifications and future perspectives.

PubMed

Sarwar, Nadeem; Imran, Muhammad; Shaheen, Muhammad Rashid; Ishaque, Wajid; Kamran, Muhammad Asif; Matloob, Amar; Rehim, Abdur; Hussain, Saddam

2017-03-01

Presence of heavy metals in agricultural soils is of major environmental concern and a great threat to life on the earth. A number of human health risks are associated with heavy metals regarding their entry into food chain. Various physical, chemical and biological techniques are being used to remove heavy metals and metalloids from soils. Among them, phytoremediation is a good strategy to harvest heavy metals from soils and have been proven as an effective and economical technique. In present review, we discussed various sources and harmful effects of some important heavy metals and metalloids, traditional phytoremediation strategies, mechanisms involved in phytoremediation of these metals, limitations and some recent advances in phytoremediation approaches. Since traditional phytoremediation approach poses some limitations regarding their applications at large scale, so there is a dire need to modify this strategy using modern chemical, biological and genetic engineering tools. In view of above, the present manuscript brings both traditional and advanced phytoremediation techniques together in order to compare, understand and apply these strategies effectively to exclude heavy metals from soil keeping in view the economics and effectiveness of phytoremediation strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metals and metalloids in whole blood and tissues of Olive Ridley turtles (Lepidochelys olivacea) from La Escobilla Beach (Oaxaca, Mexico).

PubMed

Cortés-Gómez, Adriana A; Fuentes-Mascorro, Gisela; Romero, Diego

2014-12-15

Concentrations of eight metals and metalloids (Pb, Cd, Cu, Zn, Mn, Se, Ni and As) were evaluated from 41 nesting females (blood) and 13 dead (tissues) Olive Ridley turtles (Lepidochelys olivacea), a species classified as vulnerable and also listed in Appendix I of the Convention of International Trade in Endangered Species (CITES). The mean blood, liver and kidney lead concentration were 0.02 ± 0.01, 0.11 ± 0.08 and 0.06 ± 0.03 μ gg(-1) ww respectively, values lower than other turtle species and locations, which it could be due to the gradual disuse of leaded gasoline in Mexico and Central America since the 1990s. Mean concentration of cadmium was 0.17 ± 0.08 (blood), 82.88 ± 36.65 (liver) and 150.88 ± 110.9 9μg g(-1) (kidney). To our knowledge, the mean renal cadmium levels found is the highest ever reported worldwide for any sea turtle species, while other six elements showed a concentration similar to other studies in sea turtles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing Metal Exposures in a Community near a Cement Plant in the Northeast U.S.

PubMed Central

Dong, Zhao; Bank, Michael S.; Spengler, John D.

2015-01-01

Cement production is a major source of metals and metalloids in the environment, while exposures to metals and metalloids may impact human health in the surrounding communities. We recruited 185 participants living in the vicinity of a cement plant in the northeast U.S., and measured the levels of aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in blood and Hg in hair samples from them. A questionnaire was used to assess potential sources of Hg exposure. Multivariate regressions and spatial analyses were performed to evaluate the relative importance of different routes of exposures. The metal concentrations in blood or hair samples of our study participants were comparable to the U.S. general or regional population. Smoking contributed significantly to Cd and Pb exposures, and seafood consumption contributed significantly to Hg and As exposures, while variables related to the cement plant were not significantly associated with metal concentrations. Our results suggest that our study population was not at elevated health risk due to metal exposures, and that the contribution of the cement plant to metal exposures in the surrounding community was minimal. PMID:25607604

Biosynthesis of nanoparticles of metals and metalloids by basidiomycetes. Preparation of gold nanoparticles by using purified fungal phenol oxidases.

PubMed

Vetchinkina, Elena P; Loshchinina, Ekaterina A; Vodolazov, Ilya R; Kursky, Viktor F; Dykman, Lev A; Nikitina, Valentina E

2017-02-01

The work shows the ability of cultured Basidiomycetes of different taxonomic groups-Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum, and Grifola frondosa-to recover gold, silver, selenium, and silicon, to elemental state with nanoparticles formation. It examines the effect of these metal and metalloid compounds on the parameters of growth and accumulation of biomass; the optimal cultivation conditions and concentrations of the studied ion-containing compounds for recovery of nanoparticles have been identified. Using the techniques of transmission electron microscopy, dynamic light scattering, X-ray fluorescence and X-ray phase analysis, the degrees of oxidation of the bioreduced elements, the ζ-potential of colloidal solutions uniformity, size, shape, and location of the nanoparticles in the culture fluid, as well as on the surface and the inside of filamentous hyphae have been determined. The study has found the part played by homogeneous chromatographically pure fungal phenol-oxidizing enzymes (laccases, tyrosinases, and Mn-peroxidases) in the recovery mechanism with formation of electrostatically stabilized colloidal solutions. A hypothetical mechanism of gold(III) reduction from HAuCl 4 to gold(0) by phenol oxidases with gold nanoparticles formation of different shapes and sizes has been introduced.

Disorders of metal metabolism

PubMed Central

Ferreira, Carlos R.; Gahl, William A.

2017-01-01

Trace elements are chemical elements needed in minute amounts for normal physiology. Some of the physiologically relevant trace elements include iodine, copper, iron, manganese, zinc, selenium, cobalt and molybdenum. Of these, some are metals, and in particular, transition metals. The different electron shells of an atom carry different energy levels, with those closest to the nucleus being lowest in energy. The number of electrons in the outermost shell determines the reactivity of such an atom. The electron shells are divided in sub-shells, and in particular the third shell has s, p and d sub-shells. Transition metals are strictly defined as elements whose atom has an incomplete d sub-shell. This incomplete d sub-shell makes them prone to chemical reactions, particularly redox reactions. Transition metals of biologic importance include copper, iron, manganese, cobalt and molybdenum. Zinc is not a transition metal, since it has a complete d sub-shell. Selenium, on the other hand, is strictly speaking a nonmetal, although given its chemical properties between those of metals and nonmetals, it is sometimes considered a metalloid. In this review, we summarize the current knowledge on the inborn errors of metal and metalloid metabolism. PMID:29354481

Element mobilization from Bakken shales as a function of water chemistry.

PubMed

Wang, Lin; Burns, Scott; Giammar, Daniel E; Fortner, John D

2016-04-01

Waters that return to the surface after injection of a hydraulic fracturing fluid for gas and oil production contain elements, including regulated metals and metalloids, which are mobilized through interactions between the fracturing fluid and the shale formation. The rate and extent of mobilization depends on the geochemistry of the formation and the chemical characteristics of the fracturing fluid. In this work, laboratory scale experiments investigated the influence of water chemistry on element mobilization from core samples taken from the Bakken formation, one of the most productive shale oil plays in the US. Fluid properties were systematically varied and evaluated with regard to pH, oxidant level, solid:water ratio, temperature, and chemical additives. Element mobilization strongly depended on solution pH and redox conditions and to a lesser extent on the temperature and solid:water ratio. The presence of oxygen and addition of hydrogen peroxide or ammonium persulfate led to pyrite oxidation, resulting in elevated sulfate concentrations. Further, depending on the mineral carbonates available to buffer the system pH, pyrite oxidation could lower the system pH and enhance the mobility of several metals and metalloids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Formation of amorphous metal alloys by chemical vapor deposition

DOEpatents

Mullendore, Arthur W.

1990-01-01

Amorphous alloys are deposited by a process of thermal dissociation of mixtures or organometallic compounds and metalloid hydrides, e.g., transition metal carbonyl such as nickel carbonyl, and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit.

JPRS Report East Europe

DTIC Science & Technology

1990-09-19

which Yugoslavia has had clearing payments up until now. This is also indicated by the fact, cited last week by Zarko Trbojevic of the National Bank of... Trbojevic . The last exports to the USSR that have been paid carry the date of 25 April, and the surplus is growing. It seems that Yugoslav...and derivative products, chemicals, metalloids, and mineral oil products. D . Chemical installations. E. Installations for producing biological

Selenium speciation in human serum and its implications for epidemiologic research: a cross-sectional study.

PubMed

Vinceti, Marco; Grill, Peter; Malagoli, Carlotta; Filippini, Tommaso; Storani, Simone; Malavolti, Marcella; Michalke, Bernhard

2015-01-01

Observational studies addressing the relation between selenium and human health, particularly cancer risk, yielded inconsistent results, while most recent randomized trials showed a fairly consistent pattern suggesting null or adverse effects of the metalloid. One of the most plausible explanations for such inconsistencies is inadequate exposure assessment in observational studies, commonly carried out by measuring total Se content without taking into account the specific exposure to the individual chemical forms of the metalloid, whose toxic and nutritional properties may vary greatly. Data on the distribution of these species in human blood and their correlation with overall selenium levels are very limited. The concentrations of organic and inorganic selenium species were analyzed in serum of fifty subjects sampled from the general population of the municipality of Modena, northern Italy, aged from 35 to 70 years. Samples were collected during a 30-month period, and determinations of selenium species were carried out using high pressure liquid chromatography coupled with inductively coupled plasma dynamic reaction cell mass spectrometry. The majority of selenium was found to be present as organic species, but the inorganic forms showed higher levels than expected. These species showed limited correlations with age, sex and body mass index, while the organic forms increased in subjects consuming selenium-containing dietary supplements and decreased in smokers. The length of the sample storage period strongly influenced the distribution of selenium compounds, with a clear tendency towards higher inorganic and lower organic selenium levels over time. In multivariate analysis adjusting for potential confounders, total serum selenium correlated with human serum albumin-bound selenium and, in males, with two organic species of the metalloid (selenocysteine and glutathione peroxidase-bound selenium), while little association existed with the other organic forms and the inorganic ones. These findings highlight the potential for exposure misclassification of observational epidemiologic investigations based on overall selenium content in blood and possibly other tissues, and the critical role of the storage conditions for speciation analysis. Copyright © 2015 Elsevier GmbH. All rights reserved.

Nanoscale zero-valent iron for metal/metalloid removal from model hydraulic fracturing wastewater.

PubMed

Sun, Yuqing; Lei, Cheng; Khan, Eakalak; Chen, Season S; Tsang, Daniel C W; Ok, Yong Sik; Lin, Daohui; Feng, Yujie; Li, Xiang-Dong

2017-06-01

Nanoscale zero-valent iron (nZVI) was tested for the removal of Cu(II), Zn(II), Cr(VI), and As(V) in model saline wastewaters from hydraulic fracturing. Increasing ionic strength (I) from 0.35 to 4.10 M (Day-1 to Day-90 wastewaters) increased Cu(II) removal (25.4-80.0%), inhibited Zn(II) removal (58.7-42.9%), slightly increased and then reduced Cr(VI) removal (65.7-44.1%), and almost unaffected As(V) removal (66.7-75.1%) by 8-h reaction with nZVI at 1-2 g L -1 . The removal kinetics conformed to pseudo-second-order model, and increasing I decreased the surface area-normalized rate coefficient (k sa ) of Cu(II) and Cr(VI), probably because agglomeration of nZVI in saline wastewaters restricted diffusion of metal(loid)s to active surface sites. Increasing I induced severe Fe dissolution from 0.37 to 0.77% in DIW to 4.87-13.0% in Day-90 wastewater; and Fe dissolution showed a significant positive correlation with Cu(II) removal. With surface stabilization by alginate and polyvinyl alcohol, the performance of entrapped nZVI in Day-90 wastewater was improved for Zn(II) and Cr(VI), and Fe dissolution was restrained (3.20-7.36%). The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in removal trends from Day-1 to Day-90 wastewaters was attributed to: (i) distinctive removal mechanisms of Cu(II) and Cr(VI) (adsorption, (co-)precipitation, and reduction), compared to Zn(II) (adsorption) and As(V) (bidentate inner-sphere complexation); and (ii) changes in solution speciation (e.g., from Zn 2+ to ZnCl 3 - and ZnCl 4 2- ; from CrO 4 2- to CaCrO 4 complex). Bare nZVI was susceptible to variations in wastewater chemistry while entrapped nZVI was more stable and environmentally benign, which could be used to remove metals/metalloids before subsequent treatment for reuse/disposal. Copyright © 2017 Elsevier Ltd. All rights reserved.

Degassing of metals and metalloids from erupting seamount and mid-ocean ridge volcanoes: Observations and predictions

NASA Astrophysics Data System (ADS)

Rubin, Ken

1997-09-01

Recently, it has been reported that the element polonium degasses from mid-ocean ridge and seamount volcanoes during eruptions. Published and new observations on other volatile metal and metalloid elements can also be interpreted as indicating significant degassing of magmatic vapors during submarine eruptions. This process potentially plays an important role in the net transfer of chemical elements from erupting volcanoes to seawater in addition to that arising from sea floor hydrothermal systems. In this paper, a framework is constructed for predicting and assessing semiquantitatively the potential magnitude and chemical fingerprints in the water column of metal and metalloid degassing using (1) predictions from a summary of element volatilities during mafic subaerial volcanism worldwide and (2) limited data from submarine volcanic effusives. The latter include analyses of polonium and trace metals in near-volcano water masses sampled following a submarine eruption at Loihi seamount, Hawaii (1000 m bsl) in 1996. The element volatility predictions and observations show good agreement, considering the limited dataset. Some of the highest volatility main group and transition element enrichments in seawater over Loihi are predicted by the degassing mass transfer model I present. When expanded to cover all submarine volcanic activity, it is predicted that exit fluxes of these elements are up to 10 2-10 3 greater by degassing than by normal MOR hydrothermalism. In contrast, MOR exit fluxes of low volatility alkali and alkaline earth elements are likely 10 2-10 6 greater from hydrothermal inputs. Degassing inputs to the ocean are probably highly episodic, occurring almost entirely during eruptions; these are times of enhanced and abnormal hydrothermalism as well. Although major hydrothermal and degassing events may not be chemically recognizable in real water masses as wholly distinct entities, it is nevertheless possible to predict to what extent each process flavors the effluents of the other. Degassing at mid-ocean ridges may explain a variety of observations previously ascribed to complexities occurring during hydrothermal venting and/or fluid ascent in the buoyant hydrothermal plumes above ridges.

SERDP and ESTCP Expert Panel Workshop on Research and Development Needs for the In Situ Management of Contaminated Sediments

DTIC Science & Technology

2004-10-01

40 In Situ Treatment B15. Investigate technologies to examine the feasibility of in situ treatment, phytoremediation , and...44 C18. Develop a fundamental understanding of degradation pathways in support of biodegradation and phytoremediation technologies...www.atsdr.cdc.gov). Metals and metalloids including arsenic , cadmium, chromium, copper, and lead are natural earth elements that are released into the

Optoelectronic tuning of organoborylazadipyrromethenes via effective electronegativity at the metalloid center.

PubMed

Berhe, Seare A; Rodriguez, Marco T; Park, Eunsol; Nesterov, Vladimir N; Pan, Hongjun; Youngblood, W Justin

2014-03-03

Organoborylazadipyrromethenes were synthesized from free base and fluoroborylazadipyrromethenes and characterized with regard to their structural and electronic properties. B-N bond lengths, along with photophysical and redox behavior, appear dependent on the effective electronegativity at the boron atom as tuned by its substituents, with stronger electronegativity correlating to a shorter B-N bond length, red-shifted absorbance, enhanced fluorescence lifetime and yield, and positively shifted redox potentials.

Formation of amorphous metal alloys by chemical vapor deposition

DOEpatents

Mullendore, A.W.

1988-03-18

Amorphous alloys are deposited by a process of thermal dissociation of mixtures of organometallic compounds and metalloid hydrides,e.g., transition metal carbonyl, such as nickel carbonyl and diborane. Various sizes and shapes of deposits can be achieved, including near-net-shape free standing articles, multilayer deposits, and the like. Manipulation or absence of a magnetic field affects the nature and the structure of the deposit. 1 fig.

Ultrasound enhanced process for extracting metal species in supercritical fluids

DOEpatents

Wai, Chien M.; Enokida, Youichi

2006-10-31

Improved methods for the extraction or dissolution of metals, metalloids or their oxides, especially lanthanides, actinides, uranium or their oxides, into supercritical solvents containing an extractant are disclosed. The disclosed embodiments specifically include enhancing the extraction or dissolution efficiency with ultrasound. The present methods allow the direct, efficient dissolution of UO₂ or other uranium oxides without generating any waste stream or by-products.

Petroleum Quality Information System 2012 Annual Report

DTIC Science & Technology

2012-01-01

Data Summary ................................................................................. 26 Table 3- 9 : Neat Alcohol- to -Jet (ATJ8), 2012 Test... Metals : (ppm) 0.5 0.01 0.10 0.03 0.01 Alkali Metals and Metalloids: (ppm) 1.0 0.01 0.11 0.04 0.03 Hydrocarbon Composition...Alcohol- to -Jet (ATJ8), 2012 Test Results Table 3- 9 displays Neat Alcohol- to -Jet (ATJ8) results for the 2012 reporting period. Three analyses were

Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake.

PubMed

Thienpont, Joshua R; Korosi, Jennifer B; Hargan, Kathryn E; Williams, Trisha; Eickmeyer, David C; Kimpe, Linda E; Palmer, Michael J; Smol, John P; Blais, Jules M

2016-08-17

Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed $1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large quantities of arsenic and metals from the roasting of arsenopyrite ore. We examined the long-term ecological effects of roaster emissions on Pocket Lake, a small lake at the edge of the Giant Mine lease boundary, using a spectrum of palaeoenvironmental approaches. A dated sedimentary profile tracked striking increases (approx. 1700%) in arsenic concentrations coeval with the initiation of Giant Mine operations. Large increases in mercury, antimony and lead also occurred. Synchronous changes in biological indicator assemblages from multiple aquatic trophic levels, in both benthic and pelagic habitats, indicate dramatic ecological responses to extreme metal(loid) contamination. At the peak of contamination, all Cladocera, a keystone group of primary consumers, as well as all planktonic diatoms, were functionally lost from the sediment record. No biological recovery has been inferred, despite the fact that the bulk of metal(loid) emissions occurred more than 50 years ago, and the cessation of all ore-roasting activities in Yellowknife in 1999. © 2016 The Author(s).

Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples.

PubMed

Gil, F; Hernández, A F

2015-06-01

Human biomonitoring has become an important tool for the assessment of internal doses of metallic and metalloid elements. These elements are of great significance because of their toxic properties and wide distribution in environmental compartments. Although blood and urine are the most used and accepted matrices for human biomonitoring, other non-conventional samples (saliva, placenta, meconium, hair, nails, teeth, breast milk) may have practical advantages and would provide additional information on health risk. Nevertheless, the analysis of these compounds in biological matrices other than blood and urine has not yet been accepted as a useful tool for biomonitoring. The validation of analytical procedures is absolutely necessary for a proper implementation of non-conventional samples in biomonitoring programs. However, the lack of reliable and useful analytical methodologies to assess exposure to metallic elements, and the potential interference of external contamination and variation in biological features of non-conventional samples are important limitations for setting health-based reference values. The influence of potential confounding factors on metallic concentration should always be considered. More research is needed to ascertain whether or not non-conventional matrices offer definitive advantages over the traditional samples and to broaden the available database for establishing worldwide accepted reference values in non-exposed populations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multi-trophic level response to extreme metal contamination from gold mining in a subarctic lake

PubMed Central

Korosi, Jennifer B.; Hargan, Kathryn E.; Williams, Trisha; Eickmeyer, David C.; Kimpe, Linda E.; Palmer, Michael J.; Smol, John P.; Blais, Jules M.

2016-01-01

Giant Mine, located in the city of Yellowknife (Northwest Territories, Canada), is a dramatic example of subarctic legacy contamination from mining activities, with remediation costs projected to exceed $1 billion. Operational between 1948 and 2004, gold extraction at Giant Mine released large quantities of arsenic and metals from the roasting of arsenopyrite ore. We examined the long-term ecological effects of roaster emissions on Pocket Lake, a small lake at the edge of the Giant Mine lease boundary, using a spectrum of palaeoenvironmental approaches. A dated sedimentary profile tracked striking increases (approx. 1700%) in arsenic concentrations coeval with the initiation of Giant Mine operations. Large increases in mercury, antimony and lead also occurred. Synchronous changes in biological indicator assemblages from multiple aquatic trophic levels, in both benthic and pelagic habitats, indicate dramatic ecological responses to extreme metal(loid) contamination. At the peak of contamination, all Cladocera, a keystone group of primary consumers, as well as all planktonic diatoms, were functionally lost from the sediment record. No biological recovery has been inferred, despite the fact that the bulk of metal(loid) emissions occurred more than 50 years ago, and the cessation of all ore-roasting activities in Yellowknife in 1999. PMID:27534958

Geochemical disturbance of soil cover in the nonferrous mining centers of the Selenga River basin.

PubMed

Timofeev, Ivan V; Kosheleva, Natalia E

2017-08-01

The anthropogenic geochemical transformation of soil cover in large nonferrous mining centers of the Selenga River basin was assessed. The results of the geochemical survey of 2010-2012 revealed the spatial distribution patterns and abundances of 18 hazardous heavy metals and metalloids in the soils of Erdenet (Mongolia) and Zakamensk (Buryat republic, Russian Federation). In both cities, mining activities disturbed soil cover which accumulates Mo, Cu, As, Sb, W in Erdenet and Bi, W, Cd, Be, Pb, Mo, Sb in Zakamensk. Maximum accumulation of elements in Erdenet is restricted to the industrial zone. In Zakamensk, it has spread on ½ of the territory with the degree of multielemental pollution exceeding the extremely dangerous level by 16 times. The effect of mining centers on the state of the river system is local and does not spread to the Selenga River. Downstream from Erdenet, an artificial pool intercepts heavy metal and metalloid flows of the Erdenetii-Gol River. By contrast, downstream from the tailing dumps of the Dzhida tungsten-molybdenum plant the concentrations of ore elements W and Mo and their accessories Bi and Cd in the Modonkul River exceed background values by 146, 20, 57, and 21 times, respectively, decreasing by an order of magnitude 30 km downstream.

Use of a moss biomonitoring method to compile emission inventories for small-scale industries.

PubMed

Varela, Z; Aboal, J R; Carballeira, A; Real, C; Fernández, J A

2014-06-30

We used a method of detecting small-scale pollution sources (DSSP) that involves measurement of the concentrations of elements in moss tissues, with the following aims: (i) to determine any common qualitative patterns of contaminant emissions for individual industrial sectors, (ii) to compare any such patterns with previously described patterns, and (iii) to compile an inventory of the metals and metalloids emitted by the industries considered. Cluster analysis revealed that there were no common patterns of emission associated with the industrial sectors, probably because of differences in production processes and in the types of fuel and raw materials. However, when these variables were shared by different factories, the concentrations of the elements in moss tissues enabled the factories to be grouped according to their emissions. We compiled a list of the metals and metalloids emitted by the factories under study and found that the DSSP method was satisfactory for this purpose in most cases (53 of 56). The method appears to be a useful tool for compiling contaminant inventories; it may also be useful for determining the efficacy of technical improvements aimed at reducing the industrial emission of contaminants and could be incorporated in environmental monitoring and control programmes. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioremediation of a Complex Industrial Effluent by Biosorbents Derived from Freshwater Macroalgae

PubMed Central

Kidgell, Joel T.; de Nys, Rocky; Hu, Yi; Paul, Nicholas A.; Roberts, David A.

2014-01-01

Biosorption with macroalgae is a promising technology for the bioremediation of industrial effluents. However, the vast majority of research has been conducted on simple mock effluents with little data available on the performance of biosorbents in complex effluents. Here we evaluate the efficacy of dried biomass, biochar, and Fe-treated biomass and biochar to remediate 21 elements from a real-world industrial effluent from a coal-fired power station. The biosorbents were produced from the freshwater macroalga Oedogonium sp. (Chlorophyta) that is native to the industrial site from which the effluent was sourced, and which has been intensively cultivated to provide a feed stock for biosorbents. The effect of pH and exposure time on sorption was also assessed. These biosorbents showed specificity for different suites of elements, primarily differentiated by ionic charge. Overall, biochar and Fe-biochar were more successful biosorbents than their biomass counterparts. Fe-biochar adsorbed metalloids (As, Mo, and Se) at rates independent of effluent pH, while untreated biochar removed metals (Al, Cd, Ni and Zn) at rates dependent on pH. This study demonstrates that the biomass of Oedogonium is an effective substrate for the production of biosorbents to remediate both metals and metalloids from a complex industrial effluent. PMID:24919058

Arsenic, Lead, and Cadmium in U.S. Mushrooms and Substrate in Relation to Dietary Exposure.

PubMed

Seyfferth, Angelia L; McClatchy, Colleen; Paukett, Michelle

2016-09-06

Wild mushrooms can absorb high quantities of metal(loid)s, yet the concentration, speciation, and localization of As, Pb, and Cd in cultivated mushrooms, particularly in the United States, are unresolved. We collected 40 samples of 12 types of raw mushrooms from 2 geographic locations that produce the majority of marketable U.S. mushrooms and analyzed the total As, Pb, and Cd content, the speciation and localization of As in select samples, and assessed the metal sources and substrate-to-fruit transfer at one representative farm. Cremini mushrooms contained significantly higher total As concentrations than Shiitake and localized the As differently; while As in Cremini was distributed throughout the fruiting body, it was localized to the hymenophore region in Shiitake. Cd was significantly higher in Royal Trumpet than in White Button, Cremini, and Portobello, while no difference was observed in Pb levels among the mushrooms. Concentrations of As, Pb, and Cd were less than 1 μg g(-1) d.w. in all mushroom samples, and the overall risk of As, Cd, and Pb intake from mushroom consumption is low in the U.S. However, higher percentages of tolerable intake levels are observed when calculating risk based on single serving-sizes or when substrate contains elevated levels of metal(loid)s.

Dynamics of multiple elements in fast decomposing vegetable residues.

PubMed

Cao, Chun; Liu, Si-Qi; Ma, Zhen-Bang; Lin, Yun; Su, Qiong; Chen, Huan; Wang, Jun-Jian

2018-03-01

Litter decomposition regulates the cycling of nutrients and toxicants but is poorly studied in farmlands. To understand the unavoidable in-situ decomposition process, we quantified the dynamics of C, H, N, As, Ca, Cd, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, and Zn during a 180-d decomposition study in leafy lettuce (Lactuca sativa var. longifoliaf) and rape (Brassica chinensis) residues in a wastewater-irrigated farmland in northwestern China. Different from most studied natural ecosystems, the managed vegetable farmland had a much faster litter decomposition rate (half-life of 18-60d), and interestingly, faster decomposition of roots relative to leaves for both the vegetables. Faster root decomposition can be explained by the initial biochemical composition (more O-alkyl C and less alkyl and aromatic C) but not the C/N stoichiometry. Multi-element dynamics varied greatly, with C, H, N, K, and Na being highly released (remaining proportion<20%), Ca, Cd, Cr, Mg, Ni, and Zn released, and As, Cu, Fe, Hg, Mn, and Pb possibly accumulated. Although vegetable residues serve as temporary sinks of some metal(loid)s, their fast decomposition, particularly for the O-alkyl-C-rich leafy-lettuce roots, suggest that toxic metal(loid)s can be released from residues, which therefore become secondary pollution sources. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved Density Functional Tight Binding Potentials for Metalloid Aluminum Clusters

DTIC Science & Technology

2016-06-01

simulations of the oxidation of Al4Cp * 4 show reasonable comparison with a DFT-based Car -Parrinello method, including correct prediction of hydride transfers...comparison with a DFT-based Car -Parrinello method, including correct prediction of hydride transfers from Cp* to the metal centers during the...initio molecular dynamics of the oxidation of Al4Cp * 4 using a DFT-based Car -Parrinello method. This simulation, which 43 several months on the

The Effect of Soil Properties on Metal Bioavailability: Field Scale Validation to Support Regulatory Acceptance

DTIC Science & Technology

2014-06-01

unacceptable levels of the toxic metal(loid)s arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb). With the exception of Pb contaminated soils, human...remediation and closure. Lead (Pb), arsenic (As), chromium (Cr), and cadmium (Cd) are toxic (i.e., capable of producing an unwanted, deleterious effect...lagoon are contaminated with high concentrations of lead , chromium, and cadmium . 14 Deseret Chemical Depot: The Deseret Chemical Depot is

Demonstration/Validation of the Snap Sampler Passive Groundwater Sampling Device at the Former McClellan Air Force Base

DTIC Science & Technology

2011-02-01

and Development Center Fe Iron gpd Gallons per Day HDPE High Density Polyethylene Hg Mercury ICP Inductively Coupled Plasma ICP/MS...Inductively Coupled Plasma Mass Spectrometry IROD Interim Record of Decision ITRC Interstate Technology and Regulatory Council K Potassium Kow...alkaline earth metals, alkali metals, and a metalloid, were sampled. This particular demonstration took place at the McClellan Air Force Base (AFB) in

Iron(II)-Catalyzed Iron Atom Exchange and Mineralogical Changes in Iron-rich Organic Freshwater Flocs: An Iron Isotope Tracer Study.

PubMed

ThomasArrigo, Laurel K; Mikutta, Christian; Byrne, James; Kappler, Andreas; Kretzschmar, Ruben

2017-06-20

In freshwater wetlands, organic flocs are often found enriched in trace metal(loid)s associated with poorly crystalline Fe(III)-(oxyhydr)oxides. Under reducing conditions, flocs may become exposed to aqueous Fe(II), triggering Fe(II)-catalyzed mineral transformations and trace metal(loid) release. In this study, pure ferrihydrite, a synthetic ferrihydrite-polygalacturonic acid coprecipitate (16.7 wt % C), and As- (1280 and 1230 mg/kg) and organic matter (OM)-rich (18.1 and 21.8 wt % C) freshwater flocs dominated by ferrihydrite and nanocrystalline lepidocrocite were reacted with an isotopically enriched 57 Fe(II) solution (0.1 or 1.0 mM Fe(II)) at pH 5.5 and 7. Using a combination of wet chemistry, Fe isotope analysis, X-ray absorption spectroscopy (XAS), 57 Fe Mössbauer spectroscopy and X-ray diffraction, we followed the Fe atom exchange kinetics and secondary mineral formation over 1 week. When reacted with Fe(II) at pH 7, pure ferrihydrite exhibited rapid Fe atom exchange at both Fe(II) concentrations, reaching 76 and 89% atom exchange in experiments with 0.1 and 1 mM Fe(II), respectively. XAS data revealed that it transformed into goethite (21%) at the lower Fe(II) concentration and into lepidocrocite (73%) and goethite (27%) at the higher Fe(II) concentration. Despite smaller Fe mineral particles in the coprecipitate and flocs as compared to pure ferrihydrite (inferred from Mössbauer-derived blocking temperatures), these samples showed reduced Fe atom exchange (9-30% at pH 7) and inhibited secondary mineral formation. No release of As was recorded for Fe(II)-reacted flocs. Our findings indicate that carbohydrate-rich OM in flocs stabilizes poorly crystalline Fe minerals against Fe(II)-catalyzed transformation by surface-site blockage and/or organic Fe(II) complexation. This hinders the extent of Fe atom exchange at mineral surfaces and secondary mineral formation, which may consequently impair Fe(II)-activated trace metal(loid) release. Thus, under short-term Fe(III)-reducing conditions facilitating the fast attainment of solid-solution equilibria (e.g., in stagnant waters), Fe-rich freshwater flocs are expected to remain an effective sink for trace elements.

Aging effects on chemical transformation and metal(loid) removal by entrapped nanoscale zero-valent iron for hydraulic fracturing wastewater treatment.

PubMed

Sun, Yuqing; Lei, Cheng; Khan, Eakalak; Chen, Season S; Tsang, Daniel C W; Ok, Yong Sik; Lin, Daohui; Feng, Yujie; Li, Xiang-Dong

2018-02-15

In this study, alginate and polyvinyl alcohol (PVA)-alginate entrapped nanoscale zero-valent iron (nZVI) was tested for structural evolution, chemical transformation, and metals/metalloids removal (Cu(II), Cr(VI), Zn(II), and As(V)) after 1-2month passivation in model saline wastewaters from hydraulic fracturing. X-ray diffraction analysis confirmed successful prevention of Fe 0 corrosion by polymeric entrapment. Increasing ionic strength (I) from 0 to 4.10M (deionized water to Day-90 fracturing wastewater (FWW)) with prolonged aging time induced chemical instability of alginate due to dissociation of carboxyl groups and competition for hydrogen bonding with nZVI, which caused high Na (7.17%) and total organic carbon (24.6%) dissolution from PVA-alginate entrapped nZVI after 2-month immersion in Day-90 FWW. Compared to freshly-made beads, 2-month aging of PVA-alginate entrapped nZVI in Day-90 FWW promoted Cu(II) and Cr(VI) uptake in terms of the highest removal efficiency (84.2% and 70.8%), pseudo-second-order surface area-normalized rate coefficient k sa (2.09×10 -1 Lm -2 h -1 and 1.84×10 -1 Lm -2 h -1 ), and Fe dissolution after 8-h reaction (13.9% and 8.45%). However, the same conditions inhibited Zn(II) and As(V) sequestration in terms of the lowest removal efficiency (31.2% and 39.8%) by PVA-alginate nZVI and k sa (4.74×10 -2 Lm -2 h -1 and 6.15×10 -2 Lm -2 h -1 ) by alginate nZVI. The X-ray spectroscopic analysis and chemical speciation modelling demonstrated that the difference in metals/metalloids removal by entrapped nZVI after aging was attributed to distinctive removal mechanisms: (i) enhanced Cu(II) and Cr(VI) removal by nZVI reduction with accelerated electron transfer after pronounced dissolution of non-conductive polymeric immobilization matrix; (ii) suppressed Zn(II) and As(V) removal by nZVI adsorption due to restrained mass transfer after blockage of surface-active micropores. Entrapped nZVI was chemically fragile and should be properly stored and regularly replaced for good performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical Speciation and Metallomics.

PubMed

de Jesus, Jemmyson Romário; da Costa, Luana Ferreira; Lehmann, Eraldo Luiz; Galazzi, Rodrigo Moretto; Madrid, Katherine Chacón; Arruda, Marco Aurélio Zezzi

2018-01-01

Chemical speciation approaches is an inherent part of metallomics, once metals/metalloids and organic structures need to be currently evaluated for attaining metallomics studies. Then, this chapter focuses on the applications of the chemical speciation applied to the human health risk, food and human diet, drugs, forensic, nanoscience, and geological metallomics, also pointing out the advances in such area. Some aspects regarding sample preparation is commented along this chapter, and some strategies for maintaining the integrity of the metallomics information are also emphasized.

Petroleum Quality Information System (PQIS) 2011 Annual Report

DTIC Science & Technology

2011-01-01

page 9 ) shows their locations worldwide. These regional designations are used throughout the report to identify the procurement source by geographic...0.370 0.370 Thermal Stability: Pressure Difference, mm Hg @ 280 °C 25 0.00 0.00 0.00 0.00 Metals : (ppm) 0.5 0.01 0.01 0.01 0.01... Alkali Metals and Metalloids: (ppm) 1.0 0.01 0.02 0.01 0.01 Hydrocarbon Composition: Paraffins (normal and iso), (mass %) Balance

Applying carbon dioxide, plant growth-promoting rhizobacterium and EDTA can enhance the phytoremediation efficiency of ryegrass in a soil polluted with zinc, arsenic, cadmium and lead.

PubMed

Guo, Junkang; Feng, Renwei; Ding, Yongzhen; Wang, Ruigang

2014-08-01

This study was conducted to investigate the use of elevated carbon dioxide (CO2), plant growth-promoting rhizobacterium Burkholderia sp. D54 (PGPR) and ethylenediaminetetraacetic acid (EDTA) to enhance the phytoextraction efficiency of ryegrass in response to multiple heavy metal (or metalloid)-polluted soil containing zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). All of the single or combined CO2, PGPR and EDTA treatments promoted ryegrass growth. The stimulation of ryegrass growth by CO2 and PGPR could primarily be attributed to the regulation of photosynthesis rather than decreased levels of Zn, As and Cd in the shoots. Most treatments seemed to reduce the Zn, As and Cd contents in the shoots, which might be associated with enhanced shoot biomass, thus causing a "dilution effect" regarding their levels. The combined treatments seemed to perform better than single treatments in removing Zn, As, Cd and Pb from soil, judging from the larger biomass and relatively higher total amounts (TAs) of Zn, As, Cd and Pb in both the shoots and roots. Therefore, we suggest that the CO2 plus PGPR treatment will be suitable for removing Zn, As, Cd and Pb from heavy metal (or metalloid)-polluted soils using ryegrass as a phytoremediation material. Copyright © 2014 Elsevier Ltd. All rights reserved.

The pH-dependent long-term stability of an amorphous manganese oxide in smelter-polluted soils: implication for chemical stabilization of metals and metalloids.

PubMed

Ettler, Vojtěch; Tomášová, Zdeňka; Komárek, Michael; Mihaljevič, Martin; Šebek, Ondřej; Michálková, Zuzana

2015-04-09

An amorphous manganese oxide (AMO) and a Pb smelter-polluted agricultural soil amended with the AMO and incubated for 2 and 6 months were subjected to a pH-static leaching procedure (pH 3-8) to verify the chemical stabilization effect on metals and metalloids. The AMO stability in pure water was pH-dependent with the highest Mn release at pH 3 (47% dissolved) and the lowest at pH 8 (0.14% dissolved). Secondary rhodochrosite (MnCO3) was formed at the AMO surfaces at pH>5. The AMO dissolved significantly less after 6 months of incubation. Sequential extraction analysis indicated that "labile" fraction of As, Pb and Sb in soil significantly decreased after AMO amendment. The pH-static experiments indicated that no effect on leaching was observed for Cd and Zn after AMO treatments, whereas the leaching of As, Cu, Pb and Sb decreased down to 20%, 35%, 7% and 11% of the control, respectively. The remediation efficiency was more pronounced under acidic conditions and the time of incubation generally led to increased retention of the targeted contaminants. The AMO was found to be a promising agent for the chemical stabilization of polluted soils. Copyright © 2015 Elsevier B.V. All rights reserved.

Ecological Risk of Heavy Metals and a Metalloid in Agricultural Soils in Tarkwa, Ghana

PubMed Central

Bortey-Sam, Nesta; Nakayama, Shouta M. M.; Akoto, Osei; Ikenaka, Yoshinori; Baidoo, Elvis; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-01-01

Heavy metals and a metalloid in agricultural soils in 19 communities in Tarkwa were analyzed to assess the potential ecological risk. A total of 147 soil samples were collected in June, 2012 and analyzed for As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn. Mean concentrations (mg/kg dw) of heavy metals in the communities decreased in order of Zn (39) ˃ Cr (21) ˃ Pb (7.2) ˃ Cu (6.2) ˃ As (4.4) ˃ Ni (3.7) ˃ Co (1.8) ˃ Hg (0.32) ˃ Cd (0.050). Correlations among heavy metals and soil properties indicated that soil organic matter could have substantial influence on the total contents of these metals in soil. From the results, integrated pollution (Cdeg) in some communities such as, Wangarakrom (11), Badukrom (13) and T–Tamso (17) indicated high pollution with toxic metals, especially from As and Hg. Potential ecological risk (RI) indices indicated low (Mile 7) to high risks (Wangarakrom; Badukrom) of metals. Based on pollution coefficient (Cif), Cdeg, monomial ecological risk (Eir) and RI, the investigated soils fall within low to high contamination and risk of heavy metals to the ecological system especially plants, soil invertebrates and/or mammalian wildlife. This represented moderate potential ecological risk in the study area, and mining activities have played a significant role. PMID:26378563

Pyridine-2,6-Bis(Thiocarboxylic Acid) Produced by Pseudomonas stutzeri KC Reduces and Precipitates Selenium and Tellurium Oxyanions

PubMed Central

Zawadzka, Anna M.; Crawford, Ronald L.; Paszczynski, Andrzej J.

2006-01-01

The siderophore of Pseudomonas stutzeri KC, pyridine-2,6-bis(thiocarboxylic acid) (pdtc), is shown to detoxify selenium and tellurium oxyanions in bacterial cultures. A mechanism for pdtc's detoxification of tellurite and selenite is proposed. The mechanism is based upon determination using mass spectrometry and energy-dispersive X-ray spectrometry of the chemical structures of compounds formed during initial reactions of tellurite and selenite with pdtc. Selenite and tellurite are reduced by pdtc or its hydrolysis product H2S, forming zero-valent pdtc selenides and pdtc tellurides that precipitate from solution. These insoluble compounds then hydrolyze, releasing nanometer-sized particles of elemental selenium or tellurium. Electron microscopy studies showed both extracellular precipitation and internal deposition of these metalloids by bacterial cells. The precipitates formed with synthetic pdtc were similar to those formed in pdtc-producing cultures of P. stutzeri KC. Culture filtrates of P. stutzeri KC containing pdtc were also active in removing selenite and precipitating elemental selenium and tellurium. The pdtc-producing wild-type strain KC conferred higher tolerance against selenite and tellurite toxicity than a pdtc-negative mutant strain, CTN1. These observations support the hypothesis that pdtc not only functions as a siderophore but also is involved in an initial line of defense against toxicity from various metals and metalloids. PMID:16672449

Electronic shell structure in Ga12 icosahedra and the relation to the bulk forms of gallium.

PubMed

Schebarchov, D; Gaston, N

2012-07-28

The electronic structure of known cluster compounds with a cage-like icosahedral Ga(12) centre is studied by first-principles theoretical methods, based on density functional theory. We consider these hollow metalloid nanostructures in the context of the polymorphism of the bulk, and identify a close relation to the α phase of gallium. This previously unrecognised connection is established using the electron localisation function, which reveals the ubiquitous presence of radially-pointing covalent bonds around the Ga(12) centre--analogous to the covalent bonds between buckled deltahedral planes in α-Ga. Furthermore, we find prominent superatom shell structure in these clusters, despite their hollow icosahedral motif and the presence of covalent bonds. The exact nature of the electronic shell structure is contrasted with simple electron shell models based on jellium, and we demonstrate how the interplay between gallium dimerisation, ligand- and crystal-field effects can alter the splitting of the partially filled 1F shell. Finally, in the unique compound where the Ga(12) centre is bridged by six phosphorus ligands, the electronic structure most closely resembles that of δ-Ga and there are no well-defined superatom orbitals. The results of this comprehensive study bring new insights into the nature of chemical bonding in metalloid gallium compounds and the relation to bulk gallium metal, and they may also guide the development of more general models for ligand-protected clusters.

Removal of hydrogen sulfide and sulfur dioxide by carbons impregnated with triethylenediamine.

PubMed

Wu, Li-Chun; Chang, Tsu-Hua; Chung, Ying-Chien

2007-12-01

Activated carbon (AC) adsorption has long been considered to be a readily available technology for providing protection against exposure to acutely toxic gases. However, ACs without chemical impregnation have proven to be much less efficient than impregnated ACs in terms of gas removal. The impregnated ACs in current use are usually modified with metalloid impregnation agents (ASC-carbons; copper, chromium, or silver) to simultaneously enhance the chemical and physical properties of the ACs in removing specific poisonous gases. These metalloid agents, however, can cause acute poisoning to both humans and the environment, thereby necessitating the search for organic impregnation agents that present a much lower risk. The aim of the study reported here was to assess AC or ASC-carbon impregnated with triethylenediamine (TEDA) in terms of its adsorption capability for simulated hydrogen sulfide (H2S) and sulfur dioxide (SO2) gases. The investigation was undergone in a properly designed laboratory-scale and industrial fume hood evaluation. Using the system reported here, we obtained a significant adsorption: the removal capability for H2S and SO2 was 375 and 229 mg/g-C, respectively. BET measurements, element analysis, scanning electron microscopy, and energy dispersive spectrometry identified the removal mechanism for TEDA-impregnated AC to be both chemical and physical adsorption. Chemical adsorption and oxidation were the primary means by which TEDA-impregnated ASC-carbons removed the simulated gases.

Arsenic toxicity in the human nerve cell line SK-N-SH in the presence of chromium and copper

PubMed Central

HU, LIGANG; GREER, JUSTIN B.; SOLO-GABRIELE, HELENA; FIEBER, LYNNE A.; CAI, YONG

2013-01-01

As, Cr, and Cu represent one potential combination of multiple metals/metalloids exposures since these three elements are simultaneously leached from chromated copper arsenate (CCA)-treated wood, a common product used for building construction, at levels that can be potentially harmful. This study investigated the neurotoxicity of As associated with CCA-treated wood when accompanied by Cr and Cu. The toxicity was evaluated on basis of a cytotoxicity model using human neuroblastoma cell line SK-N-SH. The cells were cultured with CCA-treated wood leachates or with solutions containing arsenate [As(V)], divalent copper [Cu(II)], trivalent chromium [Cr(III)] alone or in different combinations of the three elements. The toxicity was evaluated using variations in cell replication compared to controls after 96 hrs exposure. Among the three elements present in wood leachates, As played the primary role in the observed toxic effects, which exerted through multiple pathways, including the generation of oxidative stress. DOM affected the absorption of metals/metalloids into the test cells, which however did not obviously appear to impact toxicity. As toxicity was enhanced by Cu(II) and inhibited by Cr(III) at concentrations below U.S. EPA’s allowable maximum contaminant levels in drinking waters. Thus assessing As toxicity in real environments is not sufficient if based solely on the result from As. PMID:23473430

Patterns of metal distribution in hypersaline microbialites during early diagenesis: Implications for the fossil record.

PubMed

Sforna, M C; Daye, M; Philippot, P; Somogyi, A; van Zuilen, M A; Medjoubi, K; Gérard, E; Jamme, F; Dupraz, C; Braissant, O; Glunk, C; Visscher, P T

2017-03-01

The use of metals as biosignatures in the fossil stromatolite record requires understanding of the processes controlling the initial metal(loid) incorporation and diagenetic preservation in living microbialites. Here, we report the distribution of metals and the organic fraction within the lithifying microbialite of the hypersaline Big Pond Lake (Bahamas). Using synchrotron-based X-ray microfluorescence, confocal, and biphoton microscopies at different scales (cm-μm) in combination with traditional geochemical analyses, we show that the initial cation sorption at the surface of an active microbialite is governed by passive binding to the organic matrix, resulting in a homogeneous metal distribution. During early diagenesis, the metabolic activity in deeper microbialite layers slows down and the distribution of the metals becomes progressively heterogeneous, resulting from remobilization and concentration as metal(loid)-enriched sulfides, which are aligned with the lamination of the microbialite. In addition, we were able to identify globules containing significant Mn, Cu, Zn, and As enrichments potentially produced through microbial activity. The similarity of the metal(loid) distributions observed in the Big Pond microbialite to those observed in the Archean stromatolites of Tumbiana provides the foundation for a conceptual model of the evolution of the metal distribution through initial growth, early diagenesis, and fossilization of a microbialite, with a potential application to the fossil record. © 2016 John Wiley & Sons Ltd.

Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples

PubMed Central

Lombi, Enzo; de Jonge, Martin D.; Donner, Erica; Kopittke, Peter M.; Howard, Daryl L.; Kirkham, Robin; Ryan, Chris G.; Paterson, David

2011-01-01

Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples. PMID:21674049

Influence of environmental parameters and of their interactions on the release of metal(loid)s from a construction material in hydraulic engineering.

PubMed

Schmukat, A; Duester, L; Goryunova, E; Ecker, D; Heininger, P; Ternes, T A

2016-03-05

Besides the leaching behaviour of a construction material under standardised test-specific conditions with laboratory water, for some construction materials it is advisable to test their environmental behaviour also under close to end use conditions. The envisaged end use combined with the product characteristics (e.g. mineral phases) is decisive for the choice of environmental factors that may change the release of substance that potentially cause adverse environmental effects (e.g. fertilisation or ecotoxicity). At the moment an experimental link is missing between mono-factorial standardised test systems and non standardised complex incubation experiments such as mesocosms which are closer to environmental conditions. Multi-factorial batch experiments may have the potential to close the gap. To verify this, batch experiments with copper slag were performed which is used as armour stones in hydraulic engineering. Design of experiments (DoE) was applied to evaluate the impact of pH, ionic strength, temperature and sediment content on the release of As, Cu, Mo, Ni, Pb, Sb and Zn. The study shows that release and sediment-eluent partitioning of metal(loid)s are impacted by interactions between the studied factors. Under the prevalent test conditions sediment acts as a sink enhancing most strongly the release of elements from the material. Copyright © 2015 Elsevier B.V. All rights reserved.

Physiological response of Cistus monspeliensis L. growing in two mine areas of the Iberian Pyrite Belt

NASA Astrophysics Data System (ADS)

Arenas Lago, Daniel; Carvalho, Luisa C.; Santos, Erika S.; Abreu, Maria Manuela; Andrade, María Luisa

2015-04-01

São Domingos and Lousal mines, nowadays in abandoned state, are located in Portugal, in the Iberian Pyrite Belt, a world-class volcanic-hosted massive sulfide. As a result of the intense mining activity large volumes of wastes containing metal(loid)s were partly exposed to weathering realising potential hazardous elements contaminating waters, soils and sediments. In both mines, a great part of the contaminated areas is relatively covered by several wild species. These species have developed mechanisms of response to oxidative stress originated by high concentration of metal(loid)s in plant tissues, whose presence leads to the formation of reactive oxygen species, thus causing oxidative damage. The main objective of this study was to evaluate changes in the ecophysiological behaviour of Cistus monspeliensis L., which grows spontaneously in both mine areas, in soils containing high concentrations of metal(loid)s. With this purpose, the variation of some physiological parameters was analysed in order to identify which parameters can be indicators of the plant'sresponse to oxidative stress. Representative soils from rhizosphere and plants were sampled, in the same locations, in different areas of São Domingos and Lousal mines and in an uncontaminated area nearby São Domingos. Soils were characterized for the classic properties. Multielemental total concentration was analysed in soils and plants (shoots and roots), and multielemental concentration in the available fraction of soils. Pigments (chlorophylls, anthocyanins and carotenoids), glutathione, ascorbate, H2O2 and antioxidative enzyme activities were measured in plant shoots. In general, total and available concentrations (mg/kg) of Zn (total 149-463; available 2-16), As (total 62-3030; available 0.03-1.9), Cd (total 0.3-1.2; available 0.01-0.05), Cu (total 79-375; available 0.8-10) and Pb (total 95-9210; available 0.2-40) are significantly higher in mine soils than in uncontaminated soils Zn (total 92-123; available <0.6), As (total 18-20; available <0.08), Cd (total <0.3; available <0.01), Cu (total 25-47; available <0.1) and Pb (total 28-50; < available 0.08). Also, shoots and roots of the plants collected in both mine areas contain in general higher concentrations (mg/kg) of As (shoot 0.6-75; root 0.8-13.5)and Pb (shoot 2.5-35; root 1.8-91) than plants from uncontaminated soils (As (shoot 0.8-1.2; root <0.8); Pb (shoot <3.2; root 4-9)). Physiological analyses showed a decrease in chlorophylls, anthocyanins, ascorbic acid levels and percentage of glutathione in shoots of C. monspeliensis collected in contaminated areas compared to the plants growing on uncontaminated soils. The decrease in anthocyanins is correlated with the content of Cd and Zn in plants shoots. A negative correlation was observed between carotenoid contents and Cd concentration in shoots in both mine areas. Arsenic and Cd concentrations were correlated positively with an increase of glutathione in plants grown on mine soils. Moreover, high concentrations of metals in mine soils triggered defence mechanisms against oxidative stress, in the form of increased antioxidative enzyme activity. Therefore, these results reveal that C. monspeliensis is a species adapted to unfavourable environments with high concentrations of metal(loid)s, adjusting its tolerance mechanisms at the metabolic and physiological levels.

Linear combination fitting data

EPA Pesticide Factsheets

The dataset shows the weighted percentage of arsenic speciation for untreated and treated soil samples with amendments designed to immobilize arsenic in soils.This dataset is associated with the following publication:Mele, E., E. Donner, A. Juhasz, G. Brunetti, E. Smith, A. Betts , P. Castaldi, S. Deiana, K. Scheckel , and E. Lombi. In situ fixation of metal(loid)s in contaminated soils: a comparison of conventional, by product and engineered soil amendments. David L. Sedlak ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 49: 13501-13509, (2015).

Mineral resource of the month: boron

USGS Publications Warehouse

Crangle, Robert D.

2012-01-01

The article offers information on the mineral, boron. Boron compounds, particularly borates, have more commercial applications than its elemental relative which is a metalloid. Making up the 90% of the borates that are used worldwide are colemanite, kernite, tincal, and ulexite. The main borate deposits are located in the Mojave Desert of the U.S., the Tethyan belt in southern Asia, and the Andean belt of South America. Underground and surface mining are being used in gathering boron compounds. INSETS: Fun facts;Boron production and consumption.

Critical Elements in Produced Fluids from Nevada and Utah

DOE Data Explorer

Simmons, Stuart

2017-07-27

Critical elements and related analytical data for produced fluids from geothermal fields in Nevada and Utah, Sevier thermal belt hot springs, Utah, and Uinta basin oil-gas wells, Utah are reported. Analytical results include pH, major species, trace elements, transition metals, other metals, metalloids and REEs. Gas samples were collected and analyzed from Beowawe, Dixie Valley, Roosevelt Hot Springs, and Thermo. Helium gases and helium isotopes were analyzed on samples collected at Patua, San Emido and two wells in the Uinta basin.

Petroleum Quality Information System 2013 Annual Report

DTIC Science & Technology

2013-01-01

Content: (ppm) 10 0.10 Metals : (ppm) 0.5 total 0.10 Alkali Metals and Metalloids: (ppm) 1 total 0.99 Table 3-12 displays Direct Sugar to ...183 146 189 185 111 143 0 50 100 150 200 250 300 350 400 450 2005 2006 2007 2008 2009 2010 2011 2012 2013 To ta l S am pl es Calendar Year In-Line...Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour

Oxidation of aqueous EDTA and associated organics and coprecipitation of inorganics by ambient iron-mediated aeration.

PubMed

Englehardt, James D; Meeroff, Daniel E; Echegoyen, Luis; Deng, Yang; Raymo, Françisco M; Shibata, Tomoyuki

2007-01-01

Cationic metal and radionuclide contaminants can be extracted from soils to groundwater with sequestering agents such as EDTA. However, EDTA must then be removed fromthe groundwater, by advanced oxidation or specialized biological treatment. In this work, aqueous individual metal-EDTA solutions were aerated with steel wool for 25 h, at ambient pH, temperature, and pressure. Removal of approximately 99% of EDTA (0.09-1.78 mM); glyoxylic acid (0.153 mM); chelated Cd2+ (0.94 and 0.0952 mM), Pb2+ (0.0502 mM), and Hg2+ (0.0419 mM); and free chromate and vanadate was shown. EDTA was oxidized to glyoxylic acid and formaldehyde, and metals/metalloids were coprecipitated together with iron oxyhydroxide floc. Free arsenite and arsenate were each removed at 99.97%. Free Sr2+, and chelated Ni2+ were removed at 92% and 63%, respectively. Similar removals were obtained from mixtures, including 99.996+/-0.004% removal of total arsenic (95% confidence). Traces of iminodiacetic acid, nitrilotriacetic acid, and ethylenediaminetriacetic acid were detected after 25 h. Results are consistent with first-order, solution-phase oxidation of EDTA and glyoxylic acid by ferryl ion and H202, respectively, with inhibition due to sludge accumulation, and equilibrium metal coprecipitation. This ambient process, to our knowledge previously unknown, agrees with recently reported findings and shows promise for remediation of metals, metalloids, and radionuclides in wastewater, soil, and sediment.

Analysis of arsenic and antimony distribution within plants growing at an old mine site in Ouche (Cantal, France) and identification of species suitable for site revegetation.

PubMed

Jana, Ulrike; Chassany, Vincent; Bertrand, Georges; Castrec-Rouelle, Maryse; Aubry, Emmanuel; Boudsocq, Simon; Laffray, Daniel; Repellin, Anne

2012-11-15

One of the objectives of this study was to assess the contamination levels in the tailings of an old antimony mine site located in Ouche (Cantal, France). Throughout the 1.3 ha site, homogenous concentrations of antimony and arsenic, a by-product of the operation, were found along 0-0.5 m-deep profiles. Maximum concentrations for antimony and arsenic were 5780 mg kg(-1) dry tailings and 852 mg kg(-1) dry tailings, respectively. Despite the presence of the contaminants and the low pH and organic matter contents of the tailings, several patches of vegetation were found. Botanical identification determined 12 different genera/species. The largest and most abundant plants were adult pines (Pinus sylvestris), birches (Betula pendula) and the bulrush (Juncus effusus). The distribution of the metalloids within specimens of each genera/species was analysed in order to deduce their concentration and translocation capacities. This was the second goal of this work. All plant specimens were highly contaminated with both metalloids. Most were root accumulators with root to shoot translocation factors <1. Whereas contamination levels were high overall, species with both a low translocation factor and a low root accumulation coefficient were identified as suitable candidates for the complete revegetation of the site. Species combining those characteristics were the perennials P. sylvestris, B. pendula, Cytisus scoparius and the herbaceous Plantago major, and Deschampsia flexuosa. Copyright © 2012 Elsevier Ltd. All rights reserved.

Selenite Protection of Tellurite Toxicity Toward Escherichia coli

PubMed Central

Vrionis, Helen A.; Wang, Siyuan; Haslam, Bronwyn; Turner, Raymond J.

2015-01-01

In this work the influence of selenite on metal resistance in Escherichia coli was examined. Both synergistic and antagonistic resistance and toxicities were found upon co exposure with selenite. In wild type cells co-exposure to selenite had little effect on arsenic resistance, decreased resistance to cadmium and mercury but led to a dramatically increased resistance to tellurite of 32-fold. Due to the potential importance of thiol chemistry in metal biochemistry, deletion strains in γ-glutamylcysteine synthetase (key step in glutathione biosynthesis, encoded by gshA), thioredoxin (trxA), glutaredoxin (grxA), glutathione oxidoreductase (gor), and the periplasmic glutathione transporter (cydD) were also evaluated for resistance to various metals in the presence of selenite. The protective effect of selenite on tellurite toxicity was seen in several of the mutants and was pronounced in the gshA mutant were resistance to tellurite was increased up to 1000-fold relative to growth in the absence of selenite. Thiol oxidation studies revealed a faster rate of loss of reduced thiol content in the cell with selenite than with tellurite, indicating differential thiol reactivity. Selenite addition resulted in reactive oxygen species (ROS) production equivalent to levels associated with H2O2 addition. Tellurite addition resulted in considerably lower ROS generation while vanadate and chromate treatment did not increase ROS production above that of background. This work shows increased resistance toward most oxyanions in mutants of thiol redox suggesting that metalloid reaction with thiol components such as glutathione actually enhances toxicity of some metalloids. PMID:26732755

PERIODIC CLASSIFICATION AND THE PROUST LAW (in French)

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

Rinck, E.; Feschotte, P.

1962-04-01

Progress realized in the knowledge of the solid state has permitted the identification of numerous crystalline phases whose composition was not defined in the meaning of the Proust law. Its rigorous validity has nevertheless served as a beginning for atomic theory; it continues to be utilized in the measurement of atomic weights and remains valid for the vast region of organic chemistry. The investigation of the limits of the validity of the Proust law leads to some peculiarities of the metallic state which are closely connected to the periodic classification of elements. A new arrangement of the periodic table, permittingmore » for the first time the integration of the rare earths and giving to hydrogen a very special place, takes into consideration a distinction between true metals and earth metals. This distinction is imposed by the fact that the Proust law, valid for compounds between metalloids and earth metals, is not always followed when these same metalloids unite with true metals. Finally. this law loses all significance in alloys between true metals. The exceptions to this rule are explained by the specialization of chemical properties which is shown when one passes from short periods to long periods, hydrogen and the metals with short period being considered as undifferentiated elements. The usage of a point of view borrowed from embryology permits, thus, the chemical and even the physical properties of these elements to be better connected. (tr-auth)« less

Phosphorus recovery and leaching of trace elements from incinerated sewage sludge ash (ISSA).

PubMed

Fang, Le; Li, Jiang-Shan; Guo, Ming Zhi; Cheeseman, C R; Tsang, Daniel C W; Donatello, Shane; Poon, Chi Sun

2018-02-01

Chemical extraction of phosphorus (P) from incinerated sewage sludge ash (ISSA) is adversely influenced by co-dissolution of metals and metalloids. This study investigated P recovery and leaching of Zn, Cu, Pb, As and Ni from ISSA using inorganic acids (sulphuric acid and nitric acid), organic acids (oxalic acid and citric acid), and chelating agents (ethylenediaminetetraacetic acid (EDTA) and ethylene diamine tetramethylene phosphonate (EDTMP)). The aim of this study was to optimize a leaching process to recover P-leachate with high purity for P fertilizer production. The results show that both organic and inorganic acids extract P-containing phases but organic acids leach more trace elements, particularly Cu, Zn, Pb and As. Sulphuric acid was the most efficient for P recovery and achieved 94% of total extraction under the optimal conditions, which were 2-h reaction with 0.2 mol/L H 2 SO 4 at a liquid-to-solid ratio of 20:1. EDTA extracted only 20% of the available P, but the leachates were contaminated with high levels of trace elements under optimum conditions (3-h reaction with EDTA at 0.02 mol/L, pH 2, and liquid-to-solid ratio of 20:1). Therefore, EDTA was considered an appropriate pre-treatment agent for reducing the total metal/metalloid content in ISSA, which produced negligible changes in the structure of ISSA and reduced contamination during subsequent P extraction using sulphuric acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Thermodynamics of Molybdate Binding to Humic Acid

NASA Astrophysics Data System (ADS)

Thalhammer, K.; Gilbert, B.

2016-12-01

Molybdenum is an essential nutrient for diazotrophic bacteria that use nitrogenase I to fix atmospheric nitrogen in soils into bioavailable forms such as ammonia. This metalloid is released during rock weathering processes and at neutral pH it exists primarily as the soluble oxyanion molybdate, MoO42-. It has been established that molybdate mobility and bioavailability in soils is influenced by sorption to mineral surfaces and complexation by natural organic matter (NOM). The molybdate ion is readily bound by ortho dihydroxybenzene molecules such as catechol and catechol groups in siderophores. Humic acids (HA) found in NOM contain abundant phenolic groups and extended X-ray absorption fine structure (EXAFS) spectroscopy demonstrated that molybdate is bound by catechol-containing molecules in soil organic matter1. However, to our knowledge no quantitative determination of the affinity of molybdate to HA has been reported. We studied the interactions of molybdate with Suwannee River HA using ultraviolet-visible (UV-vis) absorption spectroscopy and isothermal titration calorimetry (ITC) to determine the conditional equilibrium constant for complexation at neutral pH. We further used ITC to investigate the thermodynamic contributions to complexation and the interaction kinetics. Addition of molybdate to HA caused the formation of complexes with UV-vis absorption spectra in good agreement with molybdate-catechol species indicating catechol groups to be the primary ligands in HA. ITC data revealed that binding enthalpies and kinetics were strongly influenced by ionic strength, suggesting a role for macromolecular reorganization driven by metalloid addition. 1. Wichard et al., Nature Geoscience 2, 625 - 629 (2009).

Washing as a remediation technology applicable in soils heavily polluted by mining-metallurgical activities.

PubMed

Moutsatsou, A; Gregou, M; Matsas, D; Protonotarios, V

2006-06-01

A permanent solution in order to remediate a heavily contaminated soil is washing it utilizing the appropriate reagents. The study presented in this paper deals with the washing of a soil highly polluted by mining and metallurgical activities. Pollution consists of slags, sulphur compound waste and various low grade lead condensates, all rich in heavy metals and metalloids (Pb, As, Cu, Zn, Mn and Fe). Soil was washed with deionized water, 6, 3, 2 and 1 M HCl, 6 M H(2)SO(4), 6 M HNO(3) and 0.1 M Na(2)EDTA. High extraction efficiency was achieved with respect to hydrochloric acid even at the lowest concentration; the solubility of pollutants in nitric acid was low, while sulphuric acid was proven to be problematic with respect to lead. Mobilization of metals and metalloids under DI water effect was minimal indicating that the elements fraction that is weakly bound to soil particles is insignificant. Furthermore, a kinetic study was undertaken, utilizing 1 M HCl and 0.1 M Na(2)EDTA. Results illustrated that 1 M HCl was more effective for intermediate mixing times (up to 4 h) while 0.1 M Na(2)EDTA was better applicable to short mixing times (<1 h) and low pH values (pH < 7.1). 1 M HCl was proven to be very effective for the removal of pollutants from contaminated soil but the high metal content of the resulting solution necessitates further treatment for the retention of metals.

Arbuscular Mycorrhizal Fungi Community Structure, Abundance and Species Richness Changes in Soil by Different Levels of Heavy Metal and Metalloid Concentration

PubMed Central

Krishnamoorthy, Ramasamy; Kim, Chang-Gi; Subramanian, Parthiban; Kim, Ki-Yoon; Selvakumar, Gopal; Sa, Tong-Min

2015-01-01

Arbuscular Mycorrhizal Fungi (AMF) play major roles in ecosystem functioning such as carbon sequestration, nutrient cycling, and plant growth promotion. It is important to know how this ecologically important soil microbial player is affected by soil abiotic factors particularly heavy metal and metalloid (HMM). The objective of this study was to understand the impact of soil HMM concentration on AMF abundance and community structure in the contaminated sites of South Korea. Soil samples were collected from the vicinity of an abandoned smelter and the samples were subjected to three complementary methods such as spore morphology, terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) for diversity analysis. Spore density was found to be significantly higher in highly contaminated soil compared to less contaminated soil. Spore morphological study revealed that Glomeraceae family was more abundant followed by Acaulosporaceae and Gigasporaceae in the vicinity of the smelter. T-RFLP and DGGE analysis confirmed the dominance of Funneliformis mosseae and Rhizophagus intraradices in all the study sites. Claroideoglomus claroideum, Funneliformis caledonium, Rhizophagus clarus and Funneliformis constrictum were found to be sensitive to high concentration of soil HMM. Richness and diversity of Glomeraceae family increased with significant increase in soil arsenic, cadmium and zinc concentrations. Our results revealed that the soil HMM has a vital impact on AMF community structure, especially with Glomeraceae family abundance, richness and diversity. PMID:26035444

Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain).

PubMed

Peña-Fernández, A; Lobo-Bedmar, M C; González-Muñoz, M J

2015-01-01

Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. Copyright © 2014 Elsevier Inc. All rights reserved.

Leaching capacity of metals-metalloids and recovery of valuable materials from waste LCDs.

PubMed

Savvilotidou, Vasiliki; Hahladakis, John N; Gidarakos, Evangelos

2015-11-01

The purpose of Directive 2012/19/EU which is related to WEEE (Waste Electrical and Electronic Equipment), also known as "e-waste", is to contribute to their sustainable production and consumption that would most possibly be achieved by their recovery, recycling and reuse. Under this perspective, the present study focused on the recovery of valuable materials, metals and metalloids from LCDs (Liquid Crystal Displays). Indium (In), arsenic (As) and stibium (Sb) were selected to be examined for their Leaching Capacity (R) from waste LCDs. Indium was selected mainly due to its rarity and preciousness, As due to its high toxicity and wide use in LCDs and Sb due to its recent application as arsenic's replacement to improve the optimal clarity of a LCD screen. The experimental procedure included disassembly of screens along with removal and recovery of polarizers via thermal shock, cutting, pulverization and digestion of the shredded material and finally leaching evaluation of the aforementioned elements. Leaching tests were conducted under various temperatures, using various solid:liquid (S/L) ratios and solvents (acid mixtures), to determine the optimal conditions for obtaining the maximum leaching capacities. The examined elements exhibited different leaching behaviors, mainly due to the considerable diversity in their inherent characteristic properties. Indium demonstrated the highest recovery percentages (approximately 60%), while the recovery of As and Sb was unsuccessful, obtaining poor leaching percentages (0.16% and 0.5%, respectively). Copyright © 2015 Elsevier Ltd. All rights reserved.

The magnetic properties of a magnetic detector using oxidized amorphous Co 95- xFe 5(BSi) x alloys

NASA Astrophysics Data System (ADS)

Ahn, S. J.; Kim, C. K.; Kim, S. J.; Choi, D. K.; O'Handley, R. C.

2000-07-01

A comparative oxidation study of several amorphous Co 75- xFe 5(BSi) 20+ x alloys was carried out. Reentrant magnetization behavior and field-induced anisotropy which are of a critical importance for a magnetic detector were obtained after oxidation of the amorphous Co-rich ribbons. During this oxidation, the ribbons develop surface oxides which are primarily nonmagnetic borosilicate or a combination of borosilicate and magnetic oxides such CoO or FeO. Beneath this lies a 100-1000 Å thick Co-rich magnetic alloy which may be either HCP or FCC in its crystal structure. The thickness of the Co-crystallized layer is determined by the type of the surface oxides. The oxidation products such as appear to affect the reentrant magnetization behavior of Co-rich amorphous alloys significantly. We have determined the amount of metalloids (a critical concentration of B and Si) which is necessary to form a continuous layer of the most thermodynamically stable oxide, in our case borosilicate, on the surface. We also observed that there is a good correlation between reentrant magnetization and the thickness of Co layer. The best reentrant M- H loop for the magnetic detector was obtained in ribbons with a surface borate-rich borosilicate since it ensures conditions such as (1) metalloid depletion in the substrate and (2) formation of oxygen impurity faults in Co grains that are required for strong reentrant magnetization behavior.

Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations

PubMed Central

Csavina, Janae; Landázuri, Andrea; Wonaschütz, Anna; Rine, Kyle; Rheinheimer, Paul; Barbaris, Brian; Conant, William; Sáez, A. Eduardo; Betterton, Eric A.

2013-01-01

Mining operations are potential sources of airborne metal and metalloid contaminants through both direct smelter emissions and wind erosion of mine tailings. The warmer, drier conditions predicted for the Southwestern US by climate models may make contaminated atmospheric dust and aerosols increasingly important, with potential deleterious effects on human health and ecology. Fine particulates such as those resulting from smelting operations may disperse more readily into the environment than coarser tailings dust. Fine particles also penetrate more deeply into the human respiratory system, and may become more bioavailable due to their high specific surface area. In this work, we report the size-fractionated chemical characterization of atmospheric aerosols sampled over a period of a year near an active mining and smelting site in Arizona. Aerosols were characterized with a 10-stage (0.054 to 18 μm aerodynamic diameter) multiple orifice uniform deposit impactor (MOUDI), a scanning mobility particle sizer (SMPS), and a total suspended particulate (TSP) collector. The MOUDI results show that arsenic and lead concentrations follow a bimodal distribution, with maxima centered at approximately 0.3 and 7.0 μm diameter. We hypothesize that the sub-micron arsenic and lead are the product of condensation and coagulation of smelting vapors. In the coarse size, contaminants are thought to originate as aeolian dust from mine tailings and other sources. Observation of ultrafine particle number concentration (SMPS) show the highest readings when the wind comes from the general direction of the smelting operations site. PMID:23441050

Heavy metals in soil at a waste electrical and electronic equipment processing area in China.

PubMed

Gu, Weihua; Bai, Jianfeng; Yao, Haiyan; Zhao, Jing; Zhuang, Xuning; Huang, Qing; Zhang, Chenglong; Wang, JingWei

2017-11-01

For the objective of evaluating the contamination degree of heavy metals and analysing its variation trend in soil at a waste electrical and electronic equipment processing area in Shanghai, China, evaluation methods, which include single factor index method, geo-accumulation index method, comprehensive pollution index method, and potential ecological risk index method, were adopted in this study. The results revealed that the soil at a waste electrical and electronic equipment processing area was polluted by arsenic, cadmium, copper, lead, zinc, and chromium. It also demonstrated that the concentrations of heavy metals were increased over time. Exceptionally, the average value of the metalloid (arsenic) was 73.31 mg kg -1 in 2014, while it was 58.31 mg kg -1 in the first half of 2015, and it was 2.93 times and 2.33 times higher than that of the Chinese Environmental Quality Standard for Soil in 2014 and the first half of 2015, respectively. The sequences of the contamination degree of heavy metals in 2014 and the first half of 2015 were cadmium > lead > copper > chromium > zinc and cadmium > lead > chromium > zinc > copper. From the analysis of the potential ecological risk index method, arsenic and cadmium had higher ecological risk than other heavy metals. The integrated ecological risk index of heavy metals (cadmium, copper, lead, zinc, and chromium) and metalloid (arsenic) was 394.10 in 2014, while it was 656.16 in the first half of 2015, thus documenting a strong ecological risk.

Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA

NASA Astrophysics Data System (ADS)

Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.

2008-09-01

Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with heated meteoric water to create precious metal ore-forming fluids. Colloidal nanoparticles of Au-Ag alloy (electrum), naumannite (Ag2Se), silica, and adularia, likely nucleated at depth, traveled upward, and deposited where they grew large enough to aggregate along vein walls. Silica and gold colloids have been reported in hot springs from Yellowstone National Park, suggesting that such processes may continue to some extent to the present. However, it is possible that the initial development of the mantle plume led to a major but short-lived “distillation” process which led to the mid-Miocene bonanza ore-forming event.

Impacts of anthropogenic pressures on the water quality of the Gironde Estuary (SW France) from the Urban Agglomeration of Bordeaux: spatial characterization and inputs of trace metal elements (Ag, As, Cd, Cu, Pb and Zn)

NASA Astrophysics Data System (ADS)

Kessaci, Kahina; Coynel, Alexandra; Blanc, Gérard; Deycard, Victoria N.; Derriennic, Hervé; Schäfer, Jörg

2014-05-01

Recent European legislation (2000/60/CE) has listed eight trace metal elements as priority toxic substances for water quality. Urban metal inputs into hydrosystems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. The Gironde Estuary (SW France; 625 km2) is known for its metal/metalloid pollution originating from industrial (e.g. Cd, Zn, Cu, As, Ag, Hg) or agricultural sources (e.g. Cu) in the main fluvial tributaries (Garonne and Dordogne Rivers). However, little peer-reviewed scientific work has addressed the impact of urban sources on the Gironde Estuary, especially the Urban Agglomeration of Bordeaux (~1 million inhabitants) located on the downstream branch of the Garonne River. In this study, a snapshot sampling campaign was performed in 2011 for characterizing the spatial distribution of dissolved and particulate metal/metalloid (As, Ag, Cd, Pb, Zn, Cu) concentrations in three suburban watersheds: the Jalle of Blanquefort (330 km2), Eau Bourde (140 km2), and Peugue (112 km2). Furthermore, particulate metal Enrichment Factors (EF) were calculated using local geochemical background measured at the bottom of a sediment core (492 cm). Results indicated that metal concentrations displayed a high spatial variability depending on the suburban watershed and the studied element. Local concentrations anomalies were observed for: (i) As in the Eau Bourde River in dissolved (4.2 μg/l) and particulate phases (246 mg/kg; EF= 20) and attributed to a nearby industrial incinerator; (ii) Zn in the Peugue River with maximum dissolved and particulate concentrations of 87 μg/l and 1580 mg/kg (EF=17), respectively, probably due to urban habitation runoff; (iii) Ag in the Jalle of Blanquefort River with high dissolved (74 ng/l) and particulate concentrations (33.7 mg/kg; EF=117) due to industrial activities in the downstream part. Based on hydro-geochemical monitoring of both suburban rivers and local wastewater treatment plants (WWTPs), we present a first estimate of metal/metalloid fluxes and compare them to the respective loads in the Garonne River. Our results suggest that suburban metal inputs may significantly increase metal concentrations and fluxes in the fluvial Gironde Estuary, especially for Ag due to inputs exported by WWTPS and the Jalle of Blanquefort River.

Environmental impact assessment of the 2011 Tohoku-oki tsunami on the Sendai Plain

NASA Astrophysics Data System (ADS)

Chagué-Goff, Catherine; Niedzielski, Przemyslaw; Wong, Henri K. Y.; Szczuciński, Witold; Sugawara, Daisuke; Goff, James

2012-12-01

Large areas of farmland in the Sendai Plain, Japan, were inundated by the 11 March 2011 Tohoku-oki tsunami and covered by a discontinuous 30-0.2 cm thick sediment layer consisting of sand and/or mud and generally thinning and fining inland. Two months after the tsunami, numerous rice paddy fields and depressions remained ponded with brackish or saline water. A series of field surveys in May, August and October 2011 were carried out north of Sendai airport, in order to assess the environmental impact of the tsunami. While evaporation had resulted in elevated conductivity in ponded water in May (up to 68.2 mS cm- 1), rainfall over the next five months led to dilution, although brackish water was still recorded in depressions and on paddy fields. Tsunami sediments, underlying soil and soil beyond the tsunami inundation limit were collected at 43 sites along and near a transect extending over 5 km inland, and analysed for grain size, organic content, water leachable ions, acid leachable metals and exchangeable metalloids. Water leachable anion and cation concentrations were elevated in sandy and muddy tsunami deposits and soils particularly in areas, where seawater had stagnated for a longer period of time after the tsunami, with up to 10.5% Cl, 6.6% Na, 2.8% SO4, 440 mg kg- 1 Br measured in surface sediments (< 0.5 cm depth). Vertical variations were also recorded, with higher concentrations often measured in the surface samples. A similar trend could be observed for some of the metalloids (As) and metals (Zn, Cu and Ni), although in general, maximum concentrations of metals and metalloids were not much higher than in soils not inundated by the tsunami and were within background levels for uncontaminated Japanese soils. The impact of saltwater inundation was documented in the chemistry of soils underlying tsunami sediments, which were affected by salt contamination down to ~ 15 cm depth, and soils not covered by tsunami deposits. The latter implies that the extent of tsunami inundation may successfully be determined using geochemical markers in absence of any sedimentological evidence. Water leachable ions mostly decreased over time, however, they remained high enough to impact on rice farming, which was completely halted in 2011. Although further work is required to assess the longer term impact of tsunami inundation, flushing of salt with freshwater, as well as the possible removal of sandy/muddy sediments and underlying soil are recommended to allow crop production to resume.

Sampling of trace volatile metal(loid) compounds in ambient air using polymer bags: a convenient method.

PubMed

Haas, K; Feldmann, J

2000-09-01

The sampling of volatile metal(loid) compounds (VOMs) such as hydrides, methylated, and permethylated species of arsenic, antimony, and tin is described using Tedlar bags. Advantages as well as limitations and constraints are discussed and compared to other widely used sampling techniques within this area, namely, stainless steel canisters, cryotrapping, and solid adsorbent cartridges. To prove the suitability of Tedlar bags for the sampling of volatile metal(loid) compounds, series of stability tests have been run using both laboratory synthetic and real samples analyzed periodically after increasing periods of storage. The samples have been stored in the dark at 20 degrees C and at 50 degrees C. Various volatile arsenic species (AsH3, MeAsH2, Me2AsH, Me3As), tin species (SnH4, MeSnH3, Me2SnH2, Me3SnH, Me4Sn, BuSnH3), and antimony species (SbH3, MeSbH2, Me2SbH, Me3Sb) have been generated using hydride generation methodology and mixed with moisturized air. Three static gaseous atmospheres with concentrations of 0.3-18 ng/L for the various compounds have been generated in Tedlar bags, and the stability of the VOMs has been monitored over a period of 5 weeks. Sewage sludge digester gas samples have been stored only at 20 degrees C for a period of 48 h. Cryotrapping GC/ICPMS has been used for the determination of the VOMs with a relative standard deviation of 5% for 100 pg. After 8 h, the recovery rate of all the compounds in the air atmospheres was better than 95% at 20 and 50 degrees C, whereas the recovery after 24 h was found to be between 81 and 99% for all VOMs at 20 and 50 degrees C except for Me3Sb and Me3As. These species show a loss between 48 and 73% at both temperatures. After 5 weeks at 20 degrees C, a loss of only 25-50% for arsine and stibine and the above-mentioned tin compounds was determined. Only Me3Sb, Me3Bi, and Me2Te were present in the digester gas sample. After 24 h, losses of 44, 10, and 12%, respectively, could be determined. Given these results, Tedlar bags could even be used, with some limitations, for long-term sampling of air containing traces of VOMs. The loss is more pronounced at higher temperatures.

Fine structure of the K X-ray absorption spectra of titanium in some hydrides, borides, and silicides (in Russian)

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

Vainshtein, �. E.; Zhurakovskii, E. A.

1959-08-01

X-ray spectral analyses confirmed the hypothesis on the metal-like state of hydrogen in tithnium hydrides. Experiments with titunium borides and silicides indicate the special character and degree of the 3d--level participation in the metallic'' bond between the atoms of various complexes. The structure of metalloid elements becomes more complicated with an increase in the specific number of boron and silicon atoms and the bond between the atoms tends to become covalent. (R.V.J.)

Mineral Resource of the Month: Antimony

USGS Publications Warehouse

Guberman, David E.

2015-01-01

Antimony is a lustrous silvery-white semimetal or metalloid. Archaeological and historical studies indicate that antimony and its mineral sulfides have been used by humans for at least six millennia. The alchemist Basil Valentine is sometimes credited with “discovering” the element; he described the extraction of metallic antimony from stibnite in his treatise “The Triumphal Chariot of Antimony,” published sometime between 1350 and 1600. In the early 18th century, Jöns Jakob Berzelius chose the periodic symbol for antimony (Sb) based on stibium, which is the Latin name for stibnite.

Metal/metalloid content in plant parts and soils of Corylus spp. influenced by mining-metallurgical production of copper.

PubMed

Radojevic, Ana A; Serbula, Snezana M; Kalinovic, Tanja S; Kalinovic, Jelena V; Steharnik, Mirjana M; Petrovic, Jelena V; Milosavljevic, Jelena S

2017-04-01

The town of Bor and its surroundings (Serbia) have been under environmental pollution for more than a century, due to exploitation of large copper deposits. Naturally present Corylus spp. were sampled in the surroundings of the mine and flotation tailings at 12 sites distributed in six zones with different pollution loads, under the assumption that all the zones were endangered except for the background. As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn inputs from soil and the air were evaluated in plant parts, in terms of absorption, accumulation and indication abilities of Corylus spp. The obtained results showed that As and Cu were the most enriched elements in soil, and their concentration exceeded the limit and remediation values proposed by the regulation. Plant parts (root, branch, leaf and catkin) also showed enrichment of most studied elements in wide ranges. According to the enrichment factor for plant, metal/metalloid inputs, particularly in leaves, were from anthropogenic origin. Plant absorption which occurred at the soil-root interface was low, based on the bioaccumulation factor, which could be indicative of resistance mechanisms of root to abiotic stress induced by a high content of elements in soil substrate. The values of bioaccumulation coefficient suggested weak and intermediate absorption and exclusion abilities of Corylus spp. to the studied elements. Element concentrations differ in unwashed and washed leaves, as well as pollution loads in plant and soil samples from the background, traffic and the sites with clear mining-metallurgical influence. Therefore, Corylus spp. could be promising in biomonitoring studies.

Using amorphous manganese oxide for remediation of smelter-polluted soils: a pH-dependent long-term stability study

NASA Astrophysics Data System (ADS)

Ettler, Vojtech; Tomasova, Zdenka; Komarek, Michael; Mihaljevic, Martin; Sebek, Ondrej

2015-04-01

In soil systems, manganese (Mn) oxides are commonly found to be powerful sorbents of metals and metalloids and are thus potentially useful in soil remediation. A novel amorphous manganese oxide (AMO) and a Pb smelter-polluted agricultural soil amended with the AMO and incubated for 2 and 6 months were subjected to a pH-static leaching procedure (pH = 3 - 8) to verify the chemical stabilization effect on metals and metalloids. The AMO stability in pure water was pH-dependent with the highest Mn release at pH 3 (47% dissolved) and the lowest at pH 8 (0.14% dissolved). Secondary rhodochrosite (MnCO3) was formed at the AMO surfaces at pH > 5. The AMO dissolved significantly less after 6 months of incubation. Sequential extraction analysis indicated that "labile" fraction of As, Pb and Sb in soil significantly decreased after AMO amendment. The pH-static experiments indicated that no effect on leaching was observed for Cd and Zn after AMO treatments, whereas the leaching of As, Cu, Pb and Sb decreased down to 20%, 35%, 7% and 11% of the control, respectively. The remediation efficiency was more pronounced under acidic conditions and the time of incubation generally led to increased retention of the targeted contaminants. The AMO was found to be a promising agent for the chemical stabilization of polluted soils and other in situ applications need to be evaluated. This study was supported by the Czech Science Foundation (GAČR 15-07117S).

Selenium bioaccumulation in stocked fish as an indicator of fishery potential in pit lakes on reclaimed coal mines in Alberta, Canada.

PubMed

Miller, L L; Rasmussen, J B; Palace, V P; Sterling, G; Hontela, A

2013-07-01

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational "put and take" fisheries.

Potential Influence of Selenium, Copper, Zinc and Cadmium on L-Thyroxine Substitution in Patients with Hashimoto Thyroiditis and Hypothyroidism.

PubMed

Rasic-Milutinovic, Z; Jovanovic, D; Bogdanovic, G; Trifunovic, J; Mutic, J

2017-02-01

Background: Besides genetic factors, it is known that some trace elements, as Selenium, Copper, and Zinc are essential for thyroid gland fuction and thyroid hormone metabolism. Moreover, there were some metals effect that suggested patterns associated with overt thyroid disease. Aim of study: Hashimoto thyroiditis (HT), chronic autoimune inflamation of thyroid gland with cosequtive hipothyroidism, is common disease in Serbia, and we thought it is worthwile to explore potential effects of essential and toxic metals and metalloides on thyroid function and ability to restore euthyroid status of them. Results: This cross-sectional, case-control, study investigated the status of essential elements (Selenium,Copper,and Zinc) and toxic metals and metalloides (Al, Cr, Mn, Co, As, Cd, Sb, Ba, Be, Pb and Ni) from the blood of 22 female, patients with Hashimoto thyroiditis and overt hypothyroidism, and compared it with those of 55 female healthy persons. We tried to establish the presence of any correlation between previous mentioned elements and thyroid function in hypothyroid patients and healthy participants. Conclusions: The results of our study suggested that the blood concentration of essential trace elements, especially the ratio of Copper, and Selenium may influence directly thyroid function in patients with HT and overt hypothyroidism.Thus, our findings may have implication to life-long substitution therapy in terms of l-thyroxine dose reduction. Furthermore, for the first time, our study shown potential toxic effect of Cadmium on thyroid function in HT patients, which may implicate the dose of l-thyroxine substitution. © Georg Thieme Verlag KG Stuttgart · New York.

Microbial Diversity and Metal Speciation Changes in Mine Tailings Following Compost-Assisted Direct Planting: A Four-Year Superfund Site Field Study

NASA Astrophysics Data System (ADS)

Maier, R. M.; Gil-Loaiza, J.; Honeker, L. K.; Hottenstein, J. D.; Valentin-Vargas, A.; Jennings, L. L.; Hammond, C.; Neilson, J. W.; Root, R. A.; Chorover, J.

2014-12-01

EPA estimates that future mine tailings remediation costs will exceed US $50 billion using present technologies based on constructing an inert or biological cap on the tailings. Both approaches require large amounts of capping materials that can be difficult and expensive to obtain especially for sites several thousand hectares in size. An alternative technology is direct planting into tailings. However, direct planting alone is not feasible for many legacy sites due to extreme acidity and high metal content which prevent plant germination and growth. Therefore the process must be "assisted" through the addition of amendments such as compost. Here we present results from the first four years of a field study at the Iron King Mine and Humboldt Smelter Superfund site demonstrating the feasibility of compost-assisted direct planting. Parameters measured during the field study included: canopy cover, pH, nutrient content, plant metal uptake, metal(loid) speciation, mineral analysis, microbiome analysis, and plant root-metal-microbe interactions. Integrated analysis of these parameters suggests that even in this "worst-case scenario" mine tailings site (pH 2.5; As and Pb each exceeding 2 g kg-1), we have created a sustainable system. In this system, phyto-catalyzed stabilization of inorganic contaminants in the root zone is driven by plant root exudates and the associated rhizosphere microbial community. The results of this research will be put into context of a larger topic- that of ecological engineering of mine tailings sites - a technique being proposed to prevent creation of acidic conditions and metal(loid) mobilization in the first place.

Microbial Diversity and Metal Speciation Changes in Mine Tailings Following Compost-Assisted Direct Planting: A Four-Year Superfund Site Field Study

NASA Astrophysics Data System (ADS)

Maier, R. M.; Gil-Loaiza, J.; Honeker, L. K.; Hottenstein, J. D.; Valentin-Vargas, A.; Jennings, L. L.; Hammond, C.; Neilson, J. W.; Root, R. A.; Chorover, J.

2015-12-01

EPA estimates that future mine tailings remediation costs will exceed US $50 billion using present technologies based on constructing an inert or biological cap on the tailings. Both approaches require large amounts of capping materials that can be difficult and expensive to obtain especially for sites several thousand hectares in size. An alternative technology is direct planting into tailings. However, direct planting alone is not feasible for many legacy sites due to extreme acidity and high metal content which prevent plant germination and growth. Therefore the process must be "assisted" through the addition of amendments such as compost. Here we present results from the first four years of a field study at the Iron King Mine and Humboldt Smelter Superfund site demonstrating the feasibility of compost-assisted direct planting. Parameters measured during the field study included: canopy cover, pH, nutrient content, plant metal uptake, metal(loid) speciation, mineral analysis, microbiome analysis, and plant root-metal-microbe interactions. Integrated analysis of these parameters suggests that even in this "worst-case scenario" mine tailings site (pH 2.5; As and Pb each exceeding 2 g kg-1), we have created a sustainable system. In this system, phyto-catalyzed stabilization of inorganic contaminants in the root zone is driven by plant root exudates and the associated rhizosphere microbial community. The results of this research will be put into context of a larger topic- that of ecological engineering of mine tailings sites - a technique being proposed to prevent creation of acidic conditions and metal(loid) mobilization in the first place.

Role of intestinal microbiota in transformation of bismuth and other metals and metalloids into volatile methyl and hydride derivatives in humans and mice.

PubMed

Michalke, Klaus; Schmidt, Annette; Huber, Britta; Meyer, Jörg; Sulkowski, Margareta; Hirner, Alfred V; Boertz, Jens; Mosel, Frank; Dammann, Philip; Hilken, Gero; Hedrich, Hans J; Dorsch, Martina; Rettenmeier, Albert W; Hensel, Reinhard

2008-05-01

The present study shows that feces samples of 14 human volunteers and isolated gut segments of mice (small intestine, cecum, and large intestine) are able to transform metals and metalloids into volatile derivatives ex situ during anaerobic incubation at 37 degrees C and neutral pH. Human feces and the gut of mice exhibit highly productive mechanisms for the formation of the toxic volatile derivative trimethylbismuth [(CH(3))(3)Bi] at rather low concentrations of bismuth (0.2 to 1 mumol kg(-1) [dry weight]). An increase of bismuth up to 2 to 14 mmol kg(-1) (dry weight) upon a single (human volunteers) or continuous (mouse study) administration of colloidal bismuth subcitrate resulted in an average increase of the derivatization rate from approximately 4 pmol h(-1) kg(-1) (dry weight) to 2,100 pmol h(-1) kg(-1) (dry weight) in human feces samples and from approximately 5 pmol h(-1) kg(-1) (dry weight) to 120 pmol h(-1) kg(-1) (dry weight) in mouse gut samples, respectively. The upshift of the bismuth content also led to an increase of derivatives of other elements (such as arsenic, antimony, and lead in human feces or tellurium and lead in the murine large intestine). The assumption that the gut microbiota plays a dominant role for these transformation processes, as indicated by the production of volatile derivatives of various elements in feces samples, is supported by the observation that the gut segments of germfree mice are unable to transform administered bismuth to (CH(3))(3)Bi.

Diversity of endophytic Pseudomonas in Halimione portulacoides from metal(loid)-polluted salt marshes.

PubMed

Rocha, Jaqueline; Tacão, Marta; Fidalgo, Cátia; Alves, Artur; Henriques, Isabel

2016-07-01

Phytoremediation assisted by bacteria is seen as a promising alternative to reduce metal contamination in the environment. The main goal of this study was to characterize endophytic Pseudomonas isolated from Halimione portulacoides, a metal-accumulator plant, in salt marshes contaminated with metal(loid)s. Phylogenetic analysis based on 16S rRNA and gyrB genes showed that isolates affiliated with P. sabulinigri (n = 16), P. koreensis (n = 10), P. simiae (n = 5), P. seleniipraecipitans (n = 2), P. guineae (n = 2), P. migulae (n = 1), P. fragi (n = 1), P. xanthomarina (n = 1), and Pseudomonas sp. (n = 1). Most of these species have never been described as endophytic. The majority of the isolates were resistant to three or more metal(loid)s. Antibiotic resistance was frequent among the isolates but most likely related to species-intrinsic features. Common acquired antibiotic resistance genes and integrons were not detected. Plasmids were detected in 43.6 % of the isolates. Isolates that affiliated with different species shared the same plasmid profile but attempts to transfer metal resistance to receptor strains were not successful. Phosphate solubilization and IAA production were the most prevalent plant growth promoting traits, and 20 % of the isolates showed activity against phytopathogenic bacteria. Most isolates produced four or more extracellular enzymes. Preliminary results showed that two selected isolates promote Arabidopsis thaliana root elongation. Results highlight the diversity of endophytic Pseudomonas in H. portulacoides from contaminated sites and their potential to assist phytoremediation by acting as plant growth promoters and as environmental detoxifiers.

Arsenic affects the production of glucosinolate, thiol and phytochemical compounds: A comparison of two Brassica cultivars.

PubMed

Pandey, Chandana; Augustine, Rehna; Panthri, Medha; Zia, Ismat; Bisht, Naveen C; Gupta, Meetu

2017-02-01

Arsenic (As), a non-essential metalloid, severely affects the normal functioning of plants, animals and humans. Plants play a crucial role in metabolic, physiological and numerous detoxification mechanisms to cope up with As induced stress. This study aimed to examine the differential response in two Brassica juncea cultivars, Varuna and Pusa Jagannath (PJn) exposed to different doses of As (50, 150, 300 μM) for 48 h duration. Change in morphological traits, concentration of individual as well as total GSL, sulfur related thiol proteins, sulfur content, and phytochemicals were analyzed in both cultivars. Accumulation pattern of As showed dose dependent accumulation in both the cultivars, being more in PJn. Our finding revealed that both cultivars were tolerant at low concentrations of As, while at higher concentration Varuna excelled over PJn. The increased tolerance of Varuna cultivar exposed to 150 and 300 μM concentration of As, correlated with its increased thiol related proteins, sulfur content and phytochemicals, which serves as defence strategy in the plant against oxidative stress. Differential pattern of total as well as individual GSLs content was observed in both Varuna and PJn cultivars. Varuna cultivar showed higher level of total and aliphatic GSLs, which serves as defence compound with other detoxification machineries to combat As stress. Our findings provide foundation for developing metalloid tolerant crops by analyzing the role of different genes involved in GSL mechanism and signaling pathways in different organs of plant. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

High temperature solar selective coatings

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

Kennedy, Cheryl E

Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (suchmore » as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.« less

Long-term impact of primary domestic sewage on metal/loid accumulation in drainage ditch sediments, plants and water: Implications for phytoremediation and restoration.

PubMed

Kumwimba, Mathieu Nsenga; Zhu, Bo; Suanon, Fidèle; Muyembe, Diana Kavidia; Dzakpasu, Mawuli

2017-03-01

We evaluate the long-term performance of a vegetated drainage ditch (VDD) treating domestic sewage with respect to heavy metal/metalloid (HM/M) accumulation in sediments, plants and water. VDD sediment contained significantly higher macro and trace elements compared to an agricultural ditch (AD) sediment. However, concentrations of HM/Ms in VDD sediment were below the ranges considered toxic to plants. Most HM/Ms were efficiently removed in the VDD, whereby removal efficiencies varied between 11% for Al and 89% for K. Accumulation of HM/Ms varied among species and plant parts, although sequestration by plants represents only a small proportion (<1%) of the inflow load. Accumulation of Al, As, Cd, Pb, Cr, Fe and Ni in VDD plants were mostly distributed in the roots, indicating an exclusive strategy for metal tolerance. The opposite was found for Zn, Cu, K, Ca, P, K, Na, N and Mg, which were accumulated either in the stems or leaves. Overall, concentrations of metals in sediment showed significant positive correlations with those in ditch plants. None of the studied species were identified as metal hyper-accumulators (i.e. >10,000mgkg -1 of Zn or Mn). Nevertheless, the high translocation factor (TF) values for Mn, Ni, Cu, Zn, Na, Mg, P, K and Ca in the ditch plants make them suitable for phytoextraction from water/soil, while the low TF values for Pb, Cd, As, Fe, Cr and Al make them suitable for their phytostabilization. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential impact of flowback water from hydraulic fracturing on agricultural soil quality: Metal/metalloid bioaccessibility, Microtox bioassay, and enzyme activities.

PubMed

Chen, Season S; Sun, Yuqing; Tsang, Daniel C W; Graham, Nigel J D; Ok, Yong Sik; Feng, Yujie; Li, Xiang-Dong

2017-02-01

Hydraulic fracturing has advanced the development of shale gas extraction, while inadvertent spills of flowback water may pose a risk to the surrounding environment due to its high salt content, metals/metalloids (As, Se, Fe and Sr), and organic additives. This study investigated the potential impact of flowback water on four representative soils from shale gas regions in Northeast China using synthetic flowback solutions. The compositions of the solutions were representative of flowback water arising at different stages after fracturing well establishment. The effects of solution composition of flowback water on soil ecosystem were assessed in terms of metal mobility and bioaccessibility, as well as biological endpoints using Microtox bioassay (Vibrio fischeri) and enzyme activity tests. After one-month artificial aging of the soils with various flowback solutions, the mobility and bioaccessibility of As(V) and Se(VI) decreased as the ionic strength of the flowback solutions increased. The results inferred a stronger binding affinity of As(V) and Se(VI) with the soils. Nevertheless, the soil toxicity to Vibrio fischeri only presented a moderate increase after aging, while dehydrogenase and phosphomonoesterase activities were significantly suppressed with increasing ionic strength of flowback solutions. On the contrary, polyacrylamide in the flowback solutions led to higher dehydrogenase activity. These results indicated that soil enzyme activities were sensitive to the composition of flowback solutions. A preliminary human health risk assessment related to As(V) suggested a low level of cancer risk through exposure via ingestion, while holistic assessment of environmental implications is required. Copyright © 2016 Elsevier B.V. All rights reserved.

Anchored nanostructure materials and method of fabrication

DOEpatents

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2012-11-27

Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

The ecology of arsenic

USGS Publications Warehouse

Oremland, Ronald S.; Stolz, John F.

2003-01-01

Arsenic is a metalloid whose name conjures up images of murder. Nonetheless, certain prokaryotes use arsenic oxyanions for energy generation, either by oxidizing arsenite or by respiring arsenate. These microbes are phylogenetically diverse and occur in a wide range of habitats. Arsenic cycling may take place in the absence of oxygen and can contribute to organic matter oxidation. In aquifers, these microbial reactions may mobilize arsenic from the solid to the aqueous phase, resulting in contaminated drinking water. Here we review what is known about arsenic-metabolizing bacteria and their potential impact on speciation and mobilization of arsenic in nature.

Magnetron-Sputtered Amorphous Metallic Coatings

NASA Technical Reports Server (NTRS)

Thakoor, A. P.; Mehra, M.; Khanna, S. K.

1985-01-01

Amorphous coatings of refractory metal/metalloid-based alloys deposited by magnetron sputtering provide extraordinary hardness and wear resistance. Sputtering target fabricated by thoroughly mixing powders of tungsten, rhenium, and boron in stated proportions and pressing at 1,200 degrees C and 3,000 lb/in. to second power (21 MPa). Substrate lightly etched by sputtering before deposition, then maintained at bias of - 500 V during initial stages of film growth while target material sputtered onto it. Argon gas at pressure used as carrier gas for sputter deposition. Coatings dense, pinhole-free, extremely smooth, and significantly resistant to chemical corrosion in acidic and neutral aqueous environments.

Genetic characterization, micropropagation, and potential use for arsenic phytoremediation of Dittrichia viscosa (L.) Greuter.

PubMed

Guarino, Francesco; Conte, Barbara; Improta, Giovanni; Sciarrillo, Rosaria; Castiglione, Stefano; Cicatelli, Angela; Guarino, Carmine

2018-02-01

In the last decade, many scientists have focused their attention on the search for new plant species that can offer improved capacities to reclaim polluted soils and waters via phytoremediation. In this study, seed batches from three natural populations of Dittrichia viscosa, harvested in rural, urban, and industrial areas of central and southern Italy, were used to: (i) evaluate the genetic and morphological diversity of the populations; (ii) develop an efficient protocol for in-vitro propagation from seedling microcuttings; (iii) achieve optimal acclimatization of micropropagated plants to greenhouse conditions; (iv) test the response to arsenic (As) soil contamination of micropropagated plants. The genetic biodiversity study, based on Random Amplification of Polymorphic DNA (RAPD), as well as the morphometric analysis of 20 seedlings from each population revealed some degree of differentiation among populations. Based on these data, the most biodiverse plants from the three populations (10 lines each) were clonally multiplied by micropropagation using microcuttings of in-vitro grown seedlings. Three culture media were tested and Mureshige and Skoog medium was chosen for both seedling growth and micropropagation. The micropropagated plants responded well to greenhouse conditions and over 95% survived the acclimatization phase. Four clones were tested for their capacity to grow on soil spiked with NaAsO 2 and to absorb and accumulate the metalloid. All clones tolerated up to 1.0mg As. At the end of the trial (five weeks), As was detectable only in leaves of As-treated plants and concentration varied significantly among clones. The amount of As present in plants (leaves) corresponded to ca. 0.10-1.7% of the amount supplied. However, As was no longer detectable in soil suggesting that the metalloid was taken up, translocated and probably phytovolatilized. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of the environmental plasticity in the xerohalophyte Zygophyllum fabago L. for the phytomanagement of mine tailings in semiarid areas.

PubMed

Párraga-Aguado, I; González-Alcaraz, M N; López-Orenes, A; Ferrer-Ayala, M A; Conesa, H M

2016-10-01

Phytomanagement by phytostabilisation of metal(loid)-enriched mine tailings in semiarid areas has been proposed as a suitable technique to promote a self-sustainable vegetal cover for decreasing the spread of polluted particles by erosion. The goal of this work was to evaluate the contribution of a pioneer plant species (Zygophyllum fabago) in ameliorating the soil conditions at two mine tailings piles located in a semiarid area in Southeast Spain. The ecophysiological performance of this plant species compared to a control population was assessed by analysing the nutritional and ecophysiological status. The presence of Z. fabago in mine tailings enhanced the soil microbial activity and increased the content of soil organic carbon within the rhizosphere (approx. 50% increasing). Metal(loid) concentrations in the tailings may play a minor role in the establishment of Z. fabago plants due to the low metal(loid) availability in the tailings (low CaCl2-extractable concentrations) and low uptake in the plants (e.g. up to 300 mg kg(-1) Zn in leaves). The lower δ13C and δ18O in the plants sampled at both tailings compared to the control ones may indicate softer stomatal regulation in relation to the control site plants and therefore lower WUE [corrected]. The Z. fabago plants may skip some energy-demanding mechanisms such as stomatal control and/or proline synthesis to overcome the environmental stresses posed at the tailings. The Z. fabago plants revealed high plasticity of the species for adapting to the low fertility soil conditions of the tailings and to overcome constraints associated to the dry season. Copyright © 2016 Elsevier Ltd. All rights reserved.

Usefulness of pioneer vegetation for the phytomanagement of metal(loid)s enriched tailings: grasses vs. shrubs vs. trees.

PubMed

Parraga-Aguado, Isabel; Querejeta, Jose-Ignacio; González-Alcaraz, María-Nazaret; Jiménez-Cárceles, Francisco J; Conesa, Héctor M

2014-01-15

The goal of this work was to assess the selection of the most suitable combination of plant species for the phytomanagement of mine tailings, by comparing among different plant life-forms (grasses, shrubs and trees). A comparison on induced rhizosphere changes generated by four plant species (the grass Piptatherum miliaceum, the shrub Helichrysum decumbens, and the trees, Pinus halepensis and Tetraclinis articulata) and high density vegetation patches (fertility islands) at a mine tailing located at Southeast Spain and the description of their physiological status employing stable isotopes analyses were carried out. The edaphic niches for plant growth were determined by salinity, organic matter and total soil nitrogen while metal(loid)s concentrations played a minor role. Induced changes in plant rhizospheres had a significant impact in soil microbiology. While grasses and shrubs may play an important role in primary ecological succession, trees seem to be the key to the development of fertility islands. The low δ(15)N values (-8.00‰) in P. halepensis needles may reflect higher ectomycorrhizal dependence. Large differences in leaf δ(18)O among the plant species indicated contrasting and complementary water acquisition strategies. Leaf δ(13)C values (-27.6‰) suggested that T. articulata had higher water use efficiency than the rest of species (-29.9‰). The implement of a diverse set of plant species with contrasting life forms for revegetating tailings may result in a more efficient employment of water resources and a higher biodiversity not only in relation to flora but soil microbiology too. Copyright © 2013 Elsevier Ltd. All rights reserved.

Growth and metal bioconcentration by conspecific freshwater macroalgae cultured in industrial waste water.

PubMed

Ellison, Michael B; de Nys, Rocky; Paul, Nicholas A; Roberts, David A

2014-01-01

The bioremediation of industrial waste water by macroalgae is a sustainable and renewable approach to the treatment of waste water produced by multiple industries. However, few studies have tested the bioremediation of complex multi-element waste streams from coal-fired power stations by live algae. This study compares the ability of three species of green freshwater macroalgae from the genus Oedogonium, isolated from different geographic regions, to grow in waste water for the bioremediation of metals. The experiments used Ash Dam water from Tarong power station in Queensland, which is contaminated by multiple metals (Al, Cd, Ni and Zn) and metalloids (As and Se) in excess of Australian water quality guidelines. All species had consistent growth rates in Ash Dam water, despite significant differences in their growth rates in "clean" water. A species isolated from the Ash Dam water itself was not better suited to the bioremediation of that waste water. While there were differences in the temporal pattern of the bioconcentration of metals by the three species, over the course of the experiment, all three species bioconcentrated the same elements preferentially and to a similar extent. All species bioconcentrated metals (Cu, Mn, Ni, Cd and Zn) more rapidly than metalloids (As, Mo and Se). Therefore, bioremediation in situ will be most rapid and complete for metals. Overall, all three species of freshwater macroalgae had the ability to grow in waste water and bioconcentrate elements, with a consistent affinity for the key metals that are regulated by Australian and international water quality guidelines. Together, these characteristics make Oedogonium a clear target for scaled bioremediation programs across a range of geographic regions.

The reach of human health risks associated with metals/metalloids in water and vegetables along a contaminated river catchment: South Africa and Mozambique.

PubMed

Genthe, Bettina; Kapwata, Thandi; Le Roux, Wouter; Chamier, Jessica; Wright, Caradee Y

2018-05-01

Anthropogenic pollution was identified as an environmental problem of concern when, in 2008, dozens of crocodiles died in the Olifants River catchment near the border of South Africa and Mozambique. Given the close proximity of households to the river and their making use of river water, we aimed to determine to what extent water pollution has an impact on health of indigent communities in South Africa and Mozambique in the catchment area. Water and vegetable samples were collected from the study areas. Biota samples were washed with double de-ionized Milli-Q water and freeze-dried. Heavy metal analyses in water and vegetables were done by means of Inductively Coupled Plasma Optical Emission Spectroscopy. Metal concentrations were applied in a human health risk assessment to estimate health risks. Mean concentrations of antimony, arsenic, cadmium, chromium, mercury, molybdenum, nickel and selenium in water samples from South Africa exceeded the World Health Organization guidelines for safe levels of intake. Only iron exceeded the recommended guidelines in water samples from Mozambique. Metals/metalloids were found in lower concentrations at Mozambique sites downstream of South African sites. In vegetables, uranium was between 10 and 20 times above safe guidelines in South Africa and between 3 and 6 times in Mozambique. Arsenic in water samples posed the highest cancer risk. Even with a reduction in the metal concentrations in river water from South Africa to Mozambique, the potential to cause adverse human health impacts from direct use of polluted river water is evident in both countries. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigation, Pollution Mapping and Simulative Leakage Health Risk Assessment for Heavy Metals and Metalloids in Groundwater from a Typical Brownfield, Middle China

PubMed Central

Qiu, Zhenzhen; Zhang, Jingdong; Liu, Wenchu; Liu, Chaoyang; Zeng, Guangming

2017-01-01

Heavy metal and metalloid (Cr, Pb, Cd, Zn, Cu, Ni, As and Hg) concentrations in groundwater from 19 typical sites throughout a typical brownfield were detected. Mean concentrations of toxic metals in groundwater decreased in the order of Cr > Zn > Cu > Cd > Ni > Pb > Hg > As. Concentration of Cr6+ in groundwater was detected to further study chromium contamination. Cr6+ and Cd in groundwater were recommended as the priority pollutants because they were generally 1399-fold and 12-foldgreater than permissible limits, respectively. Owing to the fact that a waterproof curtain (WPC) in the brownfield is about to pass the warranty period, a steady two-dimensional water quality model and health risk assessment were applied to simulate and evaluate adverse effects of Cr6 + and Cd on the water quality of Xiangjiang River and the drinking-water intake of Wangcheng Waterworks. The results indicated that when groundwater in the brownfield leaked with valid curtain prevention, the water quality in Xiangjiang River and drinking-water intake downstream were temporarily unaffected. However, if there was no curtain prevention, groundwater leakage would have adverse impact on water quality of Xiangjiang River. Under the requirements of Class III surface water quality, the pollution belt for Cr6+ was 7500 m and 200 m for Cd. The non-carcinogenic risk of toxic metals in Xiangjiang River exceeded the threshold in a limited area, but did not threaten Wangcheng Waterworks. By contrast, the carcinogenic risk area for adults was at a transverse distance of 200 m and a longitudinal distance of 18,000 m, which was close to the Wangcheng Waterworks (23,000 m). Therefore, it was essential to reconstruct the WPC in the brownfield for preventing pollution diffusion. PMID:28703781

Vermiremediation of metal(loid)s via Eichornia crassipes phytomass extraction: A sustainable technique for plant amelioration.

PubMed

Majumdar, Arnab; Barla, Anil; Upadhyay, Munish Kumar; Ghosh, Dibyarpita; Chaudhuri, Punarbasu; Srivastava, Sudhakar; Bose, Sutapa

2018-08-15

Eichhornia crassipes (water hyacinth), imparts deficiency of soluble arsenic and other toxic metal (loid)s through rhizofiltration and phytoaccumulation. Without proper management strategy, this phytoremediation of metal (loid)s might fail and get reverted back to the environment, contaminating the nearby water bodies. This study, focused on bio-conversion of phytoremediating hyacinths, spiked with 100 times and greater arsenic, lead and cadmium concentrations than the average water contamination, ranging in 58.81 ± 0.394, 16.74 ± 0.367, 12.18 ± 0.153 mg Kg -1 arsenic, 18.95 ± 0.212, 9.53 ± 0.054, 6.83 ± 0.306 mg kg -1 lead and 2.79 ± 0.033, 1.39 ± 0.025, 0.92 ± 0.045 mg kg -1 cadmium, respectively in root, shoot and leaves, proving it's phytoaccumulation capacity. Next, these hyacinths has been used as a source of organic supplement for preparing vermicompost using Eisenia fetida following analysis of total metal content and sequential extraction. Control soil was having 134.69 ± 2.47 mg kg -1 arsenic in compare to 44.6 ± 0.91 mg kg -1 at premature stage of compost to 23.9 ± 1.55 mg kg -1 at mature compost indicating sustainable fate of phytoremediated vermicompost. This vermiremediation of arsenic and other toxic elements, restricted the bioavailability of soil pollutants. Furthermore, processed compost amended as organic fertilizer, growing chickpea, coriander, tomato and chilli plant, resulted in negligible metal(loid)s in treated samples, enhancing also plant's growth and production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Two facets of world arsenic problem solution: crop poisoning restriction and enforcement of phytoremediation.

PubMed

Kofroňová, Monika; Mašková, Petra; Lipavská, Helena

2018-05-07

This review provides insights into As toxicity in plants with focus on photosynthesis and sugar metabolism as important arsenic targets and simultaneously defence tools against accompanying oxidative stress. Heavy metal contamination is a great problem all over the world. Arsenic, a metalloid occurring naturally in the Earth's crust, also massively spreads out in the environment by human activities. Its accumulation in crops poses a severe health risk to humans and animals. Besides the restriction of human-caused contamination, there are two basic ways how to cope with the problem: first, to limit arsenic accumulation in harvestable parts of the crops; second, to make use of some arsenic hyperaccumulating plants for phytoremediation of contaminated soils and waters. Progress in the use of both strategies depends strongly on the level of our knowledge on the physiological and morphological processes resulting from arsenic exposure. Arsenic uptake is mediated preferentially by P and Si transporters and its accumulation substantially impairs plant metabolism at numerous levels including damages through oxidative stress. Rice is a predominantly studied crop where substantial progress has been made in understanding of the mechanisms of arsenic uptake, distribution, and detoxification, though many questions still remain. Full exploitation of plant potential for soil and water phytoremediations also requires deep understanding of the plant response to this toxic metalloid. The aim of this review is to summarize data regarding the effect of arsenic on plant physiology with a focus on mechanisms providing increased arsenic tolerance and/or hyperaccumulation. The emphasis is placed on the topic unjustifiably neglected in the previous reviews - i.e., carbohydrate metabolism, tightly connected to photosynthesis, and beside others involved in plant ability to cope with arsenic-induced oxidative and nitrosative stresses.

Sewage sludge biochar influence upon rice (Oryza sativa L) yield, metal bioaccumulation and greenhouse gas emissions from acidic paddy soil.

PubMed

Khan, Sardar; Chao, Cai; Waqas, Muhammad; Arp, Hans Peter H; Zhu, Yong-Guan

2013-08-06

Biochar addition to soil has been proposed to improve plant growth by increasing soil fertility, minimizing bioaccumulation of toxic metal(liod)s and mitigating climate change. Sewage sludge (SS) is an attractive, though potentially problematic, feedstock of biochar. It is attractive because of its large abundance; however, it contains elevated concentrations of metal(loid)s and other contaminants. The pyrolysis of SS to biochar (SSBC) may be a way to reduce the availability of these contaminants to the soil and plants. Using rice plant pot experiments, we investigated the influence of SSBC upon biomass yield, bioaccumulation of nutrients, and metal(loid)s, and green housegas (GHG) emissions. SSBC amendments increased soil pH, total nitrogen, soil organic carbon and available nutrients and decreased bioavailable As, Cr, Co, Ni, and Pb (but not Cd, Cu, and Zn). Regarding rice plant properties, SSBC amendments significantly (P ≤ 0.01) increased shoot biomass (71.3-92.2%), grain yield (148.8-175.1%), and the bioaccumulation of phosphorus and sodium, though decreased the bioaccumulation of nitrogen (except in grain) and potassium. Amendments of SSBC significantly (P ≤ 0.05) reduced the bioaccumulation of As, Cr, Co, Cu, Ni, and Pb, but increased that of Cd and Zn, though not above limits set by Chinese regulations. Finally regarding GHG emissions, SSBC significantly (P < 0.01) reduced N2O emissions and stimulated the uptake/oxidation of CH4 enough to make both the cultivated and uncultivated paddy soil a CH4 sink. SSBC can be beneficial in rice paddy soil but the actual associated benefits will depend on site-specific conditions and source of SS; long-term effects remain a further unknown.

Elevational and Spatial Gradients of Atmospheric Metal Pollution in the North Pacific

NASA Astrophysics Data System (ADS)

Jongebloed, U. A.; Osterberg, E. C.; Kreutz, K. J.; Ferris, D. G.; Campbell, S.; Saylor, P. L.; Winski, D.; Handley, M.

2017-12-01

The industrial revolution has led to a several-fold increase in the atmospheric concentrations of heavy metals and metalloids including Pb, Cd, Cu, Zn, Hg and As. Modern emissions inventories identify Asia as the largest emitter of many of these toxic pollutants, which are subsequently transported eastwards across the North Pacific Ocean by prevailing westerly winds in the mid-upper troposphere. Previous ice cores collected from the Yukon Territory in the eastern North Pacific reveal evolution-dependent metal pollution histories; the highest (5300 m elevation) core from Mt. Logan records a nearly pure trans-Pacific Asian pollution record, whereas cores from lower sites like the Eclipse Icefield (3017 m) record a complex combination of Asian and more local North American emission. However, it is unclear if this elevation gradient of pollution sources is found in other regions of the North Pacific. Furthermore, the previous ice core records end in the late 1990's, before efforts by some Asian nations to reduce metal pollution, and it is unknown if North Pacific atmospheric metal concentrations have declined in response to these efforts. Here we investigate metal and metalloid concentrations and sources recorded in ice core and snow pit samples recovered from a vertical transect spanning 2200 - 5242 m within Denali National Park in the Central Alaska Range. We compare these metal concentrations and crustal enrichment factors to data from the Yukon Territory to investigate North Pacific regional metal gradients. We also present preliminary results from a new 60 m ice core from the Eclipse Icefield to evaluate recent trends in metal concentrations since the end of the Mt. Logan and original Eclipse records in 1998, and compare this to the recent metal pollution history recorded in the 2013 Denali Ice Core collected from the summit plateau (3900 m) of Mt. Hunter.

Composition formulas of Fe-based transition metals-metalloid bulk metallic glasses derived from dual-cluster model of binary eutectics.

PubMed

Naz, Gul Jabeen; Dong, Dandan; Geng, Yaoxiang; Wang, Yingmin; Dong, Chuang

2017-08-22

It is known that bulk metallic glasses follow simple composition formulas [cluster](glue atom) 1 or 3 with 24 valence electrons within the framework of the cluster-plus-glue-atom model. Though the relevant nearest-neighbor cluster can be readily identified from a devitrification phase, the glue atoms remains poorly defined. The present work is devoted to understanding the composition rule of Fe-(B,P,C) based multi-component bulk metallic glasses, by introducing a cluster-based eutectic liquid model. This model regards a eutectic liquid to be composed of two stable liquids formulated respectively by cluster formulas for ideal metallic glasses from the two eutectic phases. The dual cluster formulas are first established for binary Fe-(B,C,P) eutectics: [Fe-Fe 14 ]B 2 Fe + [B-B 2 Fe 8 ]Fe ≈ Fe 83.3 B 16.7 for eutectic Fe 83 B 17 , [P-Fe 14 ]P + [P-Fe 9 ]P 2 Fe≈Fe 82.8 P 17.2 for Fe 83 P 17 , and [C-Fe 6 ]Fe 3  + [C-Fe 9 ]C 2 Fe ≈ Fe 82.6 C 17.4 for Fe 82.7 C 17.3 . The second formulas in these dual-cluster formulas, being respectively relevant to devitrification phases Fe 2 B, Fe 3 P, and Fe 3 C, well explain the compositions of existing Fe-based transition metals-metalloid bulk metallic glasses. These formulas also satisfy the 24-electron rule. The proposition of the composition formulas for good glass formers, directly from known eutectic points, constitutes a new route towards understanding and eventual designing metallic glasses of high glass forming abilities.

Chelant-enhanced washing of CCA-contaminated soil: Coupled with selective dissolution or soil stabilization.

PubMed

Beiyuan, Jingzi; Lau, Abbe Y T; Tsang, Daniel C W; Zhang, Weihua; Kao, Chih-Ming; Baek, Kitae; Ok, Yong Sik; Li, Xiang-Dong

2018-01-15

Remediation of CCA-contaminated soil (Cr, Cu, and As) by biodegradable chelant-enhanced washing (EDDS, S,S-ethylene-diamine-disuccinic-acid) needs further enhancement. This study investigated the effectiveness of coupling with pre-treatment by selective dissolution and post-treatment by soil amendments, respectively. Three groups of reagents (reductants, alkaline solvents, and organic ligands) were adopted in the pre-treatment to dissolve the oxide minerals before EDDS extraction. In the post-treatment, soil amendments (coal fly ash (CFA), acid mine drainage sludge (AMDS), green waste compost (GWC)), and their mixtures) were used for a 2-month stabilization after 2-h EDDS washing. Multi-endpoint evaluation was performed by assessing the chemical state, leachability, mobility, bioaccessibility, and plant-availability of residual metal(loid)s as well as the cytotoxicity, enzyme activities, and available nutrients of the treated soils. Pre-treatment by dithionite-citrate-bicarbonate significantly enhanced extraction efficiency, but also increased the leachability of As and Cr and bioaccessibility of Cr in the treated soils. While sodium hydroxide removed the majority of As without increasing its leachability and bioaccessibility, it increased the cytotoxicity and inhibited the acid phosphatase activity. Post-treatment with AMDS and CFA effectively controlled the mobility and leachability of residual As and Cr after EDDS washing. However, destabilized Cu was only marginally immobilized by GWC due to strong Cu-EDDS complexation. The bioaccessibility and phytoavailability of Cu was primarily reduced by EDDS washing, while those of As and Cr could be attenuated by AMDS and CFA. This study indicates that coupling chemical extraction with subsequent soil amendment plays complementary roles in mitigating effects of residual metal(loid)s and improving environmental quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of the availability of As and Pb in soils after in situ stabilization.

PubMed

Zhang, Wanying; Yang, Jie; Li, Zhongyuan; Zhou, Dongmei; Dang, Fei

2017-10-01

The in situ stabilization has been widely used to remediate metal-contaminated soil. However, the long-term retaining performance of heavy metals and the associated risk after in situ stabilization remains unclear and has evoked amounting concerns. Here, Pb- or As-contaminated soil was stabilized by a commercial amendment. The availability of Pb and As after in situ stabilization were estimated by ten different in vitro chemical extractions and DGT technique. After amendment application, a significant decline in extractable Pb or As was observed in treatments of Milli-Q water, 0.01 M CaCl 2 , 0.1 M NaNO 3 , 0.05 M (NH 4 ) 2 SO 4 , and 0.43 M HOAc. Potential available metal(loid)s determined by DGT also showed remarkable reduction. Meanwhile, the results of in vivo uptake assays demonstrated that Pb concentrations in shoots of ryegrass Lolium perenne L. declined to 12% of the control samples, comparable to the extraction ratio of 0.1 M NaNO 3 (15.8%) and 0.05 M (NH 4 ) 2 SO 4 (17.3%). For As-contaminated soil, 0.43 M HOAC provided a better estimation of relative phytoavailability (64.6 vs. 65.4% in ryegrass) compared to other extraction methods. We propose that 0.1 M NaNO 3 or 0.05 M (NH 4 ) 2 SO 4 for Pb and 0.43 M HOAc for As may serve as surrogate measures to estimate the lability of metal(loid)s after soil remediation of the tested contaminated soils. Further studies over a wider range of soil types and amendments are necessary to validate extraction methods.

Improved detection of coastal acid sulfate soil hotspots through biomonitoring of metal(loid) accumulation in water lilies (Nymphaea capensis).

PubMed

Stroud, Jacqueline L; Collins, Richard N

2014-07-15

Anthropogenically disturbed coastal acid sulfate soils along the east coast of Australia, and worldwide, periodically result in the discharge of acid waters containing high concentrations of metals. Identifying priority sites (hotspots) within a catchment for acid sulfate soil remediation activities typically involves long-term monitoring of drainwater chemistry, including the capture of data on unpredictable rain-induced groundwater discharge events. To improve upon this monitoring approach, this study investigated using the water lily (Nymphaea capensis) as a biomonitor of drainage waters to identify hotspots in three acid sulfate soil impacted catchments (83 km(2)) in north-eastern New South Wales, Australia. In one catchment where the location of hotspots was known, water lily lamina concentrations of a suite of metal(loid)s were significantly (p<0.05) higher than plants collected from an unpolluted 'reference' drainage channel, thus validating the concept of using this species as a biomonitor. A catchment-scale water lily sampling program undertaken in catchments with unidentified hotspots revealed within catchment variation of plant metal concentrations up to 70-fold. High resolution maps produced from these results, therefore, provided strong evidence for the location of potential hotspots which were confirmed with measurements of drainwater chemistry during rain-induced groundwater discharge events. Median catchment lily accumulation was ca. 160 mg Al kg(-1) and 1,300 mg Fe kg(-1), with hotspots containing up to 6- and 10-fold higher Al and Fe concentrations. These findings suggest that biomonitoring with N. capensis can be an important tool to rapidly identify priority sites for remediation in acid sulfate soil impacted landscapes. Copyright © 2014 Elsevier B.V. All rights reserved.

Arsenic speciation in newberyite (MgHPO(4)·3H(2)O) determined by synchrotron X-ray absorption and electron paramagnetic resonance spectroscopies: implications for the fate of arsenic in green fertilizers.

PubMed

Lin, Jinru; Chen, Ning; Pan, Yuanming

2014-06-17

Newberyite (MgHPO4·3H2O), a biomineral and common constituent in guano deposits, is an important decomposition product of struvite that is an increasingly popular green fertilizer recovered from wastewaters. Two samples of newberyite containing 1099 and 25 ppm As have been obtained at pH = 6.4, by using Na2HAsO4·7H2O and NaAsO2 as the dopant, respectively (i.e., Synthesis 1 and Synthesis 2). Synchrotron arsenic K-edge X-ray absorption spectroscopic data of newberyite from Synthesis 1 show that As(5+) is dominant and has a local environment typical of the arsenate species. Single-crystal electron paramagnetic resonance (EPR) spectra of gamma-ray-irradiated newberyite from Synthesis 1 contain two arsenic-associated oxyradicals: [AsO3](2-) and [AsO2](2-) derived from As(5+) and As(3+), respectively, at the P site. Quantitative analyses of powder EPR spectra allow determinations of the As(5+) and As(3+) contents in newberyite from Synthesis 1 and Synthesis 2. Elevated concentrations of arsenic also occur in natural newberyite transformed from struvite in guano deposits and record the accumulation of this metalloid in the food chain. Therefore, newberyite, which sequesters As during crystallization and retains this metalloid during the transformation from struvite, can attenuate arsenic contamination from green fertilizers in moderately acidic soils. Also, the capacity for accommodating both As(5+) and As(3+) in the crystal lattice coupled with simple chemistry and easy crystallization at ambient conditions makes newberyite an attractive material for remediation of arsenic contamination in aqueous environments.

Chemical and physical characterization of produced waters from conventional and unconventional fossil fuel resources.

PubMed

Alley, Bethany; Beebe, Alex; Rodgers, John; Castle, James W

2011-09-01

Characterization of produced waters (PWs) is an initial step for determining potential beneficial uses such as irrigation and surface water discharge at some sites. A meta-analysis of characteristics of five PW sources [i.e. shale gas (SGPWs), conventional natural gas (NGPWs), conventional oil (OPWs), coal-bed methane (CBMPWs), tight gas sands (TGSPWs)] was conducted from peer-reviewed literature, government or industry documents, book chapters, internet sources, analytical records from industry, and analyses of PW samples. This meta-analysis assembled a large dataset to extract information of interest such as differences and similarities in constituent and constituent concentrations across these sources of PWs. The PW data analyzed were comprised of 377 coal-bed methane, 165 oilfield, 137 tight gas sand, 4000 natural gas, and 541 shale gas records. Majority of SGPWs, NGPWs, OPWs, and TGSPWs contain chloride concentrations ranging from saline (>30000 mg L(-1)) to hypersaline (>40000 mg L(-1)), while most CBMPWs were fresh (<5000 mg L(-1)). For inorganic constituents, most SGPW and NGPW iron concentrations exceeded the numeric criterion for irrigation and surface water discharge, while OPW and CBMPW iron concentrations were less than the criterion. Approximately one-fourth of the PW samples in this database are fresh and likely need minimal treatment for metal and metalloid constituents prior to use, while some PWs are brackish (5000-30000 mg Cl(-) L(-1)) to saline containing metals and metalloids that may require considerable treatment. Other PWs are hypersaline and produce a considerable waste stream from reverse osmosis; remediation of these waters may not be feasible. After renovation, fresh to saline PWs may be used for irrigation and replenishing surface waters. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of nano zero-valent iron application on As, Cd, Pb, and Zn availability in the rhizosphere of metal(loid) contaminated soils.

PubMed

Vítková, Martina; Puschenreiter, Markus; Komárek, Michael

2018-06-01

Characterisation of geochemical transformations and processes in soils with special focus on the rhizosphere is crucial for assessing metal(loid) bioavailability to plants during in situ immobilisation and phytostabilisation. In this study, the effects of nano zero-valent iron (nZVI) were investigated in terms of the immobilisation of As, Zn, Pb and Cd in two soil types and their potential uptake by plants using rhizobox experiments. Such system allowed monitoring the behaviour of trace elements in rooted and bulk soil compartments separately. Sunflower (Helianthus annuus L.) and ryegrass (Lolium perenne L.) were tested for As-rich (15.9 g As kg -1 ) and Zn-rich (4.1 g Zn kg -1 ) soil samples, respectively. The application of nZVI effectively lowered the uptake of all target risk elements into plant tissues. Efficient immobilisation of As was determined in the As-soil without a significant difference between plant and bulk soil compartments. Similarly, a significant decrease was determined for CaCl 2 -available fractions of Zn, Pb and Cd in nZVI-treated Zn-soil. The behaviour of As corresponded to changes in Eh, while Zn and Cd showed to be mainly pH-dependent. However, despite the observed stabilisation effect of nZVI, high amounts of As and Zn still remained available for plants. Furthermore, the accumulation of the target risk elements in roots and the overall effect of nZVI transformations in the rhizosphere were verified and visualised by SEM/EDS. The following immobilising mechanisms were suggested: (i) sorption onto both existing and newly formed Fe (hydr)oxides, (ii) formation of secondary Fe-As phases, and (iii) sorption onto Mn (hydr)oxides. Copyright © 2018 Elsevier Ltd. All rights reserved.

Deriving site-specific clean-up criteria to protect ecological receptors (plants and soil invertebrates) exposed to metal or metalloid soil contaminants via the direct contact exposure pathway

PubMed Central

Checkai, Ron; Van Genderen, Eric; Sousa, José Paulo; Stephenson, Gladys; Smolders, Erik

2014-01-01

Soil contaminant concentration limits for the protection of terrestrial plants and soil invertebrates are commonly based on thresholds derived using data from laboratory ecotoxicity tests. A comprehensive assessment has been made for the derivation of ecological soil screening levels (Eco-SSL) in the United States; however, these limits are conservative because of their focus on high bioavailability scenarios. Here, we explain and evaluate approaches to soil limit derivation taken by 4 jurisdictions, 2 of which allow for correction of data for factors affecting bioavailability among soils, and between spiked and field-contaminated soils (Registration Evaluation Authorisation and Restriction of Chemicals [REACH] Regulation, European Union [EU], and the National Environment Protection Council [NEPC], Australia). Scientifically advanced features from these methods have been integrated into a newly developed method for deriving soil clean-up values (SCVs) within the context of site-specific baseline ecological risk assessment. Resulting site-specific SCVs that account for bioavailability may permit a greater residual concentration in soil when compared to generic screening limit concentrations (e.g., Eco-SSL), while still affording acceptable protection. Two choices for selecting the level of protection are compared (i.e., allowing higher effect levels per species, or allowing a higher percentile of species that are potentially unprotected). Implementation of this new method is presented for the jurisdiction of the United States, with a focus on metal and metalloid contaminants; however, the new method can be used in any jurisdiction. A case study for molybdate shows the large effect of bioavailability corrections and smaller effects of protection level choices when deriving SCVs. Integr Environ Assess Manag 2014;10:346–357. PMID:24470189

Should legislation regarding maximum Pb and Cd levels in human food also cover large game meat?

PubMed

Taggart, Mark A; Reglero, Manuel M; Camarero, Pablo R; Mateo, Rafael

2011-01-01

Game meat may be contaminated with metals and metalloids if animals reside in anthropogenically polluted areas, or if ammunition used to kill the game contaminates the meat. Muscle tissue from red deer and wild boar shot in Ciudad Real province (Spain) in 2005-06 was analysed for As, Pb, Cu, Zn, Se and Cd. Samples were collected from hunting estates within and outside an area that has been historically used for mining, smelting and refining various metals and metalloids. Meat destined for human consumption, contained more Pb, As and Se (red deer) and Pb (boar) when harvested from animals that had resided in mined areas. Age related accumulation of Cd, Zn and As (in deer) and Cd, Cu and Se (in boar) was also observed. Two boar meat samples contained high Pb, at 352 and 2408 μg/g d.w., and these were likely to have been contaminated by Pb ammunition. Likewise, 19-84% of all samples (depending on species and sampling area) had Pb levels > 0.1 μg/g w.w., the EU maximum residue level (MRL) for farm reared meat. Between 9 and 43% of samples exceeded comparable Cd limits. Such data highlight a discrepancy between what is considered safe for human consumption in popular farmed meat (chicken, beef, lamb), and what in game may often exist. A risk assessment is presented which describes the number of meals required to exceed current tolerable weekly intakes (PTWIs) for Pb and Cd, and the potential contribution of large game consumption to such intake limit criteria. Copyright © 2010 Elsevier Ltd. All rights reserved.

Comparative accumulation of (109)Cd and (75)Se from water and food by an estuarine fish (Tetractenos glaber).

PubMed

Alquezar, Ralph; Markich, Scott J; Twining, John R

2008-01-01

Few data are available on the comparative accumulation of metal(loid)s from water and food in estuarine/marine fish. Smooth toadfish (Tetractenos glaber), commonly found in estuaries in south-eastern Australia, were separately exposed to radio-labelled seawater (14kBqL(-1) of (109)Cd and 24kBqL(-1) of (75)Se) and food (ghost shrimps; Trypaea australiensis: 875Bqg(-1)(109)Cd and 1130Bqg(-1)(75)Se) for 25 days (uptake phase), followed by exposure to radionuclide-free water or food for 30 days (loss phase). Toadfish accumulated (109)Cd predominantly from water (85%) and (75)Se predominantly from food (62%), although the latter was lower than expected. For both the water and food exposures, (109)Cd was predominantly located in the gut lining (60-75%) at the end of the uptake phase, suggesting that the gut may be the primary pathway of (109)Cd uptake. This may be attributed to toadfish drinking large volumes of water to maintain osmoregulation. By the end of the loss phase, (109)Cd had predominantly shifted to the excretory organs - the liver (81%) in toadfish exposed to radio-labelled food, and in the liver, gills and kidney (82%) of toadfish exposed to radio-labelled water. In contrast, (75)Se was predominantly located in the excretory organs (gills, kidneys and liver; 66-76%) at the end of the uptake phase, irrespective of the exposure pathway, with minimal change in percentage distribution (76-83%) after the loss phase. This study emphasises the importance of differentiating accumulation pathways to better understand metal(loid) transfer dynamics and subsequent toxicity, in aquatic biota.

Importance of intra- and interspecific plant interactions for the phytomanagement of semiarid mine tailings using the tree species Pinus halepensis.

PubMed

Martinez-Oró, Duli; Parraga-Aguado, Isabel; Querejeta, Jose Ignacio; Conesa, Héctor M

2017-11-01

The objective of this work was to evaluate the effects of plant interactions (intra- and interspecific) on the growth and metal(loid) uptake of the tree species Pinus halepensis to determine its suitability for the phytomanagement of semiarid mine tailings. The pioneer tailings colonizer grass Piptatherum miliaceum was selected for assessing interspecific interactions. The experiment was conducted following a pot experimental design employing mine tailings soil. Pots containing single individuals of P. halepensis or P. miliaceum and pots containing combinations with pines (two pines per pot, or one pine and one grass per pot) were used. The analyses included the determination of plant biomass, foliar element status and stable isotope composition, metal(loid) uptake and its translocation to different plant organs. P. halepensis strongly favoured the growth of P. miliaceum by increasing 9-fold the latter's biomass and alleviating its P limitation. In this interspecific treatment P. halepensis showed a strong N limitation (N/P = 7), which negatively affected its growth, (to about half the biomass of that obtained for the other treatments) and exhibited a significant increase in some metals translocation (especially Cd) into aerial parts. Interestingly, P. miliaceum showed a decrease in the root to leaves translocation factor for most of metals when growing together with pines. The effects of the intraespecific combination on growth and metal uptake in P. halepensis were less relevant than those obtained for the interspecific one. Further research should be focused on testing the behaviour of plant co-cultures under the addition of N or P amendments which could alleviate the negative effects of plant competition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Speciation of metal(loid)s in environmental samples by X-ray absorption spectroscopy: a critical review.

PubMed

Gräfe, Markus; Donner, Erica; Collins, Richard N; Lombi, Enzo

2014-04-25

Element specificity is one of the key factors underlying the widespread use and acceptance of X-ray absorption spectroscopy (XAS) as a research tool in the environmental and geo-sciences. Independent of physical state (solid, liquid, gas), XAS analyses of metal(loid)s in complex environmental matrices over the past two decades have provided important information about speciation at environmentally relevant interfaces (e.g. solid-liquid) as well as in different media: plant tissues, rhizosphere, soils, sediments, ores, mineral process tailings, etc. Limited sample preparation requirements, the concomitant ability to preserve original physical and chemical states, and independence from crystallinity add to the advantages of using XAS in environmental investigations. Interpretations of XAS data are founded on sound physical and statistical models that can be applied to spectra of reference materials and mixed phases, respectively. For spectra collected directly from environmental matrices, abstract factor analysis and linear combination fitting provide the means to ascertain chemical, bonding, and crystalline states, and to extract quantitative information about their distribution within the data set. Through advances in optics, detectors, and data processing, X-ray fluorescence microprobes capable of focusing X-rays to micro- and nano-meter size have become competitive research venues for resolving the complexity of environmental samples at their inherent scale. The application of μ-XANES imaging, a new combinatorial approach of X-ray fluorescence spectrometry and XANES spectroscopy at the micron scale, is one of the latest technological advances allowing for lateral resolution of chemical states over wide areas due to vastly improved data processing and detector technology. Copyright © 2014. Published by Elsevier B.V.

Investigation, Pollution Mapping and Simulative Leakage Health Risk Assessment for Heavy Metals and Metalloids in Groundwater from a Typical Brownfield, Middle China.

PubMed

Li, Fei; Qiu, Zhenzhen; Zhang, Jingdong; Liu, Wenchu; Liu, Chaoyang; Zeng, Guangming

2017-07-13

Heavy metal and metalloid (Cr, Pb, Cd, Zn, Cu, Ni, As and Hg) concentrations in groundwater from 19 typical sites throughout a typical brownfield were detected. Mean concentrations of toxic metals in groundwater decreased in the order of Cr > Zn > Cu > Cd > Ni > Pb > Hg > As. Concentration of Cr 6+ in groundwater was detected to further study chromium contamination. Cr 6+ and Cd in groundwater were recommended as the priority pollutants because they were generally 1399-fold and 12-foldgreater than permissible limits, respectively. Owing to the fact that a waterproof curtain (WPC) in the brownfield is about to pass the warranty period, a steady two-dimensional water quality model and health risk assessment were applied to simulate and evaluate adverse effects of Cr 6 + and Cd on the water quality of Xiangjiang River and the drinking-water intake of Wangcheng Waterworks. The results indicated that when groundwater in the brownfield leaked with valid curtain prevention, the water quality in Xiangjiang River and drinking-water intake downstream were temporarily unaffected. However, if there was no curtain prevention, groundwater leakage would have adverse impact on water quality of Xiangjiang River. Under the requirements of Class III surface water quality, the pollution belt for Cr 6+ was 7500 m and 200 m for Cd. The non-carcinogenic risk of toxic metals in Xiangjiang River exceeded the threshold in a limited area, but did not threaten Wangcheng Waterworks. By contrast, the carcinogenic risk area for adults was at a transverse distance of 200 m and a longitudinal distance of 18,000 m, which was close to the Wangcheng Waterworks (23,000 m). Therefore, it was essential to reconstruct the WPC in the brownfield for preventing pollution diffusion.

Supercritical fluid extraction

DOEpatents

Wai, Chien M.; Laintz, Kenneth

1994-01-01

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Semiconducting glasses with flux pinning inclusions

DOEpatents

Johnson, William L.; Poon, Siu-Joe; Duwez, Pol E.

1981-01-01

A series of amorphous superconducting glassy alloys containing 1% to 10% by volume of flux pinning crystalline inclusions have been found to have potentially useful properties as high field superconducting magnet materials. The alloys are prepared by splat cooling by the piston and anvil technique. The alloys have the composition (TM).sub.90-70 (M).sub.10-30 where TM is a transition metal selected from at least one metal of Groups IVB, VB, VIB, VIIB or VIIIB of the Periodic Table such as Nb, Mo, Ru, Zr, Ta, W or Re and M is at least one metalloid such as B, P, C, N, Si, Ge or Al.

Microbial transformations of arsenic in the environment: From soda lakes to aquifers

USGS Publications Warehouse

Lloyd, J.R.; Oremland, R.S.

2006-01-01

Arsenic is a highly toxic element that supports a surprising range of biogeochemical transformations. The biochemical basis of these microbial interactions is described, with an emphasis on energy-yielding redox biotransformations that cycle between the As5+ and As3+ oxidation states. The subsequent impact of As3+-oxidising and As 5+-reducing prokaryotes on the chemistry of selected environments is also described, focusing on soda lakes with naturally high concentrations of the metalloid and on Southeast Asian aquifer sediments, where the microbial reduction of sorbed As5+ and subsequent mobilisation of As 3+ into water abstracted for drinking and irrigation threaten the lives of millions.

Developing Medical Geology in Uruguay: A Review

PubMed Central

Mañay, Nelly

2010-01-01

Several disciplines like Environmental Toxicology, Epidemiology, Public Health and Geology have been the basis of the development of Medical Geology in Uruguay during the last decade. The knowledge and performance in environmental and health issues have been improved by joining similar aims research teams and experts from different institutions to face environmental problems dealing with the population’s exposure to metals and metalloids and their health impacts. Some of the Uruguayan Medical Geology examples are reviewed focusing on their multidisciplinary approach: Lead pollution and exposed children, selenium in critically ill patients, copper deficiency in cattle and arsenic risk assessment in ground water. Future actions are also presented. PMID:20623004

Developing medical geology in Uruguay: a review.

PubMed

Mañay, Nelly

2010-05-01

Several disciplines like Environmental Toxicology, Epidemiology, Public Health and Geology have been the basis of the development of Medical Geology in Uruguay during the last decade. The knowledge and performance in environmental and health issues have been improved by joining similar aims research teams and experts from different institutions to face environmental problems dealing with the population's exposure to metals and metalloids and their health impacts. Some of the Uruguayan Medical Geology examples are reviewed focusing on their multidisciplinary approach: Lead pollution and exposed children, selenium in critically ill patients, copper deficiency in cattle and arsenic risk assessment in ground water. Future actions are also presented.

Ge14 Br8 (PEt3 )4 : A Subhalide Cluster of Germanium.

PubMed

Kunz, Tanja; Schrenk, Claudio; Schnepf, Andreas

2018-04-03

Heating a metastable solution of Ge I Br to room temperature led to the first structurally characterized metalloid subhalide cluster Ge 14 Br 8 (PEt 3 ) 4 (1). Furthermore 1 can be seen as the first isolated binary halide cluster on the way from Ge I Br to elemental germanium, giving insight into the complex reaction mechanism of its disproportionation reaction. Quantum chemical calculations further indicate that a classical bonding situation is realized within 1 and that the last step of the formation of 1 might include the trapping of GeBr 2 units. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasmonics and SERS activity of post-transition metal nanoparticles

NASA Astrophysics Data System (ADS)

Bezerra, A. G.; Machado, T. N.; Woiski, T. D.; Turchetti, D. A.; Lenz, J. A.; Akcelrud, L.; Schreiner, W. H.

2018-05-01

Nanoparticles of the post-transition metals, In, Sn, Pb, and Bi, and of the metalloid Sb were produced by laser ablation synthesis in solution (LASiS) and tested for localized surface plasmon resonances (LSPR) and surface-enhanced Raman scattering (SERS). The nanoparticles were characterized by UV-Vis optical absorption, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Several organic and biological molecules were tested, and SERS activity was demonstrated for all tested nanoparticles and molecules. The Raman enhancement factor for each nanoparticle class and molecule was experimentally determined. The search for new plasmonic nanostructures is important mainly for life sciences-related applications and this study expands the range of SERS active systems.

Disaster waste characteristics and radiation distribution as a result of the Great East Japan Earthquake.

PubMed

Shibata, Tomoyuki; Solo-Gabriele, Helena; Hata, Toshimitsu

2012-04-03

The compounded impacts of the catastrophes that resulted from the Great East Japan Earthquake have emphasized the need to develop strategies to respond to multiple types and sources of contamination. In Japan, earthquake and tsunami-generated waste were found to have elevated levels of metals/metalloids (e.g., mercury, arsenic, and lead) with separation and sorting more difficult for tsunami-generated waste as opposed to earthquake-generated waste. Radiation contamination superimposed on these disaster wastes has made it particularly difficult to manage the ultimate disposal resulting in delays in waste management. Work is needed to develop policies a priori for handling wastes from combined catastrophes such as those recently observed in Japan.

Theoretical design and discovery of the most-promising, previously overlooked hybrid perovskite compounds

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

Zunger, Alex; Kazmerski, Lawrence L.; Dalpian, Gustavo M.

The material class of hybrid organic-inorganic perovskites (AMX3) has risen rapidly from a virtually unknown material in photovoltaic applications a short 8-years ago into 20-23% efficient thin-film solar cell devices. As promising as this class of materials is, however, there are limitations associated with its poor long-term stability, non-optimal band gap, and the presence of toxic Pb atom on the metalloid site. An Edisonian laboratory exploration (i.e., growth + characterization) via trial-and-error processes of all other candidate materials, is unpractical. Our approach uses high speed computational design and discovery to screen the ‘best of class” candidates based upon optimal functionalities.

Phytostabilization of mine tailings using compost-assisted direct planting: Translating greenhouse results to the field.

PubMed

Gil-Loaiza, Juliana; White, Scott A; Root, Robert A; Solís-Dominguez, Fernando A; Hammond, Corin M; Chorover, Jon; Maier, Raina M

2016-09-15

Standard practice in reclamation of mine tailings is the emplacement of a 15 to 90cm soil/gravel/rock cap which is then hydro-seeded. In this study we investigate compost-assisted direct planting phytostabilization technology as an alternative to standard cap and plant practices. In phytostabilization the goal is to establish a vegetative cap using native plants that stabilize metals in the root zone with little to no shoot accumulation. The study site is a barren 62-hectare tailings pile characterized by extremely acidic pH as well as lead, arsenic, and zinc each exceeding 2000mgkg(-1). The study objective is to evaluate whether successful greenhouse phytostabilization results are scalable to the field. In May 2010, a 0.27ha study area was established on the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site with six irrigated treatments; tailings amended with 10, 15, or 20% (w/w) compost seeded with a mix of native plants (buffalo grass, arizona fescue, quailbush, mountain mahogany, mesquite, and catclaw acacia) and controls including composted (15 and 20%) unseeded treatments and an uncomposted unseeded treatment. Canopy cover ranging from 21 to 61% developed after 41 months in the compost-amended planted treatments, a canopy cover similar to that found in the surrounding region. No plants grew on unamended tailings. Neutrophilic heterotrophic bacterial counts were 1.5 to 4 orders of magnitude higher after 41months in planted versus unamended control plots. Shoot tissue accumulation of various metal(loids) was at or below Domestic Animal Toxicity Limits, with some plant specific exceptions in treatments receiving less compost. Parameters including % canopy cover, neutrophilic heterotrophic bacteria counts, and shoot uptake of metal(loids) are promising criteria to use in evaluating reclamation success. In summary, compost amendment and seeding, guided by preliminary greenhouse studies, allowed plant establishment and sustained growth over 4years demonstrating feasibility for this phytostabilization technology. Copyright © 2016 Elsevier B.V. All rights reserved.

Metal leaching in mine tailings: short-term impact of biochar and wood ash amendments.

PubMed

Beauchemin, Suzanne; Clemente, Joyce S; MacKinnon, Ted; Tisch, Bryan; Lastra, Rolando; Smith, Derek; Kwong, John

2015-01-01

Biochar is perceived as a promising amendment to reclaim degraded, metal-contaminated lands. The objective of this study was to compare the potential of biochar and wood ash amendments to reduce metal(loid) leaching in mine tailings. A 2-mo leaching experiment was conducted in duplicate on acidic and alkaline tailings, each mixed with 5 wt.% of one of the following amendments: three wood-derived, fast-pyrolysis biochars (OC > 57 wt.%) and two wood ash materials (organic carbon [OC] ≤ 16 wt.%); a control test with no carbon input was also added. The columns were leached with water after 1, 2, 4, 8, 16, 32, and 64 d, and the leachates were monitored for dissolved metals, OC, and pH. For the acidic and alkaline tailings, the most significant impact on metal mobility was observed with wood ash materials due to their greater neutralization potential (>15% CaCO eq.) compared with biochar (≤3.3% CaCO eq.). An increase of 1 pH unit in the wood ash-treated alkaline tailings led to an undesirable mobilization of As and Se. The addition of biochar did not significantly reduce the leaching of the main contaminants (Cu and Ni in the acidic tailings and As in the alkaline tailings) over 2 mo. The Se attenuation noted in some biochar-treated acid tailings may be mainly due to a slight alkaline effect rather than Se removal by biochar, given the low capacity for the fresh biochars to retain Se under acidic conditions (pH 4.5). The increased loss of dissolved OC in the biochar-amended systems was of short duration and was not associated with metal(loid) mobilization. Copyright © Her Majesty the Queen in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada.

A subgroup of plant aquaporins facilitate the bi-directional diffusion of As(OH)3 and Sb(OH)3 across membranes

PubMed Central

Bienert, Gerd P; Thorsen, Michael; Schüssler, Manuela D; Nilsson, Henrik R; Wagner, Annemarie; Tamás, Markus J; Jahn, Thomas P

2008-01-01

Background Arsenic is a toxic and highly abundant metalloid that endangers human health through drinking water and the food chain. The most common forms of arsenic in the environment are arsenate (As(V)) and arsenite (As(III)). As(V) is a non-functional phosphate analog that enters the food chain via plant phosphate transporters. Inside cells, As(V) becomes reduced to As(III) for subsequent extrusion or compartmentation. Although much is known about As(III) transport and handling in microbes and mammals, the transport systems for As(III) have not yet been characterized in plants. Results Here we show that the Nodulin26-like Intrinsic Proteins (NIPs) AtNIP5;1 and AtNIP6;1 from Arabidopsis thaliana, OsNIP2;1 and OsNIP3;2 from Oryza sativa, and LjNIP5;1 and LjNIP6;1 from Lotus japonicus are bi-directional As(III) channels. Expression of these NIPs sensitized yeast cells to As(III) and antimonite (Sb(III)), and direct transport assays confirmed their ability to facilitate As(III) transport across cell membranes. On medium containing As(V), expression of the same NIPs improved yeast growth, probably due to increased As(III) efflux. Our data furthermore provide evidence that NIPs can discriminate between highly similar substrates and that they may have differential preferences in the direction of transport. A subgroup of As(III) permeable channels that group together in a phylogenetic tree required N-terminal truncation for functional expression in yeast. Conclusion This is the first molecular identification of plant As(III) transport systems and we propose that metalloid transport through NIPs is a conserved and ancient feature. Our observations are potentially of great importance for improved remediation and tolerance of plants, and may provide a key to the development of low arsenic crops for food production. PMID:18544156

Cryptic Role of Zero-Valent Sulfur in Metal and Metalloid Geochemistry in Euxinic Waters

NASA Astrophysics Data System (ADS)

Helz, G. R.

2014-12-01

Natural waters that are isolated from the atmosphere in confined aquifers, euxinic basins and sediment pore waters often become sulfidic. These waters are conventionally described simply as reducing environments. But because nature does not constrain their exposure to reducing equivalents (e.g. from organic matter) and oxidizing equivalents (e.g. from Fe,Mn oxides), these reducing environments in fact vary cryptically in their redox characteristics. The implications for trace metal and metalloid cycles are only beginning to be explored. The activity of zero-valent sulfur (aS0), a virtual thermodynamic property, is a potentially useful index for describing this variation. At a particular temperature and ionic strength, aS0 can be quantified from knowledge of pH and the total S(0) to total S(-II) ratio. Although data are incomplete, the deep waters of the Black Sea (aS0 ca. 0.3) appear to be more reducing than the deep waters of the Cariaco Basin (aS0 ca. 0.5) even though both are perennially sulfidic. An apparent manifestation is a greater preponderance of greigite relative to mackinawite in the Cariaco Basin. Interestingly, greigite is stable relative to mackinawite in both basins but predominates only at the higher aS0. Values of aS0 in sulfidic natural waters span the range over which Hg-polysulfide complexes gain predominance over Hg sulfide complexes. Competition between these ligands is thought to influence biological methylation, mercury's route into aquatic and human food chains. In sulfidic deep ground waters, the redox state and consequent mobility of As, a global human hazard, will depend on aS0. At intermediate sulfide concentrations, higher aS0 favors more highly charged and thus less mobile As(V) species relative to As(III) species despite the overall reducing characteristics of such waters. Helz, G.R. (2014) Activity of zero-valent sulfur in sulfidic natural waters. Geochem. Trans. In press.

Phytostabilization of arsenic in soils with plants of the genus Atriplex established in situ in the Atacama Desert.

PubMed

Fernández, Yasna Tapia; Diaz, O; Acuña, E; Casanova, M; Salazar, O; Masaguer, A

2016-04-01

In the ChiuChiu village (Atacama Desert, Chile), there is a high concentration of arsenic (As) in the soil due to natural causes related to the presence of volcanoes and geothermal activity. To compare the levels of As and the growth parameters among plants of the same genus, three species of plants were established in situ: Atriplex atacamensis (native of Chile), Atriplex halimus, and Atriplex nummularia. These soils have an As concentration of 131.2 ± 10.4 mg kg(-1), a pH of 8.6 ± 0.1, and an electrical conductivity of 7.06 ± 2.37 dS m(-1). Cuttings of Atriplex were transplanted and maintained for 5 months with periodic irrigation and without the addition of fertilizers. The sequential extraction of As indicated that the metalloid in these soils has a high bioavailability (38 %), which is attributed to the alkaline pH, low organic matter and Fe oxide content, and sandy texture. At day 90 of the assay, the As concentrations in the leaves of A. halimus (4.53 ± 1.14 mg kg(-1)) and A. nummularia (3.85 ± 0.64 mg kg(-1)) were significantly higher than that in A. atacamensis (2.46 ± 1.82 mg kg(-1)). However, the three species accumulated higher levels of As in their roots, indicating a phytostabilization capacity. At the end of the assay, A. halimus and A. nummularia generated 30 % more biomass than A. atacamensis without significant differences in the As levels in the leaves. Despite the difficult conditions in these soils, the establishment of plants of the genus Atriplex is a recommended strategy to generate a vegetative cover that prevents the metalloid from spreading in this arid area through the soil or by wind.

Human health risks from metals and metalloid via consumption of food animals near gold mines in Tarkwa, Ghana: estimation of the daily intakes and target hazard quotients (THQs).

PubMed

Bortey-Sam, Nesta; Nakayama, Shouta M M; Ikenaka, Yoshinori; Akoto, Osei; Baidoo, Elvis; Yohannes, Yared Beyene; Mizukawa, Hazuki; Ishizuka, Mayumi

2015-01-01

Heavy metal and metalloid contamination in food resulting from mining is of major concern due to the potential risk involved. Food consumption is the most likely route of human exposure to metals. This study was therefore to assess metals in different organs and different animal species near gold mines used for human consumption (free-range chicken, goat and sheep) in Tarkwa, Ghana, and to estimate the daily intake and health risk. The concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb were measured with an inductively coupled plasma-mass spectrometer and Hg analysis was done using the mercury analyzer. Principal component analysis of the results showed a clear separation between chicken, grouped on one side, and the ruminants clustered on another side in both offal and muscle. Interestingly, As, Cd, Hg, Mn and Pb made one cluster in the offal of chicken. Chicken muscle also showed similar distribution with As, Hg and Pb clustered together. The daily intake of metals (μg/kg body weight/day) were in the following ranges; As [0.002 (kidneys of goat and sheep)-0.19 (chicken gizzard)], Cd [0.003 (chicken muscle)-0.55 (chicken liver)], Hg [0.002 (goat muscle)-0.29 (chicken liver)], Pb [0.01 (muscles and kidneys of goat and sheep)-0.96 (chicken gizzard)] and Mn [0.13 (goat kidney)-8.92 (sheep liver)]. From the results, daily intakes of As, Cd, Hg, Pb and Mn in these food animals were low compared to the provisional tolerable daily intake guidelines. The THQs although less than one, indicated that contributions of chicken gizzard and liver to toxic metal exposure in adults and especially children could be significant. Copyright © 2014. Published by Elsevier Inc.

Assessment of ambient background concentrations of elements in soil using combined survey and open-source data.

PubMed

Mikkonen, Hannah G; Clarke, Bradley O; Dasika, Raghava; Wallis, Christian J; Reichman, Suzie M

2017-02-15

Understanding ambient background concentrations in soil, at a local scale, is an essential part of environmental risk assessment. Where high resolution geochemical soil surveys have not been undertaken, soil data from alternative sources, such as environmental site assessment reports, can be used to support an understanding of ambient background conditions. Concentrations of metals/metalloids (As, Mn, Ni, Pb and Zn) were extracted from open-source environmental site assessment reports, for soils derived from the Newer Volcanics basalt, of Melbourne, Victoria, Australia. A manual screening method was applied to remove samples that were indicated to be contaminated by point sources and hence not representative of ambient background conditions. The manual screening approach was validated by comparison to data from a targeted background soil survey. Statistical methods for exclusion of contaminated samples from background soil datasets were compared to the manual screening method. The statistical methods tested included the Median plus Two Median Absolute Deviations, the upper whisker of a normal and log transformed Tukey boxplot, the point of inflection on a cumulative frequency plot and the 95th percentile. We have demonstrated that where anomalous sample results cannot be screened using site information, the Median plus Two Median Absolute Deviations is a conservative method for derivation of ambient background upper concentration limits (i.e. expected maximums). The upper whisker of a boxplot and the point of inflection on a cumulative frequency plot, were also considered adequate methods for deriving ambient background upper concentration limits, where the percentage of contaminated samples is <25%. Median ambient background concentrations of metals/metalloids in the Newer Volcanic soils of Melbourne were comparable to ambient background concentrations in Europe and the United States, except for Ni, which was naturally enriched in the basalt-derived soils of Melbourne. Copyright © 2016 Elsevier B.V. All rights reserved.

Residential metal contamination and potential health risks of exposure in adobe brick houses in Potosí, Bolivia.

PubMed

McEwen, Abigail R; Hsu-Kim, Heileen; Robins, Nicholas A; Hagan, Nicole A; Halabi, Susan; Barras, Olivo; Richter, Daniel deB; Vandenberg, John J

2016-08-15

Potosí, Bolivia, is the site of centuries of historic and present-day mining of the Cerro Rico, a mountain known for its rich polymetallic deposits, and was the site of large-scale Colonial era silver refining operations. In this study, the concentrations of several metal and metalloid elements were quantified in adobe brick, dirt floor, and surface dust samples from 49 houses in Potosí. Median concentrations of total mercury (Hg), lead (Pb), and arsenic (As) were significantly greater than concentrations measured in Sucre, Bolivia, a non-mining town, and exceeded US-based soil screening levels. Adobe brick samples were further analyzed for bioaccessible concentrations of trace elements using a simulated gastric fluid (GF) extraction. Median GF extractable concentrations of Hg, As, and Pb were 0.085, 13.9, and 32.2% of the total element concentration, respectively. Total and GF extractable concentrations of Hg, As, and Pb were used to estimate exposure and potential health risks to children following incidental ingestion of adobe brick particles. Risks were assessed using a range of potential ingestion rates (50-1000mg/day). Overall, the results of the risk assessment show that the majority of households sampled contained concentrations of bioaccessible Pb and As, but not Hg, that represent a potential health risk. Even at the lowest ingestion rate considered, the majority of households exceeded the risk threshold for Pb, indicating that the concentrations of this metal are of particular concern. To our knowledge, this is the first study to quantify key trace elements in building materials in adobe brick houses and the results indicate that these houses are a potential source of exposure to metals and metalloids in South American mining communities. Additional studies are needed to fully characterize personal exposure and to understand potential adverse health outcomes within the community. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbial contributions to coupled arsenic and sulfur cycling in the acid-sulfide hot spring Champagne Pool, New Zealand.

PubMed

Hug, Katrin; Maher, William A; Stott, Matthew B; Krikowa, Frank; Foster, Simon; Moreau, John W

2014-01-01

Acid-sulfide hot springs are analogs of early Earth geothermal systems where microbial metal(loid) resistance likely first evolved. Arsenic is a metalloid enriched in the acid-sulfide hot spring Champagne Pool (Waiotapu, New Zealand). Arsenic speciation in Champagne Pool follows reaction paths not yet fully understood with respect to biotic contributions and coupling to biogeochemical sulfur cycling. Here we present quantitative arsenic speciation from Champagne Pool, finding arsenite dominant in the pool, rim and outflow channel (55-75% total arsenic), and dithio- and trithioarsenates ubiquitously present as 18-25% total arsenic. In the outflow channel, dimethylmonothioarsenate comprised ≤9% total arsenic, while on the outflow terrace thioarsenates were present at 55% total arsenic. We also quantified sulfide, thiosulfate, sulfate and elemental sulfur, finding sulfide and sulfate as major species in the pool and outflow terrace, respectively. Elemental sulfur concentration reached a maximum at the terrace. Phylogenetic analysis of 16S rRNA genes from metagenomic sequencing revealed the dominance of Sulfurihydrogenibium at all sites and an increased archaeal population at the rim and outflow channel. Several phylotypes were found closely related to known sulfur- and sulfide-oxidizers, as well as sulfur- and sulfate-reducers. Bioinformatic analysis revealed genes underpinning sulfur redox transformations, consistent with sulfur speciation data, and illustrating a microbial role in sulfur-dependent transformation of arsenite to thioarsenate. Metagenomic analysis also revealed genes encoding for arsenate reductase at all sites, reflecting the ubiquity of thioarsenate and a need for microbial arsenate resistance despite anoxic conditions. Absence of the arsenite oxidase gene, aio, at all sites suggests prioritization of arsenite detoxification over coupling to energy conservation. Finally, detection of methyl arsenic in the outflow channel, in conjunction with increased sequences from Aquificaceae, supports a role for methyltransferase in thermophilic arsenic resistance. Our study highlights microbial contributions to coupled arsenic and sulfur cycling at Champagne Pool, with implications for understanding the evolution of microbial arsenic resistance in sulfidic geothermal systems.

UV-vis spectroscopy and colorimetric models for detecting anthocyanin-metal complexes in plants: An overview of in vitro and in vivo techniques.

PubMed

Fedenko, Volodymyr S; Shemet, Sergiy A; Landi, Marco

2017-05-01

Although anthocyanin (ACN) biosynthesis is one of the best studied pathways of secondary metabolism in plants, the possible physiological and ecological role(s) of these pigments continue to intrigue scientists. Like other dihydroxy B-ring substituted flavonoids, ACNs have an ability to bind metal and metalloid ions, a property that has been exploited for a variety of purposes. For example, the metal binding ability may be used to stabilize ACNs from plant food sources, or to modify their colors for using them as food colorants. The complexation of metals with cyanidin derivatives can also be used as a simple, sensitive, cheap, and rapid method for determination concentrations of several metals in biological and environmental samples using UV-vis spectroscopy. Far less information is available on the ecological significance of ACN-metal complexes in plant-environment interactions. Metalloanthocyanins (protocyanin, nemophilin, commelinin, protodelphin, cyanosalvianin) are involved in the copigmentation phenomenon that leads to blue-pigmented petals, which may facilitate specific plant-pollinator interactions. ACN-metal formation and compartmentation into the vacuole has also been proposed to be part of an orchestrated detoxification mechanism in plants which experience metal/metalloid excess. However, investigations into ACN-metal interactions in plant biology may be limited because of the complexity of the analytical techniques required. To address this concern, here we describe simple methods for the detection of ACN-metal both in vitro and in vivo using UV-vis spectroscopy and colorimetric models. In particular, the use of UV-vis spectra, difference absorption spectra, and colorimetry techniques will be described for in vitro determination of ACN-metal features, whereas reflectance spectroscopy and colorimetric parameters related to CIE L * a * b * and CIE XYZ systems will be detailed for in vivo analyses. In this way, we hope to make this high-informative tool more accessible to plant physiologists and ecologists. Copyright © 2017 Elsevier GmbH. All rights reserved.

M{sub 2}X intermetallics: Nonmetal insertion in a h.c.-like metallic distribution

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

Pivan, J.Y.; Guerin, R.

A simple structural model is proposed on the basis of an ideal hexagonal close-packing (AB){sup {infinity}} of the metal atoms M. The metalloid atoms X, located in an ordered manner in the metallic planes with the stacking sequence ..(A){sup {infinity}}.. or ..(B){sup {infinity}}.., generate two types of elementary units called units U{sub I} and U{sub II}. These units are hexagonal prisms with the fundamental vectors a{sub 0}, b{sub 0}, c{sub 0} and the elementary volume V{sub 0}. When the exclusive occurrence of U{sub I} (or U{sub II}) only yields 6-prismatic and triangular sites of metalloid atoms X, additional tetrahedral andmore » pyramidal sites of X atoms are present when units U{sub I} and U{sub II} exist simultaneously. The structures of compounds with the general formula M{sub 2}X (M = 3d, 4d, 5d and (or) 4f, 5f elements, X = B, P, As, Sb, Si, Ge, {hor_ellipsis}) are described in terms of intergrowth mechanisms. Binary, ternary, or even quaternary structures of compounds, with M/X ratios equal or close to two, appear as superstructures of the elementary units. Insofar as no ordering is considered along the stacking direction, the vectorial combinations of the fundamental vectors in the form A = h.a{sub 0}+s.b{sub 0}, B = k.a{sub 0}+t.b{sub 0}, C = c{sub 0} result in supercells with the volume V = (h.t {minus} k.s).V{sub 0}. The attainable symmetry (hexagonal, tetragonal, orthorhombic, monoclinic, {hor_ellipsis}) strongly depends on the particular values of the integers h, s, k, t. The criteria of occurrence of various series of compounds are presented together with their crystallographic features and structural relationships are emphasized. Moreover, the model demonstrates that numerous compounds with the predicted unit cell parameters should be obtained in each crystal system.« less

Supercritical water treatment of heavy metal and arsenic metalloid-bioaccumulating-biomass.

PubMed

Li, Jianxin; Chen, Jinbo; Chen, Shan

2018-08-15

Hyperaccumulator biomass, as a promising resource for renewable energy that can be converted into valuable fuel productions with high conversion efficiency, must be considered as hazardous materials and be carefully treated before further reuse due to the high contents of heavy metals. In this study, Pteris vittata L., an As-hyperaccumulator biomass was treated by an effective and environmental friendly method-supercritical water gasification (SCWG) using a bench-scale batch reactor. The contents of heavy metals (Cd, Pb and Zn) and arsenic metalloid in solid, liquid and gaseous products during SCWG process were thoroughly investigated. The speciation fractions including exchangeable, reducible, oxidizable and residual fractions of each heavy metal as the proportion of the total contents in solid residue were presented and the transformations trend of these heavy metals during the SCWG process was especially demonstrated. The significant operating parameters, including reaction temperature (395-445 °C), pressure (21-27 MPa) and residence time (0-40 min) were varied to explore their effects on the contents and forms. Moreover, the environmental risks of heavy metals in solid residues were evaluated based on risk assessment code, taking into consideration the speciation fractions and bioavailability. It was highlighted that although heavy metals particularly Pb and Zn tended to accumulate in solid residues with a maximum increment of about 50% in the total content, they were mostly converted to more stable oxidizable and residual fractions, and thus the ecotoxicity and bioavailability were greatly mitigated with no obvious increase in direct toxicity fractions. Each tested heavy metal presented no or low risk to the environments after SCWG treatments, meaning that the environmental pollution levels were markedly reduced with no or low risk to the environment. This study highlights the remarkable ability of SCWG for the heavy metal stabilization. Copyright © 2018 Elsevier Inc. All rights reserved.

Acid rock drainage passive remediation using alkaline clay and impacts of vegetation and saturated sand barrier

NASA Astrophysics Data System (ADS)

Plaza, F.; Wen, Y.; Liang, X.

2017-12-01

Acid rock drainage (ARD) caused by abundance of coal refuse (CR) deposits in mining regions requires adequate treatment to prevent serious water pollution due to its acidity and high concentrations of sulfate and metals/metalloids. Over the past decades, various approaches have been explored and developed to remediate ARD. This study uses laboratory experiments to investigate the effectiveness and impacts of ARD passive remediation using alkaline clay (AC), a by-product of the aluminum refining process. Twelve column kinetic leaching experiments were set up with CR/AC mixing ratios ranging from 1%AC to 10%AC. Samples were collected from these columns to measure the pH, sulfate, metals/metalloids, acidity and alkalinity. Additional tests of XRD and acid base accounting were also conducted to better characterize the mineral phase in terms of the alkalinity and acidity potential. Based on the leachate measurement results, these columns were further classified into two groups of neutral/near neutral pH and acidic pH for further analysis. In addition, impacts of the vegetation and saturated sand layer on the remediation effectiveness were explored. The results of our long-term (more than three years in some cases) laboratory experiments show that AC is an effective ARD remediation material for the neutralization of leachate pH and immobilization of sulfate and metals such as Fe, Mn, Cu, Zn, Ni, Pb, Cd, Co. The CR/AC mixing ratios higher than 3%AC are found to be effective, with 10% close to optimal. Moreover, the results demonstrate the benefits of using vegetation and a saturated sand barrier. Vegetation acted as a phytoaccumulation/phytoextraction agent, causing an additional immobilization of metals. The saturated sand barrier blocked the oxygen and water diffusion downwards, leading to a reduction of the pyrite oxidation rate. Finally, the proposed remediation approach shows that the acidity consumption will likely occur before all the alkalinity is exhausted, guaranteeing an adequate long-term performance of this remediation approach.

Heavy metals and metalloids in egg contents and eggshells of passerine birds from Arizona

USGS Publications Warehouse

Mora, Miguel A.

2003-01-01

Concentrations of inorganic elements were determined in eggs of passerine birds including the endangered southwestern willow flycatcher (Empidonax traillii extimus) from four regions in Arizona. The main aim of the study was to determine the distribution of metals in egg contents and eggshells, with emphasis on the deposition of Sr in eggshells. Seventy eggs of 11 passerine species were collected at four nesting locations during 2000. Aluminum, Ba, Cr, Cu, Mn, Se, Sr, and Zn, were detected primarily in egg contents of all bird species. Arsenic, Ni, Pb, and V were detected primarily in eggshells. A proportion of most inorganic elements accumulated in the eggshell. Concentrations of Ba, Cu, Mn, Se, Sr, and Zn in egg contents and As, Ba, Cu, and V in eggshells of yellow-breasted chats (Icteria virens) were similar among locations. However, concentrations of Mn, Ni, Sr, and Zn in eggshells were significant different among locations. Except for Cu, Mn, Se, and Zn, concentrations of inorganic elements were 2–35 times greater in eggshells than in eggs. Most concentrations of metals and metalloids in eggs and eggshells of all the bird species were below levels known to affect reproduction or that have other deleterious effects. However, I found somewhat elevated concentrations of Sr in eggshells (highest mean=1505 μg/g dw, n=3) of yellow-breasted chats and willow flycatchers, and in egg contents of yellow warblers (Dendroica petechia) and song sparrows (Melospiza melodia). Whether current observed concentrations of Sr in eggshells are affecting nesting birds in Arizona remains to be determined. Strontium and other metals could be associated with lower hatching success in some areas. This study shows that a proportion of many inorganic elements accumulates in the eggshell and that the potential effects on the proper structure and functioning of the eggshell should not be ignored.

Achnanthidium minutissimum (Bacillariophyta) valve deformities as indicators of metal enrichment in diverse widely-distributed freshwater habitats.

PubMed

Cantonati, Marco; Angeli, Nicola; Virtanen, Laura; Wojtal, Agata Z; Gabrieli, Jacopo; Falasco, Elisa; Lavoie, Isabelle; Morin, Soizic; Marchetto, Aldo; Fortin, Claude; Smirnova, Svetlana

2014-03-15

In the presence of different environmental stressors, diatoms can produce frustules presenting different types of deformities. Metals and trace elements are among the most common causes of these teratological forms. Metal enrichment in water bodies can be attributed to the geological setting of the area or to pollution. The widespread benthic diatom Achnanthidium minutissimum (ADMI) is one of the most metal-tolerant species. In the present study, ADMI teratologies were defined from samples taken from eight very diverse, widely-distributed inland-water habitats: streams affected by active and abandoned mining areas, a metal-contaminated stream, a spring in an old chalcopyrite mine, a mineral-water fountain, and a sediment core taken from a lake affected by metal contamination in the past. Deformed frustules of ADMI were characterised mainly by one (sometimes two) more or less bent off ending, conferring to the specimens a cymbelloid outline (cymbelliclinum-like teratology, CLT). Marked teratologies were distinguished from slight deformities. Hydrochemical analyses, including metals and trace elements, were carried out and enrichment factors (EF) relative to average crustal composition were calculated. To improve our knowledge on the potential of different metals and trace elements to trigger the occurrence of ADMI CLT, we carefully selected 15 springs out of 110 (CRENODAT dataset) where both ADMI and above-average metal or metalloid concentrations occurred, and re-analysed these samples. The results from the eight widely-distributed core sites as well as from the 15 selected CRENODAT springs led to the hypothesis that two metals (copper and zinc) and a metalloid (antimony) were the most likely triggers of ADMI CLT formation. From a quantitative point of view, it is worth noting that the lowest concentrations triggering ADMI CLT can be fairly low, particularly in the case of copper contamination. The antimony-rich site was characterised by a marked-teratology variant where both ends of ADMI were bent off. © 2013 Elsevier B.V. All rights reserved.

Influence of organic substrates on the kinetics of bacterial As(III) oxidation

NASA Astrophysics Data System (ADS)

Lescure, T.; Joulian, C.; Bauda, P.; Hénault, C.; Battaglia-Brunet, F.

2012-04-01

Soil microflora plays a major role on the behavior of metals and metalloids. Arsenic speciation, in particular, is related to the activity of bacteria able to oxidize, reduce or methylate this element, and determines mobility, bioavailability and toxicity of As. Arsenite (AsIII) is more toxic and more mobile than arsenate (AsV). Bacterial As(III)-oxidation tends to reduce the toxicity of arsenic in soils and the risk of transfer toward underlying aquifers, that would affect the quality of water resources. Previous results suggest that organic matter may affect kinetics or efficiency of bacterial As(III)-oxidation in presence of oxygen, thus in conventional physico-chemical conditions of a surface soil. Different hypothesis can be proposed to explain the influence of organic matter on As(III) oxidation. Arsenic is a potential energy source for bacteria. The presence of easily biodegradable organic matter may inhibit the As(III) oxidation process because bacteria would first metabolize these more energetic substrates. A second hypothesis would be that, in presence of organic matter, the Ars system involved in bacterial resistance to arsenic would be more active and would compete with the Aio system of arsenite oxidation, decreasing the global As(III) oxidation rate. In addition, organic matter influences the solubility of iron oxides which often act as the main pitfalls of arsenic in soils. The concentration and nature of organic matter could therefore have a significant influence on the bioavailability of arsenic and hence on its environmental impact. The influence of organic matter on biological As(III) oxidation has not yet been determined in natural soils. In this context, soil amendment with organic matter during operations of phytostabilization or, considering diffuse pollutions, through agricultural practices, may affect the mobility and bio-availability of the toxic metalloid. The objective of the present project is to quantify the influence of organic matter on the bacterial speciation of arsenic in contaminated soils. Moreover, the biogeochemical consequences of this phenomenon on the mobility and ecotoxicity of this metalloid will be studied. The first task of this program is the precise and systematic investigation of the influence of different types and concentrations of organic matters on the activity of As(III)-oxidizing pure strains. Influence of aspartate, succinate (simple substrates) and yeast extract (complex substrate) on As(III)-oxidation kinetics has been studied. For each experiment, the bacterial growth and the expression of genes involved in the speciation of arsenic, i.e. aio and ars genes, has been monitored. A direct perspective of this work will be to perform experiments with humic and fulvic acids (complex organic matter commonly found in soils), and with water-extracted organic matter from polluted soils. Then the As(III)-oxidation activity of bacterial communities extracted from contaminated soils will be followed. These assays should allow the screening of conditions which will be applied in subsequent experiments with several real contaminated soils, including a former mining site, impacted industrial sites, and a forest soil heavily contaminated after arsenical ammunitions storage. This work is co-funded by BRGM and ADEME (convention TEZ 11-16).

Improvement of glass-forming ability and phase separation in Cu Ti-rich

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

Park, E S; Chang, H J; Kim, D H

2010-01-01

Present study reports improvement of glass-forming ability (GFA) and phase separation in Cu Ti-rich Cu Ti Zr Ni Si bulk metallic glasses (BMGs) by tailoring the constituent elements. The MA of metalloid element, Sn having relatively large negative enthalpy of mixing can lead to improve GFA (up to 8mm in diameter) as well as thermal stability (up toTx = 48K) by optimizing the substitution element. And the addition of elements having relatively large positive enthalpy of mixing (partial substitution of Zr or Ti with Y) can lead to the liquid state phase separation in Cu Ti Sn Zr Ni Simore » BMG, although the addition lead to drastic deterioration of the GFA.« less

Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

PubMed Central

Miazek, Krystian; Iwanek, Waldemar; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2015-01-01

Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles) from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed. PMID:26473834

Natural decrease of dissolved arsenic in a small stream receiving drainages of abandoned silver mines in Guanajuato, Mexico.

PubMed

Arroyo, Yann Rene Ramos; Muñoz, Alma Hortensia Serafín; Barrientos, Eunice Yanez; Huerta, Irais Rodriguez; Wrobel, Kazimierz; Wrobel, Katarzyna

2013-11-01

Arsenic release from the abandoned mines and its fate in a local stream were studied. Physicochemical parameters, metals/metalloids and arsenic species were determined. One of the mine drainages was found as a point source of contamination with 309 μg L(-1) of dissolved arsenic; this concentration declined rapidly to 10.5 μg L(-1) about 2 km downstream. Data analysis confirmed that oxidation of As(III) released from the primary sulfide minerals was favored by the increase of pH and oxidation reduction potential; the results obtained in multivariate approach indicated that self-purification of water was due to association of As(V) with secondary solid phase containing Fe, Mn, Ca.

Microbial processing of tellurium as a tool in biotechnology.

PubMed

Turner, Raymond J; Borghese, Roberto; Zannoni, Davide

2012-01-01

Here, we overview the most recent advances in understanding the bacterial mechanisms that stay behind the reduction of tellurium oxyanions in both planktonic cells and biofilms. This is a topic of interest for basic and applied research because microorganisms are deeply involved in the transformation of metals and metalloids in the environment. In particular, the recent observation that toxic tellurite can be precipitated either inside or outside the cells being used as electron sink to support bacterial growth, opens new perspectives for both microbial physiologists and biotechnologists. As promising nanomaterials, tellurium based nanoparticles show unique electronic and optical properties due to quantum confinement effects to be used in the area of chemistry, electronics, medicine and environmental biotechnologies. Copyright © 2011 Elsevier Inc. All rights reserved.

Thermochemical production of hydrogen

DOEpatents

Dreyfuss, Robert M.

1976-07-13

A thermochemical reaction cycle for the generation of hydrogen from water comprising the following sequence of reactions wherein M represents a metal and Z represents a metalloid selected from the arsenic-antimony-bismuth and selenium-tellurium subgroups of the periodic system: 2MO + Z + SO.sub.2 .fwdarw. MZ + MSO.sub.4 (1) mz + h.sub.2 so.sub.4 .fwdarw. mso.sub.4 + h.sub.2 z (2) 2mso.sub.4 .fwdarw. 2mo + so.sub.2 + so.sub.3 + 1/20.sub.2 (3) h.sub.2 z .fwdarw. z + h.sub.2 (4) h.sub.2 o + so.sub.3 .fwdarw. h.sub.2 so.sub.4 (5) the net reaction is the decomposition of water into hydrogen and oxygen.

Arsenic incorporation into FeS 2 pyrite and its influence on dissolution: A DFT study

NASA Astrophysics Data System (ADS)

Blanchard, Marc; Alfredsson, Maria; Brodholt, John; Wright, Kate; Catlow, C. Richard A.

2007-02-01

FeS 2 pyrite can incorporate large amounts of arsenic (up to ca. 10 wt%) and hence has a strong impact on the mobility of this toxic metalloid. Focussing on the lowest arsenic concentrations for which the incorporation occurs in solid solution, the substitution mechanisms involved have been investigated by assuming simple incorporation reactions in both oxidising and reducing conditions. The solution energies were calculated by Density Functional Theory (DFT) calculations and we predict that the formation of AsS dianion groups is the most energetically favourable mechanism. The results also suggest that the presence of arsenic will accelerate the dissolution and thus the generation of acid drainage, when the crystal dissolves in oxidising conditions.

Synthesis of silicon containing materials using liquid hydrosilane compositions through direct injection

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

Srinivasan, Guruvenket; Sailer, Robert A.; Hoey, Justin

An apparatus and a non-vapor-pressure dependent method of chemical vapor deposition of Si based materials using direct injection of liquid hydrosilane(s) are presented. Liquid silane precursor solutions may also include metal, non-metal or metalloid dopants, nanomaterials and solvents. An illustrative apparatus has a precursor solution and carrier gas system, atomizer and deposit head with interior chamber and a hot plate supporting the substrate. Atomized liquid silane precursor solutions and carrier gas moves through a confined reaction zone that may be heated and the aerosol and vapor are deposited on a substrate to form a thin film. The substrate may bemore » heated prior to deposition. The deposited film may be processed further with thermal or laser processing.« less

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

Weeks, J.M.; Svendsen, C.

A simple subcellular histochemical staining technique employing the lysosomal probe neutral red has been developed for use with the epiendogeic earthworm Lumbricus rubellus Hoffmeister. Coelomocytes extracted from the coelomic cavity of earthworms into an isotonic earthworm Ringer solution were allowed to adhere to a microscope slide for 30 s before the application of a neutral red dye. This red dye was rapidly accumulated within the lysosomes. Observation of the loss of this dye from these lysosomes into the surrounding cytosol has enabled the quantification of the degree of lysosomal damage caused to earthworms with exposure to an increasing range ofmore » soil copper concentrations, in both laboratory and mesocosm studies. This simple in vitro biomarker has potential for the rapid assessment of the toxic effects to earthworms from soils contaminated with heavy metals and metalloids.« less

Influence of mycorhization and soil organic matters on lead and antimony transfers to vegetables cultivated in urban gardens: environmental and sanitary consequences

NASA Astrophysics Data System (ADS)

Pierart, Antoine; Braud, Armelle; Lebeau, Thierry; Séjalon-Delmas, Nathalie; Dumat, Camille

2014-05-01

The European Environment Agency estimates that c.a. 250 000 sites required clean up and that about 100 000 ha could have been contaminated by metals in Europe. Numerous remediation techniques have been therefore tested and phytoremediation appears as a sustainable and low cost in situ technique particularly for large-scale remediation of polluted arable soils. Arbuscular Mycorrhizal Fungi (AMF) are already used in phytoextraction or phytostabilisation of many metal(loid)s (GU ET AL., 2013, SHARMA AND SHARMA, 2013). However, while plant inoculation with AMF will mostly result of an increase of the plant biomass, the response for lead accumulation in shoots is contrasted (LEBEAU ET AL., 2008). Furthermore, nothing is actually known for Sb transfer to plants phytoremediation-assisted AMF. Yet recently, many researches concern the accumulation of Sb in the environment, its (eco)toxicity and the risk of bioaccumulation in vegetables (FENG ET AL., 2013), especially in some China areas where Sb mining activities have widely contaminated arable lands (WU ET AL., 2011). Our research project, which is part of a national program for urban gardens (JASSUR, http://www.agence-nationale-recherche.fr), focused on polluted soils in associative urban gardens with both geogenic and anthropogenic origins for Pb and Sb. The impact of Pb and Sb on AMF density and diversity was studied using morphological and biomolecular approaches. The role of AMF symbiosis with Lettuce (Lactuca sativa L.) on Pb and Sb compartmentalization, speciation and phytoavailability was investigated. The influence of soil organic matters on these processes was examined. Eventually, the part of metal(loid)s available for humans in case of ingestion of lettuces unfit for human consumption (FOUCAULT ET AL., 2013; XIONG ET AL., 2013) will be assessed in relation with the influence of AMF symbiosis and organic matter. Key Words: Mycorrhiza, Antimony, Compartmentation, Speciation, Edible Plants, Urban Agriculture. References: Feng, R., Wei, C., Tu, S., Ding, Y., Wang, R., Guo, J., 2013. The uptake and detoxification of antimony by plants: a review. Environ. Exp. Bot. 96, 28-34. Foucault, Y., Lévêque, T., Xiong, T., Schreck, E., Austruy, A., Shahid, M., Dumat, C., 2013. Green manure plants for remediation of soils polluted by metals and metalloids: Ecotoxicity and human bioavailability assessment. Chemosphere 93, 1430-1435. Gu, H.H., Li, F.P., Yu, Q., Gao, Y.Q., Yuan, X.T., 2013. The Roles of Arbuscular Mycorrhizal Fungus Glomus mosseae and Festuca arundinacea in Phytostabilization of Lead/Zinc Tailings. Adv. Mater. Res. 699, 245-250. Lebeau, T., Braud, A., Jézéquel, K., 2008. Performance of bioaugmentation-assisted phytoextraction applied to metal contaminated soils: A review. Environ. Pollut. 153, 497-522. Sharma, A., Sharma, H., 2013. Role of Vesicular Arbuscular Mycorrhiza in the Mycoremediation of Heavy Toxic Metals From Soil. Int J LifeSc Bt Pharm Res 2, 2418-2431. Wu, F., Fu, Z., Liu, B., Mo, C., Chen, B., Corns, W., Liao, H., 2011. Health risk associated with dietary co-exposure to high levels of antimony and arsenic in the world's largest antimony mine area. Sci. Total Environ. 409, 3344-3351. Xiong, T., Austruy, A., Dappe, V., Leveque, T., Sobanska, S., Foucault, Y., Dumat, C., 2013. Phytotoxicity and bioaccessibility of metals for vegetables exposed to atmosphere fine particles in polluted urban areas". Urban Environmental Pollution, Asian Edition, 17-20, Beijing, China.

Citric acid assisted phytoextraction of chromium by sunflower; morpho-physiological and biochemical alterations in plants.

PubMed

Farid, Mujahid; Ali, Shafaqat; Rizwan, Muhammad; Ali, Qasim; Abbas, Farhat; Bukhari, Syed Asad Hussain; Saeed, Rashid; Wu, Longhua

2017-11-01

Soil and water contamination from heavy metals and metalloids is one of the most discussed and burning global issues due to its potential to cause the scarcity of healthy food and safe water. The scientific community is proposing a range of lab and field based physical, chemical and biological solutions to remedy metals and metalloids contaminated soils and water. The present study finds out a possibility of Chromium (Cr) extraction by sunflower from spiked soil under chelating role of citric acid (CA). The sunflower plants were grown under different concentrations of Cr (0, 5, 10 & 20mgkg -1 ) and CA (0, 2.5 & 5mM). Growth, biomass, gas exchange, photosynthesis, electrolyte leakage (EL), reactive oxygen species (ROS; malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ) and the activities of antioxidant enzymes such as, superoxide dismutase (SOD), guaiacole values peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT) were measured. The results depicted a clear decline in plant height, root length, leaf area, number of leaves and flowers per plant along with fresh and dry biomass of all parts of plant with increasing concentration of Cr in soil. Similar reduction was observed in chlorophyll a and b, total chlorophyll, carotenoids, soluble protein, gas exchange attributes and SPAD. The increasing concentration of Cr also enhanced the Cr uptake and accumulation in plant roots, stem and leaves along with the production of ROS and EL. The activities of antioxidant enzymes increased with increasing Cr concentration from 0 to 10mg, but decreased at 20mgkg -1 soil. The CA application significantly alleviated Cr-induced inhibition of plant growth, biomass, photosynthesis, gas exchange, soluble proteins and SPAD value. Presence of CA also enhanced the activities of all antioxidant enzymes and reduced the production of ROS and EL. The chelating potential of CA increased the concentration and accumulation of Cr in plant roots, stem and leaves. It is concluded that the sunflower can be a potential candidate for the remediation of Cr under CA treatment, while the possibility may vary with genotype, Cr level and CA concentration. Copyright © 2017 Elsevier Inc. All rights reserved.

Cross-sectional Biomonitoring of Metals in Adult Populations in Post-war Eastern Croatia: Differences Between Areas of Moderate and Heavy Combat

PubMed Central

Jergović, Matijana; Miškulin, Maja; Puntarić, Dinko; Gmajnić, Rudika; Milas, Josip; Sipos, Laszlo

2010-01-01

Aim To determine differences in metal and metalloid exposure between residents of areas in eastern Croatia exposed to heavy fighting during the war in Croatia and residents of areas exposed to moderate fighting. Methods Concentrations of aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), uranium (U), vanadium (V), and zinc (Zn), reported to be associated with military operations, were determined in hair, serum, and urine samples using inductively-coupled plasma mass spectroscopy. A total of 127 and 46 participants from areas of heavy and moderate fighting, respectively, were included. Results Compared with participants from areas exposed to moderate fighting, participants from areas exposed to heavy fighting had significantly higher serum concentrations of Al (87.61 vs 42.75 μg/L, P = 0.007), As (5.05 ± 1.79 vs 4.16 ± 1.55 μg/L, P = 0.003), Ba (7.12 vs 6.01 μg/L, P = 0.044), and V (17.98 vs 16.84 μg/L, P = 0.008); significantly higher urine concentrations of As (43.90 vs 11.51 μg/L, P < 0.001) and Cd (0.67 vs 0.50 μg/L, P = 0.031); and significantly higher hair concentrations of Al (12.61 vs 7.33 μg/L, P < 0.001), As (0.32 vs 0.05 μg/L, P < 0.001), Cd (0.03 vs 0.02 μg/L, P = 0.002), Fe (22.58 vs 12.68 μg/L, P = 0.001), Pb (1.04 vs 0.69 μg/L, P = 0.006), and V (0.07 vs 0.03 μg/L, P < 0.001). Conclusion Differences between populations from eastern Croatian areas exposed to heavy and populations exposed to moderate fighting point to the need for extensive monitoring of metal and metalloid exposure, emphasizing the role of biomonitoring through ecologic and preventive activities. PMID:20960595

Synthesis and Antibacterial Activity of Metal(loid) Nanostructures by Environmental Multi-Metal(loid) Resistant Bacteria and Metal(loid)-Reducing Flavoproteins.

PubMed

Figueroa, Maximiliano; Fernandez, Valentina; Arenas-Salinas, Mauricio; Ahumada, Diego; Muñoz-Villagrán, Claudia; Cornejo, Fabián; Vargas, Esteban; Latorre, Mauricio; Morales, Eduardo; Vásquez, Claudio; Arenas, Felipe

2018-01-01

Microbes are suitable candidates to recover and decontaminate different environments from soluble metal ions, either via reduction or precipitation to generate insoluble, non-toxic derivatives. In general, microorganisms reduce toxic metal ions generating nanostructures (NS), which display great applicability in biotechnological processes. Since the molecular bases of bacterial reduction are still unknown, the search for new -environmentally safe and less expensive- methods to synthesize NS have made biological systems attractive candidates. Here, 47 microorganisms isolated from a number of environmental samples were analyzed for their tolerance or sensitivity to 19 metal(loid)s. Ten of them were highly tolerant to some of them and were assessed for their ability to reduce these toxicants in vitro . All isolates were analyzed by 16S rRNA gene sequencing, fatty acids composition, biochemical tests and electron microscopy. Results showed that they belong to the Enterobacter, Staphylococcus, Acinetobacter , and Exiguobacterium genera. Most strains displayed metal(loid)-reducing activity using either NADH or NADPH as cofactor. While Acinetobacter schindleri showed the highest tellurite ( TeO 3 2 - ) and tetrachloro aurate ( AuCl 4 - ) reducing activity, Staphylococcus sciuri and Exiguobacterium acetylicum exhibited selenite ( SeO 3 2 - ) and silver (Ag + ) reducing activity, respectively. Based on these results, we used these bacteria to synthetize, in vivo and in vitro Te, Se, Au, and Ag-containing nanostructures. On the other hand, we also used purified E. cloacae glutathione reductase to synthesize in vitro Te-, Ag-, and Se-containing NS, whose morphology, size, composition, and chemical composition were evaluated. Finally, we assessed the putative anti-bacterial activity exhibited by the in vitro synthesized NS: Te-containing NS were more effective than Au-NS in inhibiting Escherichia coli and Listeria monocytogenes growth. Aerobically synthesized TeNS using MF09 crude extracts showed MICs of 45- and 66- μg/ml for E. coli and L. monocytogenes , respectively. Similar MIC values (40 and 82 μg/ml, respectively) were observed for TeNS generated using crude extracts from gorA -overexpressing E. coli . In turn, AuNS MICs for E. coli and L. monocytogenes were 64- and 68- μg/ml, respectively.

Evaluation of a new optic-enabled portable X-ray fluorescence spectrometry instrument for measuring toxic metals/metalloids in consumer goods and cultural products

NASA Astrophysics Data System (ADS)

Guimarães, Diana; Praamsma, Meredith L.; Parsons, Patrick J.

2016-08-01

X-ray fluorescence spectrometry (XRF) is a rapid, non-destructive multi-elemental analytical technique used for determining elemental contents ranging from percent down to the μg/g level. Although detection limits are much higher for XRF compared to other laboratory-based methods, such as inductively coupled plasma mass spectrometry (ICP-MS), ICP-optical emission spectrometry (OES) and atomic absorption spectrometry (AAS), its portability and ease of use make it a valuable tool, especially for field-based studies. A growing necessity to monitor human exposure to toxic metals and metalloids in consumer goods, cultural products, foods and other sample types while performing the analysis in situ has led to several important developments in portable XRF technology. In this study, a new portable XRF analyzer based on the use of doubly curved crystal optics (HD Mobile®) was evaluated for detecting toxic elements in foods, medicines, cosmetics and spices used in many Asian communities. Two models of the HD Mobile® (a pre-production and a final production unit) were investigated. Performance parameters including accuracy, precision and detection limits were characterized in a laboratory setting using certified reference materials (CRMs) and standard solutions. Bias estimates for key elements of public health significance such as As, Cd, Hg and Pb ranged from - 10% to 11% for the pre-production, and - 14% to 16% for the final production model. Five archived public health samples including herbal medicine products, ethnic spices and cosmetic products were analyzed using both XRF instruments. There was good agreement between the pre-production and final production models for the four key elements, such that the data were judged to be fit-for-purpose for the majority of samples analyzed. Detection of the four key elements of interest using the HD Mobile® was confirmed using archived samples for which ICP-OES data were available based on digested sample materials. The HD Mobile® XRF units were shown to be suitable for rapid screening of samples likely to be encountered in field based studies.

Expression profiling of Crambe abyssinica under arsenate stress identifies genes and gene networks involved in arsenic metabolism and detoxification

PubMed Central

2010-01-01

Background Arsenic contamination is widespread throughout the world and this toxic metalloid is known to cause cancers of organs such as liver, kidney, skin, and lung in human. In spite of a recent surge in arsenic related studies, we are still far from a comprehensive understanding of arsenic uptake, detoxification, and sequestration in plants. Crambe abyssinica, commonly known as 'abyssinian mustard', is a non-food, high biomass oil seed crop that is naturally tolerant to heavy metals. Moreover, it accumulates significantly higher levels of arsenic as compared to other species of the Brassicaceae family. Thus, C. abyssinica has great potential to be utilized as an ideal inedible crop for phytoremediation of heavy metals and metalloids. However, the mechanism of arsenic metabolism in higher plants, including C. abyssinica, remains elusive. Results To identify the differentially expressed transcripts and the pathways involved in arsenic metabolism and detoxification, C. abyssinica plants were subjected to arsenate stress and a PCR-Select Suppression Subtraction Hybridization (SSH) approach was employed. A total of 105 differentially expressed subtracted cDNAs were sequenced which were found to represent 38 genes. Those genes encode proteins functioning as antioxidants, metal transporters, reductases, enzymes involved in the protein degradation pathway, and several novel uncharacterized proteins. The transcripts corresponding to the subtracted cDNAs showed strong upregulation by arsenate stress as confirmed by the semi-quantitative RT-PCR. Conclusions Our study revealed novel insights into the plant defense mechanisms and the regulation of genes and gene networks in response to arsenate toxicity. The differential expression of transcripts encoding glutathione-S-transferases, antioxidants, sulfur metabolism, heat-shock proteins, metal transporters, and enzymes in the ubiquitination pathway of protein degradation as well as several unknown novel proteins serve as molecular evidence for the physiological responses to arsenate stress in plants. Additionally, many of these cDNA clones showing strong upregulation due to arsenate stress could be used as valuable markers. Further characterization of these differentially expressed genes would be useful to develop novel strategies for efficient phytoremediation as well as for engineering arsenic tolerant crops with reduced arsenic translocation to the edible parts of plants. PMID:20546591

Environmental impacts of unmanaged solid waste at a former base metal mining and ore processing site (Kirki, Greece).

PubMed

Liakopoulos, Alexandros; Lemière, Bruno; Michael, Konstantinos; Crouzet, Catherine; Laperche, Valérie; Romaidis, Ioannis; Drougas, Iakovos; Lassin, Arnault

2010-11-01

The Kirki project aimed to identify, among the mining waste abandoned at a mine and processing plant, the most critical potential pollution sources, the exposed milieus and the main pathways for contamination of a littoral area. This was accompanied by the definition of a monitoring network and remedial options. For this purpose, field analytical methods were extensively used to allow a more precise identification of the source, to draw relevant conceptual models and outline a monitoring network. Data interpretation was based on temporal series and on a geographical model. A classification method for mining waste was established, based on data on pollutant contents and emissions, and their long-term pollution potential. Mining waste present at the Kirki mine and plant sites comprises (A) extraction waste, mainly metal sulfide-rich rocks; (B) processing waste, mainly tailings, with iron and sulfides, sulfates or other species, plus residues of processing reagents; and (C) other waste, comprising leftover processing reagents and Pb-Zn concentrates. Critical toxic species include cadmium and cyanide. The stormy rainfall regime and hilly topography favour the flush release of large amounts of pollutants. The potential impacts and remedial options vary greatly. Type C waste may generate immediate and severe chemical hazards, and should be dealt with urgently by careful removal, as it is localised in a few spots. Type B waste has significant acid mine drainage potential and contains significant amounts of bioavailable heavy metals and metalloids, but they may also be released in solid form into the surface water through dam failure. The most urgent action is thus dams consolidation. Type A waste is by far the most bulky, and it cannot be economically removed. Unfortunately, it is also the most prone to acid mine drainage (seepage pH 1 to 2). This requires neutralisation to prevent acid water accelerating heavy metals and metalloids transfer. All waste management options require the implementation of a monitoring network for the design of a remediation plan, efficiency control, and later, community alert in case of accidental failure of mitigation/remediation measures. A network design strategy based on field measurements, laboratory validation and conceptual models is proposed.

Synthesis and Antibacterial Activity of Metal(loid) Nanostructures by Environmental Multi-Metal(loid) Resistant Bacteria and Metal(loid)-Reducing Flavoproteins

PubMed Central

Figueroa, Maximiliano; Fernandez, Valentina; Arenas-Salinas, Mauricio; Ahumada, Diego; Muñoz-Villagrán, Claudia; Cornejo, Fabián; Vargas, Esteban; Latorre, Mauricio; Morales, Eduardo; Vásquez, Claudio; Arenas, Felipe

2018-01-01

Microbes are suitable candidates to recover and decontaminate different environments from soluble metal ions, either via reduction or precipitation to generate insoluble, non-toxic derivatives. In general, microorganisms reduce toxic metal ions generating nanostructures (NS), which display great applicability in biotechnological processes. Since the molecular bases of bacterial reduction are still unknown, the search for new -environmentally safe and less expensive- methods to synthesize NS have made biological systems attractive candidates. Here, 47 microorganisms isolated from a number of environmental samples were analyzed for their tolerance or sensitivity to 19 metal(loid)s. Ten of them were highly tolerant to some of them and were assessed for their ability to reduce these toxicants in vitro. All isolates were analyzed by 16S rRNA gene sequencing, fatty acids composition, biochemical tests and electron microscopy. Results showed that they belong to the Enterobacter, Staphylococcus, Acinetobacter, and Exiguobacterium genera. Most strains displayed metal(loid)-reducing activity using either NADH or NADPH as cofactor. While Acinetobacter schindleri showed the highest tellurite (TeO32-) and tetrachloro aurate (AuCl4-) reducing activity, Staphylococcus sciuri and Exiguobacterium acetylicum exhibited selenite (SeO32-) and silver (Ag+) reducing activity, respectively. Based on these results, we used these bacteria to synthetize, in vivo and in vitro Te, Se, Au, and Ag-containing nanostructures. On the other hand, we also used purified E. cloacae glutathione reductase to synthesize in vitro Te-, Ag-, and Se-containing NS, whose morphology, size, composition, and chemical composition were evaluated. Finally, we assessed the putative anti-bacterial activity exhibited by the in vitro synthesized NS: Te-containing NS were more effective than Au-NS in inhibiting Escherichia coli and Listeria monocytogenes growth. Aerobically synthesized TeNS using MF09 crude extracts showed MICs of 45- and 66- μg/ml for E. coli and L. monocytogenes, respectively. Similar MIC values (40 and 82 μg/ml, respectively) were observed for TeNS generated using crude extracts from gorA-overexpressing E. coli. In turn, AuNS MICs for E. coli and L. monocytogenes were 64- and 68- μg/ml, respectively. PMID:29869640

Atriplex atacamensis and Atriplex halimus resist As contamination in Pre-Andean soils (northern Chile).

PubMed

Tapia, Y; Diaz, O; Pizarro, C; Segura, R; Vines, M; Zúñiga, G; Moreno-Jiménez, E

2013-04-15

The Pre-Andean area of Chile exhibits saline soils of volcanic origin naturally contaminated with arsenic (As), and we hypothesise that revegetation with resistant species may be a valid alternative for soil management in this area. Thus, the xerophytic and halophytic shrubs Atriplex halimus and Atriplex atacamensis were cultivated in containers for 90 days in Pre-Andean soil, As-soil, (111±19 mg As kg(-1), pH8.4±0.1) or control soil (12.7±1.1 mg As kg(-1), pH7.8±0.1) to evaluate As accumulation and resistance using stress bioindicators (chlorophylls, malondialdehyde (MDA) and total thiols). Sequential extraction of As-soil indicated that 52.3% of As was found in the most available fraction. The As distribution was significantly different between the species: A. halimus translocated the As to leaves, whilst A. atacamensis retained the As in roots. At 30 and 90 days, A. halimus showed similar As concentrations in the leaves (approximately 5.5 mg As kg(-1)), and As increased in stems and roots (up to 4.73 and 16.3 mg As kg(-1), respectively). In A. atacamensis, As concentration was lower (2.6 in leaves; 3.2 in stems and 6.9 in roots in mg As kg(-1)). Both species exhibited a high concentration of B in leaves (362-389 mg kg(-1)). If the plants are used for animal feed, it should be considered that A. halimus accumulates higher concentration of As and B in the leaves than A. atacamensis. Neither plant growth nor stress bioindicators were negatively affected by the high levels of available As, with the exception of MDA in the leaves of A. halimus. The results indicate that these plants resist contamination by arsenic, accumulating mainly the metalloid in the roots and can be recommended to generate plant cover in As-contaminated soils in the Pre-Andean region, under saline conditions controlled, preventing the dispersion of this metalloid via wind and leaching. Copyright © 2013 Elsevier B.V. All rights reserved.

Major intrinsic proteins in biomimetic membranes.

PubMed

Nielsen, Claus Hélix

2010-01-01

Biological membranes define the structural and functional boundaries in living cells and their organelles. The integrity of the cell depends on its ability to separate inside from outside and yet at the same time allow massive transport of matter in and out the cell. Nature has elegantly met this challenge by developing membranes in the form of lipid bilayers in which specialized transport proteins are incorporated. This raises the question: is it possible to mimic biological membranes and create a membrane based sensor and/or separation device? In the development of a biomimetic sensor/separation technology, a unique class of membrane transport proteins is especially interesting-the major intrinsic proteins (MIPs). Generally, MIPs conduct water molecules and selected solutes in and out of the cell while preventing the passage of other solutes, a property critical for the conservation of the cells internal pH and salt concentration. Also known as water channels or aquaporins they are highly efficient membrane pore proteins some of which are capable of transporting water at very high rates up to 10(9) molecules per second. Some MIPs transport other small, uncharged solutes, such as glycerol and other permeants such as carbon dioxide, nitric oxide, ammonia, hydrogen peroxide and the metalloids antimonite, arsenite, silicic and boric acid depending on the effective restriction mechanism of the protein. The flux properties of MIPs thus lead to the question ifMIPs can be used in separation devices or as sensor devices based on, e.g., the selective permeation of metalloids. In principle a MIP based membrane sensor/separation device requires the supporting biomimetic matrix to be virtually impermeable to anything but water or the solute in question. In practice, however, a biomimetic support matrix will generally have finite permeabilities to both electrolytes and non-electrolytes. The feasibility of a biomimetic MIP device thus depends on the relative transport contribution from both protein and biomimetic support matrix. Also the biomimetic matrix must be encapsulated in order to protect it and make it sufficiently stable in a final application. Here, I specifically discuss the feasibility of developing osmotic biomimetic MIP membranes, but the technical issues are of general concern in the design ofbiomimetic membranes capable of supporting selective transmembrane fluxes.

Establishing the importance of human health risk assessment for metals and metalloids in urban environments.

PubMed

Peña-Fernández, A; González-Muñoz, M J; Lobo-Bedmar, M C

2014-11-01

Rapid development, industrialisation, and urbanisation have resulted in serious contamination of soil by metals and metalloids from anthropogenic sources in many areas of the world, either directly or indirectly. Exponential urban and economic development has resulted in human populations settling in urban areas and as a result being exposed to these pollutants. Depending on the nature of the contaminant, contaminated urban soils can have a deleterious effect on the health of exposed populations and may require decontamination, recovery, remediation and restoration. Therefore, human health risk assessments in urban environments are very important. In the case of Spain, there are few studies regarding risk assessment of trace elements in urban soils, and those that exist have been derived mainly from areas potentially exposed to industrial contamination or in the vicinity of point pollution. The present study analysed Al, As, Be, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Ti, Tl, V and Zn soil concentrations in and around the city of Alcalá de Henares (35 km NE of Madrid). Soil samples were collected in public parks and recreation areas within the city and in an industrial area on the periphery of the city. From these results, an assessment of the health risk for the population was performed following the methodology described by the US EPA (1989). In general, it was observed that there could be a potential increased risk of developing cancer over a lifetime from exposure to arsenic (As) through ingestion of the soils studied (oral intake), as well as an increased risk of cancer due to inhalation of chromium (Cr) present in re-suspended soils from the industrial area. Our group has previously reported (Granero and Domingo, 2002; Peña-Fernández et al., 2003) that there was an increased risk of developing cancer following exposure to As in the same soils in a previous study. Therefore, it is necessary to reduce the levels of contaminants in these soils, especially As and Cr as these have been found to exceed safe levels for human health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessing the potential of group 13 and 14 metal/metalloid phthalocyanines as hole transport layers in organic light emitting diodes

NASA Astrophysics Data System (ADS)

Plint, Trevor; Lessard, Benoît H.; Bender, Timothy P.

2016-04-01

In this study, we have assessed the potential application of group 13 and 14 metal and metalloid phthalocyanines ((X)n-MPcs) and their axially substituted derivatives as hole-transporting layers in organic light emitting diodes (OLEDs). OLEDs studied herein have the generic structure of glass/ITO/(N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) or (X)n-MPc)(50 nm)/Alq3 (60 nm)/LiF (1 nm)/Al (80 nm), where X is an axial substituent group. OLEDs using chloro aluminum phthalocyanine (Cl-AlPc) showed good peak luminance values of 2620 ± 113 cd/m2 at 11 V. To our knowledge, Cl-AlPc has not previously been shown to work as a hole transport material (HTL) in OLEDs. Conversely, the di-chlorides of silicon, germanium, and tin phthalocyanine (Cl2-SiPc, Cl2-GePc, and Cl2-SnPc, respectively) showed poor performance compared to Cl-AlPc, having peak luminances of only 38 ± 4 cd/m2 (12 V), 23 ± 1 cd/m2 (8.5 V), and 59 ± 5 cd/m2 (13.5 V), respectively. However, by performing a simple axial substitution of the chloride groups of Cl2-SiPc with pentafluorophenoxy groups, the resulting bis(pentafluorophenoxy) silicon phthalocyanine (F10-SiPc) containing OLED had a peak luminance of 5141 ± 941 cd/m2 (10 V), a two order of magnitude increase over its chlorinated precursor. This material showed OLED characteristics approaching those of a baseline OLED based on the well-studied triarylamine NPB. Attempts to attach the pentafluorophenoxy axial group to both SnPc and GePc were hindered by synthetic difficulties and low thermal stability, respectively. In light of the performance improvements observed by simple axial substitution of SiPc in OLEDs, the use of axially substituted MPcs in organic electronic devices remains of continuing interest to us and potentially the field in general.

Ganga water pollution: A potential health threat to inhabitants of Ganga basin.

PubMed

Dwivedi, Sanjay; Mishra, Seema; Tripathi, Rudra Deo

2018-05-18

The water quality of Ganga, the largest river in Indian sub-continent and life line to hundreds of million people, has severely deteriorated. Studies have indicated the presence of high level of carcinogenic elements in Ganga water. We performed extensive review of sources and level of organic, inorganic pollution and microbial contamination in Ganga water to evaluate changes in the level of various pollutants in the recent decade in comparison to the past and potential health risk for the population through consumption of toxicant tainted fishes in Ganga basin. A systematic search through databases, specific websites and reports of pollution regulatory agencies was conducted. The state wise level of contamination was tabulated along the Ganga river. We have discussed the major sources of various pollutants with particular focus on metal/metalloid and pesticide residues. Bioaccumulation of toxicants in fishes of Ganga water and potential health hazards to humans through consumption of tainted fishes was evaluated. The level of pesticides in Ganga water registered a drastic reduction in the last decade (i.e. after the establishment of National Ganga River Basin Authority (NGRBA) in 2009), still the levels of some organochlorines are beyond the permissible limits for drinking water. Conversely the inorganic pollutants, particularly carcinogenic elements have increased several folds. Microbial contamination has also significantly increased. Hazard quotient and hazard index indicated significant health risk due to metal/metalloid exposure through consumption of tainted fishes from Ganga. Target cancer risk assessment showed high carcinogenic risk from As, Cr, Ni and Pb as well as residues of DDT and HCHs. Current data analysis showed that Ganga water quality is deteriorating day by day and at several places even in upper stretch of Ganga the water is not suitable for domestic uses. Although there is positive impact of ban on persistent pesticides with decreasing trend of pesticide residues in Ganga water, the increasing trend of trace and toxic elements is alarming and the prolong exposure to polluted Ganga water and/or consumption of Ganga water fishes may cause serious illness including cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

Inorganic arsenic represses interleukin-17A expression in human activated Th17 lymphocytes

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

Morzadec, Claudie; Macoch, Mélinda; Robineau, Marc

2012-08-01

Trivalent inorganic arsenic [As(III)] is an efficient anticancer agent used to treat patients suffering from acute promyelocytic leukemia. Recently, experimental studies have clearly demonstrated that this metalloid can also cure lymphoproliferative and/or pro-inflammatory syndromes in different murine models of chronic immune-mediated diseases. T helper (Th) 1 and Th17 lymphocytes play a central role in development of these diseases, in mice and humans, especially by secreting the potent pro-inflammatory cytokine interferon-γ and IL-17A, respectively. As(III) impairs basic functions of human T cells but its ability to modulate secretion of pro-inflammatory cytokines by differentiated Th lymphocytes is unknown. In the present study,more » we demonstrate that As(III), used at concentrations clinically achievable in plasma of patients, has no effect on the secretion of interferon-γ from Th1 cells but almost totally blocks the expression and the release of IL-17A from human Th17 lymphocytes co-stimulated for five days with anti-CD3 and anti-CD28 antibodies, in the presence of differentiating cytokines. In addition, As(III) specifically reduces mRNA levels of the retinoic-related orphan receptor (ROR)C gene which encodes RORγt, a key transcription factor controlling optimal IL-17 expression in fully differentiated Th17 cells. The metalloid also blocks initial expression of IL-17 gene induced by the co-stimulation, probably in part by impairing activation of the JNK/c-Jun pathway. In conclusion, our results demonstrate that As(III) represses expression of the major pro-inflammatory cytokine IL-17A produced by human Th17 lymphocytes, thus strengthening the idea that As(III) may be useful to treat inflammatory immune-mediated diseases in humans. -- Highlights: ► Arsenic inhibits secretion of IL-17A from human naïve and memory Th17 lymphocytes. ► Arsenic represses early expression of IL-17A gene in human activated T lymphocytes. ► Arsenic interferes with activation of the JNK/c-Jun pathway in human T lymphocytes.« less

Uranium Interaction with Two Multi-Resistant Environmental Bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris

PubMed Central

Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

2012-01-01

Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations. PMID:23251623

Phytoremediation of Metal-Contaminated Soil for Improving Food Safety

NASA Astrophysics Data System (ADS)

Shilev, Stefan; Benlloch, Manuel; Dios-Palomares, R.; Sancho, Enrique D.

The contamination of the environment is a serious problem which provokes great interest in our society and in the whole scientific community. The input of metals into soils has increased during the last few decades as a consequence of different human activities (storage of industrial and municipal wastes, burning of fuels, mining and wastewater treatments, functioning of non-ferrous-metal-producing smelters, etc.). Nowadays, this type of contamination is one of the most serious concerning the chronic toxic effect which it renders on human health and the environment. As a consequence of all these activities, a huge number of toxic metals and metalloids, such as Cu, Zn, Pb, Cd, Hg and As, among many others, have been accumulated in soils, reaching toxic values. Unfortunately, much contaminated land is still in use for crop production, despite the danger that the metal content poses.

Assessment of the environmental impacts of ocean acidification (OA) and carbon capture and storage (CCS) leaks using the amphipod Hyale youngi.

PubMed

Goulding, T A; De Orte, M R; Szalaj, D; Basallote, M D; DelValls, T A; Cesar, A

2017-05-01

This study aims to ascertain the effects of CO 2 induced water acidification and leaks from Carbon Capture and Storage activities on the South American amphipod Hyale youngi. A 10-day acute toxicity test was performed using sediments from two sites located inside the Santos Estuarine System. They were subjected to five pH treatments (8.1, 7.6, 7.0, 6.5, and 6.0). Metals (Cd, Cu, Cr, Pb, Ni and Zn) and the metalloid As were analyzed to determine the influence of their acidification-related mobility on the amphipods mortality. The results showed that mortality becomes significant when compared to control in pH 6.5 in the Canal de Piaçaguera sediment (contaminated) and at pH 6.0 in Ilha das Palmas sediment (reference).

Liquid-phase microextraction combined with graphite furnace atomic absorption spectrometry: A review.

PubMed

de la Calle, Inmaculada; Pena-Pereira, Francisco; Lavilla, Isela; Bendicho, Carlos

2016-09-14

An overview of the combination of liquid-phase microextraction (LPME) techniques with graphite furnace atomic absorption spectrometry (GFAAS) is reported herein. The high sensitivity of GFAAS is significantly enhanced by its association with a variety of miniaturized solvent extraction approaches. LPME-GFAAS thus represents a powerful combination for determination of metals, metalloids and organometallic compounds at (ultra)trace level. Different LPME modes used with GFAAS are briefly described, and the experimental parameters that show an impact in those microextraction processes are discussed. Special attention is paid to those parameters affecting GFAAS analysis. Main issues found when coupling LPME and GFAAS, as well as those strategies reported in the literature to solve them, are summarized. Relevant applications published on the topic so far are included. Copyright © 2016 Elsevier B.V. All rights reserved.

Chelation in Metal Intoxication

PubMed Central

Flora, Swaran J.S.; Pachauri, Vidhu

2010-01-01

Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents) or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications. PMID:20717537

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

Yang, Ying

Radiation-induced segregation (RIS) has been frequently reported in structural materials such as austenitic, ferritic, and ferritic-martensitic stainless steels (SS) that have been widely used in light water reactors (LWRs). RIS has been linked to secondary degradation effects in SS including irradiation-induced stress corrosion cracking (IASCC). Earlier studies on thermal segregation in Fe-based alloys found that metalloids elements such as P, S, Si, Ge, Sn, etc., embrittle the materials when enrichment was observed at grain boundaries (GBs). RIS of Fe-Cr-Ni-based austenitic steels has been modeled in the U.S. 2015 fiscal year (FY2015), which identified the pre-enrichment due to thermal segregation canmore » have an important role on the subsequent RIS. The goal of this work is to develop thermal segregation models for alloying elements in steels for future integration with RIS modeling.« less

Metal and metalloid accumulation in shrews (Soricomorpha, Mammalia) from two protected Mediterranean coastal sites.

PubMed

Sánchez-Chardi, Alejandro; López-Fuster, María José

2009-04-01

Although ecotoxicological data on heavy metals are abundant, information on other potentially toxic elements with attributed deficiency and/or toxic disturbances is scarce. Here we quantify zinc, copper, iron, manganese, chromium, molybdenum, strontium, barium, and boron in bones of greater white-toothed shrews, Crocidura russula, inhabiting two protected Mediterranean coastal sites: the Ebro Delta, a wetland impacted by human activities, and the Medas Islands, a reference site. Natural and anthropogenic inputs significantly increase Fe, Mn, Mo, Sr, Ba, and B in specimens from the Ebro Delta, whereas Cu and Cr were higher in Medas' shrews. Principal component analysis allowed complete separation between sites along the first two axes in particular due to B, Sr, and Cu. This study provides metal reference values in bones of insectivores, explores their variability and bioaccumulation patterns in depth, and assesses the potential environmental risk and toxicity for biota exposed to the above elements.

Evaluating the suitability of different environmental samples for tracing atmospheric pollution in industrial areas.

PubMed

Francová, Anna; Chrastný, Vladislav; Šillerová, Hana; Vítková, Martina; Kocourková, Jana; Komárek, Michael

2017-01-01

Samples of lichens, snow and particulate matter (PM 10 , 24 h) are used for the source identification of air pollution in the heavily industrialized region of Ostrava, Upper Silesia, Czech Republic. An integrated approach that uses different environmental samples for metal concentration and Pb isotope analyses was applied. The broad range of isotope ratios in the samples indicates a combination of different pollution sources, the strongest among them being the metallurgical industry, bituminous coal combustion and traffic. Snow samples are proven as the most relevant indicator for tracing metal(loid)s and recent local contamination in the atmosphere. Lichens can be successfully used as tracers of the long-term activity of local and remote sources of contamination. The combination of PM 10 with snow can provide very useful information for evaluation of current pollution sources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Implementation of ferric hydroxide-based media for removal of toxic metalloids

NASA Astrophysics Data System (ADS)

Szlachta, Małgorzata; Wójtowicz, Patryk

2017-11-01

Effective removal of inorganic arsenic species is possible by application of the sorption technique with the use of iron-based sorbents. This study investigates the removal of arsenic(III) and arsenic(V) from an aqueous solution by application of a granular ferric hydroxide-based sorbent. The performance of tested media was evaluated based on the batch and fixed-bed adsorption studies. The efficiency of the process was determined with various treatment times, adsorbent doses, initial concentrations of arsenic and various solution temperatures. The obtained adsorption data were fitted with pseudo-first and second-order kinetic models and Langmuir and Freundlich isotherm equations. It was observed that the overall arsenite removal was lower when compared to the arsenate, and all tested operating parameters influenced the process efficiency. The experiments under dynamic conditions showed high treatment capacity and stability of tested adsorbent over a long period of time.

Mesoporous metal oxides and processes for preparation thereof

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

Suib, Steven L.; Poyraz, Altug Suleyman

A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier,more » a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.« less

Heavy metals in marine fish meat and consumer health: a review.

PubMed

Bosch, Adina C; O'Neill, Bernadette; Sigge, Gunnar O; Kerwath, Sven E; Hoffman, Louwrens C

2016-01-15

The numerous health benefits provided by fish consumption may be compromised by the presence of toxic metals and metalloids such as lead, cadmium, arsenic and mercury, which can have harmful effects on the human body if consumed in toxic quantities. The monitoring of metal concentrations in fish meat is therefore important to ensure compliance with food safety regulations and consequent consumer protection. The toxicity of these metals may be dependent on their chemical forms, which requires metal speciation processes for direct measurement of toxic metal species or the identification of prediction models in order to determine toxic metal forms from measured total metal concentrations. This review addresses various shortcomings in current knowledge and research on the accumulation of metal contaminants in commercially consumed marine fish globally and particularly in South Africa, affecting both the fishing industry as well as fish consumers. © 2015 Society of Chemical Industry.

Evaluation of the potential of Pistia stratiotes L. (water lettuce) for bioindication and phytoremediation of aquatic environments contaminated with arsenic.

PubMed

Farnese, F S; Oliveira, J A; Lima, F S; Leão, G A; Gusman, G S; Silva, L C

2014-08-01

Specimens of Pistia stratiotes were subjected to five concentrations of arsenic (As) for seven days. Growth, As absorption, malondialdehyde (MDA) content, photosynthetic pigments, enzymatic activities, amino acids content and anatomical changes were assessed. Plant arsenic accumulation increased with increasing metalloid in the solution, while growth rate and photosynthetic pigment content decreased. The MDA content increased, indicating oxidative stress. Enzymatic activity and amino acids content increased at the lower doses of As, subsequently declining in the higher concentrations. Chlorosis and necrosis were observed in the leaves. Leaves showed starch accumulation and increased thickness of the mesophyll. In the root system, there was a loss and darkening of roots. Cell layers formed at the insertion points on the root stems may have been responsible for the loss of roots. These results indicate that water lettuce shows potential for bioindication and phytoremediation of As-contaminated aquatic environments.

Arsenic Uptake and Translocation in Plants.

PubMed

Li, Nannan; Wang, Jingchao; Song, Won-Yong

2016-01-01

Arsenic (As) is a highly toxic metalloid that is classified as a non-threshold class-1 carcinogen. Millions of people worldwide suffer from As toxicity due to the intake of As-contaminated drinking water and food. Reducing the As concentration in drinking water and food is thus of critical importance. Phytoremediation of soil contaminated with As and the reduction of As contamination in food depend on a detailed understanding of As uptake and transport in plants. As transporters play essential roles in As uptake, translocation and accumulation in plant cells. In this review, we summarize the current understanding of As transport in plants, with an emphasis on As uptake, mechanisms of As resistance and the long-distance translocation of As, especially the accumulation of As in grains through phloem-mediated transport. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Arsenic: A Review of the Element's Toxicity, Plant Interactions, and Potential Methods of Remediation.

PubMed

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

2015-08-19

Arsenic is a naturally occurring element with a long history of toxicity. Sites of contamination are found worldwide as a result of both natural processes and anthropogenic activities. The broad scope of arsenic toxicity to humans and its unique interaction with the environment have led to extensive research into its physicochemical properties and toxic behavior in biological systems. The purpose of this review is to compile the results of recent studies concerning the metalloid and consider the chemical and physical properties of arsenic in the broad context of human toxicity and phytoremediation. Areas of focus include arsenic's mechanisms of human toxicity, interaction with plant systems, potential methods of remediation, and protocols for the determination of metals in experimentation. This assessment of the literature indicates that controlling contamination of water sources and plants through effective remediation and management is essential to successfully addressing the problems of arsenic toxicity and contamination.

Interactions between earthworms and arsenic in the soil environment: a review.

PubMed

Langdon, Caroline J; Piearce, Trevor G; Meharg, Andrew A; Semple, Kirk T

2003-01-01

Chemical pollution of the environment has become a major source of concern. In particular, many studies have investigated the impact of pollution on biota in the environment. Studies on metalliferous contaminated mine spoil wastes have shown that some soil organisms have the capability to become resistant to metal/metalloid toxicity. Earthworms are known to inhabit arsenic-rich metalliferous soils and, due to their intimate contact with the soil, in both the solid and aqueous phases, are likely to accumulate contaminants present in mine spoil. Earthworms that inhabit metalliferous contaminated soils must have developed mechanisms of resistance to the toxins found in these soils. The mechanisms of resistance are not fully understood; they may involve physiological adaptation (acclimation) or be genetic. This review discusses the relationships between earthworms and arsenic-rich mine spoil wastes, looking critically at resistance and possible mechanisms of resistance, in relation to soil edaphic factors and possible trophic transfer routes.

The unicellular fungal tool RhoTox for risk assessments in groundwater systems.

PubMed

Lategan, Maria Josie; Klare, William; Kidd, Sarah; Hose, Grant C; Nevalainen, Helena

2016-10-01

The recent inclusion of yeasts in environmental monitoring recognizes their ecological significance and sensitivity to toxicants. Here we present a robust and simple two-step toxicity assay and demonstrate the sensitivity of an ubiquitous groundwater yeast, Rhodotorula minuta, to a range of metals and metalloids. The test species was sensitive to copper with a 24h EC50 of 35µg Cu/L, followed in order of decreasing sensitivity by zinc, chromium (VI) and arsenic (EC50 4.40mg As (III)/L). The strain demonstrated an unexpected tolerance to chromium (VI), having an EC50 value (3.45mg Cr (VI)/L) similar to that of arsenic. The inclusion of a unicellular, microbial test-species into the suite of existing multicellular test species for toxicity evaluation is a key step towards strengthening the assessment of risk for groundwater ecosystems. Copyright © 2016 Elsevier Inc. All rights reserved.

Chemical stabilization of metals and arsenic in contaminated soils using oxides--a review.

PubMed

Komárek, Michael; Vaněk, Aleš; Ettler, Vojtěch

2013-01-01

Oxides and their precursors have been extensively studied, either singly or in combination with other amendments promoting sorption, for in situ stabilization of metals and As in contaminated soils. This remediation option aims at reducing the available fraction of metal(loid)s, notably in the root zone, and thus lowering the risks associated with their leaching, ecotoxicity, plant uptake and human exposure. This review summarizes literature data on mechanisms involved in the immobilization process and presents results from laboratory and field experiments, including the subsequent influence on higher plants and aided phytostabilization. Despite the partial successes in the field, recent knowledge highlights the importance of long-term and large-scale field studies evaluating the stability of the oxide-based amendments in the treated soils and their efficiency in the long-term. Copyright © 2012 Elsevier Ltd. All rights reserved.

Solar cells with perovskite-based light sensitization layers

DOEpatents

Kanatzidis, Mercouri G.; Chang, Robert P.H.; Stoumpos, Konstantinos; Lee, Byunghong

2018-05-08

Solar cells are provided which comprise an electron transporting layer and a light sensitizing layer of perovskite disposed over the surface of the electron transporting layer. The perovskite may have a formula selected from the group consisting of A₂MX₆, Z₂MX₆ or YMX₆, wherein A is an alkali metal, M is a metal or a metalloid, X is a halide, Z is selected from the group consisting of a primary ammonium, an iminium, a secondary ammonium, a tertiary ammonium, and a quaternary ammonium, and Y has formula M_b(L)₃, wherein M_b is a transition metal in the 2+ oxidation state L is an N--N neutral chelating ligand. Methods of making the solar cells are also provided, including methods based on electrospray deposition.

Method for separating metal chelates from other materials based on solubilities in supercritical fluids

DOEpatents

Wai, Chien M.; Smart, Neil G.; Phelps, Cindy

2001-01-01

A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

Method of producing catalytic material for fabricating nanostructures

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

Seals, Roland D.; Menchhofer, Paul A.; Howe, Jane Y.

Methods of fabricating nano-catalysts are described. In some embodiments the nano-catalyst is formed from a powder-based substrate material and is some embodiments the nano-catalyst is formed from a solid-based substrate material. In some embodiments the substrate material may include metal, ceramic, or silicon or another metalloid. The nano-catalysts typically have metal nanoparticles disposed adjacent the surface of the substrate material. The methods typically include functionalizing the surface of the substrate material with a chelating agent, such as a chemical having dissociated carboxyl functional groups (--COO), that provides an enhanced affinity for metal ions. The functionalized substrate surface may then bemore » exposed to a chemical solution that contains metal ions. The metal ions are then bound to the substrate material and may then be reduced, such as by a stream of gas that includes hydrogen, to form metal nanoparticles adjacent the surface of the substrate.« less

Process for producing dispersed particulate composite materials

DOEpatents

Henager, Jr., Charles H.; Hirth, John P.

1995-01-01

This invention is directed to a process for forming noninterwoven dispersed particulate composite products. In one case a composite multi-layer film product comprises a substantially noninterwoven multi-layer film having a plurality of discrete layers. This noninterwoven film comprises at least one discrete layer of a first material and at least one discrete layer of a second material. In another case the first and second materials are blended together with each other. In either case, the first material comprises a metalloid and the second material a metal compound. At least one component of a first material in one discrete layer undergoes a solid state displacement reaction with at least one component of a second material thereby producing the requisite noninterwoven composite film product. Preferably, the first material comprises silicon, the second material comprises Mo.sub.2 C, the third material comprises SiC and the fourth material comprises MoSi.sub.2.

In-plane magnetic anisotropy and coercive field dependence upon thickness of CoFeB

NASA Astrophysics Data System (ADS)

Kipgen, Lalminthang; Fulara, Himanshu; Raju, M.; Chaudhary, Sujeet

2012-09-01

The structural and magnetic properties of as-grown 5-50 nm thin ion-beam sputter deposited transition metal-metalloid Co20Fe60B20 (CFB) films are reported in this communication. A broad peak observed at 2θ∼45° in the glancing angle X-ray diffraction pattern revealed the formation of very fine nano-sized grains embedded in majority amorphous CFB matrix. Although no magnetic field is applied during deposition, the longitudinal magneto-optic Kerr effect measurements performed at 300 K in these as-grown films clearly established the presence of in-plane uniaxial magnetic anisotropy (Ku). It is argued that this observed anisotropy is strain-induced. This is supported by the observed dependence of direction of Ku on the angle between applied magnetic field and crystallographic orientation of the underlying Si(100) substrate, and increase in the coercivity with the increase of the film thickness.

Method of producing catalytic materials for fabricating nanostructures

DOEpatents

Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

2013-02-19

Methods of fabricating nano-catalysts are described. In some embodiments the nano-catalyst is formed from a powder-based substrate material and is some embodiments the nano-catalyst is formed from a solid-based substrate material. In some embodiments the substrate material may include metal, ceramic, or silicon or another metalloid. The nano-catalysts typically have metal nanoparticles disposed adjacent the surface of the substrate material. The methods typically include functionalizing the surface of the substrate material with a chelating agent, such as a chemical having dissociated carboxyl functional groups (--COO), that provides an enhanced affinity for metal ions. The functionalized substrate surface may then be exposed to a chemical solution that contains metal ions. The metal ions are then bound to the substrate material and may then be reduced, such as by a stream of gas that includes hydrogen, to form metal nanoparticles adjacent the surface of the substrate.

Microbial antimony biogeochemistry: Enzymes, regulation, and related metabolic pathways

USGS Publications Warehouse

Li, Jingxin; Qian Wang,; Oremland, Ronald S.; Kulp, Thomas R.; Rensing, Christopher; Wang, Gejiao

2016-01-01

Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of “antimonotrophs.”

Carbon and metal-carbon implantations into tool steels for improved tribological performance

NASA Astrophysics Data System (ADS)

Hirvonen, J.-P.; Harskamp, F.; Torri, P.; Willers, H.; Fusari, A.; Gibson, N.; Haupt, J.

1997-05-01

The high-fluence implantation of carbon and dual implantations of metal-metalloid pairs into steels with different microstructures are briefly reviewed. A previously unexamined system, the implantation of Si and C into two kinds of tool steels, M3 and D2, have been studied in terms of microstructure and tribological performance. In both cases ion implantation transfers a surface into an amorphous layer. However, the tribological behavior of these two materials differs remarkably: in the case of ion-implanted M3 a reduction of wear in a steel pin is observed even at high pin loads, whereas in the case of ion-implanted D2 the beneficial effects of ion implantation were limited to the lowest pin load. The importance of an initial phase at the onset of sliding is emphasized and a number of peculiarities observed in ion-implanted M3 steel are discussed.

Enhanced Toxic Metal Accumulation in Engineered Bacterial Cells Expressing Arabidopsis thaliana Phytochelatin Synthase

PubMed Central

Sauge-Merle, Sandrine; Cuiné, Stéphan; Carrier, Patrick; Lecomte-Pradines, Catherine; Luu, Doan-Trung; Peltier, Gilles

2003-01-01

Phytochelatins (PCs) are metal-binding cysteine-rich peptides, enzymatically synthesized in plants and yeasts from glutathione in response to heavy metal stress by PC synthase (EC 2.3.2.15). In an attempt to increase the ability of bacterial cells to accumulate heavy metals, the Arabidopsis thaliana gene encoding PC synthase (AtPCS) was expressed in Escherichia coli. A marked accumulation of PCs was observed in vivo together with a decrease in the glutathione cellular content. When bacterial cells expressing AtPCS were placed in the presence of heavy metals such as cadmium or the metalloid arsenic, cellular metal contents were increased 20- and 50-fold, respectively. We discuss the possibility of using genes of the PC biosynthetic pathway to design bacterial strains or higher plants with increased abilities to accumulate toxic metals, and also arsenic, for use in bioremediation and/or phytoremediation processes. PMID:12514032

Speciation Methods Used to Assess Potential Health Effects of Toxic Metals in Environmental Materials

USGS Publications Warehouse

Wolf, Ruth E.; Morman, Suzette A.; Plumlee, Geoffrey S.

2008-01-01

Assessing potential exposures to toxic metals or metalloids such as arsenic and chromium in environmental materials is important in protecting public health. The chemical form of an element in, or released from, a material is also important, since some forms, such as Cr(VI), are more toxic than others, for example, Cr(III). We have used a variety of procedures to assess potential exposures to hexavalent chromium in ash and burned soils from October 2007 southern California wildfires. Synthetic lung-fluid and de-ionized water extractions simulate release in the lungs and potential environmental releases due to rainfall. Extracts were analyzed for specific chromium and arsenic species using HPLC-ICP-MS methodology. Results indicate that the highly oxidizing environment in wildfires promotes some chromium conversion to Cr(VI), and that the caustic alkalinity of ash enhances Cr(VI) release and stability in lung fluids and rainfall.

Z-H Bond Activation in (Di)hydrogen Bonding as a Way to Proton/Hydride Transfer and H2 Evolution.

PubMed

Belkova, Natalia V; Filippov, Oleg A; Shubina, Elena S

2018-02-01

The ability of neutral transition-metal hydrides to serve as a source of hydride ion H - or proton H + is well appreciated. The hydride ligands possessing a partly negative charge are proton accepting sites, forming a dihydrogen bond, M-H δ- ⋅⋅⋅ δ+ HX (M=transition metal or metalloid). On the other hand, some metal hydrides are able to serve as a proton source and give hydrogen bond of M-H δ+ ⋅⋅⋅X type (X=organic base). In this paper we analyse recent works on transition-metal and boron hydrides showing i) how formation of an intermolecular complex between the reactants changes the Z-H (M-H and X-H) bond polarity and ii) what is the implication of such activation in the mechanisms of hydrides reactions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Human health implications, risk assessment and remediation of As-contaminated water: A critical review.

PubMed

Shakoor, Muhammad Bilal; Nawaz, Rab; Hussain, Fida; Raza, Maimoona; Ali, Shafaqat; Rizwan, Muhammad; Oh, Sang-Eun; Ahmad, Sajjad

2017-12-01

Arsenic (As) is a naturally occurring metalloid and Class-A human carcinogen. Exposure to As via direct intake of As-contaminated water or ingestion of As-contaminated edible crops is considered a life threatening problem around the globe. Arsenic-laced drinking water has affected the lives of over 200 million people in 105 countries worldwide. Limited data are available on various health risk assessment models/frameworks used to predict carcinogenic and non-carcinogenic health effects caused by As-contaminated water. Therefore, this discussion highlights the need for future research focusing on human health risk assessment of individual As species (both organic and inorganic) present in As-contaminated water. Various conventional and latest technologies for remediation of As-contaminated water are also reviewed along with a discussion of the fate of As-loaded waste and sludge. Copyright © 2017 Elsevier B.V. All rights reserved.

Applications of biochar in redox-mediated reactions.

PubMed

Yuan, Yong; Bolan, Nanthi; Prévoteau, Antonin; Vithanage, Meththika; Biswas, Jayanta Kumar; Ok, Yong Sik; Wang, Hailong

2017-12-01

Biochar is chemically more reduced and reactive than the original feedstock biomass. Graphite regions, functional groups, and redox-active metals in biochar contribute to its redox characteristics. While the functional groups such as phenolic species in biochar are the main electron donating moieties (i.e., reducers), the quinones and polycondensed aromatic functional groups are the components accepting electrons (oxidants). The redox capacity of biochar depends on feedstock properties and pyrolysis conditions. This paper aims to review and summarize the various synthesis techniques for biochars and the methods for probing their redox characteristics. We review the abiotic and microbial applications of biochars as electron donors, electron acceptors, or electron shuttles for pollutant degradation, metal(loid)s (im)mobilization, nutrient transformation, and discuss the underlying mechanisms. Furthermore, knowledge gaps that exist in the exploration and differentiation of the electron transfer mechanisms involving biochars are also identified. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multiple approaches to assess the safety of artisanal marine food in a tropical estuary.

PubMed

Padovan, A C; Neave, M J; Munksgaard, N C; Gibb, K S

2017-03-01

In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference.

Antimony (SbIII) reduces growth, declines photosynthesis, and modifies leaf tissue anatomy in sunflower (Helianthus annuus L.).

PubMed

Vaculík, Marek; Mrázová, Anna; Lux, Alexander

2015-12-01

The role of antimony (Sb)--a non-essential trace metalloid--in physiological processes running in crops is still poorly understood. Present paper describes the effect of Sb tartrate (SbIII) on growth, Sb uptake, photosynthesis, photosynthetic pigments, and leaf tissue organization in young sunflower plants grown in hydroponics. We found that growth of below- and aboveground part was reduced with increasing concentration of Sb in the medium. Although Sb was mostly taken up by sunflower roots and only small part (1-2%) was translocated to the shoots, decline in photosynthesis, transpiration, and decreased content of photosynthetic pigments were observed. This indicates that despite relatively low mobility of Sb in root-shoot system, Sb in shoot noticeably modifies physiological status and reduced plant growth. Additionally, leaf anatomical changes indicated that Sb reduced the size of intercellular spaces and made leaf tissue more compact.

Comparative study of ageing, heat treatment and accelerated carbonation for stabilization of municipal solid waste incineration bottom ash in view of reducing regulated heavy metal/metalloid leaching.

PubMed

Santos, Rafael M; Mertens, Gilles; Salman, Muhammad; Cizer, Özlem; Van Gerven, Tom

2013-10-15

This study compared the performance of four different approaches for stabilization of regulated heavy metal and metalloid leaching from municipal solid waste incineration bottom ash (MSWI-BA): (i) short term (three months) heap ageing, (ii) heat treatment, (iii) accelerated moist carbonation, and (iv) accelerated pressurized slurry carbonation. Two distinct types of MSWI-BA were tested in this study: one originating from a moving-grate furnace incineration operation treating exclusively household refuse (sample B), and another originating from a fluid-bed furnace incineration operation that treats a mixture of household and light industrial wastes (sample F). The most abundant elements in the ashes were Si (20-27 wt.%) and Ca (16-19 wt.%), followed by significant quantities of Fe, Al, Na, S, K, Mg, Ti, and Cl. The main crystalline substances present in the fresh ashes were Quartz, Calcite, Apatite, Anhydrite and Gehlenite, while the amorphous fraction ranged from 56 to 73 wt.%. The leaching values of all samples were compared to the Flemish (NEN 7343) and the Walloon (DIN 38414) regulations from Belgium. Batch leaching of the fresh ashes at natural pH showed that seven elements exceeded at least one regulatory limit (Ba, Cr, Cu, Mo, Pb, Se and Zn), and that both ashes had excess basicity (pH > 12). Accelerated carbonation achieved significant reduction in ash basicity (9.3-9.9); lower than ageing (10.5-12.2) and heat treatment (11.1-12.1). For sample B, there was little distinction between the leaching results of ageing and accelerated carbonation with respect to regulatory limits; however carbonation achieved comparatively lower leaching levels. Heat treatment was especially detrimental to the leaching of Cr. For sample F, ageing was ineffective and heat treatment had marginally better results, while accelerated carbonation delivered the most effective performance, with slurry carbonation meeting all DIN limits. Slurry carbonation was deemed the most effective treatment process, achieving consistently significant leaching stabilization, while also effectively washing out Cl ions, a requirement for the utilization of the ashes in construction applications. The benefits of carbonation were linked to the formation of significant quantities of Ca-carbonates, including appreciable quantities of the Aragonite polymorph formed in the slurry carbonated samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dissolved metals and associated constituents in abandoned coal-mine discharges, Pennsylvania, USA. Part 1: Constituent quantities and correlations

USGS Publications Warehouse

Cravotta, C.A.

2008-01-01

Complete hydrochemical data are rarely reported for coal-mine discharges (CMD). This report summarizes major and trace-element concentrations and loadings for CMD at 140 abandoned mines in the Anthracite and Bituminous Coalfields of Pennsylvania. Clean-sampling and low-level analytical methods were used in 1999 to collect data that could be useful to determine potential environmental effects, remediation strategies, and quantities of valuable constituents. A subset of 10 sites was resampled in 2003 to analyze both the CMD and associated ochreous precipitates; the hydrochemical data were similar in 2003 and 1999. In 1999, the flow at the 140 CMD sites ranged from 0.028 to 2210 L s-1, with a median of 18.4 L s-1. The pH ranged from 2.7 to 7.3; concentrations (range in mg/L) of dissolved (0.45-??m pore-size filter) SO4 (34-2000), Fe (0.046-512), Mn (0.019-74), and Al (0.007-108) varied widely. Predominant metalloid elements were Si (2.7-31.3 mg L-1), B ( C > P = N = Se) were not elevated in the CMD samples compared to average river water or seawater. Compared to seawater, the CMD samples also were poor in halogens (Cl > Br > I > F), alkalies (Na > K > Li > Rb > Cs), most alkaline earths (Ca > Mg > Sr), and most metalloids but were enriched by two to four orders of magnitude with Fe, Al, Mn, Co, Be, Sc, Y and the lanthanide rare-earth elements, and one order of magnitude with Ni and Zn. The ochre samples collected at a subset of 10 sites in 2003 were dominantly goethite with minor ferrihydrite or lepidocrocite. None of the samples for this subset contained schwertmannite or was Al rich, but most contained minor aluminosilicate detritus. Compared to concentrations in global average shale, the ochres were rich in Fe, Ag, As and Au, but were poor in most other metals and rare earths. The ochres were not enriched compared to commercial ore deposits mined for Au or other valuable metals. Although similar to commercial Fe ores in composition, the ochres are dispersed and present in relatively small quantities at most sites. Nevertheless, the ochres could be valuable for use as pigment.

Field investigation of the quality of fresh and aged leachates from selected landfills receiving e-waste in an arid climate.

PubMed

Kiddee, Peeranart; Naidu, Ravi; Wong, Ming H; Hearn, Laurence; Muller, Jochen F

2014-11-01

The management of electronic waste (e-waste) is a serious problem worldwide and much of it is landfilled. A survey of four selected landfills in an arid region of South Australia was conducted to determine the proportion of e-waste in municipal waste and the properties of each landfill site. Leachate and groundwater samples were collected upgradient and downgradient of the landfills for analysis of polybrominated diphenyl ethers (PBDEs) and 14 metals and metalloids, including Al, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, V and Zn. Our data demonstrate that the selected landfills in South Australia continue to receive municipal waste containing in excess of 6%, or 25,000 tonnes per year, of e-waste. The leachates and groundwater collected from the landfills contained significantly elevated concentrations of Pb with the highest concentration in groundwater of 38 μg/l, almost four times higher than the Australian drinking water guideline of 10 μg/l. The presence of PBDEs was detected in both leachate and groundwater samples. Total PBDEs values of 2.13-59.75 ng/l in leachate samples were 10 times higher than in groundwater samples, which recorded a range of 0.41-6.53 ng/l at all sites. Moreover, the concentrations of metals and metalloids in sampled groundwater contained elevated levels of Al, As, Fe, Ni and Pb that exceeded Australian drinking water guideline values. For these reasons potential leaching of these contaminants is of concern and while difficult to attribute elevated contaminant levels to e-waste, we do not recommend continued disposal of e-waste in old landfills that were not originally designed to contain leachates. The survey also revealed temporal variation in the electrical conductivity and concentrations of As, Cd and Pb present in leachates of landfills in arid Mediterranean climates. These results are consistent with the marked variations in rainfall patterns observed for such climates. The solute concentration (EC and other ions including As, Cd and Pb) declines in the leachates during wet winter months (June to September), in contrast to tropical countries where such changes are observed during wet summer months. Copyright © 2014 Elsevier Ltd. All rights reserved.

Geomicrobiological cycling of antimony

NASA Astrophysics Data System (ADS)

Kulp, T. R.; Terry, L.; Dovick, M. A.; Braiotta, F.

2013-12-01

Microbiologically catalyzed oxidation and reduction of toxic metalloids (e.g., As, Se, and Te) generally proceeds much faster than corresponding abiotic reactions. These microbial transformations constitute biogeochemical cycles that control chemical speciation and environmental behavior of metalloids in aqueous environments. Particular progress has been made over the past two decades in documenting microbiological biotransformations of As, which include anaerobic respiratory reduction of As(V) to As(III), oxidation of As(III) to As(V) linked to chemoautotrophy or photoautotrophy, and cellular detoxification pathways. By contrast, microbial interactions with Sb, As's group 15 neighbor and a toxic element of emerging global concern, are poorly understood. Our work with sediment microcosms, enrichment cultures, and bacterial isolates suggests that prokaryotic metabolisms may be similarly important to environmental Sb cycling. Enrichment cultures and isolates from a Sb-contaminated mine site in Idaho exhibited Sb(V)-dependent heterotrophic respiration under anaerobic conditions and Sb(III)-dependent autotrophic growth in the presence of air. Live, anoxic cultures reduced 2 mM Sb(V) to Sb(III) within 5 d, while no activity occurred in killed controls. Sb(V) reduction was stimulated by lactate or acetate and was quantitatively coupled to the oxidation of lactate. The oxidation of radiolabeled 14C-acetate (monitored by GC-GPC) demonstrated Sb(V)-dependent oxidation to 14CO2, suggesting a dissimilatory process. Sb(V) dependent growth in cultures was demonstrated by direct counting. Microbiological reduction of Sb(V) also occurred in anerobic sediment microcosms from an uncontaminated suburban lake, but did not appear to be linked to growth and is interpreted as a mechanism of biological detoxification. Aerobic microcosms and cultures from the Idaho mine oxidized 2 mM Sb(III) to Sb(V) within 7 d and coupled this reaction to cell growth quantified by direct counting. An anoxygenic photosynthetic community of purple sulfur bacteria from Pyramid Lake, NV, however, that was capable of growth via anoxygenic photosynthesis using As(III) as an electron donor was not capable of similar growth using Sb(III). These results suggest that geomicrobiological Sb cycling is an important influence on the environmental speciation and behavior of Sb, and portend the presence of a global biogeochemical Sb cycle that is analogous to but distinct from that for As.

Tellurium Mobility Through Mine Environments

NASA Astrophysics Data System (ADS)

Dorsk, M.

2015-12-01

Tellurium is a rare metalloid that has received minimal research regarding environmental mobility. Observations of Tellurium mobility are mainly based on observations of related metalloids such as selenium and beryllium; yet little research has been done on specific Tellurium behavior. This laboratory work established the environmental controls that influence Tellurium mobility and chemical speciation in aqueous driven systems. Theoretical simulations show possible mobility of Te as Te(OH)3[+] at highly oxidizing and acidic conditions. Movement as TeO3[2-] under more basic conditions may also be possible in elevated Eh conditions. Mobility in reducing environments is theoretically not as likely. For a practical approach to investigate mobility conditions for Te, a site with known Tellurium content was chosen in Colorado. Composite samples were selected from the top, center and bottom of a tailings pile for elution experiments. These samples were disintegrated using a rock crusher and pulverized with an automated mortar and pestle. The material was then classified to 70 microns. A 10g sample split was digested in concentrated HNO3 and HF and analyzed by Atomic Absorption Spectroscopy to determine initial Te concentrations. Additional 10g splits from each location were subjected to elution in 100 mL of each of the following solutions; nitric acid to a pH of 1.0, sulfuric acid to a pH of 2.0, sodium hydroxide to a pH of 12, ammonium hydroxide to a pH of 10, a pine needle/soil tea from material within the vicinity of the collection site to a pH of 3.5 and lastly distilled water to serve as control with a pH of 7. Sulfuric acid was purposefully chosen to simulate acid mine drainage from the decomposition of pyrite within the mine tailings. Sample sub sets were also inundated with 10mL of a 3% hydrogen peroxide solution to induce oxidizing conditions. All collected eluates were then analyzed by atomic absorption spectroscopy (AAS) to measure Tellurium concentrations in each sample. The results provide a comparison of possible environmental Te mobility factors. While the process of bioavailability is not specifically addressed, preliminary data indicate a reference to perhaps assess impact to the local community and livestock relying on the San Miguel River, which is effected by run-off from the mine site.

Development of magnesium-based biodegradable metals with dietary trace element germanium as orthopaedic implant applications.

PubMed

Bian, Dong; Zhou, Weirui; Deng, Jiuxu; Liu, Yang; Li, Wenting; Chu, Xiao; Xiu, Peng; Cai, Hong; Kou, Yuhui; Jiang, Baoguo; Zheng, Yufeng

2017-12-01

From the perspective of element biosafety and dietetics, the ideal alloying elements for magnesium should be those which are essential to or naturally presented in human body. Element germanium is a unique metalloid in the carbon group, chemically similar to its group neighbors, Si and Sn. It is a dietary trace element that naturally presents in human body. Physiological role of Ge is still unanswered, but it might be necessary to ensure normal functioning of the body. In present study, novel magnesium alloys with dietary trace element Ge were developed. Feasibility of those alloys to be used as orthopaedic implant applications was systematically evaluated. Mg-Ge alloys consisted of α-Mg matrix and eutectic phases (α-Mg + Mg 2 Ge). Mechanical properties of Mg-Ge alloys were comparable to current Mg-Ca, Mg-Zn and Mg-Sr biodegradable metals. As-rolled Mg-3Ge alloy exhibited outstanding corrosion resistance in vitro (0.02 mm/y, electrochemical) with decent corrosion rate in vivo (0.6 mm/y, in rabbit tibia). New bone could directly lay down onto the implant and grew along its surface. After 3 months, bone and implant were closely integrated, indicating well osseointegration being obtained. Generally, this is a pioneering study on the in vitro and in vivo performances of novel Mg-Ge based biodegradable metals, and will benefit the future development of this alloy system. The ideal alloying elements for magnesium-based biodegradable metals should be those which are essential to or naturally presented in human body. Element germanium is a unique metalloid in the carbon group. It is a dietary trace element that naturally presents in human body. In present study, feasibility of Mg-Ge alloys to be utilized as orthopedic applications was systematically investigated, mainly focusing on the microstructure, mechanical property, corrosion behavior and biocompatibility. Our findings showed that Mg-3Ge alloy exhibited superior corrosion resistance to current Mg-Ca, Mg-Zn and Mg-Sr alloys with favorable biocompatibility. This is a pioneering study on the in vitro &in vivo performances of Mg-Ge biodegradable metals, and will benefit the future development of this alloy system. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Inorganic arsenic impairs differentiation and functions of human dendritic cells

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

Macoch, Mélinda; Morzadec, Claudie; Fardel, Olivier

2013-01-15

Experimental studies have demonstrated that the antileukemic trivalent inorganic arsenic prevents the development of severe pro-inflammatory diseases mediated by excessive Th1 and Th17 cell responses. Differentiation of Th1 and Th17 subsets is mainly regulated by interleukins (ILs) secreted from dendritic cells (DCs) and the ability of inorganic arsenic to impair interferon-γ and IL-17 secretion by interfering with the physiology of DCs is unknown. In the present study, we demonstrate that high concentrations of sodium arsenite (As(III), 1–2 μM) clinically achievable in plasma of arsenic-treated patients, block differentiation of human peripheral blood monocytes into immature DCs (iDCs) by inducing their necrosis.more » Differentiation of monocytes in the presence of non-cytotoxic concentrations of As(III) (0.1 to 0.5 μM) only slightly impacts endocytotic activity of iDCs or expression of co-stimulatory molecules in cells activated with lipopolysaccharide. However, this differentiation in the presence of As(III) strongly represses secretion of IL-12p70 and IL-23, two major regulators of Th1 and Th17 activities, from iDCs stimulated with different toll-like receptor (TLR) agonists in metalloid-free medium. Such As(III)-exposed DCs also exhibit reduced mRNA levels of IL12A and/or IL12B genes when activated with TLR agonists. Finally, differentiation of monocytes with non-cytotoxic concentrations of As(III) subsequently reduces the ability of activated DCs to stimulate the release of interferon-γ and IL-17 from Th cells. In conclusion, our results demonstrate that clinically relevant concentrations of inorganic arsenic markedly impair in vitro differentiation and functions of DCs, which may contribute to the putative beneficial effects of the metalloid towards inflammatory autoimmune diseases. Highlights: ► Inorganic arsenic impairs differentiation and functions of human dendritic cells (DCs) ► Arsenite (> 1 μM) blocks differentiation of dendritic cells by inducing necrosis ► Arsenite (0.1 to 0.5 μM) slightly reduces endocytotic activity of immature DCs ► Arsenite (0.1 to 0.5 μM) represses expression of IL-12p70 and IL-23 in activated DCs ► Arsenite (0.1 to 0.5 μM) reduces the ability of DCs to activate human T lymphocytes.« less

Cu-As Decoupling in Hydrothermal Systems: A Link Between Pyrite Chemistry and Fluid Composition

NASA Astrophysics Data System (ADS)

Reich, M.; Tardani, D.; Deditius, A.; Chryssoulis, S.; Wrage, J.; Sanchez-Alfaro, P.; Andrea, H.; Cinthia, J.

2016-12-01

Chemical zonations in pyrite have been recognized in most hydrothermal ore deposit types, showing in some cases marked oscillatory alternation of metals and metalloids in pyrite growth zones (e.g., of Cu-rich, As-(Au)-depleted zones and As-(Au)-rich, Cu-depleted zones). This decoupled geochemical behavior of Cu and As has been interpreted as a result of chemical changes in ore-forming fluids, although direct evidence connecting fluctuations in hydrothermal fluid composition with metal partitioning into pyrite growth zones is still lacking. Here we report a comprehensive trace element database of pyrite from an active hydrothermal system, the Tolhuaca Geothermal System (TGS) in southern Chile. We combined high-spatial resolution and X-ray mapping capabilities of electron microprobe analysis (EMPA) with low detection limits and depth-profiling capabilities of secondary-ion mass spectrometry (SIMS) in a suite of pyrite samples retrieved from a 1 km drill hole that crosses the argillic and propylitic alteration zones of the geothermal system. We show that the concentrations of precious metals (e.g., Au, Ag), metalloids (e.g., As, Sb, Se, Te), and base and heavy metals (e.g., Cu, Co, Ni, Pb) in pyrite at the TGS are significant. Among the elements analyzed, arsenic, Cu and Co are the most abundant with concentrations that vary from sub-ppm levels to a few wt. %. Pyrites from the deeper propylitic zone do not show significant zonation and high Cu-(Co)-As concentrations correlate with each other. In contrast, well-developed zonations were detected in pyrite from the shallow argillic alteration zone, where Cu(Co)-rich, As-depleted cores alternate with Cu(Co)-depleted, As-rich rims. These microanalytical data were contrasted with chemical data of fluid inclusion in quartz veins (high Cu/Na and low As/Na) and borehole fluids (low Cu/Na and high As/Na) reported at the TGS, showing a clear correspondence between Cu and As concentrations in pyrite-forming fluids and chemical zonation in pyrite. These observations provide direct evidence supporting the selective partitioning of metals into pyrite as a result of changes in ore-forming fluid composition, most likely due to separation of a single-phase fluid into a low-density vapor and a denser brine, capable to fractionate Cu and As.

Analysis of the Genome and Mobilome of a Dissimilatory Arsenate Reducing Aeromonas sp. O23A Reveals Multiple Mechanisms for Heavy Metal Resistance and Metabolism

PubMed Central

Uhrynowski, Witold; Decewicz, Przemyslaw; Dziewit, Lukasz; Radlinska, Monika; Krawczyk, Pawel S.; Lipinski, Leszek; Adamska, Dorota; Drewniak, Lukasz

2017-01-01

Aeromonas spp. are among the most ubiquitous microorganisms, as they have been isolated from different environmental niches including waters, soil, as well as wounds and digestive tracts of poikilothermic animals and humans. Although much attention has been paid to the pathogenicity of Aeromonads, the role of these bacteria in environmentally important processes, such as transformation of heavy metals, remains to be discovered. Therefore, the aim of this study was a detailed genomic characterization of Aeromonas sp. O23A, the first representative of this genus capable of dissimilatory arsenate reduction. The strain was isolated from microbial mats from the Zloty Stok mine (SW Poland), an environment strongly contaminated with arsenic. Previous physiological studies indicated that O23A may be involved in both mobilization and immobilization of this metalloid in the environment. To discover the molecular basis of the mechanisms behind the observed abilities, the genome of O23A (∼5.0 Mbp) was sequenced and annotated, and genes for arsenic respiration, heavy metal resistance (hmr) and other phenotypic traits, including siderophore production, were identified. The functionality of the indicated gene modules was assessed in a series of minimal inhibitory concentration analyses for various metals and metalloids, as well as mineral dissolution experiments. Interestingly, comparative analyses revealed that O23A is related to a fish pathogen Aeromonas salmonicida subsp. salmonicida A449 which, however, does not carry genes for arsenic respiration. This indicates that the dissimilatory arsenate reduction ability may have been lost during genome reduction in pathogenic strains, or acquired through horizontal gene transfer. Therefore, particular emphasis was placed upon the mobilome of O23A, consisting of four plasmids, a phage, and numerous transposable elements, which may play a role in the dissemination of hmr and arsenic metabolism genes in the environment. The obtained results indicate that Aeromonas sp. O23A is well-adapted to the extreme environmental conditions occurring in the Zloty Stok mine. The analysis of genome encoded traits allowed for a better understanding of the mechanisms of adaptation of the strain, also with respect to its presumable role in colonization and remediation of arsenic-contaminated waters, which may never have been discovered based on physiological analyses alone. PMID:28611742

Analysis of the Genome and Mobilome of a Dissimilatory Arsenate Reducing Aeromonas sp. O23A Reveals Multiple Mechanisms for Heavy Metal Resistance and Metabolism.

PubMed

Uhrynowski, Witold; Decewicz, Przemyslaw; Dziewit, Lukasz; Radlinska, Monika; Krawczyk, Pawel S; Lipinski, Leszek; Adamska, Dorota; Drewniak, Lukasz

2017-01-01

Aeromonas spp. are among the most ubiquitous microorganisms, as they have been isolated from different environmental niches including waters, soil, as well as wounds and digestive tracts of poikilothermic animals and humans. Although much attention has been paid to the pathogenicity of Aeromonads, the role of these bacteria in environmentally important processes, such as transformation of heavy metals, remains to be discovered. Therefore, the aim of this study was a detailed genomic characterization of Aeromonas sp. O23A, the first representative of this genus capable of dissimilatory arsenate reduction. The strain was isolated from microbial mats from the Zloty Stok mine (SW Poland), an environment strongly contaminated with arsenic. Previous physiological studies indicated that O23A may be involved in both mobilization and immobilization of this metalloid in the environment. To discover the molecular basis of the mechanisms behind the observed abilities, the genome of O23A (∼5.0 Mbp) was sequenced and annotated, and genes for arsenic respiration, heavy metal resistance ( hmr ) and other phenotypic traits, including siderophore production, were identified. The functionality of the indicated gene modules was assessed in a series of minimal inhibitory concentration analyses for various metals and metalloids, as well as mineral dissolution experiments. Interestingly, comparative analyses revealed that O23A is related to a fish pathogen Aeromonas salmonicida subsp. salmonicida A449 which, however, does not carry genes for arsenic respiration. This indicates that the dissimilatory arsenate reduction ability may have been lost during genome reduction in pathogenic strains, or acquired through horizontal gene transfer. Therefore, particular emphasis was placed upon the mobilome of O23A, consisting of four plasmids, a phage, and numerous transposable elements, which may play a role in the dissemination of hmr and arsenic metabolism genes in the environment. The obtained results indicate that Aeromonas sp. O23A is well-adapted to the extreme environmental conditions occurring in the Zloty Stok mine. The analysis of genome encoded traits allowed for a better understanding of the mechanisms of adaptation of the strain, also with respect to its presumable role in colonization and remediation of arsenic-contaminated waters, which may never have been discovered based on physiological analyses alone.

Size-Resolved Dust and Aerosol Contaminants Associated with Copper and Lead Smelting Emissions: Implications for Emissions Management and Human Health

PubMed Central

Csavina, Janae; Taylor, Mark P.; Félix, Omar; Rine, Kyle P.; Sáez, A. Eduardo; Betterton, Eric A.

2014-01-01

Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb and other potentially toxic elements. In this work, we show that size-resolved concentrations of As and Pb generally follow a bimodal distribution with the majority of contaminants in the fine size fraction (< 1 μm) around mining activities that include smelting operations at various sites in Australia and Arizona. This evidence suggests that contaminated fine particles (< 1 μm) are the result of vapor condensation and coagulation from smelting operations while coarse particles are most likely the result of windblown dust from contaminated mine tailings and fugitive emissions from crushing and grinding activities. These results on the size distribution of contaminants around mining operations are reported to demonstrate the ubiquitous nature of this phenomenon so that more effective emissions management and practices that minimize health risks associated with metal extraction and processing can be developed. PMID:24995641

Soil and brownfield bioremediation.

PubMed

Megharaj, Mallavarapu; Naidu, Ravi

2017-09-01

Soil contamination with petroleum hydrocarbons, persistent organic pollutants, halogenated organic chemicals and toxic metal(loid)s is a serious global problem affecting the human and ecological health. Over the past half-century, the technological and industrial advancements have led to the creation of a large number of brownfields, most of these located in the centre of dense cities all over the world. Restoring these sites and regeneration of urban areas in a sustainable way for beneficial uses is a key priority for all industrialized nations. Bioremediation is considered a safe economical, efficient and sustainable technology for restoring the contaminated sites. This brief review presents an overview of bioremediation technologies in the context of sustainability, their applications and limitations in the reclamation of contaminated sites with an emphasis on brownfields. Also, the use of integrated approaches using the combination of chemical oxidation and bioremediation for persistent organic pollutants is discussed. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Cumulative index to chemicals and to common and scientific names of species listed in Contaminant Hazard Reviews 1 through 34

USGS Publications Warehouse

Eisler, Ronald

1999-01-01

The Contaminant Hazard Review (CHR) series--sponsored by the U.S. Geological Survey, Patuxent Wildlife Research Center--synthesizes ecotoxicological data for selected environmental contaminants, with emphasis on hazards to native species of flora and fauna. From 1985 through 1998, 34 reviews were published in various report series of the U.S. Department of the Interior on agricultural pesticides (acrolein, atrazine, carbofuran, chlordane, chlorpyrifos, diazinon, diflubenzuron, famphur, fenvalerate, mirex, paraquat, toxaphene), metals and metalloids (arsenic, boron, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium, silver, tin, zinc), mammalian biocides (sodium monofluoroacetate), organic industrial and municipal wastes (dioxins, pentachlorophenol, polycyclic aromatic hydrocarbons, polychlorinated biphenyls), minin wastes (cyanide), and ionizing radiations. This current report is a cumulative index to the common and scientific names of all biological species listed in the first 34 reports in the CHR series, with individual species cross-referenced with contaminant hazard review and corresponding page numbers. A similar index for chemicals is included.

Cumulative Index to Chemicals and to Common and Scientific Names of Species Listed in Contaminant Hazard Reviews 1 through 34

USGS Publications Warehouse

Eisler, R.

1999-01-01

The Patuxent Wildlife Research Center Contaminant Hazard Reviews (CHR) series synthesizes ecotoxicological data of selected environmental contaminants, with emphasis on hazards to native species of flora and fauna. From 1985 through 1998 a total of 34 reviews were published in various Reports series of the U.S. Department of the Interior on agricultural pesticides (carbofuran, chlordane, chlorpyrifos, diazinon, diflubenzuron, fenvalerate, mirex, paraquat, toxaphene), herbicides (acrolein, atrazine), metals and metalloids (arsenic, boron, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium, silver, tin, zinc), predacides (sodium monofluoroacetate), organic industrial wastes (dioxins, pentachlorophenol), veterinary chemicals (famphur), polycyclic aromatic hydrocarbons, polychlorinated biphenyls, mining wastes (cyanide), and ionizing radiations. This report is a cumulative index to the common and scientific names of all biological species listed in the first 34 reports in the CHR series, with individual species cross-referenced by contaminant and corresponding page numbers. A similar index is shown for chemicals.

Physical, Chemical, and Biological Methods for the Removal of Arsenic Compounds

PubMed Central

Lim, K. T.; Shukor, M. Y.; Wasoh, H.

2014-01-01

Arsenic is a toxic metalloid which is widely distributed in nature. It is normally present as arsenate under oxic conditions while arsenite is predominant under reducing condition. The major discharges of arsenic in the environment are mainly due to natural sources such as aquifers and anthropogenic sources. It is known that arsenite salts are more toxic than arsenate as it binds with vicinal thiols in pyruvate dehydrogenase while arsenate inhibits the oxidative phosphorylation process. The common mechanisms for arsenic detoxification are uptaken by phosphate transporters, aquaglyceroporins, and active extrusion system and reduced by arsenate reductases via dissimilatory reduction mechanism. Some species of autotrophic and heterotrophic microorganisms use arsenic oxyanions for their regeneration of energy. Certain species of microorganisms are able to use arsenate as their nutrient in respiratory process. Detoxification operons are a common form of arsenic resistance in microorganisms. Hence, the use of bioremediation could be an effective and economic way to reduce this pollutant from the environment. PMID:24696853

A new aerobic chemolithoautotrophic arsenic oxidizing microorganism isolated from a high Andean watershed.

PubMed

Anguita, Javiera M; Rojas, Claudia; Pastén, Pablo A; Vargas, Ignacio T

2018-02-01

Biological arsenic oxidation has been suggested as a key biogeochemical process that controls the mobilization and fate of this metalloid in aqueous environments. To the best of our knowledge, only four aerobic chemolithoautotrophic arsenite-oxidizing (CAO) bacteria have been shown to grow via direct arsenic oxidation and to have the essential genes for chemolithoautotrophic arsenite oxidation. In this study, a new CAO bacterium was isolated from a high Andean watershed evidencing natural dissolved arsenic attenuation. The bacterial isolate, designated TS-1, is closely related to the Ancylobacter genus, in the Alphaproteobacteria class. Results showed that TS-1 has genes for arsenite oxidation and carbon fixation. The dependence of bacterial growth from arsenite oxidation was demonstrated. In addition, a mathematical model was suggested and the kinetic parameters were obtained by simultaneously fitting the biomass growth, arsenite depletion curves, and arsenate production. This research increases the knowledge of chemolithoautotrophic arsenic oxidizing microorganisms and its potential role as a driver for natural arsenic attenuation.

Metals and metalloids in fruits of tomatoes (Solanum lycopersicum) and their cultivation soils in the Basque Country: concentrations and accumulation trends.

PubMed

Rodriguez-Iruretagoiena, Azibar; Trebolazabala, Josu; Martinez-Arkarazo, Irantzu; de Diego, Alberto; Madariaga, Juan Manuel

2015-04-15

The concentrations of several elements (Al, Fe, As, Cu, Cd, Co, Cr, Mn, Ni, Pb, Sn, V, and Zn) were measured in soils and the edible part of different vegetables (tomatoes (Solanum lycopersicum "Raf") peppers (Capsicum annuum), chards (Betavulgaris var. cicla), artichokes (Cynarascholymus)) and fruits (Raspberries (Rubusidaeus)) from 13 orchards in the Basque Country affected by different pollution sources. Multivariate analysis of data was used to look for possible correlations between metals in soil and metals in the edible part of the plant. Only manganese showed a correlation significantly different from zero. The metal concentrations found in the edible part were always below the upper limits recommended by the European legislation in force. The Bioaccumulation Index was used to investigate how efficient the plant is to uptake an element from the cultivation soil and to preserve its edible part from the element. Copyright © 2014 Elsevier Ltd. All rights reserved.

Geochemical recovery of the Torna-Marcal river system after the Ajka red mud spill, Hungary.

PubMed

Anton, Á D; Klebercz, O; Magyar, Á; Burke, I T; Jarvis, A P; Gruiz, K; Mayes, W M

2014-12-01

The failure of the Ajka red mud depository in October 2010 led to the largest single release of red mud into the surface water environment. This study provides a comparative assessment of stream sediment quality in the Torna-Marcal-Rába catchment between post-disaster surveys (2010) and follow up surveys at an identical suite of 21 locations in 2013. The signature of red mud apparent in initial surveys with high Al, As, Cr, Na, V was only apparent at a small number of sample stations in recent surveys. These constitute <1 km of stream, compared to the >20 km reach of affected sediments in the immediate aftermath of the spill. Concentrations of red mud-derived contaminants are predominately associated with fine fractions of the red mud (<8 μm). This enhances transport out of the system of red mud-derived contaminants and, along with extensive remedial efforts, has substantially limited the within-channel inventory of potentially ecotoxic metals and metalloids.

Biomonitoring of atmospheric pollution by moss bags: Discriminating urban-rural structure in a fragmented landscape.

PubMed

Capozzi, F; Giordano, S; Di Palma, A; Spagnuolo, V; De Nicola, F; Adamo, P

2016-04-01

In this paper we investigated the possibility to use moss bags to detect pollution inputs - metals, metalloids and polycyclic aromatic hydrocarbons (PAHs) - in sites chosen for their different land use (agricultural, urban/residential scenarios) and proximity to roads (sub-scenarios), in a fragmented conurbation of Campania (southern Italy). We focused on thirty-nine elements including rare earths. For most of them, moss uptake was higher in agricultural than in urban scenarios and in front road sites. Twenty PAHs were analyzed in a subset of agricultural sites; 4- and 5-ringed PAHs were the most abundant, particularly chrysene, fluoranthene and pyrene. Overall results indicated that investigated pollutants have a similar spatial distribution pattern over the entire study area, with road traffic and agricultural practices as the major diffuse pollution sources. Moss bags proved a very sensitive tool, able to discriminate between different land use scenarios and proximity to roads in a mixed rural-urban landscape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Results and evaluation of the first study of organochlorine contaminants (PCDDs, PCDFs, PCBs and DDTs), heavy metals and metalloids in birds from Baja California, México.

PubMed

Jiménez, Begoña; Rodríguez-Estrella, Ricardo; Merino, Rubén; Gómez, Gema; Rivera, Laura; José González, María; Abad, Esteban; Rivera, Josep

2005-01-01

Organochlorine compounds (OCs) including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p-p'-DDE), heavy metals (Pb, Cd, Zn, Cu), and arsenic were measured in house sparrows (Passer domesticus) and common ground doves (Columbina passerina) from Baja California Sur, México. Concentrations of PCDD/Fs were low, with 21 pg/g for house sparrows, and 7.7 pg/g for common ground doves. Non-ortho-PCB concentrations in house sparrow and common ground doves were 58 and 254 pg/g, respectively, and are within the highest concentrations reported in species that are in the low levels of food webs. The major differences in organochlorine levels between species were found for ortho-PCBs and DDTs. ortho-PCB levels were higher in the seedeater species, whereas DDT levels were higher in the omnivorous species. Heavy metal levels were far below those associated with negative effects.

Asymmetric Distribution of Metals in the Xenopus Laevis Oocyte: a Synchrotron X-Ray Fluorescence Microprobe Study

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

Popescu, B.F.Gh.; Belak, Z.R.; Ignatyev, K.

2009-06-04

The asymmetric distribution of many components of the Xenopus oocyte, including RNA, proteins, and pigment, provides a framework for cellular specialization during development. During maturation, Xenopus oocytes also acquire metals needed for development, but apart from zinc, little is known about their distribution. Synchrotron X-ray fluorescence microprobe was used to map iron, copper, and zinc and the metalloid selenium in a whole oocyte. Iron, zinc, and copper were asymmetrically distributed in the cytoplasm, while selenium and copper were more abundant in the nucleus. A zone of high copper and zinc was seen in the animal pole cytoplasm. Iron was alsomore » concentrated in the animal pole but did not colocalize with zinc, copper, or pigment accumulations. This asymmetry of metal deposition may be important for normal development. Synchrotron X-ray fluorescence microprobe will be a useful tool to examine how metals accumulate and redistribute during fertilization and embryonic development.« less

Asymmetri Distribution of Metals in the Xenopus Laevis Oocyte: a Synchrotron X-Ray Fluorescence Microprobe Study

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

Popescu, B.F.G.; Belak, Z.R.; Ignatyev, K.

2009-04-29

The asymmetric distribution of many components of the Xenopus oocyte, including RNA, proteins, and pigment, provides a framework for cellular specialization during development. During maturation, Xenopus oocytes also acquire metals needed for development, but apart from zinc, little is known about their distribution. Synchrotron X-ray fluorescence microprobe was used to map iron, copper, and zinc and the metalloid selenium in a whole oocyte. Iron, zinc, and copper were asymmetrically distributed in the cytoplasm, while selenium and copper were more abundant in the nucleus. A zone of high copper and zinc was seen in the animal pole cytoplasm. Iron was alsomore » concentrated in the animal pole but did not colocalize with zinc, copper, or pigment accumulations. This asymmetry of metal deposition may be important for normal development. Synchrotron X-ray fluorescence microprobe will be a useful tool to examine how metals accumulate and redistribute during fertilization and embryonic development.« less

In utero exposure to carcinogens: Epigenetics, developmental disruption and consequences in later life.

PubMed

Waring, R H; Harris, R M; Mitchell, S C

2016-04-01

The uterine environment is often viewed as a relatively safe haven, being guarded by the placenta which acts as a filter, permitting required materials to enter and unwanted products to be removed. However, this defensive barrier is sometimes breached by potential chemical hazards to which the mother may be subjected. Many of these toxins have immediate and recognisable deleterious effects on the embryo, foetus or neonate, but a few are insidious and leave a legacy of health issues that may emerge in later life. Several substances, falling into the categories of metals and metalloids, endocrine disruptors, solvents and other industrial chemicals, have been implicated in the development of long-term health problems in the offspring following maternal and subsequent in utero exposure. The mechanisms involved are complex but often involve epigenetic changes which disrupt normal cell processes leading to the development of cancers and also dysregulation of biochemical pathways. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Heavy metal contamination and health risk assessment in three commercial fish species in the Persian Gulf.

PubMed

Keshavarzi, Behnam; Hassanaghaei, Mina; Moore, Farid; Rastegari Mehr, Meisam; Soltanian, Siyavash; Lahijanzadeh, Ahmad Reza; Sorooshian, Armin

2018-04-01

Five heavy metals/metalloids and related potential health risks were investigated in three commercially important fish species (Anodontostoma chacunda, Belangerii, and Cynoglossurs arel) in Musa Estuary and Mahshahr Harbour of the Persian Gulf. A total of 116 fish samples were collected, and their liver and muscle organs were separately analyzed using ICP-MS. Results revealed that studied metals concentrations (with some exceptions) varied among sampling stations, fish species and their organs. Human health risk is evaluated using different indices. The results indicated that arsenic and mercury are the most hazardous elements. Estimated daily intake (EDI) for the metals exceeded the provisional tolerable daily intake (PTDI) for all studied fish species. Also, target risk (TR) of arsenic indicated that consumption over a long period of time may result in a carcinogenic effect. The results are expected to create awareness among the public on the safety of consuming food products grown in particular areas. Copyright © 2018. Published by Elsevier Ltd.

Glutathione Reductase-Mediated Synthesis of Tellurium-Containing Nanostructures Exhibiting Antibacterial Properties

PubMed Central

Pugin, Benoit; Cornejo, Fabián A.; Muñoz-Díaz, Pablo; Muñoz-Villagrán, Claudia M.; Vargas-Pérez, Joaquín I.; Arenas, Felipe A.

2014-01-01

Tellurium, a metalloid belonging to group 16 of the periodic table, displays very interesting physical and chemical properties and lately has attracted significant attention for its use in nanotechnology. In this context, the use of microorganisms for synthesizing nanostructures emerges as an eco-friendly and exciting approach compared to their chemical synthesis. To generate Te-containing nanostructures, bacteria enzymatically reduce tellurite to elemental tellurium. In this work, using a classic biochemical approach, we looked for a novel tellurite reductase from the Antarctic bacterium Pseudomonas sp. strain BNF22 and used it to generate tellurium-containing nanostructures. A new tellurite reductase was identified as glutathione reductase, which was subsequently overproduced in Escherichia coli. The characterization of this enzyme showed that it is an NADPH-dependent tellurite reductase, with optimum reducing activity at 30°C and pH 9.0. Finally, the enzyme was able to generate Te-containing nanostructures, about 68 nm in size, which exhibit interesting antibacterial properties against E. coli, with no apparent cytotoxicity against eukaryotic cells. PMID:25193000

Uncovering hidden heterogeneity: Geo-statistical models illuminate the fine scale effects of boating infrastructure on sediment characteristics and contaminants.

PubMed

Hedge, L H; Dafforn, K A; Simpson, S L; Johnston, E L

2017-06-30

Infrastructure associated with coastal communities is likely to not only directly displace natural systems, but also leave environmental footprints' that stretch over multiple scales. Some coastal infrastructure will, there- fore, generate a hidden layer of habitat heterogeneity in sediment systems that is not immediately observable in classical impact assessment frameworks. We examine the hidden heterogeneity associated with one of the most ubiquitous coastal modifications; dense swing moorings fields. Using a model based geo-statistical framework we highlight the variation in sedimentology throughout mooring fields and reference locations. Moorings were correlated with patches of sediment with larger particle sizes, and associated metal(loid) concentrations in these patches were depressed. Our work highlights two important ideas i) mooring fields create a mosaic of habitat in which contamination decreases and grain sizes increase close to moorings, and ii) model- based frameworks provide an information rich, easy-to-interpret way to communicate complex analyses to stakeholders. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Effects of Sediment Containing Coal Ash from the Kingston Ash Release on Embryo-Larval Development in the Fathead Minnow, Pimephales promelas (Rafinesque, 1820)

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

Greeley Jr, Mark Stephen; Elmore, Logan R; McCracken, Kitty

2014-01-01

The largest environmental release of coal ash in U.S. history occurred in December 2008 with the failure of a retention structure at the Tennessee Valley Authority (TVA) Kingston Fossil Plant in East Tennessee. A byproduct of coal-burning power plants, coal ash is enriched in metals and metalloids such as selenium and arsenic with known toxicity to fish including embryonic and larval stages. The effects of contact exposure to sediments containing up to 78 % coal ash from the Kingston spill on the early development of fish embryos and larvae were examined in 7-day laboratory tests with the fathead minnow (Pimephalesmore » promelas). No significant effects were observed on hatching success, incidences of gross developmental abnormalities, or embryo-larval survival. Results suggest that direct exposures to sediment containing residual coal ash from the Kingston ash release may not present significant risks to fish eggs and larvae in waterways affected by the spill.« less

Use of weathered and fresh bottom ash mix layers as a subbase in road constructions: environmental behavior enhancement by means of a retaining barrier.

PubMed

Del Valle-Zermeño, R; Chimenos, J M; Giró-Paloma, J; Formosa, J

2014-12-01

The presence of neoformed cement-like phases during the weathering of non-stabilized freshly quenched bottom ash favors the development of a bound pavement material with improved mechanical properties. Use of weathered and freshly quenched bottom ash mix layers placed one over the other allowed the retention of leached heavy metals and metalloids by means of a reactive percolation barrier. The addition of 50% of weathered bottom ash to the total subbase content diminished the release of toxic species to below environmental regulatory limits. The mechanisms of retention and the different processes and factors responsible of leaching strongly depended on the contaminant under concern as well as on the chemical and physical factors. Thus, the immediate reuse of freshly quenched bottom ash as a subbase material in road constructions is possible, as both the mechanical properties and long-term leachability are enhanced. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of gravity on the precise measurement of solute diffusion coefficients in dilute liquid metals and metalloids.

PubMed

Smith, Reginald W; Zhu, Xiaohe; Tunnicliffe, Mark C; Smith, Timothy J N; Misener, Lowell; Adamson, Josee

2002-10-01

It is now well known that the diffusion coefficient (D) measured in a laboratory in low earth orbit (LEO) is less than the corresponding value measured in a terrestrial laboratory. However, all LEO laboratories are subject to transient accelerations (g-jitter) superimposed on the steady reduced gravity environment of the space platform. In measurements of the diffusion coefficients for dilute binary alloys of Pb-(Ag, Au,Sb), Sb-(Ga,In), Bi-(Ag,Au,Sb), Sn-(Au,Sb), Al-(Fe, Ni,Si), and In-Sb in which g-jitter was suppressed, it was found that D proportional to T (temperature) if g-jitter was suppressed, rather than D proportional to T(2) as observed by earlier workers with g-jitter present. Furthermore, when a forced g-jitter was applied to a diffusion couple, the value measured for D increased. The significance of these results is reviewed in the light of recent work in which ab initio molecular dynamics simulations predicted a D proportional to T relationship.

A New Strategy for Heavy Metal Polluted Environments: A Review of Microbial Biosorbents

PubMed Central

Ayangbenro, Ayansina Segun; Babalola, Olubukola Oluranti

2017-01-01

Persistent heavy metal pollution poses a major threat to all life forms in the environment due to its toxic effects. These metals are very reactive at low concentrations and can accumulate in the food web, causing severe public health concerns. Remediation using conventional physical and chemical methods is uneconomical and generates large volumes of chemical waste. Bioremediation of hazardous metals has received considerable and growing interest over the years. The use of microbial biosorbents is eco-friendly and cost effective; hence, it is an efficient alternative for the remediation of heavy metal contaminated environments. Microbes have various mechanisms of metal sequestration that hold greater metal biosorption capacities. The goal of microbial biosorption is to remove and/or recover metals and metalloids from solutions, using living or dead biomass and their components. This review discusses the sources of toxic heavy metals and describes the groups of microorganisms with biosorbent potential for heavy metal removal. PMID:28106848

Metal fractionation in marine sediments acidified by enrichment of CO2: A risk assessment.

PubMed

de Orte, Manoela Romanó; Bonnail, Estefanía; Sarmiento, Aguasanta M; Bautista-Chamizo, Esther; Basallote, M Dolores; Riba, Inmaculada; DelValls, Ángel; Nieto, José Miguel

2018-06-01

Carbon-capture and storage is considered to be a potential mitigation option for climate change. However, accidental leaks of CO 2 can occur, resulting in changes in ocean chemistry such as acidification and metal mobilization. Laboratory experiments were performed to provide data on the effects of CO 2 -related acidification on the chemical fractionation of metal(loid)s in marine-contaminated sediments using sequential extraction procedures. The results showed that sediments from Huelva estuary registered concentrations of arsenic, copper, lead, and zinc that surpass the probable biological effect level established by international protocols. Zinc had the greatest proportion in the most mobile fraction of the sediment. Metals in this fraction represent an environmental risk because they are weakly bound to sediment, and therefore more likely to migrate to the water column. Indeed, the concentration of this metal was lower in the most acidified scenarios when compared to control pH, indicating probable zinc mobilization from the sediment to the seawater. Copyright © 2018 Elsevier Ltd. All rights reserved.

Metal recovery by bioleaching of sulfidic mining wastes — Application to a European case study

NASA Astrophysics Data System (ADS)

Guézennec, A. G.; Jacob, J.; Joulian, C.; Dupraz, S.; Menard, Y.; d'Hugues, P.

The non-energy extractive industry (NEEI) of the EU-25 generated a direct turnover of about €40 billion, and provided employment to about 250000 people in 16629 companies in 2004. The use of primary raw materials in the production of other branches of EU industry means they have a central role in guaranteeing industrial and economic sustainability. Nevertheless current demand exceeds production, and so the EU is heavily dependent on minerals and metals imports. In this context of securing access to metals, turning mining wastes into new resources of currently unexploited valuable metals is an important challenge. The mining wastes can contain base and precious metals, but also metalloids and rare earth elements that are nowadays considered as highly critical for the industrial development of the European Union. Nevertheless, the development of alternative routes to conventional processing is still required in order to decrease the cost associated to the treatment of these unconventional resources which are more complex in composition and with lower grades.

Toxic metals in ayurvedic preparations from a public health lead poisoning cluster investigation.

PubMed

Mikulski, Marek A; Wichman, Michael D; Simmons, Donald L; Pham, Anthony N; Clottey, Valentina; Fuortes, Laurence J

2017-07-01

Background Herbal formulations, traditional medicine, and complementary and alternative medicine are used by the majority of the world's population. Toxicity associated with use of Ayurvedic products due to metal content is an increasingly recognized potential public health problem. Objectives Report on toxic metals content of Ayurvedic products obtained during an investigation of lead poisoning among users of Ayurvedic medicine. Methods Samples of Ayurvedic formulations were analyzed for metals and metalloids following established US. Environmental Protection Agency methods. Results Lead was found in 65% of 252 Ayurvedic medicine samples with mercury and arsenic found in 38 and 32% of samples, respectively. Almost half of samples containing mercury, 36% of samples containing lead and 39% of samples containing arsenic had concentrations of those metals per pill that exceeded, up to several thousand times, the recommended daily intake values for pharmaceutical impurities. Conclusions Lack of regulations regarding manufacturing and content or purity of Ayurvedic and other herbal formulations poses a significant global public health problem.

Trace element distribution in the snow cover from an urban area in central Poland.

PubMed

Siudek, Patrycja; Frankowski, Marcin; Siepak, Jerzy

2015-05-01

This work presents the first results from winter field campaigns focusing on trace metals and metalloid chemistry in the snow cover from an urbanized region in central Poland. Samples were collected between January and March 2013 and trace element concentrations were determined using GF-AAS. A large inter-seasonal variability depending on anthropogenic emission, depositional processes, and meteorological conditions was observed. The highest concentration (in μg L(-1)) was reported for Pb (34.90), followed by Ni (31.37), Zn (31.00), Cu (13.71), Cr (2.36), As (1.58), and Cd (0.25). In addition, several major anthropogenic sources were identified based on principal component analysis (PCA), among which the most significant was the activity of industry and coal combustion for residential heating. It was stated that elevated concentrations of some trace metals in snow samples were associated with frequent occurrence of south and southeast advection of highly polluted air masses toward the sampling site, suggesting a large impact of regional urban/industrial pollution plumes.

Nanoparticle interactions with co-existing contaminants: joint toxicity, bioaccumulation and risk.

PubMed

Deng, Rui; Lin, Daohui; Zhu, Lizhong; Majumdar, Sanghamitra; White, Jason C; Gardea-Torresdey, Jorge L; Xing, Baoshan

2017-06-01

With their growing production and application, engineered nanoparticles (NPs) are increasingly discharged into the environment. The released NPs can potentially interact with pre-existing contaminants, leading to biological effects (bioaccumulation and/or toxicity) that are poorly understood. Most studies on NPs focus on single analyte exposure; the existing literature on joint toxicity of NPs and co-existing contaminants is rather limited but beginning to develop rapidly. This is the first review paper evaluating the current state of knowledge regarding the joint effects of NPs and co-contaminants. Here, we review: (1) methods for investigating and evaluating joint effects of NPs and co-contaminants; (2) simultaneous toxicities from NPs co-exposed with organic contaminants, metal/metalloid ions, dissolved organic matter (DOM), inorganic ligands and additional NPs; and (3) the influence of NPs co-exposure on the bioaccumulation of organic contaminants and heavy metal ions, as well as the influence of contaminants on NPs bioaccumulation. In addition, future research needs are discussed so as to better understand risk associated with NPs-contaminant co-exposure.

Stability of biogenic metal(loid) nanomaterials related to the colloidal stabilization theory of chemical nanostructures.

PubMed

Piacenza, Elena; Presentato, Alessandro; Turner, Raymond J

2018-02-25

In the last 15 years, the exploitation of biological systems (i.e. plants, bacteria, mycelial fungi, yeasts, and algae) to produce metal(loid) (Me)-based nanomaterials has been evaluated as eco-friendly and a cost-effective alternative to the chemical synthesis processes. Although the biological mechanisms of biogenic Me-nanomaterial (Bio-Me-nanomaterials) production are not yet completely elucidated, a key advantage of such bio-nanostructures over those chemically synthesized is related to their natural thermodynamic stability, with several studies ascribed to the presence of an organic layer surrounding these Bio-Me-nanostructures. Different macromolecules (e.g. proteins, peptides, lipids, DNA, and polysaccharides) or secondary metabolites (e.g. flavonoids, terpenoids, glycosides, organic acids, and alkaloids) naturally produced by organisms have been indicated as main contributors to the stabilization of Bio-Me-nanostructures. Nevertheless, the chemical-physical mechanisms behind the ability of these molecules in providing stability to Bio-Me-nanomaterials are unknown. In this context, transposing the stabilization theory of chemically synthesized Me-nanomaterials (Ch-Me-nanomaterials) to biogenic materials can be used towards a better comprehension of macromolecules and secondary metabolites role as stabilizing agents of Bio-Me-nanomaterials. According to this theory, nanomaterials are generally featured by high thermodynamic instability in suspension, due to their high surface area and surface energy. This feature leads to the necessity to stabilize chemical nanostructures, even during or directly after their synthesis, through the development of (i) electrostatic, (ii) steric, or (iii) electrosteric interactions occurring between molecules and nanomaterials in suspension. Based on these three mechanisms, this review is focused on parallels between the stabilization of biogenic or chemical nanomaterials, suggesting which chemical-physical mechanisms may be involved in the natural stability of Bio-Me-nanomaterials. As a result, macromolecules such as DNA, polyphosphates and proteins may electrostatically interact with Bio-Me-nanomaterials in suspension through their charged moieties, showing the same properties of counterions in Ch-Me-nanostructure suspensions. Since several biomolecules (e.g. neutral lipids, nonionic biosurfactants, polysaccharides, and secondary metabolites) produced by metal(loid)-grown organisms can develop similar steric hindrance as compared to nonionic amphiphilic surfactants and block co-polymers generally used to sterically stabilize Ch-Me-nanomaterials. These biomolecules, most likely, are involved in the development of steric stabilization, because of their bulky structures. Finally, charged lipids and polysaccharides, ionic biosurfactants or proteins with amphiphilic properties can exert a dual effect (i.e. electrostatic and steric repulsion interactions) in the contest of Bio-Me-nanomaterials, leading to the high degree of stability observed.

Influence of metal(loid) bioaccumulation and maternal transfer on embryo-larval development in fish exposed to a major coal ash spill

DOE PAGES

Greeley, Jr., Mark Stephen; Adams, S. Marshall; Elmore, Logan R.; ...

2016-01-03

In December 2008, an earthen retaining wall at the Tennessee Valley Authority (TVA) Kingston Fossil Fuel Plant failed and released 4.1 million m 3 of coal ash to rivers flowing into Watts Bar Reservoir in east Tennessee, United States (U.S.). As part of a comprehensive effort to evaluate the risks to aquatic resources from this spill – the largest in U.S. history – we compared bioaccumulation and maternal transfer of selenium (Se), arsenic (As), and mercury (Hg) in adult redear sunfish ( Lepomis macrolophus), collected two years after the spill from both coal-ash exposed and non-exposed areas of the Emorymore » and Clinch Rivers, with the success of embryo-larval development in their offspring. Whole body and ovary concentrations of Se in female sunfish at three study sites downstream of the spill were significantly elevated (site means = 4.9–5.3 and 6.7–9.0 mg/kg d.w. whole body and ovary concentrations, respectively) compared with concentrations in fish from reference sites upstream of the spill site (2.2–3.2 mg/kg d.w. for whole bodies and 3.6–4.8 mg/kg d.w. for ovaries). However, Se concentrations in coal ash-exposed areas remain below proposed U.S. Environmental Protection Agency (USEPA) criteria for the protection of aquatic life. Site-to-site variation in fish concentrations of As and Hg were not well-correlated with ash-exposure, reflecting the multiple sources of these metal(loid)s in the affected watersheds. In 7-day laboratory tests of embryos and larvae derived from in vitro crosses of eggs and sperm from these field-collected sunfish, fertilization success, hatching success, embryo-larval survival, and incidences of developmental abnormalities did not differ significantly between ash-exposed and non-exposed fish. Furthermore, these developmental endpoints were not correlated with whole body or ovary concentrations of Se, As, or Hg in the maternal fish, or with fish size, ovary weight, or gonadal-somatic indices. Furthermore, results from this and related studies associated with the Kingston coal ash spill are consistent with proposed USEPA fish-based water quality criteria for Se, and to date continue to suggest that long-term exposures to sediment containing residual ash may not present a significant chronic risk to fish populations exposed to this major coal ash release.« less

Effects of an iron-silicon material, a synthetic zeolite and an alkaline clay on vegetable uptake of As and Cd from a polluted agricultural soil and proposed remediation mechanisms.

PubMed

Yao, Aijun; Wang, Yani; Ling, Xiaodan; Chen, Zhe; Tang, Yetao; Qiu, Hao; Ying, Rongrong; Qiu, Rongliang

2017-04-01

Economic and highly effective methods of in situ remediation of Cd and As polluted farmland in mining areas are urgently needed. Pot experiments with Brassica chinensis L. were carried out to determine the effects of three soil amendments [a novel iron-silicon material (ISM), a synthetic zeolite (SZ) and an alkaline clay (AC)] on vegetable uptake of As and Cd. SEM-EDS and XRD analyses were used to investigate the remediation mechanisms involved. Amendment with ISM significantly reduced the concentrations of As and Cd in edible parts of B. chinensis (by 84-94 % and 38-87 %, respectively), to levels that met food safety regulations and was much lower than those achieved by SZ and AC. ISM also significantly increased fresh biomass by 169-1412 % and 436-731 % in two consecutive growing seasons, while SZ and AC did not significantly affect vegetable growth. Correlation analysis suggested that it was the mitigating effects of ISM on soil acidity and on As and Cd toxicity, rather than nutrient amelioration, that contributed to the improvement in plant growth. SEM-EDS analysis showed that ISM contained far more Ca, Fe and Mn than did SZ or AC, and XRD analysis showed that in the ISM these elements were primarily in the form of silicates, oxides and phosphates that had high capacities for chemisorption of metal(loid)s. After incubation with solutions containing 800 mg L -1 AsO 4 2- or Cd 2+ , ISM bound distinctly higher levels of As (6.18 % in relative mass percent by EDS analysis) and Cd (7.21 % in relative mass percent by EDS analysis) compared to SZ and AC. XRD analysis also showed that ISM facilitated the precipitation of Cd 2+ as silicates, phosphates and hydroxides, and that arsenate combined with Fe, Al, Ca and Mg to form insoluble arsenate compounds. These precipitation mechanisms were much more active in ISM than in SZ or AC. Due to the greater pH elevation caused by the abundant calcium silicate, chemisorption and precipitation mechanisms in ISM treatments could be further enhanced. That heavy metal(loid)s fixation mechanisms of ISM ensure the remediation more irreversible and more resilient to environmental changes. With appropriate application rate and proper nutrients supplement, the readily available and economic ISM is a very promising amendment for safe crop production on multi-metal(loids) polluted soils.

Metallic elements and metalloids in Boletus luridus, B. magnificus and B. tomentipes mushrooms from polymetallic soils from SW China.

PubMed

Falandysz, Jerzy; Zhang, Ji; Wiejak, Anna; Barałkiewicz, Danuta; Hanć, Anetta

2017-08-01

Yunnan Province in China is known for its high biodiversity of mushrooms and a diverse geochemistry of soil bedrock and polymetallic soils, but our knowledge of mineral compositions of mushrooms from Yunnan is scarce. The metallic trace elements, Ag, Ba, Co, Cd, Cs, Cu, Cr, Hg, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn, and the metalloids, As and Sb, have been investigated using validated methods with a dynamic reactive cell by mass spectroscopy - inductive coupled plasma and cold vapour - atomic absorption spectroscopy on three popular species of Boletus mushrooms from Southwestern China. The trace mineral profiles in caps and stipes of B. luridus (24 individuals), B. magnificus (29 individuals) and B. tomentipes (38 individuals) have been evaluated. The interspecific differences in the content of several trace elements could be attributed to known differences in the geochemistry of soils in Yunnan, but for copper a difference was observed within species. The mean values of concentrations in composite samples of caps for B. luridus, B. magnificus and B. tomentipes from three to four locations were at the ranges (mgkg -1 dry biomass): Ag (1.3-3.7), As (0.79-53), Ba (4.0-12), Co (0.68-1.2), Cd (0.79-2.2), Cs (0.67-55), Cu (37-77), Cr (5.0-7.6), Hg (2.1-5.4), Li (0.15-0.61), Mn (13-28), Ni (0.86-4.6), Pb (0.59-1.8), Rb (90-120), Sb (0.014-0.088), Sr (0.63-1.6), V (1.4-2.2), Tl (0.017-0.054), U (0.029-0.065) and Zn (130-180). Caps of Boletus mushrooms were richer in Ag, Cu, Hg and Zn than stipes, while other elements were distributed roughly equally between both morphological parts. B. luridus, B. magnificus and B. tomentipes grew in certain sites in Yunnan contained Ag, As, Ba, Cr, Hg, Ni, Sr or V at elevated concentration. A specific geochemistry of the soils type (latosols, lateritic red earths, and red and yellow earths in the Circum-Pacific Mercuriferous Belt of Southwestern China) can explain occurrence of some minerals at greater or elevated amount in mushrooms in Yunnan, while number of available research and data on mineral composition of mushrooms due to geochemical anomalies of soil parent material is so far little. Copyright © 2017 Elsevier Inc. All rights reserved.

Soil pollution fingerprints of children playgrounds in Sarajevo city, Bosnia and Herzegovina.

PubMed

Sapcanin, Aida; Cakal, Mirsada; Jacimovic, Zeljko; Pehlic, Ekrem; Jancan, Gordan

2017-04-01

This is the first study, 10 years after the war activities, to report about the content of heavy metals and metalloids, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) found in samples of soils from selected playgrounds in Sarajevo. Due to the fact that children are in direct contact with surface soils, it has been recommended that children's playgrounds should be given special consideration in this respect. Basic properties (pH in H 2 O, pH in 1 mol dm -3 KCl, humus, and CaCO 3 ) of the examined soils were determined. Samples for the determination of heavy metals and metalloids were prepared by microwave-assisted acid digestion and determined by using an inductively coupled plasma optical emission spectrometer. Fluorine was determined potentiometrically. Gas chromatography with mass spectrometry was used for determination of PAHs and PCBs. Determined contents (mg kg -1 ) for Cd, Pb, Hg, Cr, Ni, Cu, Zn, Co, Mo, Fe, Se, As, B, and F were in the ranges from: 0.031 ± 0.03 to 0.52 ± 0.05; 26.1 ± 2.5 to 47.7 ± 4.5; 0.07 ± 0.01 to 0.50 ± 0.08; 26.2 to 50; 19.5 ± 1.6 to 33.3 ± 2.7; 12.8 ± 1.8 to 31.9 ± 4.5; 56.0 ± 4.0 to 89.0 ± 6.5; 6.7 ± 0.6 to10.6 ± 1.0; <0.8; 3.05 to 7.35; 1.98 to 2.60; 6.5 ± 0.8 to 17.2 ± 2.0; 0.4 to 3.6, and 286 to 575, respectively. The total PAHs ranged between 0.184 ± 0.32 mg kg -1 and 7.983 ± 1.389 mg kg -1 . The total PCBs was <0.002 mg kg -1 . Our preliminary results may contribute to more accurate health risk assessments of the soils, and may be included in projects planning children's health risk assessments and adopting environmental legislation which has not been sufficiently regulated in Bosnia and Herzegovina so far.

Influence of metal(loid) bioaccumulation and maternal transfer on embryo-larval development in fish exposed to a major coal ash spill

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

Greeley, Jr., Mark Stephen; Adams, S. Marshall; Elmore, Logan R.

In December 2008, an earthen retaining wall at the Tennessee Valley Authority (TVA) Kingston Fossil Fuel Plant failed and released 4.1 million m 3 of coal ash to rivers flowing into Watts Bar Reservoir in east Tennessee, United States (U.S.). As part of a comprehensive effort to evaluate the risks to aquatic resources from this spill – the largest in U.S. history – we compared bioaccumulation and maternal transfer of selenium (Se), arsenic (As), and mercury (Hg) in adult redear sunfish ( Lepomis macrolophus), collected two years after the spill from both coal-ash exposed and non-exposed areas of the Emorymore » and Clinch Rivers, with the success of embryo-larval development in their offspring. Whole body and ovary concentrations of Se in female sunfish at three study sites downstream of the spill were significantly elevated (site means = 4.9–5.3 and 6.7–9.0 mg/kg d.w. whole body and ovary concentrations, respectively) compared with concentrations in fish from reference sites upstream of the spill site (2.2–3.2 mg/kg d.w. for whole bodies and 3.6–4.8 mg/kg d.w. for ovaries). However, Se concentrations in coal ash-exposed areas remain below proposed U.S. Environmental Protection Agency (USEPA) criteria for the protection of aquatic life. Site-to-site variation in fish concentrations of As and Hg were not well-correlated with ash-exposure, reflecting the multiple sources of these metal(loid)s in the affected watersheds. In 7-day laboratory tests of embryos and larvae derived from in vitro crosses of eggs and sperm from these field-collected sunfish, fertilization success, hatching success, embryo-larval survival, and incidences of developmental abnormalities did not differ significantly between ash-exposed and non-exposed fish. Furthermore, these developmental endpoints were not correlated with whole body or ovary concentrations of Se, As, or Hg in the maternal fish, or with fish size, ovary weight, or gonadal-somatic indices. Furthermore, results from this and related studies associated with the Kingston coal ash spill are consistent with proposed USEPA fish-based water quality criteria for Se, and to date continue to suggest that long-term exposures to sediment containing residual ash may not present a significant chronic risk to fish populations exposed to this major coal ash release.« less

Heavy metal speciation in solid-phase materials from a bacterial sulfate reducing bioreactor using sequential extraction procedure combined with acid volatile sulfide analysis.

PubMed

Jong, Tony; Parry, David L

2004-04-01

Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be related to their solubility and chemical forms, and that they decrease with each successive extraction step, then the apparent mobility and bioavailability of these five heavy metals in ASM increase in the order of Cu < As < Ni < Fe < Zn. The SEM/AVS ratio was less than one in eight replicate ASM samples, indicating that the ASM was non-toxic with regards to having a low probability of bioavailable metals in the pore water.

Selenite resistant rhizobacteria stimulate SeO(3) (2-) phytoextraction by Brassica juncea in bioaugmented water-filtering artificial beds.

PubMed

Lampis, Silvia; Ferrari, Anita; Cunha-Queda, A Cristina F; Alvarenga, Paula; Di Gregorio, Simona; Vallini, Giovanni

2009-09-01

Selenium is a trace metalloid of global environmental concern. The boundary among its essentiality, deficiency, and toxicity is narrow and mainly depends on the chemical forms and concentrations in which this element occurs. Different plant species-including Brassica juncea-have been shown to play a significant role in Se removal from soil as well as water bodies. Furthermore, the interactions between such plants, showing natural capabilities of metal uptake and their rhizospheric microbial communities, might be exploited to increase both Se scavenging and vegetable biomass production in order to improve the whole phytoextraction efficiency. The aim of the present study was to evaluate the capability of selenite removal of B. juncea grown in hydroponic conditions on artificially spiked effluents. To optimize phytoextraction efficiency, interactions between B. juncea and rhizobacteria were designedly elicited. Firstly, B. juncea was grown on water-filtering agriperlite beds in the presence of three different selenite concentrations, namely, 0.2, 1.0, and 2.0 mM. Plant growth was measured after 3 and 6 weeks of incubation in order to establish the selenite concentration at which the best plant biomass production could be obtained. Afterwards, water-filtering agriperlite beds were inoculated either with a selenium-acclimated microbial community deriving from the rhizosphere of B. juncea grown, erstwhile, in a selenite-amended soil or with axenic cultures of two bacterial strains, vicelike Bacillus mycoides SeITE01 and Stenotrophomonas maltophilia SeITE02, previously isolated and described for their high resistance to selenite. These latter were seeded separately or as a dual consortium. Selenite was amended at a final concentration of 1.0 mM. Total Se content in plant tissues (both shoots and roots), plant biomass production, and persistence of bioaugmented microbial inocula during the experimental time were monitored. Moreover, parameters such as bioconcentration factor (BF) and phytoextraction efficiency (PE) were determined at the end of the testing run to evaluate the effects of the different bioaugmentation strategies adopted on selenite phytoextraction efficiency of B. juncea. A general but significant increase in capacity to extract and transport selenium to the epigeous plant compartments was recorded in B. juncea grown in beds augmented with microbial inocula, except for the treatment with B. mycoides SeITE01 alone. Nevertheless, a severe decrease in vegetable biomass production was observed after all microbial treatments with the exception of the plants that had received only S. maltophilia SeITE02. Actually, an increase in selenium phytoextraction efficiency up to 65% was observed in B. juncea, when this bacterial strain was inoculated. Emendation of B. juncea grown in water-filtering beds with a Se(IV)-acclimated microbial community caused a higher Se uptake along with a reduction of plant biomass yield with respect to plants grown without addition of the same bacterial inoculum. The increase of selenium BF in shoots suggests that the Se(IV)-acclimated microbial community not only elicited the plant capacity to absorb selenite, but also did improve the capacity to transport the metalloid to the epigeous compartments. On the other hand, the reduction in plant biomass yield might be related exactly to this improved capability of B. juncea to accumulate selenium at concentrations that are actually toxic for plants. Differently, addition of two selenite-resistant bacterial strains, namely, S. maltophilia SeITE02 and B. mycoides SEITE01, had weaker effects on plant biomass production when compared to those recorded in the presence of the Se(IV)-adapted microbial community. In particular, inoculation of water-filtering beds with the SeITE02 strain alone was the sole strategy resulting in a positive effect on both plant biomass production in stressful conditions and the capacity of shoots to accumulate selenium. In fact, its putative ability of reducing Se(IV) to organo-Se compounds significantly enhanced either selenium absorption by the plants or active metalloid translocation to epigeous parts. Bioaugmentation with the bacterial strain S. malthophila SeITE02 is suggested to elicit selenite phytoextraction efficiency in B. juncea. Manipulation of synergistic interactions between plants having phytoextraction capabilities and their associated rhizobacteria may enhance already consolidated treatment processes aimed to detoxify selenite laden wastewater.

Arsenic Hyperaccumulation Strategies: An Overview

PubMed Central

Souri, Zahra; Karimi, Naser; Sandalio, Luisa M.

2017-01-01

Arsenic (As) pollution, which is on the increase around the world, poses a growing threat to the environment. Phytoremediation, an important green technology, uses different strategies, including As uptake, transport, translocation, and detoxification, to remediate this metalloid. Arsenic hyperaccumulator plants have developed various strategies to accumulate and tolerate high concentrations of As. In these plants, the formation of AsIII complexes with GSH and phytochelatins and their transport into root and shoot vacuoles constitute important mechanisms for coping with As stress. The oxidative stress induced by reactive oxygen species (ROS) production is one of the principal toxic effects of As; moreover, the strong antioxidative defenses in hyperaccumulator plants could constitute an important As detoxification strategy. On the other hand, nitric oxide activates antioxidant enzyme and phytochelatins biosynthesis which enhances As stress tolerance in plants. Although several studies have focused on transcription, metabolomics, and proteomic changes in plants induced by As, the mechanisms involved in As transport, translocation, and detoxification in hyperaccumulator plants need to be studied in greater depth. This review updates recent progress made in the study of As uptake, translocation, chelation, and detoxification in As hyperaccumulator plants. PMID:28770198

Biogenic selenium nanoparticles: current status and future prospects.

PubMed

Wadhwani, Sweety A; Shedbalkar, Utkarsha U; Singh, Richa; Chopade, Balu A

2016-03-01

Selenium nanoparticles (SeNPs) are gaining importance in the field of medicine owing to their antibacterial and anticancer properties. SeNPs are biocompatible and non-toxic compared to the counterparts, selenite (SeO3 (-2)) and selenate (SeO4 (-2)). They can be synthesized by physical, chemical, and biological methods and have distinct bright orange-red color. Biogenic SeNPs are stable and do not aggregate owing to natural coating of the biomolecules. Various hypotheses have been proposed to describe the mechanism of microbial synthesis of SeNPs. It is primarily a two-step reduction process from SeO4 (-2) to SeO3 (-2) to insoluble elemental selenium (Se(0)) catalyzed by selenate and selenite reductases. Phenazine-1-carboxylic acid and glutathione are involved in selenite reduction. Se factor A (SefA) and metalloid reductase Rar A present on the surface of SeNPs confer stability to the nanoparticles. SeNPs act as potent chemopreventive and chemotherapeutic agents. Conjugation with antibiotics enhances their anticancer efficacy. These also have applications in nanobiosensors and environmental remediation.

Risk of chronic low-dose selenium overexposure in humans: insights from epidemiology and biochemistry.

PubMed

Vinceti, Marco; Maraldi, Tullia; Bergomi, Margherita; Malagoli, Carlotta

2009-01-01

The latest developments of epidemiologic and biochemical research suggest that current upper limits of intake for dietary selenium and for overall selenium exposure may be inadequate to protect human health. In particular, recent experimental and observational prospective studies indicate a diabetogenic effect of selenium at unexpectedly low levels of intake. Experimental evidence from laboratory studies and veterinary medicine appears to confirm previous epidemiologic observations that selenium overexposure is associated with an increased risk of amyotrophic lateral sclerosis, and a recent large trial indicated no beneficial effect in preventing prostate cancer. Moreover, the pro-oxidant properties of selenium species and the observation that the selenium-containing enzymes glutathione peroxidases are induced by oxidative stress imply that the increase in enzymatic activity induced by this metalloid may represent at least in part a compensatory response. Taken together, the data indicate that the upper safe limit of organic and inorganic selenium intake in humans may be lower than has been thought and that low-dose chronic overexposure to selenium may be considerably more widespread than supposed.

Antimony smelting process generating solid wastes and dust: characterization and leaching behaviors.

PubMed

Guo, Xuejun; Wang, Kunpeng; He, Mengchang; Liu, Ziwei; Yang, Hailin; Li, Sisi

2014-07-01

A large amount of solid waste has been produced by the antimony smelting process in the "World Capital of Antimony", Xikuangshan area in China. This study comprehensively investigated the physical and chemical characteristics of the various solid wastes, as well as the leaching behavior of the solid wastes, which included water-quenched slag, arsenic-alkali residue, desulfurized slag and blast furnace dust. These four types of waste were enriched in a variety of heavy metals and metalloids and more specifically with As and Sb levels up to 8.6 × 10⁴ and 3.16×10⁵ mg/kg, respectively, in arsenic-alkali residue. For desulfurized slag and water-quenched slag, the leaching concentration of Sb significantly exceeded the acceptable limits during the leaching tests using the toxicity characteristic leaching procedure and the synthetic precipitation leaching procedure. In addition, As leaching in arsenic-alkali residue was extraordinarily hazardous, being three orders of magnitude higher than the regulatory level of As. According to the results of the extraction tests, all the tested wastes were classified as hazardous waste. Copyright © 2014. Published by Elsevier B.V.

Implications for current regulatory waste toxicity characterisation methods from analysing metal and metalloid leaching from photovoltaic modules

NASA Astrophysics Data System (ADS)

Collins, Mary Kayla; Anctil, Annick

2017-07-01

The appropriateness of regulatory methods to characterise the toxicity of photovoltaic (PV) modules was investigated to quantify potential environmental impacts for modules disposed of in landfills. Because solar energy is perceived as a green technology, it is important to ensure that end-of-life issues will not be detrimental to solar energy's success. United States Environmental Protection Agency Method 1311, California waste extraction test, and modified versions of both were performed on a multi-crystalline silicon module and cells and a copper indium gallium diselenide (CIGS) module. Variations in metal leachate concentrations were found with changes in testing parameters. Lead concentrations from the multi-crystalline module ranged from 16.2 to 50.2 mg/L. Cadmium concentrations from the CIGS module ranged from 0.1 to 3.52 mg/L. This raises doubt that regulatory methods can adequately characterise PV modules. The results are useful for developing end-of-life procedures, which is a positive step towards avoiding an e-waste problem and continuing trends of increasing installation and cost reduction in the PV market.

Trends in hard X-ray fluorescence mapping: environmental applications in the age of fast detectors.

PubMed

Lombi, E; de Jonge, M D; Donner, E; Ryan, C G; Paterson, D

2011-06-01

Environmental samples are extremely diverse but share a tendency for heterogeneity and complexity. This heterogeneity poses methodological challenges when investigating biogeochemical processes. In recent years, the development of analytical tools capable of probing element distribution and speciation at the microscale have allowed this challenge to be addressed. Of these available tools, laterally resolved synchrotron techniques such as X-ray fluorescence mapping are key methods for the in situ investigation of micronutrients and inorganic contaminants in environmental samples. This article demonstrates how recent advances in X-ray fluorescence detector technology are bringing new possibilities to environmental research. Fast detectors are helping to circumvent major issues such as X-ray beam damage of hydrated samples, as dwell times during scanning are reduced. They are also helping to reduce temporal beamtime requirements, making particularly time-consuming techniques such as micro X-ray fluorescence (μXRF) tomography increasingly feasible. This article focuses on μXRF mapping of nutrients and metalloids in environmental samples, and suggests that the current divide between mapping and speciation techniques will be increasingly blurred by the development of combined approaches.

Metals in Cyanobacteria: Analysis of the Copper, Nickel, Cobalt and Arsenic Homeostasis Mechanisms

PubMed Central

Huertas, María José; López-Maury, Luis; Giner-Lamia, Joaquín; Sánchez-Riego, Ana María; Florencio, Francisco Javier

2014-01-01

Traces of metal are required for fundamental biochemical processes, such as photosynthesis and respiration. Cyanobacteria metal homeostasis acquires an important role because the photosynthetic machinery imposes a high demand for metals, making them a limiting factor for cyanobacteria, especially in the open oceans. On the other hand, in the last two centuries, the metal concentrations in marine environments and lake sediments have increased as a result of several industrial activities. In all cases, cells have to tightly regulate uptake to maintain their intracellular concentrations below toxic levels. Mechanisms to obtain metal under limiting conditions and to protect cells from an excess of metals are present in cyanobacteria. Understanding metal homeostasis in cyanobacteria and the proteins involved will help to evaluate the use of these microorganisms in metal bioremediation. Furthermore, it will also help to understand how metal availability impacts primary production in the oceans. In this review, we will focus on copper, nickel, cobalt and arsenic (a toxic metalloid) metabolism, which has been mainly analyzed in model cyanobacterium Synechocystis sp. PCC 6803. PMID:25501581

Biodegradation of pentachloronitrobenzene by Cupriavidus sp. YNS-85 and its potential for remediation of contaminated soils.

PubMed

Teng, Ying; Wang, Xiaomi; Zhu, Ye; Chen, Wei; Christie, Peter; Li, Zhengao; Luo, Yongming

2017-04-01

Pentachloronitrobenzene (PCNB) is a toxic chlorinated nitroaromatic compound. However, only a few bacteria have been reported to be able to utilize PCNB. In the present study, one pentachloronitrobenzene (PCNB)-degrading bacterium, Cupriavidus sp. YNS-85, was isolated from a contaminated Panax notoginseng plantation. The strain co-metabolized 200 mg L -1 PCNB in aqueous solution with a removal rate of 73.8% after 5 days. The bacterium also degraded PCNB effectively under acid conditions (pH 4-6) and showed resistance to toxic trace elements (arsenic, copper, and cadmium). Its ability to utilize proposed PCNB intermediates as sole carbon sources was also confirmed. The soil microcosm experiment further demonstrated that bacterial bioaugmentation enhanced the removal of PCNB (37.8%) from soil and the accumulation of pentachloroaniline (89.3%) after 30 days. Soil enzyme activity and microbial community functional diversity were positively influenced after bioremediation. These findings indicate that Cupriavidus sp. YNS-85 may be a suitable inoculant for in situ bioremediation of PCNB-polluted sites, especially those with acid soils co-contaminated with heavy metal(loid)s.

Formation of dimethylarsinic acid from methylation of sodium arsenite in lumbricus terrestris.

PubMed

Lin, K W; Behl, S; Furst, A; Chien, P; Toia, R F

1998-04-01

Arsenic is ubiquitous in the environment and the toxicological response of various organisms to it is dependent on the particular chemical form involved. In general, methylation of inorganic arsenic is considered to be a detoxification reaction. While this transformation is known to be mediated by methyltransferases in several species of mammals, less is known about the fate of arsenic in invertebrates. As part of a continuing interest in heavy metals and metalloid toxicology, the alkylating activity of cytosol prepared from the common earthworm, Lumbricus terrestris, towards sodium arsenite has now been investigated. Thus, S-adenosyl-l-[(14)C]methionine ([(14)C-methyl]SAM) fortified earthworm cytosol was incubated with sodium arsenite at 37 degrees C for 90 min. Initial TLC analysis of the incubation mixture suggested incorporation of radiolabel into dimethylarsinic acid. This was subsequently proven by isolation of the metabolite through radiodilution followed by recrystallization of the recovered material to constant specific activity. This result suggests that earthworm cytosol has the same methylating reactivity towards arsenite as do similar preparations from various tissues of several species of mammals.

Biogeochemistry of heavy metals in contaminated excessively moistened soils (Analytical review)

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.; Plekhanova, I. O.

2014-03-01

The biogeochemical behavior of heavy metals in contaminated excessively moistened soils depends on the development of reducing conditions (either moderate or strong). Upon the moderate biogenic reduction, Cr as the metal with variable valence forms low-soluble compounds, which decreases its availability to plants and prevents its penetration into surface- and groundwater. Creation of artificial barriers for Cr fixation on contaminated sites is based on the stimulation of natural metal-reducing bacteria. Arsenic, being a metalloid with a variable valence, is mobilized upon the moderate biogenic reduction. The mobility of siderophilic heavy metals with a constant valence grows under the moderate reducing conditions at the expense of dissolution of iron (hydr)oxides as carriers of these metals. Zinc, which can enter the newly formed goethite lattice, is an exception. Strong reduction processes in organic excessively moist and flooded soils (usually enriched in S) lead to the formation of low-soluble sulfides of heavy elements with both variable (As) and constant (Cu, Ni, Zn, and Pb) valence. On changing aquatic regime in overmoistened soils and their drying, sulfides of heavy metals are oxidized, and previously fixed metals are mobilized.

Fluid extraction

DOEpatents

Wai, Chien M.; Laintz, Kenneth E.

1999-01-01

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Effect of Solute Segregation on Fracture Toughness in a Ni-Cr Steel

NASA Astrophysics Data System (ADS)

Kameda, Jun

1981-12-01

A study has been made of the influence of intergranular solute segregation on fracture toughness K1c in a series of Ni-Cr steels individually doped with Sb, Sn, and P. By means of toughness measurements in steels having two different intergranular Sb distributions, of measurements of acoustic emissions and of scanning electron micrographs of a load-interrupted and post-test-fatigued specimen, the values of K1c, computed from the “pop-in” load of the load vs clip gauge displacement curves, are found to represent the formation of many patches of contiguous intergranular microcracks ahead of the precrack. The present experiments demonstrate that in the early stage of solute segregation, K1c decreases more substantially than does the strength of grain boundaries σ* (measured in the notched bar tests), although the embrittlement effects of metalloid elements are the same order for both K1c and σ*. A proposed model for the stress-gradient-control of brittle fracture supports the finding that the measurements of K1c give a distorted view of the progress of intergranular embrittlement.

Size-resolved dust and aerosol contaminants associated with copper and lead smelting emissions: implications for emission management and human health.

PubMed

Csavina, Janae; Taylor, Mark P; Félix, Omar; Rine, Kyle P; Eduardo Sáez, A; Betterton, Eric A

2014-09-15

Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb and other potentially toxic elements. In this work, we show that size-resolved concentrations of As and Pb generally follow a bimodal distribution with the majority of contaminants in the fine size fraction (<1 μm) around mining activities that include smelting operations at various sites in Australia and Arizona. This evidence suggests that contaminated fine particles (<1 μm) are the result of vapor condensation and coagulation from smelting operations while coarse particles are most likely the result of windblown dust from contaminated mine tailings and fugitive emissions from crushing and grinding activities. These results on the size distribution of contaminants around mining operations are reported to demonstrate the ubiquitous nature of this phenomenon so that more effective emission management and practices that minimize health risks associated with metal extraction and processing can be developed. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimization of Melt Treatment for Austenitic Steel Grain Refinement

NASA Astrophysics Data System (ADS)

Lekakh, Simon N.; Ge, Jun; Richards, Von; O'Malley, Ron; TerBush, Jessica R.

2017-02-01

Refinement of the as-cast grain structure of austenitic steels requires the presence of active solid nuclei during solidification. These nuclei can be formed in situ in the liquid alloy by promoting reactions between transition metals (Ti, Zr, Nb, and Hf) and metalloid elements (C, S, O, and N) dissolved in the melt. Using thermodynamic simulations, experiments were designed to evaluate the effectiveness of a predicted sequence of reactions targeted to form precipitates that could act as active nuclei for grain refinement in austenitic steel castings. Melt additions performed to promote the sequential precipitation of titanium nitride (TiN) onto previously formed spinel (Al2MgO4) inclusions in the melt resulted in a significant refinement of the as-cast grain structure in heavy section Cr-Ni-Mo stainless steel castings. A refined as-cast structure consisting of an inner fine-equiaxed grain structure and outer columnar dendrite zone structure of limited length was achieved in experimental castings. The sequential of precipitation of TiN onto Al2MgO4 was confirmed using automated SEM/EDX and TEM analyses.

Screening beneficial rhizobacteria from Spartina maritima for phytoremediation of metal polluted salt marshes: comparison of gram-positive and gram-negative strains.

PubMed

Paredes-Páliz, Karina I; Caviedes, Miguel A; Doukkali, Bouchra; Mateos-Naranjo, Enrique; Rodríguez-Llorente, Ignacio D; Pajuelo, Eloísa

2016-10-01

The aim of our work was the isolation and characterization of bacteria from the rhizosphere of Spartina maritima in the metal contaminated Odiel estuary (Huelva, SW Spain). From 25 strains, 84 % were identified as gram-positive, particularly Staphylococcus and Bacillus. Gram-negative bacteria were represented by Pantoea and Salmonella. Salt and heavy metal tolerance, metal bioabsorption, plant growth promoting (PGP) properties, and biofilm formation were investigated in the bacterial collection. Despite the higher abundance of gram-positive bacteria, gram-negative isolates displayed higher tolerance toward metal(loid)s (As, Cu, Zn, and Pb) and greater metal biosorption, as deduced from ICP-OES and SEM-EDX analyses. Besides, they exhibited better PGP properties, which were retained in the presence of metals and the ability to form biofilms. Gram-negative strains Pantoea agglomerans RSO6 and RSO7, together with gram-positive Bacillus aryabhattai RSO25, were selected for a bacterial consortium aimed to inoculate S. maritima plants in metal polluted estuaries for phytoremediation purposes.

Comparative proteomic analysis reveals heart toxicity induced by chronic arsenic exposure in rats.

PubMed

Huang, Qingyu; Xi, Guochen; Alamdar, Ambreen; Zhang, Jie; Shen, Heqing

2017-10-01

Arsenic is a widespread metalloid in the environment, which poses a broad spectrum of adverse effects on human health. However, a global view of arsenic-induced heart toxicity is still lacking, and the underlying molecular mechanisms remain unclear. By performing a comparative quantitative proteomic analysis, the present study aims to investigate the alterations of proteome profile in rat heart after long-term exposure to arsenic. As a result, we found that the abundance of 81 proteins were significantly altered by arsenic treatment (35 up-regulated and 46 down-regulated). Among these, 33 proteins were specifically associated with cardiovascular system development and function, including heart development, heart morphology, cardiac contraction and dilation, and other cardiovascular functions. It is further proposed that the aberrant regulation of 14 proteins induced by arsenic would disturb cardiac contraction and relaxation, impair heart morphogenesis and development, and induce thrombosis in rats, which is mediated by the Akt/p38 MAPK signaling pathway. Overall, these findings will augment our knowledge of the involved mechanisms and develop useful biomarkers for cardiotoxicity induced by environmental arsenic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extraction behavior of metallic contaminants and soil constituents from contaminated soils.

PubMed

Tokunaga, S; Park, S W; Ulmanu, M

2005-06-01

With an aim of developing an effective remediation technology for soils contaminated by heavy metals and metalloids, the extraction behavior of metallic contaminants as well as those of soil constituents was studied on a laboratory scale. Three contaminated soils collected from a former metal recycling plant were examined. These three soils were found to be contaminated by As, Cu, Pb, Sb, Se and Zn as compared to the non-contaminated soil. The pH-dependent extraction behavior of various elements from the soils was measured in a wide pH range and categorized into three groups. Hydrochloric acid (HCl), H2SO4, H3PO4, HNO3, sodium citrate, sodium tartrate, disodium dihydrogen ethylenediaminetetraacetate and diethylenetriaminepentaacetic acid were evaluated as extractants for removing contaminants from the soils. Extraction behavior of the soil constituents was also studied. The efficiency of the extraction was evaluated by the Japanese content and leaching tests. The stabilization of Pb remaining in the soil after the extraction process was conducted by the addition of iron(III) and calcium chloride.

Hydroponics as a valid tool to assess arsenic availability in mine soils.

PubMed

Moreno-Jiménez, E; Esteban, E; Fresno, T; de Egea, C López; Peñalosa, J M

2010-04-01

The low solubility of As in mine soils limits its phytoavailability. This makes the extrapolation of data obtained under hydroponic conditions unrealistic because the concentration in nutrient solution frequently overexposes plants to this metalloid. This work evaluates whether As supply in hydroponics resembles, to some extent, the As phytoavailable fraction in soils and the implications for phytoremediation. Phytotoxicity of As, in terms of biomass production, chlorophyll levels, and As concentrations in plants, was estimated and compared in both soils and hydroponics. In order for hydroponic conditions to be compared to soil conditions, plant exposure levels were measured in both cultures. Hydroponic As concentration ranging from 2-8microM equated to the same plant organ concentrations from soils with 700-3000mgkg(-1). Total and extractable As fractions exceeded those values, but As concentrations in pore water were bellow them. According to our results (i) hydroponics should include doses in the range 0-10microM As to allow the extrapolation of the results to As-polluted soils, and (ii) phytoextraction of As in mining sites will be limited by low As phytoavailability.