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Brumbaugh W.G.,U.S. Geological Survey | Hammerschmidt C.R.,Wright State University | Zanella L.,Northwestern University | Rogevich E.,Nickel Producers Environmental Research Association | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2011

An interlaboratory comparison of acid-volatile sulfide (AVS) and simultaneously extracted nickel (SEM-Ni) measurements of sediments was conducted among five independent laboratories. Relative standard deviations for the seven test samples ranged from 5.6 to 71% (mean=25%) for AVS and from 5.5 to 15% (mean=10%) for SEM-Ni. These results are in stark contrast to a recently published study that indicated AVS and SEM analyses were highly variable among laboratories. © 2011 SETAC. Source

Nguyen L.T.,Ghent University | Burton G.A.,Wright State University | Schlekat C.E.,Nickel Producers Environmental Research Association | Janssen C.R.,Ghent University
Environmental Toxicology and Chemistry | Year: 2011

A field experiment was performed in four freshwater systems to assess the effects of Ni on the benthic macroinvertebrate communities. Sediments were collected from the sites (in Belgium, Germany, and Italy), spiked with Ni, and returned to the respective field sites. The colonization process of the benthic communities was monitored during a nine-month period. Nickel effect on the benthos was also assessed in the context of equilibrium partitioning model based on acid volatile sulfides (AVS) and simultaneously extracted metals (SEM). Benthic communities were not affected at (SEM - AVS) ≤ 0.4 μmol/g, (SEM - AVS)/fraction of organic carbon (f OC) < 21 μmol/g organic carbon (OC). Sediments with (SEM - AVS) > 2 μmol/g, (SEM - AVS)/f OC > 700 μmol/g OC resulted in clear adverse effects. Uncertainty about the presence and absence of Ni toxicity occurred at (SEM - AVS) and (SEM - AVS)/f OC between 0.4 to 2 μmol/g and 21 to 700 μmol/g OC, respectively. The results of our study also indicate that when applying the SEM:AVS concept for predicting metal toxicity in the field study, stressors other than sediment characteristics (e.g., sorption capacity), such as environmental disturbances, should be considered, and the results should be carefully interpreted. Environ. Toxicol. Chem. 2011;30:162-172. © 2010 SETAC. Source

Hughson G.W.,Institute of Occupational Medicine | Hughson G.W.,University of Aberdeen | Galea K.S.,Institute of Occupational Medicine | Heim K.E.,Nickel Producers Environmental Research Association
Annals of Occupational Hygiene | Year: 2010

The aim of this study was to measure the levels of nickel in the skin contaminant layer of workers involved in specific processes and tasks within the primary nickel production and primary nickel user industries. Dermal exposure samples were collected using moist wipes to recover surface contamination from defined areas of skin. These were analysed for soluble and insoluble nickel species. Personal samples of inhalable dust were also collected to determine the corresponding inhalable nickel exposures. The air samples were analysed for total inhalable dust and then for soluble, sulfidic, metallic, and oxidic nickel species. The workplace surveys were carried out in five different workplaces, including three nickel refineries, a stainless steel plant, and a powder metallurgy plant, all of which were located in Europe. Nickel refinery workers involved with electrolytic nickel recovery processes had soluble dermal nickel exposure of 0.34 μg cm-2 [geometric mean (GM)] to the hands and forearms. The GM of soluble dermal nickel exposure for workers involved in packing nickel salts (nickel chloride hexahydrate, nickel sulphate hexahydrate, and nickel hydroxycarbonate) was 0.61 μg cm-2. Refinery workers involved in packing nickel metal powders and end-user powder operatives in magnet production had the highest dermal exposure (GM=2.59 μg cm-2 soluble nickel). The hands, forearms, face, and neck of these workers all received greater dermal nickel exposure compared with the other jobs included in this study. The soluble nickel dermal exposures for stainless steel production workers were at or slightly above the limit of detection (0.02 μg cm -2 soluble nickel). The highest inhalable nickel concentrations were observed for the workers involved in nickel powder packing (GM=0.77 mg m -3), although the soluble component comprised only 2% of the total nickel content. The highest airborne soluble nickel exposures were associated with refineries using electrolytic processes for nickel recovery (GM=0.04 mg m-3 total nickel, containing 82% soluble nickel) and those jobs involving contact with soluble nickel compounds (GM=0.02 mg m-3 total nickel content, containing 76% soluble nickel). The stainless steel workers were exposed to low concentrations of relatively insoluble airborne nickel species (GM=0.03 mg m-3 total nickel, containing 1% soluble nickel). A statistically significant correlation was observed between dermal exposures for all anatomical areas across all tasks. In addition, the dermal and inhalable (total) nickel exposures were similarly associated. Overall, dermal exposures to nickel, nickel compounds, and nickel alloys were relatively low. However, exposures were highly variable, which can be explained by the inconsistent use of personal protective equipment, varying working practices, and different standards of automation and engineering controls within each exposure category. Source

Van Genderen E.,ZINC Inc | Adams W.,Rio Tinto Alcan | Dwyer R.,International Copper Association | Garman E.,Nickel Producers Environmental Research Association | Gorsuch J.,Copper Development Association Inc
Environmental Toxicology and Chemistry | Year: 2015

The fate and biological effects of chemical mixtures in the environment are receiving increased attention from the scientific and regulatory communities. Understanding the behavior and toxicity of metal mixtures poses unique challenges for incorporating metal-specific concepts and approaches, such as bioavailability and metal speciation, in multiple-metal exposures. To avoid the use of oversimplified approaches to assess the toxicity of metal mixtures, a collaborative 2-yr research project and multistakeholder group workshop were conducted to examine and evaluate available higher-tiered chemical speciation-based metal mixtures modeling approaches. The Metal Mixture Modeling Evaluation project and workshop achieved 3 important objectives related to modeling and interpretation of biological effects of metal mixtures: 1) bioavailability models calibrated for single-metal exposures can be integrated to assess mixture scenarios; 2) the available modeling approaches perform consistently well for various metal combinations, organisms, and endpoints; and 3) several technical advancements have been identified that should be incorporated into speciation models and environmental risk assessments for metals. © 2015 SETAC. Source

Meyer J.S.,Colorado School of Mines | Meyer J.S.,Arcadis | Farley K.J.,Manhattan College | Garman E.R.,Nickel Producers Environmental Research Association
Environmental Toxicology and Chemistry | Year: 2015

Despite more than 5 decades of aquatic toxicity tests conducted with metal mixtures, there is still a need to understand how metals interact in mixtures and to predict their toxicity more accurately than what is currently done. The present study provides a background for understanding the terminology, regulatory framework, qualitative and quantitative concepts, experimental approaches, and visualization and data-analysis methods for chemical mixtures, with an emphasis on bioavailability and metal-metal interactions in mixtures of waterborne metals. In addition, a Monte Carlo-type randomization statistical approach to test for nonadditive toxicity is presented, and an example with a binary-metal toxicity data set demonstrates the challenge involved in inferring statistically significant nonadditive toxicity. This background sets the stage for the toxicity results, data analyses, and bioavailability models related to metal mixtures that are described in the remaining articles in this special section from the Metal Mixture Modeling Evaluation project and workshop. It is concluded that although qualitative terminology such as additive and nonadditive toxicity can be useful to convey general concepts, failure to expand beyond that limited perspective could impede progress in understanding and predicting metal mixture toxicity. Instead of focusing on whether a given metal mixture causes additive or nonadditive toxicity, effort should be directed to develop models that can accurately predict the toxicity of metal mixtures. © 2014 SETAC. Source

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