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BIOLOGICAL PROCESSES AFFECTING BIOACCUMULATION, TRANSFER, AND TOXICITY OF METAL CONTAMINANTS IN ESTUARINE SEDIMENTS
Chen, C.Y., N.S. Fisher, and J.R. Shaw.
Strategic Environmental Research and Development Program (SERDP), Project ER-1503, 94 pp, Dec 2011
The ecosystem and community level fate of contamination was examined by relating metal burdens to food web structure and functional feeding groups. The transfer of metal contaminants in the food chain was investigated directly in bioaccumulation studies and development of a biokinetic model linked to metal trophic transfer measured in field studies. In terms of factors determining bioavailability of metals in contaminated field sites, organic content of sediments plays an important role in decreasing bioavailability to pelagic and benthic feeding organisms. Results indicate that metal concentrations of Cd, Zn, As, Pb, and Se in sediments do not predict concentrations in biota, whereas sediment concentrations of Hg and MeHg do determine biotic exposures. Pelagic fauna bioaccumulate more MeHg than benthic feeding fauna, suggesting that chemical flux from contaminated sediments is important in determining bioaccumulation in pelagic food webs. This project also produced a set of robust genomic biomarkers that are predictive of the site-specific hazards posed by contaminated sediments. Novel comparative approaches (e.g., comparison of stable isotope values between taxa within a particular site) were applied to link metal bioaccumulation in natural food webs to bioaccumulation and assimilation of metals by sentinel species. http://www.estcp.com/content/download/14863/171438/file/ER-1503-FR.pdf
Strategic Environmental Research and Development Program (SERDP), Project ER-1503, 94 pp, Dec 2011
The ecosystem and community level fate of contamination was examined by relating metal burdens to food web structure and functional feeding groups. The transfer of metal contaminants in the food chain was investigated directly in bioaccumulation studies and development of a biokinetic model linked to metal trophic transfer measured in field studies. In terms of factors determining bioavailability of metals in contaminated field sites, organic content of sediments plays an important role in decreasing bioavailability to pelagic and benthic feeding organisms. Results indicate that metal concentrations of Cd, Zn, As, Pb, and Se in sediments do not predict concentrations in biota, whereas sediment concentrations of Hg and MeHg do determine biotic exposures. Pelagic fauna bioaccumulate more MeHg than benthic feeding fauna, suggesting that chemical flux from contaminated sediments is important in determining bioaccumulation in pelagic food webs. This project also produced a set of robust genomic biomarkers that are predictive of the site-specific hazards posed by contaminated sediments. Novel comparative approaches (e.g., comparison of stable isotope values between taxa within a particular site) were applied to link metal bioaccumulation in natural food webs to bioaccumulation and assimilation of metals by sentinel species. http://www.estcp.com/content/download/14863/171438/file/ER-1503-FR.pdf
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