Selenium and Mercury Interactions with Emphasis on Fish Tissue
SPENCER A. PETERSON, NICHOLAS V.C. RALSTON, PHILIP D. WHANGER, JAMES E. OLDFIELD, AND WAYNE D. MOSHER
U.S. Environmental Protection Agency, National Health and Ecological Effects Research Laboratory Corvallis, OR
Energy & Environmental Research Center, University of North Dakota, Grand Forks, ND
Department of Environmental and Molecular Toxicology, Oregon State University Corvallis, OR
Department of Animal Science, Oregon State University, Corvallis, OR
Oregon State University Extension Services, Oregon State University, Corvallis, OR
This review addresses the effects of mercury (Hg) in fish as it relates to the health of the fish themselves as well as potential risks of toxicity in wildlife and humans that consume fish. In particular, it addresses selenium (Se) as a bioindicator of susceptibility to harmful effects of Hg exposures and evaluates how Se moderates the toxic effects of Hg in a variety of test animals, emphasizing the importance of these potential effects in fish. A major conclusion of this review is that Hg toxicity risks to animal life cannot be accurately assessed without considering the moderating effects of Se. Therefore, Se:Hg molar ratios and their mathematical inverse are important factors that need to be considered when assessing risks from Hg exposures because exposures are related directly to toxicity outcome. In addition, actual measurement of both beneficial nutrients (e.g., Se, omega-3 fatty acids) and contaminants (e.g., Hg, polychlorinated biphenyls [PCB]) in fish tissue, rather than gross associations between the amounts of fish tissue consumed and changes in child IQ, motor skills, and verbal skill scores, has been recommended by human health effects researchers. This integrated approach will improve accuracy and reliability of environmental risk assessments for fish and fish consumers.
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