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CHEMICAL MIXTURES: CONSEQUENCES FOR WATER QUALITY
Citation:
Benson, W H., J. A. Steevens, D. S. Block, J. C. Allgood, AND M. Slattery. CHEMICAL MIXTURES: CONSEQUENCES FOR WATER QUALITY. Water Resources Research Institute, Mississippi State University , MS, 2000.
Description:
Chemicals have the potential to occur as mixtures in sediment, as well as bioaccumulate in aquatic organisms, sometimes resulting in adverse toxicological effects. Presently, assessments of contaminated sediment are based upon single chemical toxicological studies with the assumption of additive toxicity. The use of these studies and assumptions for assessments of contaminated sediments may not represent the "real world" toxicological effects of chemical mixtures because chemical mixtures have the potential to interact independently, antagonistically, or synergistically. There is limited information regarding the intereactions of chemical mixtures in contaminated sediments, specifically combinations of pesticides and metals. The current project, addresses our currently limited understanding of toxicological effects resulting from exposure to chemical mixtures having the potential to bioaccumulate. The overall goal of the project is to evaluate the interaction of "real-world" bioaccumulative chemical mixtures having the potential for toxicological effects not predicted from single chemical toxicity experiments Binary chemical interactions of the three model compounds: chlorpyrifos, dieldrin, and methyl mercury were evaluated using the amphipod, Hyalella azteca . The project is divided into three phases, each composed of one year of research. The first phase was to conduct single chemical toxicity experiments characterizing the toxicological endpoints used for mixture interaction experiments. The second phase, to be conducted in year two, will be to evaluate mixture toxicity and bioaccumulation of binary combinations of the three model chemicals utilizing a five-ray design and dose response curve mixture intereaction analysis. Additionally, in year two, binary mixture interactions of three bioaccumulative chemicals will be evaluated by utilization of biochemical measurements reflecting the mechanisms of action of the individual toxicants. The final phase of the projec