9706715 Lion This is a renewal of support for research initiated under NSF Grant No. 86-17408 and continued under 91-00209 to characterize the role that transition metals have on hazards to environmental health because of their toxicity, potential for bioaccumulation and their persistence in the environment. Chemical equilibrium models integrated with mathematical models that resulted from prior research will be extended in this project to account for biological interactions with iron oxides that control iron cycling and subsequent adsorption of environmentally significant trace metals. The research includes consideration of biological processes that affect deposition of iron, the effects that bacterial and algal cells and their extracellular polymers have on adsorption of lead by iron oxides, and amelioration of metal toxicity to microorganisms by the presence of iron. The research involves laboratory investigations with controlled chemical conditions necessary to characterize important biotic and abiotic components that will be used to guide field studies. Results of this research are expected to be an improved understanding from that which now exists of the behavior and fate of metals that pollute and contaminate natural surface and groundwaters. Knowledge gained from this research and the resultant mathematical models may be applied in engineering design of processes and treatment systems for removal of metal contaminants from polluted and contaminated natural surface water supplies, groundwater, and from domestic and industrial wastewaters prior to their discharge into the environment. ***
