With close to 100,000 chemicals presently in commercial production, it is impossible to subject each to human health or environmental risk analysis with experimentally determined data. Therefore, there is a need for predictive methods.For ecotoxicologic assessments, we are directing our efforts toward integrating independent chemical data with a variety of transport models.Physico-chemical data, such as aqueous solubility, vapor pressure, octanol-water partition coefficients, microbial and chemical degradation rates, molecular diffusivity, photolysis rates, chemical oxidation rates, etc., are needed for each compound.We have developed micro-techniques to measure many of these parameters, including chemical oxidation rates and pathways.These data sets then are used to predict properties of related compounds using a variety of theoretical and empirical models.Results from these measurements also are used to devise strategies for degrading compounds such as PCBs, dioxins, and furans in water and sediment. Once in the water, each contaminant behaves differently.The association with other solid or dissolved constituents will determine the degree of toxicity to organisms, residence time in the water column, possible degradation rates and pathways, and the rate of burial into the bottom sediments.We are working on projects designed to understand these interactions.We are focusing particularly on mercury and PCBs. Microcontaminants, such as heavy metals and chlorinated aromatic hydrocarbons, are introduced into aquatic systems via the atmosphere, rivers, waste discharges, and in lake processes.A quantitative understanding of the magnitude of these loadings is necessary if appropriate actions for remediation can be prescribed.Our group is evaluating the magnitude of atmospheric loadings of environmental contaminants to aquatic systems. WE then use these estimates with those from otyher sources to evaluate the net impact on water quality. Our research group is involved in studies that deal with transport and behavior of contaminants in natural waters.Closely related to these efforts is our research on methods to remediate contaminated water and sediments.Our projects range from laboratory experiments to elaborate field experiments in small lakes and in the Great Lakes.