Ecological risk assessment in a large river-reservoir: 1. Introduction andbackground

The U.S. Department of Energy initiated a remedial investigation of the Cli nch River/Poplar Creek system Superfund Site in 1989. This site, located in eastern Tennessee near Oak Ridge, consists of 70 river kilometers and 40 k m(2) of surface area. The purpose of this study was to evaluate the nature and extent of contamination, perform an ecological and human health risk as sessment, and evaluate possible remedial alternatives. This introductory ar ticle summarizes the environmental setting, the contamination history, and the study approach and provides some general results of the site characteri zation. Subsequent papers in this series describe the ecological risks to f ish, piscivorous and insectivorous wildlife, and benthic invertebrates.