Remedial investigation of Clinch River and Watts Bar reservoir contamination

Operations and waste disposal activities at the Oak Ridge Y-12 plant, Oak Ridge National Laboratory (ORNL), and Oak Ridge Gaseous Diffusion Plant installations on the US Department of Energy (DOE) Oak Ridge Reservation have introduced a variety of airborne, liquid, and solid wastes into the surrounding environment. Some of these wastes affect off-site surface waters, entering local streams, which ultimately drain into the Clinch and Tennessee River systems. Previously reported concentrations of radionuclides, metals, and organic compounds in the water, sediment, and biota of the Clinch River and Watts Bar Reservoir suggested the presence of a variety of contaminants of possible concern in considerations of the protection of human health and the environment. The results of the initial scoping study indicate that the highest levels of 137Cs contamination are isolated deep in the bottom sediments under deep water in the old river channels. The results of the risk screening analyses indicate that in the absence of deep-channel sediment dredging, there are no short-term imminent hazards to the environment or human health; however, most of the metals, organics, and radionuclides previously reported were recommended for further study in subsequent phases of the Clinch River remedial investigation