The status of radioactive contamination of the Clinch and Tennessee River systems from Nov. 1961 to April 1962 is reviewed. Data are included from studies on the fate of radioactive materials discharged to the Clinch River by the Oak Ridge National Laboratory, the mechanisms of dispersion of radionuclides released to the river, the direct and indirect hazards of waste disposal practices during the period, an evaluation of the over-all usefulness of this river for radioactive disposal purposes, and an evaluation of long-term monitoring procedures. The management of liquid wastes at ORNL is discussed and results are reported from studies on the accumulation and movement of radionuclides in White Oak Creek basin, the contamination of river biota, hydrologic measurements and analyses, measurements of radioactivity in the river system and in community water systems downstream from the Clinch River, and calculation of estimated radiation dosages from drinking Clinch River and Tennessee River water or immersion in the water at various downstream points. Results are included from a preimpoundment study of ecological conditions of Melton Hill Lake and estimates of the effects of Melton Hill Lake and power releases from Melton Hill Dam on hydrologic conditions in the river system. (C.H.).