Approximately 180 surface-sediment grab samples and three sediment cores were obtained from the Clinch River-Poplar Creek system around the Oak Ridge Gaseous Diffusion Plant (K-25) and screened for metal, organic, and radioisotope contamination. The results of this scoping study were evaluated to identify potential sources of contamination. Data from this study indicate that Hg, /sup 137/Cs, and /sup 60/Co originate from sources outside K-25. External sources also contribute uranium and miscellaneous organic contamination. Within K-25, the K1700 stream, K901A chromate pond, K710A powerhouse, and K1007B pond appear to be the major areas of contamination. Principal contaminants detected in these areas as a result of this survey were U, Cr, Ni, Cu, Ag, and PCBs. Although the major areas of contamination have been identified, this report does not attempt to identify the specific sources within K-25 nor to quantify the impact of K-25 sources on the major streams.