[en] As part of a study on sediment and radionuclide transport in rivers, Pacific Northwest Laboratory (PNL) is investigating the effect of sediment on the transport of radionuclides in Cattaraugus and Buttermilk Creeks, New York. A source of radioactivity in these creeks is the Western New York Nuclear Service Center which consists of a low-level waste disposal site and a nuclear fuel reprocessing plant. Other sources of radioactivity include fallout from worldwide weapons testing and natural background radioactivity. The major objective of the PNL Field Sampling Program is to provide data on sediment and radionuclide characteristics in Cattaraugus and Buttermilk Creeks to verify the use of the Sediment and Radionuclide Transport model, SERATRA, for nontidal rivers. This report covers the results of field data collection conducted during September 1978. Radiological analysis of sand, silt, and clay size fractions of suspended and bed sediment, and water were performed. Results of these analyses indicate that the principal radionuclides occurring in these two water courses, with levels significantly higher than background levels, during the Phase 2 sampling program were Cesium-137 and Strontium-90. These radionuclides had significantly higher activity levels above background in the bed sediment, suspended sediment, and water samples. Other radionuclides that are possibly being released into the surface water environment by the Nuclear Fuel Services facilities are Plutonium-238, 239, and 240, Americium-241, Curium-244, and Tritium. More radionuclides were consistently found in the bed sediment as compared to suspended sediment. The fewest radionuclides were found in the water of Buttermilk and Cattaraugus Creeks. The higher levels were found in the bed sediments for the gamma-emitters and in the suspended sediment for the alpha and beta-emitters