Ecological surveys of fish communities, and measurements of physical variables, surface-water chemistry, and organic compounds and trace elements in fish tissue and bed sediment were used to assess water quality in the South Platte River Basin. Concentrations of nutrients, trace elements, sediments, and pesticides analyzed in surface water and concentrations of synthetic organic compounds in fish tissue and bed sediment were directly related to land use at each site. In contrast, trace element concentrations in bed sediments were related to bedrock type except at sites affected by mining activities. Stream habitat modifications were evident at urban sites due to channelization and at several agricultural sites due to bank erosion. An Index of Biotic Integrity indicated that fish assemblages were indicative of water-quality conditions across the basin. Integration of results about fish communities, physical and chemical variables, and contaminants in fish tissue and bed sediment identify factors that should be considered when managing water quality .
1 U.S. Geological Survey, Box 25046, MS 415, Denver Federal Center, Lakewood, CO 80225