By Verlin C. Stephens and Jeffrey R. Deacon

Available from the U.S. Geological Survey, Branch of Information Services, Box 25286, Denver Federal Center, Denver, CO 80225, USGS Fact Sheet FS-167-97, 6 p.

The complete document is also available in pdf format: FS-167-97 (391 KB)
(Requires Adobe Acrobat Reader)

As a part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program, hydrologic and water-quality assessment of the Upper Colorado River Basin (UCOL) study unit began in 1994. Prior to the design of the integrated studies of water quality in the basin, a retrospective investigation was conducted to determine the availability of historical water-quality data and the location of previous research that occurred in the UCOL. The findings indicated that minimal data had been collected regarding the occurrence and distribution of organochlorine pesticides and polychlorinated biphenyls (PCB’s) in streambed sediment and whole-body fish in the UCOL study unit (Deacon and Stephens, 1996).

Organochlorine pesticides and PCB’s, all of which are organochlorine compounds, have been specifically targeted by standards and guidelines that exist to protect water quality for human and wildlife health. In 1995–96, a survey of selected organochlorine pesticides and PCB’s was conducted in the UCOL to (1) determine their distribution and concentrations in streambed sediment and whole-body fish, and (2) compare these concentrations to established water-quality guidelines.

Organochlorine compounds are unique because their presence can result only from human activities. These compounds disperse from their original point of application, typically agricultural fields and urban areas, to the hydrologic system through soil erosion, runoff, and precipitation. Due to the persistence, bioaccumulation, and hazards of these compounds, the use of many organochlorine pesticides has been banned or severely restricted in the United States. Organochlorine compounds are extremely persistent in the environment and have the unique property of concentrating in sediment and in the fatty tissue of aquatic life (Ware, 1989).

This fact sheet presents data for detections of selected organochlorine compounds in streambed sediment and whole-body fish. Data for all the compounds detected in samples collected for this study are in the U.S. Geological Survey National Water Information System (NWIS) data base.