Colorado River and New River Toxics Survey

1. Purpose and Objectives: The purpose is to determine the quality of selected waters in the Colorado River system. Objectives include determining the levels of toxic pollutants in the lower Colorado River and in the New River, as well as surveying of the Colorado River for conventional pollutants. Mexico has requested monitoring of the lower Colorado River due to concern about the quality of the water supply for Mexicali and Tijuana. Monitoring of the New River will help document progress resulting from implementation of the Mexicali wastewater project. Interest in New River monitoring was elevated when Imperial County and a coalition of environmental justice groups filed petitions under Toxic Substances Control Act (TSCA).

2. Funding: EPA has dedicated $769,000 to monitoring and surveying of the Colorado and New Rivers.

3. Partners: EPA funds have been awarded to USGS, California Regional Water Quality Control Board (Colorado River Basin Region), and University of California at Davis. Additional U.S. partners include: IBWC, USBR, US Fish and Wildlife Services, and State of Arizona (ADEQ, Dept. of Game and Fish). Mexican partners include CILA and CNA.

4. Description and Methodology: A binational program for the monitoring toxic pollutants on the Colorado and New Rivers has been developed. Three sites on each river will be monitored. For the U.S., the USGS will analyze water and sediment samples for specific toxic pollutants, U. C. Davis will analyze for toxicity, and California Fish and Game Department will analyze fish tissue for bioaccumulation. The regional board is continuing its monitoring of the New River at the international boundary for heavy metals and conventional pollutants. U. C. Davis is collecting samples along the length of the New River and will use the results to develop a model which will predict the behavior of toxic organic pollutants in river sediments and water.

5. Status: Project is almost complete. Discussions are underway with Mexico on expanding the Regional Board’s efforts into Mexico.

6. U. S. Contacts: Doug Eberhardt, EPA Region 9, (415) 744-1280 Roy Schroeder, USGS, (619) 637-6824 Bill Ruth, U.S. IBWC, (915) 534-6676 Phil Gruenberg, California RWQCB No. 7, (619) 346-7491