Summary

Description

The Yuma clapper rail Rallus longirostris yumanensis occurs along the Colorado River in Arizona and California, and in small marshes located around the Salton Sea in Imperial and Riverside Counties in California The Yuma clapper rail was listed as a federal endangered species in 1967 U.S. Department of the Interior 1967. This study was designed to determine the potential for selenium exposure of the Yuma clapper rail inhabiting the Imperial Valley by investigating the amounts of selenium in its environment sediments and diet crayfish. Available tissue samples were also analyzed in an effort to assess the potential forbiomagnification. Samples collected for analysis of inorganics were also analyzed for organochlorine compounds to assess the potential for impacts from these compounds. Boron was found to .bioaccumulate in most trophic levels studied in the Imperial Valley Setmire et al. 1993. This element was considered a contaminant of potential concern for the Yuma clapper rail and evaluated in this study. Mercury has been found in eggs of the California clapper rail nesting in San Francisco Bay Lonzarich et al. 1992, and may also be of concern for the Yuma clapper rail. Other trace elements considered here as contaminants of potential concern for the Yuma clapper rail are: arsenic, cadmium, chromium, copper, lead and zinc.