The State Water Resources Control Board's Surface Water Ambient Monitoring Program (SWAMP) has released the first findings from the largest survey ever conducted in California of contaminants in sport fish from lakes and reservoirs. The results are from the first year of the two year, statewide survey.

The results indicate that problems exist in some areas of the state. Mercury and polychlorinated biphenyls (PCBs) are the two greatest concerns. Mercury contamination is largely a legacy of California mining, and can also reach lakes through the air. It is a persistent problem throughout much of the state. Twenty-six percent of the lakes surveyed had at least one fish species with an average mercury level that exceeds the Office of Environmental Health Hazard Assessment (OEHHA) threshold for considering a consumption limit. OEHHA cannot develop new recommendations based solely on data from this study.

The results for area lakes are as follows (350AVE1=ANCOVA-based average for 350 mm fish at location 1 regarding Largemouth Bass): LAKE PIRU .46; CASTAIC LAGOON .18, CASTAIC LAKE .39; LAKE CASITAS .38; LAKE HUGHES .20; MALIBU LAKE .12; PYRAMID LAKE .37; WESTLAKE LAKE .09; PYRAMID LAKE .37.

PCBs were second to methylmercury as a potential health concern to consumers of fish caught from California lakes. Approximately thirty-six percent of the lakes had a fish species that exceeded OEHHA’s Fish Contaminant Goal. However, only 1 percent of the lakes sampled had a species with an average concentration level that exceeds OEHHA’s threshold for considering a recommendation of no consumption. PCBs are persistent chemicals that are now banned in electrical, industrial and other applications. Other pollutants were also found, but generally at low levels.

The Lakes Survey focuses on more than 200 of the most popular fishing lakes in the state. Random sampling of an additional 50 of California’s other 9,000 lakes is included to provide the basis for a statistical statewide assessment. This screening study is part of an effort to identify and quantify contaminants in California’s lakes for a more detailed evaluation of health and environmental impacts. The Lakes Survey is paid for by funds supplied by the United States Environmental Protection Agency (USEPA) and monitoring fees paid to the State Water Board for wastewater discharge permits. More information will be required to determine the need for consumption guidelines or cleanup plans.

The report presents results from monitoring in 2007. In that year, the study team collected over 6,000 fish from 150 lakes and reservoirs. The team sampled another 130 lakes in 2008. Results from this second round, and a more in depth analysis of possible trends, will be available in a final report early 2010.

A final report including all data collected during the two-year study will be provided early in 2010.

The Lakes Study, Year 1 report evaluating 2007 data is available on the SWAMP website at: http://www.waterboards.ca.gov/water_issues/programs/swamp/lakes_study.sh....

The State Water Resources Control Board’s mission is to preserve, enhance and restore the quality of California's water resources, and ensure their proper allocation and efficient use for the benefit of present and future generations.

PDF – Summary of year 1 results of the SWAMP Lakes Survey. - http://www.waterboards.ca.gov/water_issues/programs/swamp/docs/lakes_stu....