Executive Summary

“legacy ” (formerly used) organochlorine (OCl) pesticides, such as DDT, chlordane, dieldrin, toxaphene, etc.) in fish tissue since 1978. Those data, has shown that the concentration of some of these pesticides in some fish from some waterbodies exceeded the concentrations that represent a threat to human health for those who eat large amounts of the fish. Lee and Jones-Lee (2002) developed a comprehensive report on the TSMP and other fish tissue monitoring data that had been collected through the late 1990s. That report included a comparison of the fish tissue concentrations with the US EPA (1995) and OEHHA (1999) human health screening values for evaluating the potential human health hazards presented by consuming a certain amount of fish with legacy pesticide or PCB residue in the edible tissue. As part of an effort to provide updated information on the current Central Valley fish tissue concentration data, Dr. Chris Foe of the Central Valley Regional Water Quality Control Board (CVRWQCB) obtained funds to analyze fish that had been collected previously and stored frozen but not analyzed, and to collect and analyze additional fish. That effort resulted in a 2005 database for OCl legacy pesticide and PCB concentration