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Sample Organisms Useful For Studying Pesticide Residues in Bay
WED scientists studying the persistence of pesticide residues in San Francisco Bay say the organisms they examined in their research are potentially useful bioindicators of organochlorine contamination in estuarine ecosystems. Their research reports high concentrations of residues of DDT and dieldrin in Richmond Harbor, a Superfund site, more than 25 years after the removal of the predominant local source of the contaminants. They found high concentration gradients away from the source zone, but relatively little variability in tissue/water bioconcentration factors in sample organisms, which included mussels and small fish. The findings indicate that the mussels and the fish, a Gobiid and a shiner surfperch, are useful as bioindicators of water contamination by organochlorines. (Contact: D.R. Young, 541-867-4038, young.david@epa.gov)