Residues in fish, wildlife and estuaries: Chlorinated pesticide levels in the eastern oyster (Crassostrea virginica) from selected areas of South Atlantic and Gulf of Mexico.

Oysters were collected from estuarine areas in South Carolina, Georgia, Florida, Mississippi, Louisiana, and Texas and analyzed for pesticide residues. Pesticide levels were determined by the electron capture gas chromatography method and were confirmed by thin layer chromatography and dual-column electron capture gas chromatography. In general, chlorinated pesticides were either not detected or were found at relatively low levels in samples collected from the Atlantic and Gulf Coast areas. Of a total of 133 samples, 94.7% contained 1 or more pesticides; 89.5% contained 2 or more; 81.2% contained 3 or more; 63.9% contained 4 or more; and 31.9% contained 5 or more. The level of sensitivity for pesticide residues was 0.01 ppm. Some correlation was found between spraying operations and pesticide levels in the oysters.