Residues of toxaphene, DEF, and paraquat in plant parts and gin waste from a treated cotton field.

The origin and fate of the gin waste residues of three chemicals--toxaphene, DEF, and paraquat--used frequently in cotton production in California were studied. Residues were determined for foliage and bolls in the live plants, for lint and seed in harvested seed cotton, and for gin waste and its lint and non-lint components, following commercial treatments to the cotton crop. Gin waste residues were followed during five months of open storage to ascertain dissipation rates in a typical waste sample. Relatively high residues of each of the three chemicals persisted at harvest, during storage prior to ginning, and in stored gin waste. The major proportion of gin waste residue was associated with the non-lint components--leaf parts, burrs, stems and other foreign matter. Average stored gin residues in the lint and non-lint components were 13 and 60, 11 and 58, and 5 and 10 ppm for toxaphene, DEF, and paraquat, respectively, during the open storage period.