Toxaphene, chlordane, and other organochlorine pesticides in Alabama air

Air samples were collected in Alabama in January-October 1996 and in May 19 97, to determine the seasonal variations of toxaphene and other OC pesticid es (chlordanes, DDTs, dieldrin, and HCHs). Log partial pressure versus 1/T plots for gamma -HCH, dieldrin, chlordanes, and their metabolites showed si gnificant relationships, whereas those for toxaphene, heptachlor, and p,p'- DDE did not. The chromatographic profile of toxaphene congeners in air and soil showed depletion of certain labile congeners, notably B8-531 and B8-80 6/809; other persistent congeners (B8-1412 and B9-1679) were enriched in ai r samples. Concentrations of toxaphene in Alabama air were 6-40 times highe r than in the Great Lakes region, and chlordane in Alabama air exceeded Gre at Lakes concentrations by 3-9-fold. This suggests that transport from the southern U.S. is a continuing source of toxaphene and chlordane to the Grea t Lakes; Levels of HCHs and dieldrin in Alabama were similar to those in th e Great Lakes region. Patterns of 8-chlorinated bornanes in air more closel y resemble residues in soil than the technical toxaphene standard. Enantiom er ratios of chlordanes in air were nearly racemic, indicating that their s ource is probably evaporation from termiticide usage rather than from soils , which contain nonracemic chlordanes.