Studies of toxaphene on a local, regional, and continental scale

Toxaphene was a highly chlorinated pesticide used in the United States from the 1950's until its restriction and ban in the 1980's. It was primarily used on cotton in the southern U.S., but it was also used to a much lesser extent on other agricultural crops as well as on livestock throughout the U.S. Toxaphene is found in high concentrations in the southern U.S., near where it was heavily used, and also in moderately high concentrations in the Great Lakes, where it had limited use. Furthermore, toxaphene has been detected in distant locations, such as in the high Canadian arctic. The objective of my research has been to investigate the fate, transport, and distribution of toxaphene on these different geographical scales.; Toxaphene was investigated on local scales around Lake Apopka, FL, and the upper Great Lakes. Near Lake Apopka, previous agricultural use of toxaphene on farmland near the lake is suspected to have contaminated large areas of land and may be responsible for the death of a thousand birds in the area. The presence of toxaphene in the soil and biota was confirmed at very high concentrations. In another study, toxaphene concentrations were measured in river sediment above and below the effluent discharge points of pulp and paper mills to determine if they were inadvertently producing and discharging toxaphene into Lakes Superior and Michigan, where concentrations are known to be unusually high. Concentrations below the mills were not different than those above the mills, indicating they are not a current source of toxaphene to the Lakes. While investigating pulp and paper mills we identified a new class of compounds, the chlorinated pinosylvins, which were discovered in bleached paper products.; Toxaphene was investigated on a regional scale in the Great Lakes by measuring toxaphene in sediment cores in Lake Superior as part of a larger project to determine the fate of toxaphene in the Lake and to determine if its high toxaphene concentrations were due to its unique characteristics. Toxaphene was also measured in tree bark samples collected throughout North America to determine the extent to which this pesticide has dispersed from the high use areas of the southern U.S. Results show that toxaphene is widely distributed throughout the U.S. and Canada even 20 years after its restriction. We found that toxaphene concentrations can be predicted by an inverse square distance function.