T8 PM Measurement/ Estimation of Environmentally Relevant Physico-Chemical Properties
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 337-338

(JAN-1117-832108) Henrys Law constants of toxaphene congeners and estimates of gas exchange in Lake Superior.

Jantunen, L¹, Bidleman, T¹, Audette, C¹, ¹ Environment Canada, Meteorological Service of Canada, Egbert, ON, Canada

ABSTRACT- Toxaphene is an abundant organochlorine pesticide in the North American Great Lakes ecosystem and the Henrys Law constant (HLC, Pa m³ mol^-1) is a critical property for describing its partitioning between air and water. The HLC of the technical toxaphene mixture has been determined, but not for single congeners. The HLCs of twelve toxaphene congeners (hepta- to nonachlorobornanes) were determined by the gas stripping method over a temperature range of 5-30C, the same technique previously used to determine the HLC of total toxaphene. Past estimates of gas exchange in Lake Superior for total toxaphene predicted volatilization from the water to the air, but gas exchange of individual congeners has not been reported. During the summer of 2005, parallel air and water samples were collected in Lake Superior from aboard the CCGS Limnos. In these samples, concentrations of total toxaphene and the twelve congeners were determined. Using the air and water concentrations and the temperature dependant HLCs, the fugacity ratios and net fluxes were estimated.

Key words: toxaphene, gas-exchange, Lake Superior, Henrys-law-constant