Evidence of atmospheric transport and deposition of organochlorine pesticides and polychlorinated biphenyls in Canadian Arctic snow

Snowpack samples typical of snow accumulation for the 1985-86 winter were collected at 12 sites throughout the Northwest Territories, Canada, during the spring of 1986. The samples were analyzed for organochlorine pesticides (OCs) and total PCBs. Hexachlorocyclohexanes (HCHs), consisting of the pesticide lindane and the isomer alpha-HCH, comprised more than 75% of the total OCs measured. These were followed in abundance by alpha-endosulfan and dieldrin, chlordane, and heptachlor at concentrations less than 0.5 ng/l. PCB concentrations were in the 0.02-1.76 ng/l range, with most of the samples having concentrations less than 1.0 ng/l. The only plausible source for these pollutants is long-range atmospheric transport to the Canadian Arctic and subsequent deposition.