Deposition of organochlorine pesticides into the surface snow of East Antarctica.

Organochlorine pesticides (OCPs) were measured in surface snow collected on a ~1400-km inland traverse beginning from the coastal regions of East Antarctica during the Japanese Antarctic Research Expedition (JARE) of 2007/2008. Of the 22 OCPs, α-hexachlorocyclohexane (HCH), γ-HCH, and hexachlorobenzene (HCB) were frequently detected in the snow with concentration ranges of 17.5-83.2, 33-137, and ND-182 pg L(-1), respectively. The most abundant pesticide was γ-HCH, with a mean concentration of 69.9 pg L(-1), followed by α-HCH, with an average concentration of 44.5 pg L(-1). The spatial variability of α-HCH and γ-HCH was narrow, and the concentrations of α-HCH and γ-HCH increased slightly with increasing altitude along the traverse route. Dome Fuji, the highest altitude sampling point, had the highest γ-HCH concentrations in the snow. Backward air trajectory analysis showed that the air masses at the sampling sites came mainly from the Indian and Atlantic Oceans and over the Antarctic continent, indicating that the OCPs were subjected to long-range atmospheric transport and were deposited in the surface snow. Our data suggest that the snow of Antarctica contains low levels of OCPs.