Air-Water flux of organochlorine pesticides along the Western Antarctic Peninsula

Hexachlorobenzene (HCB), heptachlor, α- and γ- HCH and heptachlor epoxide were identified in air, seawater, sea ice, and snow. Samples were collected during the austral winter (September-October 2001) and summer (January-February 2002) along a transect in the Western Antarctic Peninsula. By comparison with previous studie they concluded HCB and HCH levels declined over the past 20 years, with a half-life of 3 28 years in Antarctic air. However, they observed that heptachlor epoxide levels did not decrease in Antarctic air over the past decade, possibly due to continued use of heptachlor in the southern hemisphere. They detected peak heptachlor concentrations in air coincident with air masses moving into the region from lower latitudes. Levels of lindane were 1.2-200 times higher in annual sea ice and snow compared to α HCH, likely due to greater atmospheric input of γ-HCH. On the basis of the ratio of α/γ-HCH <1 in Antarctic air, sea ice and snow they concluded that there is a predominance of influx of lindane versus technical HCH to the regional environment. However, they also observed that the α/γ-HCH in seawater was >1, likely due to more rapid microbial degradation of γ- versus α-HCH. Also this study concluded that the water/air fugacity ratios for HCHs demonstrate continued atmospheric influx of HCHs to coastal Antarctic seas, particularly during late summer