A circumpolar perspective of atmospheric organochlorine pesticides (OCPs): Results from six Arctic monitoring stations in 2000–2003

Air concentrations of organochlorine pesticides (OCPs) were measured on a weekly basis in 2000–2003 at six Arctic stations, which include Alert, Kinngait, and Little Fox Lake in Canada; Point Barrow in the USA; Valkarkai in Russia; and Zeppelin in Norway. These stations cover a large region in the Arctic, providing a comprehensive perspective on OCPs in the circumpolar atmosphere. Currently used pesticide endosulfan I had similar concentrations across the stations in November–May, whereas large spatial divergence was found in June–October. This implies the extensive usage of endosulfan during summertime followed by long-range transport to the Arctic. The median air concentration of endosulfan I was 3.2 pg m−3 (n=245). Seasonally and spatially uniform concentrations of legacy chlordane-related compounds indicated that the influence of primary emissions on Arctic air has become less important than volatilization emissions. Median air concentrations (pg m−3) of trans-chlordane, cis-chlordane, trans-nonachlor, oxychlordane, and heptachlor exo-epoxide were 0.20 (n=413), 0.58 (n=413), 0.44 (n=413), 0.30 (n=245), and 0.54 (n=244), respectively. Although extensive usage was banned in the 1970s, large spatial variations reflected that DDT-related compounds were not well mixed in Arctic air. Concentrations of DDT-related compounds were low in general, and median concentrations of p,p′-DDT, o,p′-DDT, p,p′-DDE, o,p′-DDE, and ∑4DDT were 0.10, 0.18, 0.37, 0.10, and 0.79 pg m−3 (n=418), respectively. Air concentrations of pentachloroanisole and dieldrin showed strong seasonal/spatial variations with median values of 3.8 and 0.48 pg m−3 (n=245). Uniform concentrations were observed for octachlorostyrene with a median of 0.32 pg m−3 (n=245). Arctic air concentrations of other measured OCPs, such as endrin, heptachlor, methoxychlor, mirex, photomirex, tetrachloroveratrole, trichloroveratrol, and trifluralin, were generally low and mostly below method detection limits.