PNNL

Abstract

Air concentrations of organochlorine pesticides (OCPs) were measured using high volume air samplers on a weekly basis in 2000-2003 at six Arctic sites, which include Alert, Kinngait, and Little Fox Lake in Canada; Point Barrow in the USA; Valkarkai in Russia; and Zeppelin in Norway. As the six sites cover a large Arctic region, the multi-year dataset provides an overall perspective of OCPs in the circumpolar atmosphere. Endosulfan I showed homogeneous behaviour in November-May, whereas large spatial divergence was found in June-October. This may suggest that endosulfan was extensively used during the summer time and subsequently transported to the Arctic, since endosulfan is used currently for pest control. The median concentration of endosulfan I was 3.2 pg•m-3 in the circumpolar atmosphere (n=245). Homogeneous behaviour of chlordane-related compounds indicated that influence of primary emissions on Arctic air was less important in 2000-2003. Mean concentrations (pg•m-3) of trans-chlordane, cis-chlordane, trans-nonachlor, oxychlordane, and heptachlor exo-epoxide were 0.25±0.17 (n=413), 0.59±0.26 (n=413), 0.46±0.23 (n=413), 0.31±0.15 (n=245), and 0.56±0.28 (n=244), respectively, in the circumpolar atmosphere. Although extensive usage was banned in the 1970s, large spatial/seasonal variations were found for DDTs, reflecting less dispersion potential comparing to other more volatile OCPs. Concentrations of DDTs were low in general, and median concentrations of p,p’-DDT, o,p’-DDT, p,p’-DDE, o,p’-DDE, and S4DDT were 0.10, 0.18, 0.37, 0.10, and 0.79 pg•m-3 (n=418), respectively, in the circumpolar atmosphere. Air concentrations of pentachloroanisole and dieldrin showed large spatial/seasonal differences with median values of 3.8 and 0.48 pg•m-3 (n=245) in the circumpolar atmosphere. Homogeneous behaviour was found for octachlorostyrene with mean of 0.36±0.20 pg•m-3 (n=245). Concentrations of some other OCPs were generally low in the circumpolar atmosphere and mostly below method detection limits, such as endrin, heptachlor, methoxychlor, mirex, photomirex, tetrachloroveratrole, trichloroveratrol, and trifluralin.