DEPOSITION OF ATMOSPHERICALLY TRANSPORTED POLYCHLORINATED-BIPHENYLS IN THE CANADIAN ARCTIC

Snow collectors were installed in 1990 at two Canadian high arctic wea ther stations (Mould-Bay {MB} and Eureka {EU}) in an effort to estimat e annual deposition of PCBs, compare these estimates to annual snowpac k measurements and to investigate the timing of the deposition. The co llectors operated successfully but tended to over collect when two sno w fences were used. The daily flux of Sigma PCBs in the snowpack for 1 990/91 generally compared well to that of the snow collector at MB. Th e snowpack sample at EU for the same period was considered to be unrep resentative, due to low snow accumulation on the ground and high winds , with resulting low concentrations and fluxes. The congener makeup of snowpack and snow collector samples was similar for both sites. Mean Sigma PCB fluxes for the collectors for the winter season were 2.0 and 3.8 ng . m(-2). day(-1) for MB and EU respectively. Due to the tenden cy of the collectors to overcatch, especially late in the season, the fluxes were corrected relative to the shielded Nipher Gauge used to me asure snowfall at the weather stations. The corrected Sigma PCB fluxes for MB reduced the overall contribution of a high concentration event in the winter, in favour of the fall season; the time of greatest sno w accumulation. Initial assessment of the collectors for measuring the timing of and composition of PCB deposition to the arctic is very enc ouraging. Work is continuing to improve the collectors and to provide a better estimate of deposition of organic contaminants to the arctic environment. Copyright (C) 1996 Elsevier Science Ltd