|
(55-07) A North Sea - North Pole surface water PCB transect: Evaluation of the global distillation hypothesis. Sobek, Anna*,1, Gustafsson, Örjan1, 1 Stockholm University, Stockholm, Sweden ABSTRACT- Due to their semi-volatile properties PCBs are subject to atmospheric long - range transport. This is a process implying evaporation of the contaminants in tropical and temperate areas followed by transport and condensation at boreal and polar latitudes, this has been termed global distillation. In order to assess at which extent congeners with varying physico-chemical properties undergo global distillation, surface water samples were taken along a transect through the Kattegatt - Skagerrak - North Sea -Barents Sea -Nansen Basin - Amundsen Basin towards the North Pole (55 N - 88 N) during the Swedish Arctic Ocean expedition in June - August 2001. Large-volume (400 -5000 L) samples were obtained underway from a high-grade stainless-steel surface seawater intake line extending into an ultra-clean laboratory. Samples were drawn approximately every 4 degree latitude along a surface water temperature gradient from +16 C to -1.8 C. Latitudinal, locational, and temperature-driven variations in both concentrations and congener patterns will be evaluated to deduce both the overall importance of "global distillation" and mechanisms/thresholds of PCB transport to the remote Polar ocean. Key words: global fractionation, long-range transport, PCB, Arctic Ocean |
