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(140) Influence of diet and sea-ice drift-route on bioaccumulation of organochlorines in arctic ice-associated amphipods. Borgå, Katrine1,2, Poltermann, Michael1, Polder, Anuschka3, Pavlova, Olga1, Gulliksen, Bjørn2, Gabrielsen, Geir1, Skaare, Janneche3,4, 1 2 3 4 ABSTRACT- Drifting sea ice is suggested as important in the transport and concentration of pollutants in the Arctic. Thus, organisms living associated with sea ice may be exposed to pollutants through ingestion of contaminated organic matter and through direct uptake. To investigate the bioaccumulation of organochlorines in ice fauna, ice-associated amphipods were collected in the marginal ice zone north of Svalbard and in the Fram Strait. All though the ice-amphipods are omnivorous, the contaminant concentration increased from the more herbivorous Apherusa glacialis to the more carnivorous Gammarus wilkitzkii and the more necrophagous Onisimus spp. Also the organochlorine pattern differed between the taxa, with a higher relative contribution of HCHs in A. glacialis. The composition of each compound class (HCHs, chlordanes, DDTs and PCBs) was similar between the taxa. The occurrence of organochlorines differed spatially in a manner that could be related to the sea ice drift route across the Arctic Ocean. The occurrence of HCHs and the a/g-HCH ratio was higher in the samples from the Fram Strait, with the sea ice originating in the central Laptev Sea and with a drift route across the central Arctic Ocean. No significant difference was found in the occurrence of the other investigated contaminants (HCB, chlordanes, DDTs, PCBs). The results imply that diet-related uptake is important in the bioaccumulation process of organic pollutants also in gilled marine invertebrates. The results also indicate that the sea ice origin and drift route influence the occurrence of certain contaminant in ice-associated organisms. To investigate the role of diet (by the aid of stable nitrogen isotopes) and the role of habitat (pelagic versus ice-associated) in the bioaccumulation of organochlorines, organochlorine data in ice fauna will be compared with levels in selected zooplankton species collected simultaneously. The levels of organochlorines will also be used to illustrate the different routes of organochlorine biomagnification in the food web from the lower trophic levels to fish (polar cod) and seabirds (little auk, Brünnich's guillemot, black guillemot and black-legged kittiwake). Key words: arctic ice-amphipods, biomagnification, organochlorines, sea ice drift route |
