Contaminants in the Barents Sea ecosystem
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Original versionThis report is not to be cited without prior reference to the authors
A baseline study of contaminants in fish and sediments from the Barents Sea was carried out by Institute of Marine Research (IMR) as a part of the Arctic Monitoring and Assessment Programme, AMAP. Sediment samples from 140 stations covering the whole Barents Sea were analysed for selected diaromatic and polyaromatic hydrocarbons (P AH). The concentrations found were lower than typical levels found at more southern latitudes such as in deposition areas of the North Sea, but higher than expected background levels. Concentrations of benzo[a]pyrene (BaP), one of the PAHs of most concern due to its toxicity, ranged from <1 to 40 ng/g dry weight. Alkylated C2- napthalenes were found in highest concentrations in sediments around Svalbard (range <1-2330 ng/g dw). Perylene concentrations ranged from <1 to 300 ng/g dw. Same of the highest levels of BaP were found in the ice melting zone. This may indicate that ice plays an important role in the transport and distribution of same aromatic hydrocarbons in the Arctic. Long range transport of air pollutants originating from fossil fuel burning is most likely the dominating source of unsubstituted PAH found in Barents Sea sediments. Fish species given priority in the AMAP monitoring plan for the marine environment include cod (Gadus morhua), polar cod (Boreogadus saida) and lang rough dab (Hippoglossoides platessoides). A total of 400 fish representing these three species were analysed for polychlorinated biphenyls (PCBs) and organochlorine pesticides (DDTs, HCHs, HCB and chlordanes). Contaminant concentrations found in the fish livers were significantly higher in cod than in polar cod and lang rough dab. PCB concentrations, expressed as the sum of 13 congeners on a ng/g wet weight basis, were in the ranges 94-685, 36-114 and 8-60 for cod, polar cod and lang rough dab, respectively. DDT (sum of p'p-DDD, p'p-DDE and p'p-DDT) ranges were 67-344, for cod, 8-50 for polar cod and 5-33 for lang rough dab. Chlordane concentration (sum of four compounds) ranged from 39 to 207 for cod, from 21 to 54 for polar cod, and from 6 to 35 for lang rough dab. HCH (sum of three compounds) concentrations found were 3-17, 7-15, and 2-8 ng/ g wet weight respectively, for the three species. Feeding habits and migration patterns are likely explanations for this observed interspecies variation. There are few local sources of PCBs and pesticides within the Arctic region. Most of these compounds find their way into the Barents Sea ecosystem through lang range transport from industrial and agricultural areas further south.