Biomagnification of organochlorines along a Barents Sea food chain

To trace the biomagnification of organochlorines in marine food chains near Svalbard, which may lead to the high organochlorine concentrations in top predators from the area, we compared concentrations and patterns of organoc hlorines in selected taxa. The pelagic crustaceans, Calanus spp. (copepods) , Thysanoessa spp. (euphausiids), Parathemisto libellula (amphipod), and th e fish species, Boreogadus saida (polar cod) and Gadus morhua (cod) were se lected to represent the lower trophic levels in the food web. Four seabird species were chosen at the higher trophic levels, Uria lomvia (Brunnich's g uillemot), Cepphus grylle (black guillemot), Rissa tridactyla (black-legged kittiwake) and Larus hyperboreus (glaucous gull). We found low concentrati ons of the organochlorines Sigma hexachlorocyolohexanes (Sigma HCHs), hexac hlorobenzene (HCB), Sigma Chlordanes, Sigma DDTs and Sigma polychlorinated biphenyls (Sigma PCBs) in crustaceans (11-50 ng g(-1) lipid wt.) and fish ( 15-222 ng g(-1) lipid wt.). In seabirds, the organochlorine concentrations biomagnified one to three orders of magnitude dependent on species and comp ound class. Glaucous gulls had the highest concentrations of all organochlo rines, The organochlorine levels in all taxa except glaucous gull were comp arable to those recorded in similar species in the Canadian Arctic. The org anochlorine pattern changed from crustaceans and fish to seabirds. Moving u p the food chain, the relative contribution of Sigma HCHs, HCB and Sigma Ch lordanes decreased, and the relative contribution of Sigma DDTs, Sigma PCBs , persistent compounds and metabolites increased. The results reflected tro phic transfer of organochlorines along the food chain as well as different elimination potentials due to direct diffusion in crustaceans and fish, and higher contaminant metabolic activity in seabirds. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.