Organochlorines and possible biochemical effects in glaucous gulls (Larus hyperboreus) from Bjornoya, the Barents sea

To study possible biochemical effects of organochlorine contaminants (OCs) in glaucous gulls (Larus hyperboreus), 40 adult individuals were collected from colonies on Bjornoya in the Barents Sea. OCs (four pesticides and nine PCB congeners), microsomal 7-ethoxyresorufin O-deethylase (EROD) activity, microsomal testosterone hydroxylation, highly carboxylated porphyrins (HCP s), retinol, and retinyl palmitate were quantified in liver samples. The he patic vitamin A stores in glaucous gulls were larger than in herring gulls (Larus argentatus) from other studies conducted in contaminated locations i n North America. No significant relationships were found between liver reti noid concentrations and OC levels. The hepatic EROD activity was low compar ed to other studies on fish-eating birds and only marginally associated wit h PCB levels. Microsomal testosterone hydroxylase activity was only observe d at the 6 beta-position and could not be related to QC levels. The low P45 0-associated enzyme activities in the glaucous gull suggests that they have a low capacity for metabolizing OCs, which may contribute to the high accu mulation of OCs in this species. HCPs were only elevated (138 pmol g(-1)) i n the sample with highest OC levels, whereas the remaining samples containe d low levels of HCPs (<30 pmol g(-1)). The weak association between EROD ac tivity and PCB levels and the low level of HCPs suggest that these biochemi cal parameters were unaffected by OCs in most of the sampled gulls. Thus, t he glaucous gull seems not to be particularly sensitive toward Ah-receptor mediated effects.