CHLORINATED ORGANIC CONTAMINANTS IN BLUBBER BIOPSIES FROM NORTHWESTERN ATLANTIC BALAENOPTERID WHALES SUMMERING IN THE GULF OF ST-LAWRENCE

Concentrations and patterns of chlorinated biphenyls (CBs) and other p ersistent organochlorine compounds (OCs) were determined from small bl ubber biopsy samples collected from northwestern Atlantic minke (Balae noptera acurostrata), fin (Balaenoptera physalus), blue (Balaenoptera musculus), and humpback (Megaptera novaeangliae) whales summering in t he Gulf of St. Lawrence, Quebec. Concentrations of Sigma PCB (sum of 1 9 congeners) in biopsy samples ranged from 0.2-10 mu g g(-1) lipid, an d congeners 52, 101, 118, 153, 138 and 180 accounted for 79% of Sigma PCB. Mean concentration of the sum of nonortho CB congeners in selecte d biopsy samples was 2 ng g(-1) lipid, and relative concentrations of these analytes were: 77 > 126 > 81 > 169. Concentrations of Sigma DDT ranged from 0.6-13 mu g g(-1) lipid, and the average proportion of DDE to Sigma DDT was 72%. All other organochlorine analytes were present at concentrations below 2 mu g g(-1) lipid. On average, cis-nonachlor, trans-nonachlor and oxychlordane accounted for 27, 26 and 23%, respec tively, of the chlordane-related analytes, and alpha-hexachlorocyclohe xane (HCH) comprised 67% of Sigma HCH. Concentrations of Sigma DDT wer e significantly lower and mirex concentrations were significantly high er in minke whales than in the other balaenopterid species. Concentrat ions of all other analytes were similar in the four whale species. Rat ios of proportions of oxychlordane to trans-nonachlor were highest in fin whales. Blue whales had the lowest proportions of alpha-HCH but th e highest proportions of DDT. Interspecies differences in the concentr ations and patterns of certain CB congeners and OC compounds may refle ct differences in diet or in metabolic capabilities. Males usually had higher mean concentrations of CBs and OCs than females, but these dif ferences were significant only for Sigma DDT, dieldrin, Sigma HCH and HCB. Higher proportions of lower chlorinated CB congeners were found i n calves compared to adult females, indicating selective reproductive transfer. (C) 1997 Elsevier Science Ltd.