ORGANOCHLORINE PESTICIDE-RESIDUE AND PCBS IN HARBOR PORPOISE (PHOCOENA-PHOCOENA) INCIDENTALLY CAUGHT IN SCANDINAVIAN WATERS

During Norwegian and Danish harbour porpoise projects 1987-1991, subcu taneous blubber samples of 34 male harbour pot-poises (Phocoena phocoe na) were collected. Animals from three geographical locations, ranging from 56 degrees N, 12 degrees E to 71 degrees N, 26 degrees E, were c hosen in order to study the organochlorine (OC) contamination in this species inhabiting the northeastern part of the North Atlantic Ocean, the northern North Sea and Kattegat, at the locations of Tufjord, Vest landet and Gilleleje, respectively. Analytical standards used consiste d of the industrial chemicals PCBs (22 individual PCB congeners and 6 industrial mixtures which contained 104 PCB congeners or group of cong eners) and HCB, and the organochlorine pesticides DDT, HCH, the cyclod ienes endrin, dieldrin and the chlordane metabolites oxychlordane and trans-nonachlor, and heptachlor epoxide. A total of 16 PCB congeners o r groups of congeners, all the DDT metabolites except o,p'-DDD, and al l the pesticides were detected in all animals. The concentrations of S igma PCB (sum of concentrations of 47 detected PCB congeners) and Sigm a DDT (sum of concentrations of all DDT detected compounds) ranged fro m 3.7-65.3 and 3.2-45.0 mu g g(-1) lipid weight, respectively. The ran ge of mean concentrations of dieldrin, endrin and trans-nonachlor was 1-3 mu g g(-1), while mean concentrations of HCHs, heptachlor epoxide, and HCB were <1 mu g g(-1). No significant variation in PCB congener pattern was apparent between geographical areas. The major PCB congene rs nos 147/123, 153, 138/163/164, 182/187 and 180 at Gilleleje, Vestla ndet and Tufjord represented 53%, 45% and 44% of Sigma PCB, respective ly. A significant difference was found between the number of PCB conge ners in blubber of newborn and older porpoises. This might indicate th e presence of a blood/placenta barrier and/or selective mammary transp ort of PCBs with specific structures. A significant OC accumulation wi th age was apparent, with the exception of HCB and HCHs. Geographical differences in the levels of OCs were apparent for all compounds excep t for dieldrin and heptachlor epoxide. Significantly higher levels of chlordane metabolites (trans-nonachlor and oxychlordane) and endrin we re found in the group of animals fi om the northern location Tufjord, while Sigma DDT, p,p'-DDTs, HCHs and PCBs were highest in the group of animals from the southern location Gilleleje. Highest levels of the o ,p'-substituted DDTs were found in specimens from the middle location Vestlander. These findings indicate little or no regular migration of harbour porpoise between these three locations. No correlations were f ound between OC concentrations and blubber thickness. Although mean va lues of Sigma DDT and Sigma PCB were in the lower end of previously re ported levels in harbour porpoise from adjacent waters in the eastern part of the North Atlantic Ocean and along the coasts of North America , these levels are relatively high. The organochlorine concentrations in harbour porpoises in the present study were 2-3 times higher than c orresponding OC levels detected in harbour seals (Phoca vitulina) from the same areas.