Spatial distribution of persistent organochlorines in ringed seal (Phoca hispida) blubber

Blubber samples, taken through the entire blubber column, were collected fr om three different anatomical locations on ringed seals (Phoca hispida). Th e outer and inner layers of these samples were analysed for concentrations of Sigma PCBs (sum of the analysed congeners, polychlorinated biphenyls) an d p,p'-DDE (4,4'-dichlorodiphenyldichloroethylene). No significant differen ces were found in blubber thickness or in per cent extractable lipid when c omparing age- and sex-groups, or in extractable lipid content when comparin g anatomical locations of the blubber or blubber depth. No significant diff erences were found between the three different anatomical locations with re spect to the concentrations of Sigma PCBs or p,p'-DDE. However, the concent rations of both Sigma PCB and p,p'-DDE were significantly higher in the out er blubber layer compared to the inner. Higher levels of both Sigma PCB and p,p'-DDE were found in males compared to females and juveniles in both the inner and outer parts of the blubber column. The most commonly used blubbe r sampling devices are biopsy tools that penetrate only the outer layer of the blubber. Analyses of such samples will not reflect the real body burden of organochlorines. Standard methods for sampling blubber of marine mammal s should be developed so that comparative studies and longitudinal monitori ng programs of pollutants in marine mammals can be conducted in a meaningfu l way. (C) 2000 Elsevier Science Ltd. All rights reserved.