Validation of the blubber biopsy technique for monitoring of organochlorine contaminants in balaenopterid whales

Techniques for collecting small biopsies from the outer strata of the blubber of live whales have been used to monitor chemical contaminant concentrations in cetaceans. In order to validate this monitoring technique, polychlorinated biphenyls (PCBs) and other organochlorine (OCs) compounds were analysed in blubber mantle samples collected from different body sites on the carcasses of three minke whales (Balaenoptera acurostrata) and one blue whale (Balaenoptera musculus). When concentration data were lipid normalized (ng/g lipid), concentrations of PCBs and other OCs in outer, middle and inner blubber mantle layers, and in different body sampling locations on the dead whales were not significantly different (p≥0.05). Patterns of PCBs and OCs were also similar in the different blubber strata and body sampling sites. Similar PCB and OC concentrations and patterns were also found in samples of the outer and middle blubber strata that were collected by the biopsy technique from live minke (n = 2) and blue (n = 3) whales. The absence of significant differences in the lipid-normalized concentrations and patterns of contamination in the blubber indicate that the distribution of PCBs and OCs in the blubber mantle of balaenopterid whales is principally governed by the lipid content. This is consistent with pharmacokinetic models describing the distribution at equilibrium of lipophilic compounds in experimental animals. Consequently, biopsies which include only the outer blubber layer at one site on the blubber mantle can provide a representative sample for monitoring PCB and OC contamination of blubber in balaenopterid whales.