PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994-1998.

For the first time, organochlorine (OC) contaminants were measured in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), to compare contaminant levels to those previously measured in dead stranded belugas. PCBs, DDTs, toxaphene and chlordane-related compounds were the major OC contaminants detected in 44 belugas biopsied in 1994-1998. SigmaPCB (the sum of 104 congeners) ranged from 2080 to 128,000 ng/g lipid in males (n=34; minimum estimated ages 8-22 years), and from 148 to 44,100 ng/g lipid in females (n=10; minimum estimated ages 7-22 years). The concentrations of PCBs and OC pesticides in the blubber of these whales overlapped those observed in stranded belugas from an earlier study, and demonstrated comparable age and sex-related trends. However, lower proportions of mirex, HCB, DDTs, and many of the highly chlorinated PCBs occurred in the biopsy samples compared to results for blubber from stranded carcasses. Most major OC compounds were present at lower concentrations in the biopsies, but this does not appear to be solely related to age differences between the two groups, or to emaciation in the stranded whales. Nor does it appear to be associated with the use of superficial biopsies, and the possible stratification of lipids and OCs in the blubber layer. Nevertheless, given these possible confounding factors, and the uncertainty in age estimates for the biopsied whales, the results point to the need for careful interpretation of biopsy results when comparing with data taken from the full depth of the blubber mantle in stranded whales. Taken together, results from both biopsied whales and previously studied stranded belugas indicate that PCB and OC pesticide contamination of St. Lawrence beluga whales may occur across a broader range of levels than previously thought, at least for males which formed the largest group in this study, possibly due to different degrees of dietary exposure. It also appears that measuring contaminant concentrations only in stranded whales, may overestimate OC levels in the population as a whole, especially for highly chlorinated OCs.

PCBs and OCPs in male harbour, grey, harp and hooded seals from the Estuary and Gulf of St Lawrence, Canada.

Blubber samples from adult male harbour seals (Phoca vitulina) from the St Lawrence Estuary, and from grey (Halichoerus grypus), harp (Phoca groenlandica) and hooded (Cystophora cristata) seals from the Gulf of St Lawrence, were analysed for polychlorinated biphenyls (PCB) and organochlorinated pesticides (OCP). All seals were between 5 and 19 years of age, and mean ages were not statistically different among the seal species. Mean concentrations of sigmaPCB and mirex were significantly higher in harbour seals, while sigmaDDT concentrations were significantly higher in hooded seals than in the other species examined. Harbour and hooded seals had similar concentrations of sigmaCHLOR, which were higher than in grey and harp seals. SigmaHCH concentrations were significantly higher in harp seals than in harbour and hooded seals and they were significantly higher in harbour and grey seals than in hooded seals. Harp and grey seals had similar levels of HCB, which were significantly higher than in either hooded or harbour seals. Patterns of PCB congeners and individual OCPs varied considerably between the four species. In PCA plots harbour, harp and hooded seals were well separated from each other, while grey seals were separated from the other species by a smaller degree. Between species variations may be explained by their dissimilar migratory patterns, habitat use and proximity to sources of industrial and agricultural pollution, their dietary regime (trophic level and individual prey items) as well as possible variations in the seals' abilities to eliminate these compounds.