Persistent organochlorine compounds in the blubber of ringed seals ( Phoca hispida) from the Belcher Islands, Northwest Territories, Canada

Abstract

Samples of blubber and morphometric data were obtained in 1991 from a population of ringed seals ( Phoca hispida) located in southeastern Hudson Bay, near the Belcher Islands. Several PCB congeners, DDT and its metabolites, components of technical chlordane, HCH compounds, dieldrin and mirex were detected at concentrations below 150 ng/g lipid in the blubber of these animals. Female seals had lower concentrations of PCB congeners, DDT compounds and chlordane compounds in the blubber than male seals from this region, but there were no sex-specific differences observed for HCH compounds, dieldrin and mirex. Correlations were observed between the age of male seals and their estimated ‘blubber burdens’ (mg) of total PCBs and total DDT. There was evidence that the male seals from the Belcher Islands had higher concentrations and blubber burdens of total PCBs and lower concentrations of total HCHs than male seals sampled in 1989 from a population at Holman Island in the northwest Canadian arctic. Morphometric data indicated that the Holman Island seals were in better condition than the Belcher Islands seals at the time of sampling. Due to the negative correlation observed between contaminant concentrations in ringed seals and the condition of the animals, analysis of blubber burdens in seals may be a preferable method for monitoring spatial and temporal trends in the contamination of ringed seals in the arctic.