Variation of Organochlorine Residue Levels with Age in Gulf of St. Lawrence Harp Seals (Pagophilus groenlandicus)

Abstract

Blubber samples from 18 harp seals taken near the Saguenay River in the Gulf of St. Lawrence were analysed for DDT metabolites, PCBs, and dieldrin. The concentration of total DDT and metabolites [Formula: see text] ranged from 3.1 to 22.6 ppm, PCBs (as Aroclor® 1254) from 2 to 22 ppm, dieldrin from 0.1 to 0.3 ppm of blubber. Rank correlation of residue level and age indicated that significant portions of the [Formula: see text] and PCB variance could be assigned to increased residue levels with age. Within the [Formula: see text] group, DDE alone showed a strong proportional increase in concentration with age. Dieldrin concentration was not appreciably correlated with age. Among factors other than age, changes in blubber thickness did not account for any significant amount of the variance in blubber residue concentration. Examination of other published data suggested that parturition and/or lactation may cause reductions in blubber residue concentrations.