Residues of persistent organochlorine contaminants in southern elephant seals (Mirounga leonina) from Elephant Island, Antarctica.

Contamination of blubber tissues by organochlorine pesticides (OC) and PCBs was assessed in female and male pups and juveniles, as well as in adult females and subdominant adult males of the Southern elephant seal, Mirounga leonina, from Elephant Island in the Antarctic Peninsula. All residues of persistent organochlorine contaminants analyzed were found in blubber samples, except for beta-HCH, endosulfan II, endrin, heptachlor, and aldrin. The relative concentrations of the analytes detected were sigmaDDT > sigmaPCB > sigmachlordane > mirex > dieldrin > HCB> sigmaendosulfan > methoxychlor > sigmaHCHs > other OC pesticides. OC and PCBs concentrations were 1 or 2 orders of magnitude lower than those found in pinnipeds from northern hemisphere. The ratio sigmaDDT/sigmaPCB was higher in southern elephant seals. The relative importance of some OC residues indicates that pesticides used either currently or in the recent past in countries in the southern hemisphere are the sources of contamination in the Antarctic region. Data showed that concentrations of contaminants generally increased from pups < juveniles < adults and suggested that pups accumulated contaminants through transfer from the mother seals via transplacental and lactational routes.