Persistent organic pollutants, including polychlorinated biphenyls PCBs , are widely distributed and detectable far from anthropogenic sources. Northern elephant seals Mirounga angustirostris biannually travel thousands of kilometers to forage in coastal and open-ocean regions of the northeast Pacific Ocean and then return to land where they fast while breeding and molting. Our study examined potential effects of age, adipose percent, and the difference between the breeding and molting fasts on PCB concentrations and congener profiles in blubber and serum of northern elephant seal females.
Between and , we sampled blubber and blood from 58 seals before and after a foraging trip, which were then analyzed for PCBs. Age did not significantly affect total PCB concentrations; however, the proportion of PCB congeners with different numbers of chlorine atoms was significantly affected by age, especially in the outer blubber.
Younger adult females had a significantly greater proportion of low-chlorinated PCBs tri-, tetra-, and penta-CBs than older females, with the opposite trend observed for hepta-CBs, indicating that an age-associated process such as parity birth may significantly affect congener profiles. The percent of adipose tissue had a significant relationship with inner blubber PCB concentrations, with the highest mean concentrations observed at the end of the molting fast.
These results highlight the importance of sampling across the entire blubber layer when assessing contaminant levels in phocid seals and taking into account the adipose stores and reproductive status of an animal when conducting contaminant research. Editor: James P. This is an open-access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Persistent organic pollutants such as polychlorinated biphenyls PCBs are harmful to wildlife because they can disrupt endocrine and immune function [1] β [3].
