Lipophilicity of PCBs and fatty acids determines their mobilisation from blubber of weaned northern elephant seal pups

Polychlorinated biphenyls (PCBs) exhibit lipophilic properties that lead to their bioaccumulation in adipose tissue. Following PCB exposition, northern elephant seals (Mirounga angustirostris) concentrate high amounts of these pollutants in their large adipose tissue stores. During lipolytic periods such as the post-weaning fast, fatty acids (FAs), which form triglycerides, and PCBs are both mobilised from adipose tissue. Our results showed that the degree of lipophilicity of FAs and PCBs impacted their release: the more lipophilic FAs and PCBs tended to be more conserved in blubber over the fast than the less lipophilic ones. This led to an enrichment of more lipophilic compounds within adipocytes with the progression of the fast. Life history patterns that include fasting may thus influence the profile of blubber lipids and contaminants. [Display omitted] •The release of PCBs and fatty acids from blubber is an heterogeneous phenomenon•The more lipophilic PCBs and fatty acids are, the more they tend to remain in blubber•Adipocytes get enriched in more lipophilic compounds with the progression of the fast.