A new study from McGill University suggests that some Icelandic killer whales have very high concentrations of PCBs (polychlorinated biphenyls) in their blubber. But it seems that other orcas from the same population have levels of PCBs that are much lower. It mainly depends on what they eat.
Click here for original story, PCB contamination in Icelandic orcas: A matter of diet
Source: Phys.org