PCB contamination in Icelandic orcas: a matter of diet

Accurate forecasting of health risks to killer whale populations may depend on looking at individual variations in their diet. Image caption: These killer whales may appear healthy, but a new study has found extremely high levels of PCB contamination in some of the whales. There was a 300-fold difference between the levels of PCBs among the most contaminated orcas compared to the least contaminated ones. The variation was mainly due to their eating habits. CREDIT: Filipa Samarra - Icelandic Orca Project 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.