Avian influenza cases are increasing across Canada, particularly in wild birds, which concerns experts who say they fear the aggressive virus could mutate to infect humans more easily.
Some Icelandic killer whales have very high concentrations of polychlorinated biphenyls in their blubber, according to a new study.
But it seems that other orcas from the same population have levels of polychlorinated biphenyls (PCBs) that are much lower. It mainly depends on what they eat.
PCBs are industrial chemicals banned decades ago, after they were found to affect the health of both humans and wildlife. But because they degrade very slowly after being released in the environment, they still accumulate in the bodies of marine mammals.
After collecting skin and blubber biopsies from 50 orcas in Iceland, the researchers found considerable variation in contaminant concentrations and profiles across the population.
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.