Most people thought the problem of polychlorinated biphenyls — known as PCBs — had been solved. But a new study based on modeling shows that they’re lingering in the blubber of killer whales — and they may end up wiping out half the world’s population of killer whales in coming decades. Whales sit at the top of their food chain. At each step in this chain, PCBs get more and more concentrated. The most at-risk killer whales are those that eat seals and other animals that are themselves fairly high on the food chain and quite contaminated, Dr. Desforges said.

Source: New York Times September 27, 2018 18:00 UTC