PCBs Contributed To Harbor Seal Mortality
Until they were phased out of producion in the 1970s, a class of industrial chemicals called PCBs were produced by the thousands of tons and used widely as lubricants and electrical insulators. PCBs were discontinued due to concerns about their health effects, but because they break down very slowly they are still in the environment. PCBs become concentrated in the bodies of top of the food chain predators such as whales, seals, eagles, humans. Every person on the planet has some PCBs in their bodies. The human health consequences of this body burden of industrial chemicals is unknown.
In the spring and summer of 1988, 20,000 harbor seals died from distemper in the Baltic Sea. These seals faced a double whammy: they had no previous exposure to distemper, so their immune systems were not prepared to fight it. Second, their immune systems were probably weakened by the PCBs in their bodies.
We spoke with Peter Ross about his work on the health effects of PCBs in marine mammals.