Norwegian scientists first discovered that artificial chemicals dumped in the sea enter killer whales’ bodies and reach their young.
Researchers at the University of Oslo in Norway found a shocking fact that high levels of polychlorinated biphenyl (PCB), used in furniture production, were being piled up in the killer whale’s body and passed down. The chemical was found in newborn killer whale bodies, suggesting that it came from its mother, although at a low level. Polychlorinated biphenyl, an artificial chemical banned from use, was found in all eight killer whales under study. The researchers pointed out that seven types of chemicals have exceeded the standard for toxic effects in marine mammals, which could harm reproduction.
Little is known about how top predators at the top of the food chain are affected by environmental pollution. The purpose of the study was to conduct tests for new pollutants and catabolism occurring in groups of Norwegian killer whales. Researchers were able to study tissue samples of seven killer whale carcasses that had been washed ashore for about three years from 2015 to 2017 and one killer whale caught in a fishing net. An autopsy to determine the cause of death allowed researchers to measure the chemical composition of killer whales in their bodies.
As a result, most of the chemicals were accumulated in the fat of killer whales, but in the case of baby killer whales, they were also found in the milk of their mothers that remained in their stomachs.
The researchers explained that the discovery of chemicals in killer whales, which are only 10 days old, is the first evidence that such unregulated pollutants are transmitted from mothers among marine mammals. The researchers also said that the level of chemicals approaching or exceeding the health impact threshold is a concern, considering that the baby killer whale’s endocrine and immune systems are still developing and the risk of premature death increases. Adult killer whales, on the other hand, are believed to have introduced chemicals while eating small prey. Accordingly, the researchers concluded that polychlorinated biphenyl, which has long been banned from use, poses a potential risk of increasing the number of killer whales known around the world.
Polychlorinated biphenyls are nonflammable and have excellent thermal and electrical insulation effects, so they are used as coolers and insulation materials such as electric transformers and capacitors. It was once included in pesticides, fire extinguishers, sealants, adhesives, paints, hydrofluids, lubricants, gas turbines, petroleum additives, heat transfer, carbon-free paper, dehydrators, fire extinguishers and plasticizers. However, their toxicity was discovered in the 1970s and banned worldwide.