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Polar bears accumulate 'cocktail' of toxins, study finds

  • Author: Doug O'Harra
  • Updated: May 31, 2016
  • Published October 18, 2011

A Danish study of Greenlandic polar bears has found a sinister "cocktail of environmental toxins" accumulating in their bones and tissues, according to a story posted this week by University of Copenhagen. Christian Sonne, a senior scientist at Aarhus University, examined the results of polar bear contaminant research between 2000 to 2010, and then analyzed bone and tissue samples from 100 bears living in eastern Greenland, all as part of his doctoral thesis.

Sonne uncovered evidence suggesting exposure could sicken bears without killing them outright. "The accumulated industrial chemicals cause diseases in the polar bears which do not lead to their immediate deaths," Sonne said here. "On the other hand, the toxins damage the bones and organs of the polar bears, their immune systems and not least their reproductive systems. However, the harm suffered by the population of polar bears in eastern Greenland is not yet fully understood."

Sonne, trained in both veterinary medicine and ecotoxicology, has previously studied how exposure to environmental toxins can damage Arctic foxes and sled dogs. The stubborn accumulation of organic pollutants produced by humans and transported on air and ocean currents into the Arctic has become one of the Far North's most pressing ecological concerns. The substances tend to concentrate in fatty tissue and organs as they move up the food chain, with the highest levels found in top predators like killer whales and polar bears.

Largely due to the loss of summer sea ice north of Alaska, the United States has listed polar bears as threatened under the Endangered Species Act and designated about 187,000 square miles as habitat critical to their survival. For more background and other details on the biology of the Arctic's iconic predator, check out Polar Bears International.

On Monday, U.S. District Judge Emmet Sullivan threw out a key section of an Interior Department rule that declared global warming is threatening the survival of the polar bear, making regulations of greenhouse gases mandatory. Sullivan said that Fish and Wildlife Service failed to conduct a proper environmental review when creating the protections for the polar bear.

Contact Doug O'Harra at doug(at)alaskadispatch.com

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