Polar bears, Arctic foxes and Inuit peoples are under threat from man-made toxins such as polychlorinated byphenyls (PCBs) that build up in the food chain, reveals new research reported in the Independent newspaper of London, England.

Environmental and animal groups are calling for a global ban on the production of the chemicals to safeguard the future health of those groups. Some scientists believe the PCBs are leading to “gender-bender” polar bears in Norway and Greenland, after the discovery of a number of female bears which had both male and female sexual organs.

The report, produced by the Arctic Monitoring and Assessment Programme based in Norway, said the toxins followed air and water currents from as far as Asia to the remote and fragile Arctic environments of North America, Greenland and the Svalbard islands north of Norway.

“Inuit in Greenland and Canada have among the world’s highest exposures to certain toxic chemicals as a result of long-range transport,” said the report, Arctic Pollution 2002.

The toxins, including potentially cancer-causing PCBs, build up in the food chain, especially in fatty tissue such as blubber in whales and seals. Blubber, being high in energy, is a key part of the diet for polar bears and the indigenous people of the Arctic.

In a separate study, female polar bears with both male and female sexual organs were discovered in 1997 on Norway’s Svalbard archipelago, about 500km north of the Norwegian mainland. Researchers at the Norwegian Polar Institute now believe the deformity may be due to PCBs and other toxins.

Arctic foxes, seals, killer whales, harbour porpoises and birds also suffer high levels of contamination by persistent organic pollutants that damage the nervous system, development and reproduction.

PCBs are chemical compounds that do not occur naturally; they were once widely used in plastics and electrical insulation and can be produced by incomplete combustion of plastics. It can take decades for them to break down. Their use is now largely banned in the West.

The Inuit Circumpolar Conference, which represents Inuit peoples in Alaska,

Canada, Greenland and Russia, expressed concern at the report’s findings and called on Arctic governments to work together to help protect the health of indigenous people.

In May, the WWF warned that polar bears could disappear from the wild within 60 years due to global warming, which it said was already causing numbers to dwindle. The pack ice, which the bears need to travel long distances for food, has been thinning as temperatures rise, leading to fears that it will eventually be too thin to let them travel. When that happens, the population of about 22,000 could die out.