Seabirds Fly Pollutants to Arctic Coast, Study Says

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The team found high levels of contaminants—including DDT, HCB, PCBs, and mercury—in ponds beneath the seabird colony.

PCBs (polychlorinated biphenyls) are human-made chemicals used in electrical equipment and flame retardants. They're also created as by-products of paper bleaching in pulp mills.

DDT (dichlor diphenyl trichlor) and HCB (hexachlorobenzene) were used in pesticides. Burning of fossil fuels accelerates the rate at which mercury gets into the atmosphere.

Other studies have linked POPs to malformed reproductive organs, reduced fertility, and increased susceptibility to tumors and infections in top Arctic predators such as seals and polar bears.

Previously, wind currents were thought to be the main source of pollutants on Arctic coasts.

The study team says that POP levels are much higher in ponds just below the seabirds' cliffside colony than in other Cape Vera ponds—HCB concentrations are ten times higher, Mercury levels are 25 times higher, and DDT levels 60 times higher.

Human Risks

Blais says these pollutants could be ingested by other animals which in turn could affect indigenous peoples who eat Arctic animals. (See "Toxins Accumulate in Arctic Peoples, Animals, Study Says.")

"The marine food chain is the main source of contaminant exposure in the human population, particularly indigenous peoples such as the Inuit," said Shearer, the Northern Contaminants Program manager. "Marine mammals which have high levels of contaminants stored in their fat, organs, and skin are heavily consumed by Inuits as part of their traditional diets."

These mammals include beluga whales, narwhals, and ring seals. Shearer says some Inuit communities have been found to have high concentrations of POPs in their blood—up to 20 times higher than World Health Organization guideline levels.

"In [some Inuit] breast milk, levels of POPs are among the highest found anywhere in the world," he added. "We're dealing with a serious public health issue for the Inuit population."

Preliminary studies by the Northern Contaminants Program suggest Inuit children are especially vulnerable to POPs.

Shearer says the pollutants are thought to affect neural development and the immune system. As a result, they may lead to IQ deficits and increased incidences of infections such as colds and earaches.

Shearer says alternative, POP-free food sources often aren't available to Inuit.

Many Inuit communities are remote and have limited access to food sources. "It's not just a case of saying, Stop eating marine-mammal tissue … ," Shearer said.

Canadian health authorities have now advised Inuit women of childbearing age to reduce their consumption of marine mammals, substituting them with other meat, such as caribou, whenever possible.

"Research that's coming out of the Canadian north has been instrumental in pushing governments to wake up and take notice of the potential impact these pollutants may have," Shearer said.

Several legally binding agreements have now been established to address the issue, including the Stockholm Convention on Persistent Organic Pollutants, an international treaty overseen by the United Nations Environment Programme.

Jules Blais, the University of Ottawa professor, calls for even stronger international controls on the production and release of POPs into the atmosphere—particularly pollutants of the type found at Cape Vera, which accumulate in food chains.

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