Melting ice releases Arctic toxins

Research from Environment Canada and Norway says toxins such as PCBs that have been locked in an Arctic deep freeze are being “remobilized” as the climate warms. ” Arctic warming could undermine global efforts to reduce environmental and human exposure to these toxic chemicals,” says a new study in the journal Nature Climate Change. (PHOTO BY JANE GEORGE)

MARGARET MUNRO
Postmedia News

Environment Canada sleuths have found that toxins such as PCBs that have been locked in an Arctic deep freeze are being “remobilized” as the climate warms.

In a report published Sunday, they say that persistent organic pollutants, known as POPs, which were banned decades ago, are being released in the Arctic as sea ice retreats and temperatures rise.

“Our results indicate that a wide range of POPs have been remobilized into the Arctic atmosphere over the past two decades as a result of climate change, confirming that Arctic warming could undermine global efforts to reduce environmental and human exposure to these toxic chemicals,” Hayley Hung, an Environment Canada research scientist, and her colleagues reported in the journal Nature Climate Change.

Large amounts of the toxic chemicals were transported to the North from factories and farmers fields on air currents and ended up trapped in Arctic ice, and frigid northern soils and sea water.

Until recently scientists and regulators thought the Arctic toxins would stay out of circulation permanently, but Hung says that view changed with some “very abnormal’ readings in recent years.

Scientists have measured the old pesticide hexachlorocyclohexane, which was banned years ago, coming out of open water in Hudson Bay and the Beaufort Sea.

And polychlorinated biphenyls, or PCBs, widely used as coolants and lubricants until they were banned in many countries more than two decades ago, have been picked up at the edge of the ice in the Atlantic Arctic.

That prompted Hung and Jianmin Ma at Environment Canada and their colleagues in Norway to look at 20-year-long records of POP concentrations in the Arctic atmosphere.

They report finding evidence showing POPs are being released from their frigid vaults.

But they cannot yet say how much of the toxins have been remobilized, and how much more could end up in circulation.

And it is not yet known how big a threat it poses to the health of northerners, Arctic wildlife and ecosystems.

“These are all valid questions,” Hung said in an interview, noting the study “is actually a beginning of a story instead of a conclusion to a story.”

But she says remobilization is a “real concern” because the chemicals are toxic and persistent.

Once the chemicals are back in the environment there is “no natural way” to get them out of circulation, she says, likening it to the way perfume wafting through the air cannot be put back in the bottle.

She says the speed of remobilization of the POPs will depend on how fast climate change affects the Arctic.