Thawing permafrost can expose northerners to cancer-causing gas: study

Thawing permafrost might be exposing people in northern Canada to higher levels of a naturally-occurring gas that causes lung cancer, says a new study out of the U.K.

Paul Glover, the study's lead researcher, said permafrost has been acting as a "hidden guardian" by keeping radon locked in the ground in the circumpolar Arctic and preventing it from travelling to the Earth's surface and accumulating in buildings.

Radon is an odourless, tasteless radioactive gas that is created from the decay of uranium in minerals found in rock, soil and water, according to Lung Cancer Canada. It is the leading cause of cancer in non-smokers, and the second-leading cause of cancer in smokers.

"With climate change, of course, that barrier of permafrost is actually degrading," said Glover, who is the chair of petrophysics at the University of Leeds. He studies the physical properties of rocks, and how things like fluids and gas can flow through them.

In his peer-reviewed study published in the journal Earth's Future last week, Glover said 42 per cent of permafrost is expected to be lost in the Arctic circumpolar permafrost region by 2050. 

"We're losing [permafrost] at a very large rate, and therefore there would be the potential for a plume of radon perhaps to be released and affect the health of people living in those zones." 

Though his study is based on modelling, Glover said he would be "very surprised" if this was not already affecting parts of the Arctic, given how quickly permafrost is thawing. 

When radon is released into the outdoor air it's not a concern, according to Health Canada. But it becomes a risk to peoples' health when it accumulates in enclosed spaces. 

Buildings that are built on piles are not affected because they have natural ventilation, said Glover. But homes with basements and homes that are either built on the ground or into the ground should be tested, he said. 

Lung Cancer Canada says radon can enter a home through an opening where the house contacts the ground — including cracks in the foundation floor or walls, construction joints, gaps around service pipes and floor drains. 

It can take several years for the gas to peak and dissipate from a building, the study said. 

"It's potentially a very big problem for health," said Glover, who also pointed to an increased risk to people who smoke. The study says smoking exacerbates radon-acquired lung cancer by 26 times, and the prevalence of smoking in northern Canada and Greenland is about three times the global average. 

But the issue of radon does not require a "medical intervention," said Glover. In fact, the solutions are relatively simple. 

Courtney Howard, an emergency room physician in Yellowknife and past president of Canadian Association of Physicians for the Environment said radon is one type of climate change impact that "we'll be able to manage" so long as "we're on top of it."