lundi 23 février 2015

It's colourless, odourless and tasteless, and it can increase your risk of developing lung cancer. Yet most Manitobans don't have radon gas on their radar of health hazards.

And that is a serious problem, says Dr. Lisa Richards, Medical Officer of Health with the Winnipeg Health Region.

Radon is a naturally occurring radioactive gas that is formed by a breakdown of uranium in the soil. It can seep into houses through cracks in the foundation.

The province of Manitoba, including Winnipeg, is known to have higher levels of radon gas in homes compared to other parts of Canada, with experts suggesting that between 10 and 30 per cent of houses in the city may have unsafe levels of the substance.

That's when the trouble starts. As people inhale the gas, the radioactive particles can enter their lungs and may contribute to the development of lung cancer, says Richards.

Studies suggest that radon is the second leading cause of lung cancer after smoking, and is the leading cause of lung cancer for non-smokers. Radon is responsible for up to 20 per cent of all lung cancers in Manitoba, says Richards, noting that its effects are especially bad for people who smoke.

"The combined effects of radon exposure and smoking create a risk for lung cancer that is greater than the two separately," says Richards. "Since an estimated one in five homes in Manitoba exceeds Canada's radon guideline, it's reason for concern."

The baseline risk for a smoker getting lung cancer is about 12 per cent, meaning that slightly more than one in ten people who smoke can expect to get cancer. But when combined with long-term, high radon exposure at 800 becquerels per metre cubed (Bq/m³), the risk jumps to about 30 per cent. Meanwhile, the lung cancer risk for a non-smoker exposed to that same high radon level is about five per cent.

"To put it another way, a smoker's chances of getting lung cancer from high levels of radon are 250 times their risk of drowning or 200 times their risk of dying in a house fire," says Richards, adding that for non-smokers exposed to radon, the numbers are 35 times the risk of drowning, or 20 times the chance of dying in a house fire.

"Despite the lower risk for non-smokers, radon is still the number one cause of lung cancer for non-smokers," she says.

Residents of Manitoba, Saskatchewan, New Brunswick and Yukon have the highest risk for radon gas exposure, according to a 2012 Health Canada study of radon concentrations in homes across the country.

The study found that 11 per cent of homes in Winnipeg have unsafe levels of radon gas. That means they have more than the 200 Bq/m³ of radon gas that is deemed to be safe. The danger may be even more pronounced during the winter months when people keep the windows closed, trapping the gas inside.

Other health regions in Manitoba showed higher numbers for the 200-plus Bq/m3 range in the Health Canada study. For example, the Interlake-Eastern RHA was 23 per cent, Southern was 26 per cent, and Prairie Mountain was 43 per cent. The Northern RHA was 11 per cent.

But at least one local expert says the 11 per cent estimate for Winnipeg is too low. Pam Warkentin, Assistant Director of the Canadian - National Radon Proficiency Program, which is the certification program recognized by Health Canada, says she believes as many as 30 per cent of Winnipeg homes may have hazardous levels of radon gas.

"We know, through surveys done here in the past, that Winnipeg's numbers are higher than in the Health Canada survey," she says. "In fact, our research has shown us that, in some areas of the city, 60 per cent of the homes have levels higher than 200 becquerels."

The only way to be sure about radon is to test your home, she says. "There are options available, including do-it-yourself radon test kits or hiring a professional," she says. "If you are worried about deploying a kit improperly, then hire a professional."

Many people hold off testing, says Warkentin, because they're worried about the cost of correcting the problem. "Get the test done, and then think about how you will install a mitigation system. You can put it into your repair budget in the future."

If your home does test above 200 Bq/m³, you still have time, says Richards. The risk of developing lung cancer depends on how much radon a person is exposed to, how long their exposure is, and whether they smoke.

A number of studies have made the link between residential radon exposure and lung cancer, she says. One, which pooled data from seven different studies, including one done in Winnipeg, found the longer the exposure, the greater the risk.

It doesn't pay to ignore the warning, adds Richards. Lung cancer is the leading cause of all cancer deaths in Canada, ahead of breast cancer for women and ahead of prostate cancer for men, she says.

"When you learn that two out of five Canadians will develop cancer in their lifetime, and lung cancer is a leading cause of deaths due to cancer, it only makes sense to reduce your exposure to what causes lung cancer," says Richards. "Stop smoking, and get your home tested for radon gas."

How radon enters your home

Potential entry routes for radon gas in homes with concrete foundations include cracks, areas with exposed soil or rocks, openings for utility fixtures or hollow objects such as support posts. Major entry points include sump pumps and floor drains.

Homes with less common types of foundations, such as concrete slab-on-grade, stone, or pressure-treated wood, may have other entry routes where openings or paths exist between the house and the ground.
"There are many factors that influence radon gas levels," says Pam Warkentin, Assistant Director of the Canadian - National Radon Proficiency Program. "Your home might have a foundation leak, but perhaps the leaky windows are letting the gas flow out of your home, keeping the level low."

Homes built in 2010 or later in Manitoba have a roughed-in system that allows home owners to install a radon mitigation device. "Anyone with a home built after 2010 should still have their home tested for radon, so they'll know if they will need to complete the roughed-in system," says Warkentin.
Reduce radon gas in your house
If you've tested your home, and the radon level is above the Canadian guideline of 200 Bq/m³, Health Canada recommends that you take action to lower the level. The higher the radon concentrations, the sooner action should be taken to reduce levels to as low as practically possible.

If you hire a contractor to measure the radon level in your home, make sure they are certified under the Canadian National Radon Proficiency Program (C-NRPP). For a list of certified professionals, visit Costs for mitigation and remediation can run from $500 to $4,000, depending on where the radon leak is and how severe it is, but can be as little as $50 to $100 to seal a sump pump.

Testing for a minimum of 90 days is recommended by Health Canada to obtain the most accurate results, because radon levels can fluctuate. Testing is best done during the colder months - when windows are closed - to give a more accurate reading.

Radon test kits can be purchased through:

Manitoba Lung Association
Phone: 204-774-5501
Toll-free: 1-888-566-5864

Canadian Cancer Society
Phone: 204-789-0886

If buying a kit from a hardware store or online, look for the Canadian National Radon Proficiency Program logo, which certifies the laboratories that give the test results.

For more information on how to reduce the levels of radon gas in your home and for information about contractors who can do the work, visit

--- By :

0 commentaires:

Enregistrer un commentaire

Subscribe to RSS Feed Follow me on Twitter!