Our practice has been providing experience for young physician trainees over the last number of years. Communicating medical issues is a vital aspect for any physician. This week's column is co-authored by medical student Katie Armstrong.
Radon is a radioactive, colorless, odorless gas that naturally exists in the environment. It is a byproduct of uranium in soil and rocks. In open spaces, the small quantities of radon gas do not pose a health risk. However, in confined, poorly ventilated spaces like basements and underground mines, radon can accumulate to higher levels that are hazardous to health.
Exposures to high levels of radon gas are associated with an increased risk of lung cancer. This is because, as radon decays further, alpha particles are emitted into the air. Inhaled alpha particles can injure bronchial and lung tissue. This accumulation of injury can lead to lung cancer. This lesson came from multiple studies that show the correlation between radon exposure and death from lung cancer among uranium miners.
More recent studies now link radon levels in the home to lung cancer. The U.S. Environmental Protection Agency (EPA) states that radon is the number one cause of lung cancer among non-smokers and the second leading cause of lung cancer overall.
Radon gas can enter the home through small cracks in the foundation. It can seep in through dirt floors, basement drains, concrete cracks, joints, and under the furnace base. Radon moves easily through porous concrete-block walls and well water can contain radon that is released into the air when the water is used.
Health Canada's studies show that high radon levels are not widespread in Canadian homes. However, it is difficult to predict the level in any one home. If you are concerned about exposure to radon gas in your home, indoor radon levels can be measured by sampling the air using alpha dosimetry. This service is commercially available for homeowners. Health Canada has published acceptable levels of indoor air radon exposure and suggested repeated readings as the level of radon changes from day to day.
There are two priniciples to reducing radon levels in homes: prevent radon from entering the home, and improve ventilation of radon out of the home. There are multiple ways to achieve theses goals. Renovating existing basement floors, particularly earth floors, can help prevent the entry of radon gases into the home.
Simply coating basement floors with epoxy paint can dramatically reduce emissions. Homeowners can also seal cracks and openings in walls and floors, and around pipes and drains to help prevent the release of radon from the ground into the building. Lastly, opening windows and filtering indoor air reduces any radon buildup in the home. Low cost Radon testing kits are available on the market.
For further ideas or more information on radon gas, please visit: Health Canada, It's Your Health: Radon at http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/environ/radon-eng.php.
● A Citizen's Guide to Radon. Radon - Indoor Air - from U.S. Environmental Protection Agency (EPA).
● Radon by Howard Frumkin, MD, PHD, and Jonathan M. Samet, MD. "Radon-222 is a colorless, odorless, radioactive gas that forms from the decay of naturally occurring uranium-238. Since U-238 occurs in soil and rock throughout the world, radon exposure is universal; radon is present not only indoors but outdoors . . . Exposure to radon is also a known cause of lung cancer in underground miners of uranium and other ores. Thus, its presence in indoor air has raised concern that it may also be a cause of lung cancer for the entire population . . . Radon decays with a half-life of 3.8 days into a series of solid elements called radon progeny. Among these elements - polonium-218, polonium-214, lead-214, and others - are several that emit alpha particles . . . While alpha particles do not penetrate deeply into tissue . . . they do carry enough energy to cause permanent changes in DNA if they reach the nucleus of a cell. As a result, when inhaled radon progeny reach the lungs, the alpha particles they emit can damage cells within the airways and thereby increase lung cancer risk."
● What Is the Radon Hotline? In the U.S.A.
● Where does radon come from? "Radon-222 is the decay product of radium-226. Radon-222 and its parent, radium-226, are part of the long decay chain for uranium-238. Since uranium is essentially ubiquitous in the earth's crust, radium-226 and radon-222 are present in almost all rock and all soil and water."
● How do we know radon is a carcinogen? "The World Health Organization (WHO), the National Academy of Sciences, the US Department of Health and Human Services, as well as EPA, have classified radon as a known human carcinogen, because of the wealth of biological and epidemiological evidence and data showing the connection between exposure to radon and lung cancer in humans."
● Radon Mitigation Techniques from HomeBuying About.com. Lowering the levels of radon gas in your home. EPA recommends you use mitigation techniques to reduce indoor radon if levels in your home are above 4 pCi/L . . . Common Radon Mitigation Methods: Soil Suction, Sealing Cracks & Openings, House Pressurization, Heat Recovery Ventilator (HRV), Eliminating Radon in Water, Radon Mitigation for Existing Homes, Radon Mitigation for New Homes.
● Radon Tips for Home Buyers: Protect your interests with contract contingencies. Includes: Radon Tips for Home Sellers.
● Radon Gas. YouTube video, 1:03 min.
● The Facts About Radon Gas - It's Deadly. YouTube video, 4:40 min.
● Radon: A Guide for Canadian Homeowners from Canada Mortgage and Housing Corporation (CMHC). Contents include: What is Radon? What is the Risk? The Canadian Guideline for Radon. How Radon Can Enter Your Home. Which Homes Have a Problem? Measuring Radon Levels. Methods for Measuring Radon. Units of Measure. Purchasing Radon Detectors and Measurement Services. Determining Your Home's Radon Level. Reducing radon levels. Reducing Radon in Existing Homes. Preventive Measures for New Homes.
● Granite counters may cause increase in radon gas levels by Times Colonist (Victoria). Can a granite countertop in the kitchen be a potential cause of lung cancer by giving off dangerously high levels of radon gas? The U.S. government agency's reply: "Some granite used for countertops may contribute variably to indoor radon levels. At this time, however, EPA does not believe sufficient data exist to conclude that the types of granite commonly used in countertops are significantly increasing indoor radon levels." Health Canada's studies show that high radon levels are not widespread in Canadian homes . . . Health Canada's guideline for exposure to radon is now 200 becquerels per cubic metre . . . Mike White owns HomePro Inspections in Ottawa . . . Radon typically enters a home through the foundations, White says, and it's usually a fairly simple matter to solve the problem by improving the ventilation.