Chlorinated Water By-Products May Increase Bladder Cancer Risk
Sunday, January 21st, 2007
In a recent study published in the American Journal of Epidemiology, researchers found that long-term exposure to trihalomethanes (THMs) may significantly increase bladder cancer risk. THMs are created when chlorine, which is used as a water disinfectant, comes in contact with organic matter in the water system, such as leaves, branches, etc.
The study’s authors examined over 1,219 people with bladder cancer and 1,271 control people without the disease. They found that long-term exposure to high THM levels through drinking, bathing, and swimming in chlorinated water significantly increased bladder cancer risk.
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Individuals who drank chlorinated water were at 35% greater risk for developing bladder cancer.
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Individuals taking the longest showers had an 83% greater risk of getting bladder cancer.
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Individuals who regularly swam in pools with chlorinated water were 57% more likely to develop bladder cancer.
Overall, households with long-term exposure to THM levels greater than 49 mcg/L had more than a two-fold increased bladder cancer risk versus households in areas with THM levels less than 8 mcg/L.
THM levels are monitored by water municipalities, with current regulations limiting THM levels in treated water to 80 mcg/L. Water municipalities in industrialized countries often have THM levels greater than 50 mcg/L. As noted above, such levels of chronic THM exposure may put consumers at risk.
Your best bet for avoiding both chlorine and their THM by-products is to use an in-home water filter. You can find information on different filters and what contaminants they remove through NSF International’s water treatment unit review database.
Note that not all filters remove THMs. It’s important to check the review listings to make sure the one you’re considering purchasing will remove THMs and other contaminants of potential concern, such as heavy metals.
