Drinking, Bathing or Swimming in Chlorinated Water May Increase Your Risk of Bladder Cancer

Chlorinated water may increase your risk of bladder cancer, whether you drink it, bathe in it or swim in it, according to a study of over 1,000 people. The study is the first to support what I have been saying for some time: that chemicals in water are not only harmful when ingested, but also when they are absorbed through the skin or inhaled.

In fact, this new study found that swimming and showering in chlorinated water may be even worse than drinking it. While study participants who drank chlorinated water had a 35 percent greater risk of bladder cancer than those who didn’t, those who swam in chlorinated pools had a 57 percent greater risk. Meanwhile, those who took longer showers or baths in areas with higher trihalomethanes (THM, a chlorine by-product) levels also had an increased cancer risk.

THM, while potentially dangerous when ingested, may be even more detrimental when it is absorbed through the skin or lungs because it does not undergo detoxification via the liver.

While installing a reverse-osmosis filter to purify your drinking water is a good step, you could still be exposed to contaminated water when you:

  • Shower or bathe
  • Wash your hands
  • Wash laundry
  • Rinse fruits and vegetables
  • Wash dishes, glasses, and other utensils

To protect your family's good health, you should have your water professionally analyzed to find out what's in it. If it's currently safe, then having a small point-of-use filter is a nice added level of protection. But if you find contamination, you should seek expert advice as to what treatment system can remove it.

American Journal of Epidemiology January 2007, Volume 165, Number 2, Pp. 148-156

ScientificAmerican.com January 18, 2007