Organic Consumers Association

Campaigning for health, justice, sustainability, peace, and democracy

Report Points to Cancer Risk From Chemicals Used to Treat Drinking Water

For related articles and more information, please visit OCA's Health Issues page and our Food Safety Research Center page.

Chemicals used to treat drinking water for millions of Americans may raise the risk of cancer and lead to other unintended health hazards, according to a report released today by the Environmental Working Group, an advocacy organization.

The group is urging the U.S. Environmental Protection Agency to reevaluate its standards for the byproducts created when water is disinfected. The Environmental Working Group also is pushing officials to clean up sources of public drinking water to reduce the need for chemical treatment in the first place.

"By failing to protect source water, Congress, EPA and polluters leave Americans with no choice but to treat it with chemical disinfectants and then consume the residual chemicals generated by the treatment process," the report says.

Chlorine and other chemicals are added to public drinking water to kill disease-causing bacteria and other microorganisms. But when they come into contact with organic material such as fallen leaves, sewage or livestock manure, reactions occur that create toxic byproducts.

Some of the resulting compounds are regulated, but most are not. "We're talking about 600 known disinfection byproducts and probably many hundreds more that haven't been identified," said Renee Sharp, a senior scientist at the Environmental Working Group and a co-author of the report.

Researchers analyzed results from water quality tests done in 2011 at 201 large municipal water systems that serve more than 100 million people in 43 states. They found trihalomethanes, a byproduct of chlorination, in every system. The EPA calls some members of this class of chemicals "probable human carcinogens" and studies have linked them to bladder cancer, birth defects and miscarriages. However, only one water treatment system exceeded the EPA's limits for the chemicals, which was set at 80 parts per billion in 1998.

But the report argued that the EPA's limits are too lax, citing several studies linking even lower levels of the chemicals to health problems. For example, in 2011 a French research team analyzing data from three countries found that men exposed to more than 50 parts per billion of trihalomethanes [try-hal-o-MEH-thanes] had significantly increased cancer risks.

In 2007, Taiwanese researchers found people who drank water with trihalomethane concentrations of more than 21 parts per billion had twice the odds of dying from bladder cancer than those who did not. In 2010, California environmental health regulators proposed a public health goal for trihalomethanes of 0.8 parts per billion - one-hundredth of the federal standard. The goal, which would not be legally binding, is in the process of being finalized.
Get 20% off Mercola products, plus 20% of the sale goes to Organic Consumers Association.

Get Local

Find News and Action for your state:
Regeneration International

Cool the planet.
Feed the world.