Chlorinated tap water called risk for pregnant women

San Francisco Chronicle, Jane Kay

Published January 9, 2002

Pregnant women who drink chlorinated tap water face a higher risk of miscarriage and birth defects in their newborns despite tougher new standards, says a study by two environmental groups.

The Environmental Working Group and the Public Interest Research Groups released the study yesterday, charging that even the federal standards that took effect Jan. 1 don't protect millions of Americans.

Chlorine is commonly used to disinfect drinking water. When it is added to water that contains organic matter such as runoff from farms or lawns, however, it can form compounds called trihalomethanes (THMs) that have been linked to cancer, miscarriages and birth defects.

"People think they can chlorinate their way to safe water, and they can't do it," said Bill Walker, West Coast representative of the Environmental Working Group. "Chlorine itself has some risks. Wouldn't it be smarter to simply prevent the pollution of the water in the first place?"

However, C.T. Howlett Jr., executive director of the Chlorine Chemistry Council, said government agencies found no compelling link between reproductive hazards and chlorinated water.

He said chlorine had been added to drinking water for more than a century, and the environmental groups' study "may unnecessarily alarm the public and, in particular, pregnant women, about risks that are not supported by scientific evidence."

In the study, the two environmental groups examined water-quality data submitted by thousands of water utilities in 30 states between 1995 and 2001. They then evaluated the data using academic and government risk assessment studies.

Their conclusion: Millions of pregnant women were at a higher risk of miscarriage and birth defects in their babies as a result of exposure to the chlorine byproducts in their tap water.

Even the tighter drinking water standards to limit disinfectant byproducts aren't strict enough to protect Americans, the study said.

This month, a new limit of 80 parts per billion of chlorine byproducts went into effect for public water utilities, down from 100 parts per billion.

Responding to the study, Corine Li, the U.S. Environmental Protection Agency's manager of the drinking water office in San Francisco, said: "Based on the information that we have, the new stringent standard provides the safest balance of ensuring protection from microbial contamination in drinking water and the impacts from exposure to disinfection byproducts."

However, she said, the EPA is in the midst of conducting research on the health effects of the byproducts, and may recommend stronger standards in the future.

In the Bay Area, the large water systems -- including San Francisco Public Utilities Commission, East Bay Municipal Utility District, Santa Clara Valley Water District and Alameda County Water District -- are serving

The latter three water companies have already switched from chlorine to chloramine, a disinfectant that produces fewer THMs. San Francisco is making the switch to chloramine as part of an improvement program begun three years ago.

Beverly Hennessey, a PUC spokeswoman, took issue with the study. "Anyone can send out a press release," she said. "Our Health Department reviewed the environmentalists' study, and we have no reason to believe there's any cause for concern."

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