WEDNESDAY, Jan. 9, 2002 (HealthDayNews) -- Chemicals in tap water threaten the pregnancies of nearly 140,000 American women each year, according to a new study by two environmental advocacy groups.
The chemicals, called chlorinated by-products (CBPs), have been linked to miscarriages and birth defects, the groups say, as well as up to 9,300 cases of bladder cancer a year. Chlorinated by-products are created when the microbe-killing additive mixes with organic compounds that enter the water supply through sewage and runoff from farms, urban areas and other sources. These chemicals, which include chloroform, are largely unstudied and mostly unregulated.
The report, from the Environmental Working Group and the U.S. Public Interest Research Group, says that between 1996 and 2001, more than 16 million Americans were exposed to water with CBP levels above the latest federal safe threshold for at least 12 months running. Some of those readings were between five and 10 times greater than the upper limit, which the Environmental Protection Agency lowered this year to 80 parts per billion (ppb).
Officials tightened the threshold because of the link between CBPs and bladder cancer, and the EPA expects the reduction to prevent about 2,000 cases a year. But the agency hasn't yet acted on studies linking the chemicals to reproductive problems in women.
The new report found that the number of pregnant women at risk is highest in large metropolitan areas, especially Washington, D.C., Philadelphia, Pittsburgh, and San Diego. Montgomery County, Md., a suburb of Washington, D.C., ranked first in the proportion of pregnant women (58 percent) exposed to CBPs above 80 ppb for an entire trimester. Texas led all states with the total number of pregnant women at risk of high CPB exposure each year, with more than 26,500.
But peak levels of the potentially harmful chemicals are highest in small, rural communities where utilities are less heavily regulated, says Jane Houlihan, research director for the Environmental Working Group.
The environmental advocates say that while chlorinating saves lives by destroying pathogens, it's no substitute for improving the quality of the nation's water supply.
"We're in a situation where many of our water sources are polluted to the point where we have to bombard the water with chlorine at the treatment plant," Houlihan says. "A comprehensive solution would involve more resources for cleaning up rivers and streams, larger buffer zones on agricultural lands to reduce runoff, and more funds to minimize sprawl."
But at least one scientist dismisses the report's conclusions. Dr. Anthony Scialli, a Georgetown University women's health expert, calls the data linking CBPs to miscarriage "very unconvincing" and says he has "no idea" where the claims of a connection to birth defects comes from.
None of the earlier studies tying tap water to miscarriage has proven that CBPs are in fact the reason for the alleged association, Scialli says. What's more, animal studies have shown that whatever adverse effects might occur don't appear until the creatures consume 10,000 to 100,000 times the doses of CBPs women ingest by drinking a liter of water a day.
The chlorine industry defended the chemical, which has been added to the nation's water supply for a century as a way to kill microbes. "There is no conclusive link," between chlorine and pregnancy problems, says Jeff Sloan, director of disinfection policy for the Chlorine Chemistry Council in Washington, D.C.
The EPA is currently working with representatives from industry and environmental groups to forge new regulations for CBPs, but these will not seek to lower the most recent mark of 80 ppb in drinking water, Sloan says. Rather, the agency is trying to come up with better ways of bringing down peak levels of the chemicals.
In a statement released today, EPA says it "agrees with the EWG's report that the presence of disinfection by-products in drinking water is an important public health concern." The agency also says it will propose new rules this summer to "mitigate reproductive and developmental risks" associated with the chlorine chemicals.
Catherine Milbourn, an EPA spokeswoman, wouldn't discuss the details of the pending regulations.
What To Do
If you're pregnant and worried about CBPs, install a carbon filter on your drinking water tap, environmental advocates say. You can also drink bottled water, but many brands contain the chemicals without noting it on the label -- so it might require a bit of research to find out which ones are free of the contaminants, Houlihan says.
Because some CBPs are also volatile and can be absorbed through the skin, Houlihan recommends that pregnant women take shorter showers and baths.
For more on the latest report, try the Environmental Working Group.
The EPA has a safe water hotline you can call toll free (800-426-4791) for the latest information on drinking water quality. Or, contact your local water agency.
To learn more about exposure to environmental chemicals, check out Health Canada, a service of the Canadian government.
