New Fears Raised Over Safety of D.C. Water

Toxic chlorine pollutants were found at unsafe levels in 40 percent of D.C. tap water samples tested this spring during the water utility's annual chlorine surge, according to a national environmental group's report to be released today.

The nonprofit Environmental Working Group conducted tests at 18 sites -- including private homes, an elementary school, the U.S. Capitol and the Environmental Protection Agency -- to measure the levels of chlorine toxins that could cause cancer, reproductive problems and developmental delays in children. In 90 percent of the samples, the tests found another class of chlorine toxin at levels that some epidemiological studies have associated with low birth weight and serious birth defects.

The findings suggest that the chemicals needed to help make Potomac River water potable could be creating a different risk to consumers. Chlorine is used to kill disease-causing microbes. Heavy use results in chemical compounds, called disinfection byproducts, that are formed when organic matter in the river water reacts with the chlorine.

The District's water utility has reported a general decrease in chlorine toxins since it switched from treating its water with chlorine to less-potent chloramine in 2000. But environmental groups and scientists said the new findings highlight a potential problem nationwide for many water utilities that, as in Washington, have switched at the EPA's urging to the chloramines and periodically flush their systems with high doses of chlorine to kill pathogens deep in their pipes.
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