Chromium-tainted drinking water: Time for a federal crackdown?
Even though scientists at the U.S. Environmental Protection Agency and National Toxicology Program have linked the ingestion of hexavalent chromium to cancer, the EPA doesn't require cities to test for the toxic metal. Nor does the EPA limit the dangerous form of chromium in drinking water.
To take a snapshot of what is flowing through taps across the nation, the Environmental Working Group, a Washington, D.C.-based nonprofit organization, hired an independent laboratory that found the metal in treated drinking water from 31 cities. The amount in Lake Michigan water pumped to 7 million people in Chicago and its suburbs was 0.18 parts per billion, three times higher than a limit California officials proposed last year.
A handful of other cities were significantly above the proposed California limit, including Norman, Okla.; Honolulu; Riverside, Calif.; and Madison, Wis., according to a report released Monday. In other major cities, hexavalent-chromium levels ranged from 0.20 parts per billion in Los Angeles and Atlanta to 0.18 in New York and 0.03 in Boston.
The new findings pose another challenge for utilities that are detecting dozens of unregulated substances in treated drinking water, including pharmaceutical drugs and industrial chemicals that can pass unfiltered through conventional treatment methods. Hexavalent chromium, also known as chromium-6, can be found naturally in the environment but also is released by industry into waterways.
Although the potential health threats of many pollutants are still being studied, researchers say there is a clear risk of stomach cancer from drinking water contaminated with hexavalent chromium.
Studies outlining the dangers of chromium-contaminated water add to longstanding concerns about inhaling metallic vapors, in particular by workers at chrome-plating factories.
Industry has fought for years to block tougher federal and state limits on chromium, which has contaminated drinking-water supplies across the country. The movie “Erin Brockovich” dramatized one of the most high-profile cases: a miles-long plume of hexavalent chromium dumped by a utility in rural Hinkley, Calif., that led to a $333-million legal settlement over illnesses and cancers.
California often sets environmental policies that later are adopted nationwide. As the scope of the chromium problem has become more apparent, drinking-water utilities that could be forced to improve treatment methods have joined companies that discharge the metal into waterways in opposing regulations.
Attorneys for both interest groups delayed California's proposed safety limit by requesting an independent review of the science behind it. They also are questioning peer-reviewed findings by California and federal scientists by commissioning their own research.
“Honeywell is committed to protecting health and the environment,” a lawyer for the aerospace conglomerate wrote in a November 2009 letter to California officials. “We also believe that decisions about chemical risks and cleanup goals must be based on sound science.”
Since then, four of the five reviewers who took another look at California's proposal supported the state's conclusions. One reviewer, Mitchell Cohen of the New York University School of Medicine, said the chromium limit “should be accepted as one based upon sound scientific knowledge, methods and practices.”
Environmental officials in New Jersey also have backed the proposed California limit. And in September, the EPA published a draft review that found hexavalent chromium in drinking water is “likely to be carcinogenic in humans.” The EPA's report could be the first step toward a national standard.
Outside of California, several drinking-water officials said they were not aware of the ongoing debate.
“This is new territory for us,” said Tom Heikkinen, general manager of the water utility in Madison, where the amount of hexavalent chromium was 1.58 parts per billion, more than 26 times higher than the proposed California safety limit. “We're going to be following this closely to see what the scientists and regulators say.”
Officials at the Chicago Department of Water Management did not respond to repeated inquiries last week, but other water officials said tap water was still safe. Bottled water, which often comes from municipal supplies, wasn't tested.
Lon Couillard, water quality manager in Milwaukee, said more study was needed to determine the sources of chromium. He suggested that in some cases it could be coming from chrome-plated plumbing fixtures, not passing through municipal treatment plants.“They're trying to scare people,” Couillard said of the environmental group that found hexavalent chromium in his city's tap water.
The source of chromium in Chicago drinking water is unclear, though federal records show that some of the nation's biggest industrial sources are four steel mills in northwestern Indiana that discharge waste water into the city's source of drinking water.
-- Michael Hawthorne, Chicago Tribune
Photo: In Hinkley, Calif., a battle over chromium-tainted groundwater has been raging for a decade. In 2001, a caution sign hung on a fence surrounding a Hinkley farm that irrigated with tainted water. Credit: Robert Gauthier/Los Angeles Times