Milwaukee water tests confirm chromium-6
Published: January 7, 2011
Tags: Biedrzycki, Carrie Lewis, chromium 6, Environmental Protection Agency, Environmental Working Group, EPA, hexavalent chromium, Leeann Brown, Milwaukee, Milwaukee Water Works, water
Tests confirmed the presence of small quantities of hexavalent chromium, a cancer-causing chemical, in the water sent to customers of the Milwaukee Water Works.
Carrie Lewis, the superintendent of the water works, said the city is not recommending any action at this point, and she said the water is safe. She also said the city is working with the Environmental Protection Agency.
“We are on top of it,” Lewis said, “and we know it is a matter of concern.”
Paul Biedrzycki, the director of communicable disease control and environmental health for the city, said the EPA promised a standard for testing and other guidance by summer but said he expects that to happen sooner.
The EPA information would determine the level of hexavalent chromium, commonly known as chromium-6, that would trigger water treatment.
In late December, the Washington D.C.-based Environmental Working Group prompted a national controversy when it released a study that found chromium-6 in the water of 31 cities including Milwaukee and Madison. The group tested 35 cities and 25, including both cities in Wisconsin that were tested, showed amounts higher than the health goal that has been proposed for water in California.
Leeann Brown, a spokeswoman for the environmental organization, said her group took the samples last spring and completed its analysis at about the same time last fall that the EPA released a draft of a study that found the amount of chromium-6 in much of the nation’s tap water likely would be a danger to humans.
The environmental group’s test of Milwaukee’s water showed .18 parts per billion of the chromium-6.
Milwaukee tested raw water, treated water and tap water from each of the two treatment plants on three different dates. Two of the three samples detected chromium-6, but only one of the three was as sensitive as the test run by the environmentalists. The results of the most sensitive test were slightly higher than those of the environmentalists.
The amount detected is equivalent to a teaspoon of water in an Olympic-size swimming pool, Lewis said.
Biedrzycki said a generally accepted standard for determining a substance is carcinogenic is whether there is a risk of more than one cancer case in a million over 70 years.
The EPA also would have to do a cost-benefit analysis before issuing regulations.
“It’s quite a balancing act,” Brown said. “How do you weigh the risk against the cost of a human life? The legal standards don’t look at just the health concerns.”
Lewis said the Milwaukee tests are indicative of a broader exposure to the chemical.
“The results show that chromium-6 is present at very low levels in Lake Michigan,” Lewis said. “Our treatment plants are not designed to remove it right now.”