An environmental research group says it's detected hexavalent chromium in drinking water in D.C. and Bethesda, Md.
Hexavalent chromium was made famous by the movie Erin Brockovich, where a small town discovered its groundwater was polluted by the substance. Rebecca Sutton, with the Environmental Working Group, says the same compound is in the water here.
"We're concerned about it in terms of gastrointestinal cancer. It's a well-known inhalation carcinogen, but more recently we've noticed it can cause harm to us when we are drinking it in the water," Sutton says.
But the levels detected are tiny -- 0.19 parts per billion - that's thousands of times lower than the levels in the movie, and the levels shown to cause effects in rats. That's one reason that Tom Jacobus, head of the Washington Aqueduct, which supplies D.C.'s water, isn't concerned.
"We are at the very edge, I believe, of understanding the science of these extraordinarily low levels," Jacobus says.
In a statement, the Washington Suburban Sanitary Commission, which provides water in Montgomery County and Prince George's County, said: "WSSC drinking water meets or exceeds all current standards mandated by the EPA. WSSC has never had a drinking water violation."
D.C.'s water is tested weekly for chromium, and the Environmental Protection Agency says that the region's water is well within current limits on total chromium.
There is not, however, a limit on the specific and more harmful hexavalent chromium. The state of California has proposed a limit on hexavalent chromium of 0.06 parts per billion. At that level, the state estimates there is a one-in-1 million chance of getting cancer from drinking water.
Jacobus says D.C.'s level would put the risk at three-in-one million.
"And that's not a high risk in a lifetime for anything," he says.
The EPA is expected to finish analyzing whether a hexavalent chromium standard is necessary and what such a standard might be by summer 2011.