December 21, 2010
By Algis G. Laukaitis, Lincoln Journal Star
Chromium, a known human carcinogen, is in the drinking water in Lincoln and other communities across Nebraska, but at very low levels, officials say.
"We test for it," said Jerry Obrist, chief engineer of the Lincoln Water System.
On Monday, an environmental group released a study showing that chromium-6 was detected in 31 of 35 tap water samples collected in major cities across the U.S.
The tests were commissioned by the Environmental Working Group, a Washington, D.C.,-based research and advocacy organization that works to protect public health and the environment.
Lincoln was not among the 35 cities tested.
Obrist said the total chromium level in the city's drinking water is 4 parts per billion, well below the 100 ppb limit set by the U.S. Environmental Protection Agency. Total chromium includes chromium-3, an essential mineral that regulates glucose metabolism, and chromium-6, which has been found by the National Toxicology Program to cause cancer in laboratory animals, increasing the risk of gastrointestinal tumors.
Chromium-6 is the hard metallic element found in drinking water in the 2000 Hollywood film, "Erin Brockovich."
Jack Daniel, in charge of public water systems for the state Department of Health and Human Services, said none of Nebraska's nearly 1,300 drinking water systems in 600 communities exceed the federal standard for chromium.
"We don't have anything close to 100 parts per billion," he said.
Daniel and Obrist said they do not know how much chromium-6 is in the drinking water because their tests don't differentiate between chromium-6 and chromium-3.
"We don't differentiate because the standard does not call for it," Daniel said.
Chromium-6 is a recognized carcinogen, he said. "The question is, at what level?"
Under state and federal law, anything under 100 ppb is considered safe, Daniel said.
"I'm sure in some areas (of the world) when they run into problems it's at much higher levels than we have here," said Obrist. "It's something we need to make sure of -- that it's not an issue for us, and so far it isn't."
Omaha was one of the 35 cities tested by the Environmental Working Group, and its total chromium levels range from 1.8 to 7.1 ppb, according to Mari Matulka, spokeswoman for the Metropolitan Utilities District.
"We share the results of our water quality tests every year with all of our customers through the consumer confidence reports we send with bill statements," she said in an e-mail. The reports are also posted on the M.U.D. website.
Lincoln Water System also issues an annual water quality report, which is sent to customers and posted at www.lincoln.ne.gov <http://lincoln.ne.gov/> (keywords: "water quality").
Last year, California officials proposed setting a "public health goal" for chromium-6 in drinking water of .06 parts per billion to reduce cancer risk.
Twenty-five of the 35 cities tested exceeded the safe limit proposed by California officials, according to the Environmental Working Group study. The highest levels of chromium-6 were found in Norman, Okla., Honolulu, Hawaii, and Riverside, Calif.
Chromium-6 gets into water supplies after being discharged from steel and pulp mills as well as metal-plating and leather-tanning facilities. It can also pollute water through erosion of soil and rock.
An EPA evaluation of new health effects data on chromium-6 is set to be completed late next year.
Obrist said his department will wait for guidance from EPA.
"It can be removed," he said. "It's a costly process to do it."
To track the status of the ongoing risk assessment:
http://cfpub.epa.gov/ncea/iristrac/index.cfm?fuseaction=viewChemical.showChemical&sw_id=1107