Omaha joins water debate
Omaha is one of several U.S. cities thrust into a starring role this week in a scientific debate over a chemical in drinking water -- the one in the movie "Erin Brockovich" -- and whether the federal government is moving too slowly to regulate the suspected cancer-causer.
The Environmental Working Group, a national nonprofit organization that lobbies for tougher water rules, issued a report this week that said drinking water tests in 31 cities found hexavalent chromium, or chromium-6, at levels higher than one proposed in California to limit the possible cancer risk to one in a million.
California's proposed limit is .06 parts per billion. Omaha's water tested at 1.07 ppb, the EWG said. Several cities had similar levels, and Norman, Okla., tested highest at 12.90 ppb.
Yet no city's water exceeded the federal standard for chromium-6, because there is none.
The U.S. Environmental Protection Agency is studying the chemical -- the review is in the public comment phase -- with a goal of deciding next year whether a limit should be set.
Until the EPA acts, water officials in Iowa, Nebraska and Omaha say they must stick with current testing methods, which they say ensure safety.
"We're very proud of our safe drinking water," said Mari Matulka, a spokeswoman for Omaha's Metropolitan Utilities District.
The issue is complex, mainly because chromium is.
The metal comes in several forms. The chromium-6 variant is toxic and thought to cause cancer. But chromium-3 is an essential nutrient, used by the body to convert food into energy. And some processes -- including human stomach acids -- can convert an unknown amount of the toxic form into the good form.
Chromium also has complex sources. It's used in some industrial processes, such as in tanning leather and making stainless steel products, which can lead to waterway pollution -- the situation depicted in the Julia Roberts movie.
But chromium also occurs naturally, as water erodes soil and rock.
The argument is part of a wider, growing debate over how aggressively government should move to regulate various chemicals in water when the potential harm is uncertain and when the costs and benefits of removing them are unclear.
In recent years, scientists have focused on an array of unregulated industrial chemicals and pharmaceutical drugs that are not filtered out by conventional water treatment methods -- even as they learn more about how the substances behave in the human body.
For instance, though "Brokovich" was a box office hit in 2000, the science behind the film is far from clear cut. The underlying real-life story was a pollution lawsuit that Pacific Gas and Electric settled for $333 million in 1996. Yet this week, the Los Angeles Times reported that three studies by the California Cancer Registry have found only normal cancer rates for two decades in Hinkley, the town the movie made famous.
"For years, scientists assumed this wasn't a problem because acids in our stomachs can convert chromium-6 into chromium-3, an essential nutrient," said Rebecca Sutton, a scientist for the Environmental Working Group. "Newer science is showing our stomachs can't take care of everything, which means the dangerous form of chromium is getting into our bodies and can cause damage."
The group says the EPA's current limit, lumping chromium-6 together with chromium-3, is illogical, "like grouping arsenic and vitamin C."
The group has long urged the EPA to take a more aggressive regulatory stance, arguing that it is better to be safe than sorry. Industries and water utilities must bear the costs of new requirements and tend to favor a slower, make-sure-it's-worth-it approach.
Most of the total chromium in Nebraska's and Iowa's drinking water probably is naturally occurring, because there aren't many obvious industrial sources, environmental officials in both states said, although some in Omaha's water might arrive from industries upstream on the Missouri River.
Treatments to remove chromium would be similar to those for other metals, such as reverse osmosis, one method used to filter out arsenic, a more common contaminant in Nebraska, said Jack Daniel, head of the drinking water program at the Nebraska Department of Health and Human Services.
One complication of the debate, said Diane Moles, a data analyst at Iowa's Department of Natural Resources, is the difficulty of reliably measuring chromium in such minute quantities.
Not all researchers are convinced that state-of-the-art testing can faithfully gauge chromium-6 at the levels described by the Environmental Working Group, she said. Moles predicted that the EPA would add chromium-6 to its watch list, marking it as a chemical whose risks need further study.
EPA Administrator Lisa Jackson on Tuesday promised senators from seven states that her agency would finish its review by next summer and decide whether to order cities to start testing their water.
The EPA said in September that chromium-6 probably causes cancer in humans.
NSF International, a nonprofit group that tests water filtration systems, says homeowners can reduce chromium levels with reverse osmosis technology or special distillation or filtration products. Inexpensive carbon filters, it said, are not certified to address chromium.
December 23, 2010
EPA to urge testing for chromium-6 in water
The U.S. Environmental Protection Agency, responding Wednesday to an advocacy group's criticism of chromium-6 in the drinking water of 31 cities, including Omaha, said it would soon recommend -- but not require -- that water utilities start testing for the metal.
To track the status of the ongoing risk assessment: