PHOENIX — More than 200 million Americans drink water containing potentially dangerous amounts of a carcinogen made famous by environmental activist
The average water sample in Phoenix had the highest level of the toxin among water utilities nationwide serving more than 1 million customers, with almost 400 times the amount of chromium-6 that California scientists set as a health goal. But because that number is an average, it doesn't quite represent the levels of chromium-6 in the water that customers drink, a city water official said.
Samples from city wells had the highest levels of the contaminant but contribute a small fraction to the tap, said Susan Kinkade, a Phoenix civil engineer. Taking that into consideration, chromium-6 levels in Phoenix drinking water are on average about 20 times the California goal.
The report also found that Glendale's water had an average chromium-6 level 320 times the health goal. But like Phoenix, the higher levels dwell in groundwater that contributes far less to the water supply than surface water, said Doug Kupel, deputy director of water services in suburban Glendale.
Glendale is already setting aside money in anticipation that the U.S. Environmental Protection Agency will mandate a new limit for chromium-6, he said.
Reaching California's legal limit of 10 parts per billion would be expensive — but reaching the health goal of .02?
"I don't think that's feasible really across the nation," Kupel said.
"Goal" is a key word there: The EPA's total chromium limit is 5,000 times the health goal, and based on preventing skin reactions. California is the only state that established a limit specifically for chromium-6, according to the non-profit Environmental Working Group, which authored the report released Monday.
But that is 500 times the amount that the California Office of Health Hazard Assessment recommended and reflects a risk that 500 people out of a million will get cancer.
Chromium-6 gained national attention in the 1990s when then-legal clerk Erin Brockovich helped residents in Hinkley, Calif., settle a massive case against Pacific Gas and Electric Co. The electric utility had polluted the groundwater with cancer-causing chemicals, which Brockovich linked to illnesses in the town.
The toxin leaches into water either naturally or from industrial runoff. Chromium is an abundant element in Earth's crust, found in rocks, plants, soil, volcanic dust, humans and animals, according to the non-profit American Water Works Association.
But research has linked chromium-6, created when chromium oxidizes, to stomach cancer. And the EPA reported in a draft risk assessment in 2010 that chromium-6 is likely to be carcinogenic to humans.
People trying to reduce their exposure to the contaminant at home can buy reverse osmosis systems for their faucets. But keep in mind that the national standard allows more chromium-6 than California does. So read the details carefully about just how much chromium-6 the system will weed out, said Andrew DiLuccia, spokesman for the California Water Resources Control Board.
The EPA has a limit for chromium, but the agency required water utilities serving more than 10,000 people to test specifically for its most harmful state, chromium-6, from 2013 to 2015. A small fraction of small systems were also required to test. The stuff turned up in more than 75 percent of the 60,000 water samples, according to the Environmental Working Group report.
The agency is considering establishing tighter limits for chromium-6 in drinking water, but cleanup costs nationwide may be a barrier. California is looking at a $20 million-per-year price tag just to meet its legal standard, according to an estimate by the California Department of Public Health.
Chromium-6 is one of many contaminants up for review for heavier standards. The EPA has put 81 compounds on that list since 1996 but has only set new limits for one, said Bill Walker, the managing editor at Environmental Working Group.
A goal of Monday's report is to pressure the EPA to set new standards on chromium-6, he said. It was the group's own testing in 2010 that pushed the agency to add chromium-6 to the 2013 to 2015 testing schedule.
But Walker said he didn't know when or if the agency would act.
"They get lobbied. They're getting heavy, heavy pressure from industry," he said. "We would like to see EPA have a stronger stance toward favoring health as opposed to listening to the arguments of industry."
The EPA would not comment on the specifics of the group's report because staff there had yet to see it. The agency released a statement saying that the EPA is working on a "comprehensive evaluation of potential health effects" of chromium-6. A draft assessment will be released for public comment in 2017, the agency expects.
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