CHICO — The cancer-causing chemical chromium-6 is found in drinking water throughout the north valley, according to two national environmental groups.
According to a news release from the groups, in tests made between 2001 and 2011, chromium-6 was found at “unsafe levels” in one-third of the more than 7,000 sources of drinking water around the state. The release said the data came from the California Department of Public Health.
The more than 2,300 sources with what the groups call dangerous levels of chromium-6 were in 55 of the state’s 58 counties.
Those 55 counties included Butte, Glenn, Tehama and Colusa, according to Serena Ingre, a spokeswoman for one of the groups, the Natural Resources Defense Council.
Ingre’s group and the Environmental Working Group on Tuesday sued the state Department of Public Health, claiming the agency violated state law by not setting a “safe standard” for chromium-6 in drinking water.
Chromium-6 (also known as hexavalent chromium) occurs naturally in the ground and also enters the water supply when it’s discharged from industrial sources, said John Graham, a water-quality project manager for the California Water Service Co. in Chico. Locally, he said, chromium-6 appears to come from natural sources.
Chromium-6 is the “chemical made infamous” in the movie “Erin Brockovich” for contaminating drinking water in the California town of Hinkley, the news release said.
Graham said a number of years ago, the state required every
drinking-water system to be tested for chromium-6 just to determine how widespread it was.
Cal Water tested all the wells and other sources of drinking water in the 70 systems it operates in California, he said.
In Chico, each of the company’s more than 65 wells was tested, he said. The results for chromium-6 ranged from zero to 9.9 parts per billion, he said. The average was 2.6 parts per billion.
One part per billion means that if a billion cups of water was tested, one cup of the chemical would be found.
In 2001, the Legislature passed a law requiring the Department of Public Health to establish a standard, known as a maximum contaminant level, for chromium-6 in drinking water. The department was given until 2004 to come up with the standard, the groups’ release stated.
According to the release, the department has not created a standard, and its officials say they won’t have one for several more years. The two groups are suing to make the department act more quickly on the issue.
Asked about the lawsuit, Ken August, a spokesman for the department, wrote in an email that he couldn’t comment on it because officials in the department haven’t seen the suit.
Sam Delson, a spokesman for the California Environmental Protection Agency (Cal/EPA), said the process for setting a standard has been tortuous.
The first step, he said, was for Cal/EPA to set what’s known as a public-health goal for chromium-6.
Delson said in setting the goal, his agency first needed to find out if chromium-6 caused cancer when people drank it in water. It was known to be a carcinogen if it was inhaled.
He said Cal/EPA asked a federal agency, the National Toxicology Program, to do a study, which showed chromium-6 in drinking water was carcinogenic.
Delson said his agency was extremely conservative in setting a .02 parts per billion goal for chromium-6. It was based on “a lifetime risk of one in a million.”
That means “if a million people drank water everyday for 70 years with that level (of chromium-6) we would expect it to cause one additional case of cancer,” he said.
The Department of Public Health is supposed to base its standard (maximum contaminant level) on the public-health goal.
“They are required to set the standard as close to the goal as is technically and economically feasible,” he said. “We always emphasize water may be safe to drink if it contains a higher level than the public-health goal.”
Graham, of Cal Water, said invariably the maximum contaminant level is higher than the public-health goal.
His company, along with a couple of other entities, is already testing a couple of methods that could be used to remove chromium-6 from drinking water.
Staff writer Larry Mitchell can be reached at 896-7759, lmitchell@chicoer.com, or followed on Twitter
@LarryMitchell7.
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