California took the first step Thursday toward setting a drinking water standard for chromium 6 that could force cities and water districts to undertake costly treatment.
Also known as hexavalent chromium, the heavy metal is one of a number of industrial contaminants in the San Fernando Valley aquifer, a source of drinking water for Los Angeles, Burbank and Glendale.
The communities now cut chromium levels by blending local groundwater with imported supplies. But the target concentrations proposed by the state are so low that sophisticated treatment would be necessary to meet them.
"We'd have to treat for it or we can't use the groundwater," said Bill Mace, an assistant general manager at Burbank Water and Power, which gets 40% to 50% of its supplies from the valley aquifer.
Mace called the draft public health goal "shockingly low."
Released by the state Office of Environmental Health Hazard Assessment, the goal will be used to set a state standard for chromium 6. But that process will probably take several more years and "it's possible the eventual standard would be higher," said Sam Delson, deputy director for external and legislative affairs.
It would be the first drinking water standard for chromium 6 in the country.
About 18% of the public drinking water sources in California have chromium 6 levels above 1 part per billion. The proposed public health goal is 0.06 part per billion.
"We do want to stress it's a goal," Delson said. The health threats of inhaling chromium 6 are well known. Research has found lung and gastrointestinal cancers in people who breathed it on the job. But whether it is carcinogenic in drinking water has been the subject of controversy, since some of it is converted to chromium 3 in the digestive system.
The health office cited a 2007 National Toxicology Program study that found a significant number of tumors in rats and mice that drank water laced with chromium 6.
Peter Kavounas, assistant general manager at Glendale Water & Power, said even if the standard eventually adopted is higher than the 0.06 goal, treatment will be necessary.
"I'm not uncomfortable with the goal," he said.Glendale draws about 25% of its water from the valley aquifer and is testing two treatment techniques to remove chromium 6.
Dr. Pankaj Parekh, director of water quality for the Los Angeles Department of Water and Power, said he was "confident that whatever drinking water standard is ultimately set, we will be able to meet it."
The San Fernando Valley aquifer is a federal Superfund site, and the industries that polluted the groundwater have paid for ongoing treatment of other contaminants.
The U.S. Environmental Protection Agency has begun the process of identifying companies responsible for the chromium contamination.