The California Environmental Protection Agency has issued the nation’s first public health goal for hexavalent chromium, the cancer-causing heavy metal made infamous after activist Erin Brockovich sued in 1993 over contaminated groundwater in the Mojave Desert town of Hinkley, about 100 miles northeast of Los Angeles.
At that time, the average hexavalent chromium level in Hinkley’s water was 1.19 parts per billion (ppb). The new state goal was set Wednesday at 0.02 ppb, the level of the element that does not pose a significant health risk in drinking water, according to state officials.
That means for every million people who drink tap water with that level of hexavalent chromium every day for 70 years, there would likely be one additional case of cancer attributable to exposure to the metal, state officials said.
The new goal is not an enforceable standard, but “will be an important tool that the Department of Public Health will use” to develop one, said George Alexeeff, acting director of the department’s Office of Environmental Health Hazard Assessment.
Other state environmental officials offered reassurances that the new goal did not indicate any increased threats from hexavalent chromium, also known as chromium 6.
California environmental officials have detected hexavalent chromium in the drinking water of an estimated 13 million people in 52 of the state’s 58 counties, including Los Angeles.
At least 74 million Americans in 42 states drink chromium-polluted tap water, much of it probably tainted with hexavalent chromium, according to studies by the nonprofit Oakland-based Environmental Working Group. They also found chromium 6 in tap water from 31 of 35 cities tested last year, with some of the highest levels in Riverside (1.69 ppb) and San Jose (1.34 ppb).
Chromium 6 occurs naturally in some drinking water, and many people don’t even know they are drinking it. More often, it enters the water supply from industrial contamination, leaching from sites such as the former disposal ponds of Pacific Gas & Electric’s Topock Compressor Station in Hinkley, near Barstow. It can be removed using expensive reverse osmosis filters.
State officials said the new goal reflected recent research suggesting that young children could be more susceptible to health risks from exposure to chromium 6. Mice and rats that drank water containing high levels of the element developed gastrointestinal tumors, according to a 2007 study by the National Toxicology Program.
Environmentalists praised the new state goal, saying they hoped it would pressure state and federal officials to set enforceable standards for the metal and other drinking water contaminants. After California regulated another such contaminant, perchlorate, other states followed suit and the U.S. Environmental Protection Agency has reconsidered its standard.
“It’s better to know than not to know,” said Dr. Gina Solomon of the San Francisco-based Natural Resources Defense Council of chromium 6 levels in drinking water. “We want to know about it so that water utilities can deal with it and get the levels down.”
California lawmakers passed legislation in 2001 requiring an enforceable drinking water standard for chromium 6 by 2004. State public health officials are still working on that standard. It will take at least 18 months to propose and 2 1/2 years to approve, according to Mike Sicilia, a spokesman for the state Department of Public Health.
California environmental officials cautioned that until the standard is set, the state goal is “not a regulatory level for cleanup of groundwater or surface water contamination” and cannot be used to justify investigations where residents suspect their water is making them sick, such as in Hinkley or the San Joaquin Valley’s Kettleman City.
The national drinking water limit for chromium is 100 ppb, but water system monitors are not required to distinguish what percentage of that is chromium 6 versus other less harmful ions such as chromium 3. But U.S. EPA officials recommended in January that water systems start testing for chromium 6, and EPA Administrator Lisa Jackson has said the agency will probably revise its standards soon.