Scientists studying chromium photo by Argonne National Laboratory
Chromium 6 or Hexavalent chromium is a carcinogenic pollutant made famous by Erin Brockovich. California's new goal for the pollutant, set by the state's Environmental Protection Agency, was set on Wednesday at 0.02 parts per billion. This is the level of the element that the state believes is not likely to cause a significant health risk in drinking water. Environmentalists supported the goal. The only shortcoming with the goal is that it is not an enforceable standard yet. This is another case where California is leading the nation, as the federal government has not yet set a national limit and does not require water systems testing to distinguish chromium 6 from other less harmful types of chromium.California lawmakers passed legislation in 2001 requiring an enforceable drinking water standard for chromium 6 by 2004. The recently state goal will be used as a tool by state public health officials who are still working on an enforceable standard. The enforceable standard will likely not be set until 2014.
Chromium 6 became well known in 1993, when Erin Brockowich sued PG&E; for contaminating the groundwater in Hinkley, California, with the chemical. In 1993, the level of chromium 6 in Hinkley's water was 1.19 parts per billion (ppb).
But Hinkley is not the only city with high levels of chromium 6. California environmental officials have detected chromium 6 in the drinking water of approximately 13 million people in 52 of the state's counties, including Los Angeles. Oakland-based Environmental Working Group, an environmental NGO, found chromium 6 in tap water in 31 out of 35 cities tested. The highest levels were found in Norman, Oklahoma; Honolulu, Hawaii; and Riverside, California.
The new chromium 6 goal reflected recent research suggesting that young children could be more susceptible to health risks from exposure to this pollutant. A 2007 study found that rodents drinking water with high level of chromium 6 developed tumors.
Although chromium 6 occurs naturally in some drinking water, elevated levels can cause cancer. It can be removed, but it is an expensive process that uses reverse osmosis filters, so it likely will not be cleaned up to higher standards until the state standards are set. Once California sets the regulatory standard for chromium 6 at this target level, Treehugger hopes the federal government will follow suit.