Hexavalent chromium, also called chromium 6, came to the public's attention with the 2000 release of the movie Erin Brockovich, which focused on the contaminated drinking water of Hinkley, California. Hexavalent chromium is a heavy metal used in producing pigments, leather tanning, electroplating, metal processing, wood preservation, and in alloys such as stainless steel. It was also used to inhibit corrosion in cooling towers - the use that contaminated Hinkley's water. Drinking water sources can become contaminated by leaks and discharges from industrial facilities and hazardous waste sites.
From 1997 through 2008 hexavalent chromium was detected in 2,208 drinking water supplies, across 52 out of 58 counties, including sources serving schools and hospitals. This means that over 13 million Californians in over 500 communities have hexavalent chromium in their tap water. Individual counties may have numerous impacted communities and show a wide range of contamination levels.
Hexavalent chromium, which was added to California's Proposition 65 list (pdf) in December 2008, is a known carcinogen and a reproductive toxicant. Exposure can occur through ingestion of contaminated water, and can cause acute gastroenteritis, gastrointestinal hemorrhage, ulcers, and kidney and liver damage. Workers and residents near industrial facilities using hexavalent chromium are particularly at risk given their long term, high levels of exposure.
Despite severe health threats posed by hexavalent chromium, there is no national or state drinking water standard. Instead, it is regulated as "total chromium," which means that drinking water suppliers do not differentiate between the toxic (hexavalent) form and non-toxic chromium. The result is that drinking water supplies can legally contain unsafe levels of hexavalent chromium. To fix that problem, the California legislature passed SB 351 (Ortiz) in 2001, requiring the state to establish a drinking water standard specifically for hexavalent chromium by 2004. It is now 2011 and California still does not have a drinking water standard for hexavalent chromium, putting the state in violation of its own law!
The first step in establishing a drinking water standard is determining the safe level of the contaminant by setting a Public Health Goal (PHG). As a result of political and legal interference by industry, the hexavalent chromium PHG has been stalled. However, on December 31st, OEHHA released a stringent PHG of .02 ppb. This is an improvement over the original PHG proposed by the agency over a year ago because it incorporates the need to protect fetuses and infants from hexavalent chromium. However, given that industry and some water providers strenuously opposed and used their influence to delay the less protective health goal, we expect even more opposition this time around. Finalizing this PHG immediately is essential because until that happens, the state cannot establish a legally enforceable drinking water standard.
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