Alameda County Superior Court Judge Evelio Grillo has ordered state health officials to propose a drinking water standard for hexavalent chromium by the end of August.
The ruling on July 18 came nearly a year after environmental groups filed a lawsuit claiming the state was eight years late in setting the standard.
The CDPH – prior to the court’s ruling – already was expected to release a proposed draft maximum contaminant level – or MCL – for chromium-6 sometime this summer. Once released, the proposed draft MCL will be circulated for public comment for 45 days during which members of the public may submit written feedback on the proposal. The department then will take the public feedback and respond to each comment.
According to the terms of the ruling, the court will consider any further deadlines in light of the volume and nature of public comments.
Since the 1970s, California has enforced a drinking water standard for total chromium, which includes chromium-6. That standard of 50 ppb is more stringent than the federal standard for total chromium of 100 ppb.
The two most common types of chromium are trivalent chromium, or chromium-3, an essential dietary nutrient, and hexavalent chromium, or chromium-6, which can be toxic. California began the process to set a separate standard for chromium-6 in 2001 after concerns that chromium-6 could cause cancer when ingested through drinking water.
The first step in the process to set a drinking water standard is the development of a public health goal (PHG), which is a level based solely on health considerations. At this level, it is estimated that not more than one person in a 1 million who consumes a half-gallon of water daily for 70 years would be expected to develop cancer as a result of exposure.
Cal/EPA’s Office of Environmental Health Hazard Assessment (OEHHA) is responsible for the development of the PHG. OEHAA completed its research in 2011 and proposed a PHG for chromium-6 of 0.02 ppb.
To establish a drinking water standard for chromium-6, CDPH will use the PHG level as a starting point, and then incorporate the technological and economic feasibility of removing chromium-6 from drinking water supplies.
Chromium-6 can occur naturally in the environment from the erosion of chromium deposits. It also is produced through industrial processes and then used in electroplating, pigments manufacture, corrosion control and other manufacturing activities. Chromium-6 also can be produced when chromium-3 enters a disinfecting treatment plant and is oxidized into chromium-6.