California's Department of Public Health (CDPH) is on the brink of making water quality history with its proposed standard for chromium-6 in drinking water. While there does exist a state and federal standard for total chromium, this would be the first standard specifically for hexavalent chromium. The proposed maximum contaminant level (MCL) is 10 parts per billion (ppb).
It's a milestone that has been many years in the making. In 2001, about a year after Erin Brockovich made "hex chrome" a household name, the state passed legislation directing the agency to adopt a standard for chromium-6 in drinking water by January 1, 2004.
Before the Department of Public Health (then known as the Department of Health Services) could develop a standard, the Office of Environmental Health Hazard Assessment (OEHHA) had to first establish a Public Health Goal (PHG) for the carcinogen. The department began working on that task in 2001; a draft did not emerge, however, until 2009. Peer reviews, revisions, and public comment periods followed. Finally in July 2011, OEHHA released its final PHG for hexavalent chromium: 0.02 parts per billion.
OEHHA said it based its determination on a study published by the National Toxicology Program in 2007 in which some laboratory rats and mice developed gastrointestinal tumors after drinking water containing high levels of chromium-6. By California state law, the Department of Public Health is required to set the MCL "as close to the PHG as economically and technically feasible."
By the summer of 2012, environmentalists grew tired of waiting for CDPH to fulfill the directive now eight years past due. The Natural Resources Defense Council (NRDC) and the Environmental Working Group (EWG) filed a lawsuit asking the court to force the agency to develop the standard, saying the delay had amounted "to a serious and unlawful failure to protect public health."
In July 2013, the Alameda County Superior Court ruled in favor of the plaintiffs, ordering CDPH to expedite its efforts to develop the standard and specifying a deadline of August 31. CDPH complied, releasing its proposed MCL of 10 ppb on August 23. Initial reactions were - as they always are - mixed.
The NRDC and EWG issued scathing criticism of the agency's proposal, pointing out that the lenient MCL is 500 times higher than the PHG and would "leave 22 million residents unprotected from the known carcinogen."
Others were more optimistic - at least cautiously so. In a statement, Rep. Adam Schiff, D-Burbank said, "While I would have liked to have seen a lower level, the setting of this standard is a welcome first step."
You may find it interesting to learn, as I did, that some California water treatment plants - like Los Angeles, Burbank and Glendale - already treat for chromium-6 at a self-imposed MCL of 5 ppb. In the absence of a formal standard, these progressive utilities went ahead and set their own targets, erring on the side of conservativeness. But what will happen if the less stringent CDPH standard is adopted?
Ramon Abueg, a chief assistant general manager for Glendale Water and Power, told the L.A. Times that his utility would most likely continue to meet its more stringent requirements. Burbank Water and Power Assistant General Manager Bill Mace, however, said BWP would probably consider adopting the CDPH standard. The less stringent MCL would require less blending, resulting in a considerable cost savings for the utility.
They may have a while yet to decide. The proposed MCL is currently available for public comment through October 11, 2013. But a final, enforceable standard is not expected until July 2014 at the earliest.
Chief Editor, WaterWorld
