OEHHA Receives Scientific Reveiw Committee's Chromium 6 Report
SACRAMENTO - A scientific panel of experts convened by the University of California has completed a review of health issues relating to the presence of chromium 6 in drinking water, and has forwarded its report to the California Environmental Protection Agency's Office of Environmental Health Hazard Assessment (OEHHA).
The Chromate Toxicity Review Committee was formed at the request of OEHHA to provide guidance in the identification of an optimum drinking-water level, or public health goal (PHG), for chromium 6 in drinking water. The committee concluded that "we found no basis in either the epidemiological or animal data published in the literature for concluding that orally ingested Cr (VI) [chromium 6] is a carcinogen."
OEHHA is preparing to develop the nation's first PHG for chromium 6. The California Health and Human Services Agency's Department of Health Services (CDHS) will use that goal to help it develop chromium 6 drinking water standard. OEHHA and CDHS will use the Review Committee's report in developing these future standards for chromium 6. Both OEHHA and CDHS will also assess health risks from chromium 6 in groundwater in the San Fernando Valley.
The committee agrees that a major study planned by the National Toxicology Project at the request of OEHHA and CDHS, is necessary in order to provide definitive data of the cancer risks of chromium 6 in drinking water. The federal study is expected to take up to five years to complete.
The committee proposes that until the federal study is complete, California should continue to consider its current drinking water standard (maximum contaminant level) of 50 parts per billion (ppb) for "total" chromium (consisting of chromium 6 and a less-toxic form of the metal, chromium 3) to be protective of public health.
The current drinking water standards apply only to total chromium. OEHHA scientists are expected to complete a public health goal for chromium 6 by the spring of 2003. The report will also assist OEHHA and CDHS in conducting an upcoming assessment of health risks posed by chromium 6 in drinking-water aquifers in the San Fernando Valley. Legislation enacted last year requires the two agencies to perform the assessment.
Last Spring CDHS adopted regulations to require all public water systems to begin statewide monitoring for chromium 6 in their drinking water supplies, making California the first state to take such an action. Water systems must report their results to CDHS by January 2003.
OEHHA had asked the committee to examine the reliability of a key German study used by OEHHA in 1998 to identify a PHG of 2.5 ppb for total chromium. The study, published in 1968, is the only one of its kind that has examined long-term cancer risks from ingestion of chromium 6. Previous UC peer reviews of the PHG document had deemed the German study data as appropriate for deriving the PHG for total chromium. However, OEHHA was aware of the study's limitations and for that reason had asked the committee to examine it.
The committee's report states that the study should not be used to assess cancer risks from chromium 6 for several reasons. OEHHA no longer plans to use the study in future risk assessments on chromium 6 because the committee presented information that a virus contracted by mice used in the study could have caused lesions mistaken by the German researchers for chromium-induced tumors.