California proposes to set drinking water goal at 0.06 ppb for Hex Chrome

There is no question that Hexavalent Chromium is a known human carcinogen when inhaled. However, there has been much controversy over whether it is a carcinogen when ingested. Now, the Office of Environmental Health Hazard Assessment (OEHHA) of Cal-EPA has proposed a Public Health Goal (PHG) of 0.06 ppb. This goal may force costly treatment on drinking water providers that obtain their groundwater supplies from heavy-metal-contaminated aquifers, such as that in the San Fernando Valley, which is used by the Cities of L.A., Burbank, and Glendale. The region has been for years and still is subject to much CERCLA litigation and administrative clean-up orders relating to Hex Chrome, perchlorate, and chlorinated solvents in groundwater.
 
OEHHA announced yesterday the availability of a draft technical support document for the proposed PHG for hexavalent chromium in drinking water. This draft document is a new risk assessment, culminating an extensive evaluation of the oral toxicity of this chemical. A PHG of 0.06 ug/L [or 0.06 parts per billion (ppb)] is proposed based on tumor incidence data from rodent cancer bioassays.
 
OEHHA is soliciting comments on the draft report during a 45-day comment period. The Office will also hold a public workshop on October 19, 2009 at the Elihu Harris Building, 1515 Clay Street, Oakland, 94612, Room 1, 10 a.m.-12 noon, or until business is concluded. The workshops and comments are to be addressed pursuant to the requirements of Health and Safety Code Sections 57003(a) and 116365.
 
Written comments must be received by 5:00 p.m. on October 19, 2009 to be considered during this document revision period. The workshop is provided to “encourage a dialogue” between OEHHA scientists and the public, to discuss the scientific basis of the proposed PHG, and to receive comments. Following the workshop, OEHHA will evaluate all the comments received, revise the document as appropriate, and make it available for another 30-day comment period. After any subsequent revisions, the final document will be posted on OEHHA’s Web site along with responses to the major comments from the public at the workshop and during the public review and scientific comment periods.
 
The PHG data is thereafter used by the Department of Public Health (formerly known as the Department of Health Services) to develop a maximum contaminant level for drinking water. The MCL takes into account not only the PHG level, but the cost of filtration.
 
The OEHHA announcement can be found at http://www.oehha.ca.gov/water/phg/pdf/HexChromfacts082009.pdf. The OEHHA press release can be found at http://www.oehha.ca.gov/water/phg/pdf/Hexchrompress082009.pdf. The 149-page draft technical report can be found at http://www.oehha.ca.gov/water/phg/pdf/Cr6PHGdraft082009.pdf.