Proposed level lowered due to public comment and scientific peer review
The California Office of Environmental Health Hazard Assessment (OEHHA) released for public comment a revised draft public health goal (PHG) for hexavalent chromium in drinking water.
The revised draft proposes a PHG of 0.02 parts per billion (ppb) for hexavalent chromium, which is also known as chromium-6. A PHG is the level of a chemical contaminant in drinking water that does not pose a significant health risk. It is not a regulatory level for cleanup of groundwater or surface water contamination.
“When finalized, the public health goal will give California a solid scientific basis for a health-protective drinking water standard for chromium-6,” said OEHHA Director Dr. Joan Denton. “We expect the goal will be the first in the nation for this contaminant.”
The new document revises an earlier draft issued in August 2009 that proposed a PHG of 0.06 ppb. OEHHA, which is part of the California Environmental Protection Agency, made changes in response to both public comments and an external scientific peer review of the earlier draft that was coordinated by the University of California.
New research has documented that young children and other sensitive populations are more susceptible than the general population to health risks from exposure to carcinogens. The changes were recommended by the peer review and reflect OEHHA’s new guidelines for early-in-life exposures, which acknowledge this susceptibility.
The PHG will serve as guidance for the California Department of Public Health (CDPH) in developing the nation’s first drinking water standard specifically for chromium-6. Current federal and state standards exist for total chromium, which includes both chromium-6 and less-toxic chromium-3.
The draft PHG is based on an estimated “one in one million” lifetime cancer risk level. This means that for every million people who drink tap water with that level of chromium-6 each day for 70 years, it is expected there would be one additional case of cancer from exposure to chromium-6.
The PHG is not meant to be the maximum “safe” level of chromium-6 in drinking water. It represents a stringent health-protective goal that CDPH will use to develop an enforceable regulatory standard for chromium-6 in drinking water. The standard will be set as close to the PHG as is economically and technically feasible.