California Seeks Comment on Hexavalent Chromium in Water

The California Office of Environmental Health Hazard Assessment (OEHHA) on Aug. 20 released for public comment a draft public health goal for hexavalent chromium in drinking water.

The draft public health goal for hexavalent chromium, also known as chromium 6, is set at 0.06 parts per billion. A public health goal (PHG) is the level of a chemical contaminant in drinking water that does not pose a significant health risk.

“This draft public health goal document is the first in the nation that identifies a health-protective level of chromium 6 in drinking water,” said OEHHA Director Dr. Joan Denton. “The final goal will be an important first step in the development of a state drinking-water standard.”

OEHHA, which is part of the California Environmental Protection Agency, develops public health goals for chemicals in drinking water. A PHG is not a regulatory standard, and it is not considered the highest level of a chemical that is safe to drink. Drinking water containing chemical levels exceeding the PHGs can still be considered acceptable for public consumption.

Under state law, the California Department of Public Health (CDPH) uses PHGs to develop the state’s regulatory drinking water standards. The PHG is a component in the DPH process of developing a drinking water standard.

State law requires CDPH to set drinking water standards as close to the corresponding PHG as is economically and technically feasible, placing primary emphasis on protection of public health. PHGs are not regulatory levels for cleanup of groundwater or surface water contamination.

CDPH and the federal government currently have regulatory drinking-water standards for “total chromium,” which consists of both chromium 6 and chromium 3. The eventual drinking-water standard for chromium 6 will enable California to more directly protect the public from health risks from this contaminant. Chromium 3 is found naturally in foods at low levels and is considered an essential human dietary nutrient.

The draft OEHHA chromium 6 assessment considered all available scientific information. The PHG is based on a study published by the National Toxicology Program in 2007 in which laboratory rats and mice were given drinking water containing high levels of chromium 6. Some of the laboratory animals developed gastrointestinal tumors. OEHHA, CDPH and other groups requested the research to provide data needed to develop a chromium 6 PHG and drinking water standard.

Chromium 6 occurs naturally in some drinking water. The metal is also used in a number of industrial applications and has entered some water supplies as a result of past waste-disposal practices.

A copy of the draft chromium 6 PHG document can be viewed or downloaded at www.oehha.ca.gov.

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