Publication of the Final Technical Support Document for the Public Health Goal for Perchlorate in Drinking Water and Responses to Major Comments on the Technical Support Document

Mar 12, 2004

In accordance with Health and Safety Code Section 116293 (SB1822, Sher, Statutes of 2002), the Office of Environmental Health Hazard Assessment (OEHHA) hereby publishes the final Public Health Goal (PHG) for perchlorate in drinking water. The PHG is also published in accordance with a court order that requires publishing a final PHG by March 12, 2004. OEHHA has completed a technical support document that provides the scientific basis for the PHG. The draft document has undergone a public workshop and two public review and comment periods in fulfillment of the requirements of Health and Safety Code, Section 116365 and Section 57003 (SB 1082). It has been peer reviewed twice by the University of California and also by the U.S. Environmental Protection Agency (U.S. EPA). The final document incorporates changes in response to peer review and public comments.

The PHG for perchlorate is a drinking water goal only. The PHG is 6 ppb (parts per billion) and there are no existing state or federal drinking water standards. The current detection level for perchlorate in drinking water is 4 ppb. This 4 ppb level has been the action level for perchlorate in California, and is being met by most municipal water systems.

The support document estimates the level of the chemical in drinking water that would pose no significant health risk to individuals, including sensitive populations, consuming the water on a daily basis over a lifetime. PHGs represent health-protective goals based solely on public health considerations and are developed based on the best available data in the scientific literature. The document provides the scientific basis for the California Department of Health Services (DHS) to establish a primary drinking water standard (state maximum contaminant level, or MCL). By law, DHS will consider economic factors and technical feasibility in setting the MCL. The PHG also provides relevant information on the chemical to federal, state, and local public health officials.

The National Academy of Sciences (NAS) is conducting an evaluation of U.S. EPA's 2002 Draft Toxicological and Risk Characterization for Perchlorate. This is an important undertaking that may help guide efforts to study the health effects of perchlorate. When that evaluation is completed, OEHHA will carefully review the NAS conclusions and will revise the PHG as necessary (Health and Safety Code Section 116365(e)(1)).

Studies are underway to quantify perchlorate levels in various food types. DHS has indicated that based on a review of current research data, there is no imminent health threat from perchlorate in food that would require a change in diet.