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Children's Health Protection

Response from Cynthia Dougherty regarding Preliminary Regulatory Determination on Perchlorate

Melanie A. Marty, Ph.D., Chair
Children’s Environmental Protection Advisory Committee
Cal/EPA, Office of Environmental
Health Hazard Assessment
1515 Clay St., 16th Floor
Oakland, CA 94612

Dear Dr. Marty:

Thank you for your November 3, 2008, letter to Stephen L. Johnson, Administrator of the Environmental Protection Agency (EPA), about the Agency’s Federal Register notice entitled Preliminary Regulatory Determination on Perchlorate. Your letter expressed concern on behalf of the Children’s Environmental Protection Advisory Council (CHPAC) about the development of health reference level used to support EPA’s determination and asked the Agency to set a maximum contaminant level for perchlorate. I have been asked to respond to your letter.

In its October 10, 2008 notice, EPA described the rationale for the preliminary determination not to regulate perchlorate in drinking water and requested public comment on that decision and its underlying rationale. In response to requests from several parties, the Agency extended the comment period through November 28, 2008. We acknowledge and understand the concerns that the CHPAC and other commentors have expressed about the preliminary determination. EPA will respond to the public comments it receives on the preliminary determination and will also review the comments from the peer review of the application of a physiologically based pharmacokinetic (PBPK) model to assess potential impacts of sensitive subpopulations. After considering comments, EPA plans to issue a final regulatory determination for perchlorate.

Thank you again for your letter.



Cynthia C. Dougherty, Director
Office of Ground Water and Drinking Water

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