Final Public Health Goals for Benzo(a)Pyrene, Methoxychlor, and TCDD

Sep 16, 2010

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency announces the publication of the final technical support documents for the Public Health Goals (PHGs) for benzo(a)pyrene, methoxychlor, and TCDD (dioxin) in drinking water. The PHG for benzo(a)pyrene is established at 0.007 parts per billion (ppb), based on carcinogenic effects in rats and mice. The PHG for methoxychlor is established at 0.09 ppb, based on effects in male offspring of female mice treated with methoxychlor during pregnancy. The PHG for TCDD is established at 0.00005 parts per trillion (ppt), based on tumors in multiple sites in female rats.

OEHHA previously offered a 45-day public comment period and held a public workshop for benzo(a)pyrene on January 6, 2010, methoxychlor on May 26, 2010, and TCDD on August 18, 2005. OEHHA follows the requirements set forth in Health and Safety Code sections 57003(a) and 116365 for conducting the workshop and obtaining public input. After addressing any comments received, all of the documents were subsequently posted for a second (30-day) comment period. Benzo(a)pyrene and TCDD were posted for third 30-day comment periods, after significant changes to the methods for calculation of cancer risk. OEHHA has now finalized the PHG documents and is posting the final versions and our responses to the major comments on the OEHHA web site.

The PHG technical support documents provide information on the health effects of contaminants in drinking water. The PHG is a level of drinking water contaminant at which adverse health effects are not expected to occur from a lifetime of exposure. The California Safe Drinking Water Act of 1996 requires OEHHA to develop PHGs based exclusively on public health considerations. PHGs published by OEHHA are considered by the California Department of Public Health in setting drinking water standards (Maximum Contaminant Levels, or MCLs).

If you would like to receive further information on this announcement or have questions, please contact our office at (510) 622-3200.

Hermelinda Jimenez (Hermelinda.Jimenez@oehha.ca.gov)
Pesticide and Environmental Toxicology Branch