Draft Technical Support Document for the Public Health Goals for Carbofuran, Diquat, Endrin, Picloram, and Thiobencarb

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The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency (CalEPA) is announcing the availability of a draft technical support document for proposed updates of the Public Health Goals (PHGs) for carbofuran, diquat, endrin, picloram, and thiobencarb in drinking water.  This draft document presents updates of these PHGs, originally published in 2000, 2000, 1999 (updated in 2008), 1997, and 2000, respectively.  The updates consider recent toxicological literature and incorporate updated methodologies.  The methodologies include the use of updated water consumption rates, factors to account for variability between individuals, and, when appropriate, benchmark dose modeling and improved estimates of dermal and inhalation exposures.

PHG technical support documents provide information on the health effects of contaminants in drinking water.  A PHG is defined as the level of a contaminant in drinking water at which adverse health effects are not expected to occur from a lifetime of exposure.  The California Safe Drinking Water Act of 1996[1] requires OEHHA to develop PHGs based exclusively on public health considerations.[2]  PHGs published by OEHHA are considered by the State Water Resources Control Board of CalEPA in setting drinking water standards (California Maximum Contaminant Levels, or California MCLs).[3]

OEHHA is soliciting comments on the draft document during a 45-day comment period.  The Office will also hold a public workshop on September 28, 2015 at the California Environmental Protection Agency Headquarters Building, 1001 I Street, Sacramento, California, 95814, Training Room 2, from 1:00 p.m. to 3:00 p.m., or until business is concluded.  OEHHA follows the requirements set forth in Health and Safety Code Sections 57003(a) and 116365 for conducting the workshop and receiving public input.

The workshop is provided to enable a dialogue between OEHHA scientists and the public, to discuss the scientific basis of the proposed PHG updates, and to receive comments.  After the public workshop, OEHHA will submit the draft risk assessment for external scientific peer review.[4]

Following the workshop and external scientific peer review, OEHHA will evaluate all of the comments received, revise the draft document as appropriate, and make it available for a 30-day comment period.  After any subsequent revisions, the final document will be posted on the OEHHA web site along with responses to the external peer review comments and to major comments received at the workshop and during the two public comment periods.

If you would like to receive further information on this announcement or have questions, please contact the PHG program at PHG.Program@oehha.ca.gov or (916) 324-7572.

Written comments must be received at the email address above or at the postal address below by 5:00 p.m. on September 28, 2015 to be considered. 

Pesticide and Environmental Toxicology Branch
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
1515 Clay St., 16th floor
Oakland, California 94612
Attention: PHG Program


[1] Codified at Health and Safety Code, section 116270 et. seq.

[2] Health and Safety Code section 116365(c)

[3] Health and Safety Code section 116365(a) and (b)

[4] Health and Safety Code section 116365(c)(3)(D), amended by Stats. 2015, Ch. 24, Sec. 18. effective June 24, 2015.