Announcement of Publication of Drinking Water Public Health Goals and Availability of Final Technical Support Document 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 is announcing the publication of updated Public Health Goals (PHGs) for carbofuran, diquat, endrin, picloram, and thiobencarb in drinking water.  The PHG is the level of a 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[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 in setting drinking water standards (Maximum Contaminant Levels, or MCLs) for California.[3]  The final technical support document is available for download below.

The technical support document presents updates of the carbofuran, diquat, endrin, picloram, and thiobencarb PHGs, originally published in 2000, 2000, 1999 (updated in 2008), 1997, and 2000, respectively.  The updated PHGs are 0.7 parts per billion (ppb) for carbofuran, 6 ppb for diquat, 0.3 ppb for endrin, 166 ppb for picloram, and 42 ppb for thiobencarb, all based on non-cancer effects.  The updates consider recent toxicological literature and incorporate updated water consumption rates, and where appropriate, updates in risk assessment methodology and provisions to account for the most sensitive members of the population.

OEHHA posted the first draft of this document on August 14, 2015 for a 45-day public comment period and held a public workshop on September 28, 2015.  Subsequently, an external scientific peer review of the draft PHGs document was conducted pursuant to Health and Safety Code Section 116365 (c)(3)(D).  The second draft PHGs document was released for a 30-day public comment period on July 29, 2016.  OEHHA received comments from the Sacramento River Source Water Protection Program during the first comment period and received no comments during the second comment period.  OEHHA has evaluated all the comments received and revised the technical support document as appropriate.  A document containing responses to the public and peer review comments is available for download below.

If you would like to receive further information on this announcement or have questions, please contact Hermelinda Jimenez at or (916) 324‑7572.  Written inquiries can also be addressed to:

Pesticide and Environmental Toxicology Branch
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
P.O. Box 4010, MS-12B
Sacramento, California 95812
Attention: PHG Program

Footnotes and References

[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)