Announcement of Second Public Comment Period for the Draft Technical Support Document on the Proposed Updates of the Public Health Goals for Nitrate and Nitrite in Drinking Water

The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency is announcing the availability of the revised draft technical support document for the proposed updates of the Public Health Goals (PHGs) for nitrate and nitrite in drinking water. 

OEHHA initiated a 45-day public comment period on the first draft document on December 16, 2016, and held a public workshop on February 13, 2017.  Subsequently, an external scientific peer review of the draft PHG document was conducted pursuant to Health and Safety Code Section 116365(c)(3)(D).  OEHHA has revised the draft document based on public and peer review comments.  Revision of the draft document included additional analyses and discussion of epidemiological studies of cancer and birth defects, among other changes.  The PHGs in the revised draft document remain unchanged. 

OEHHA is soliciting comments on the revised draft technical support document, available for download below, during a 30-day comment period.  OEHHA will evaluate all the comments received and revise the document as appropriate.  Written comments must be received by the PHG program at or at the postal address below by 5:00 p.m. on March 12, 2018 to be considered.  After any subsequent revisions, OEHHA intends to post the final document on its website along with responses to the major comments submitted during the external scientific peer review and the public comment periods.

A review of the scientific literature published since the development of the original nitrate and nitrite PHGs in 1997 has identified no new information to support changing the current PHG of 45 parts per million (ppm) for nitrate.  Nitrate can also be expressed in terms of its concentration as nitrogen.  When expressed as nitrogen, 45 ppm nitrate is equivalent to 10 ppm nitrogen.  The PHG of 3 ppm for nitrite, which when expressed as nitrogen is 1 ppm, remains the same.  The combined nitrate/nitrite PHG of 10 ppm (as nitrogen), which accounts for the additive toxicity of nitrate and nitrite, also remains unchanged.  It does not replace the individual values, and the maximum contribution from nitrite should not exceed 1 ppm nitrite-nitrogen.  These PHGs protect against the occurrence of infant methemoglobinemia, a blood disorder that results in decreased oxygen distribution to tissues, as well as other effects, such as liver toxicity, that have been shown to occur at higher levels of exposure and in the general population.

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[1] requires OEHHA to develop PHGs based exclusively on public health considerations.[2]  PHGs published by OEHHA are used by the State Water Resources Control Board in setting California’s drinking water standards (Maximum Contaminant Levels, or MCLs).[3]

If you would like to receive further information on this announcement or have questions, please contact Hermelinda Jimenez at the email address above or at (916) 324-7572.

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

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)