On December 7, 2012, California’s Office of Environmental Health Hazard Assessment (OEHHA) issued a draft technical support document in support of its public health goal (PHG) for perchlorate (pdf), in further support of its proposal to lower the PHG from 6 parts per billion to 1 part per billion.
According to the draft technical support document,
The purpose of this document is to re-evaluate current scientific information on perchlorate in order to update the health-protective estimate for perchlorate concentration in drinking water. PHGs are based on a comprehensive analysis of information on the toxicology of the compounds, and are based solely on protection of public health without regard to cost impacts or other factors. PHGs for carcinogens are set at a de minimis risk level of one in a million (10-6), assuming a lifetime of exposure to the chemical in the drinking water. PHGs for non-carcinogens are based on levels estimated to be without risk of any adverse effects for exposures up to a lifetime, to the general population as well as any significant identifiable sensitive subpopulations.
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This document represents an update of an earlier health risk assessment [pdf] of perchlorate conducted by OEHHA that resulted in the publication of a PHG in 2004. This revision takes into account information which suggests that infants can be especially susceptible to perchlorate. This revision also incorporates the higher drinking water consumption values described by OEHHA (2012) to be more protective of the entire population.
The setting of a PHG does not establish a regulatory standard for contaminants in drinking water, or a target level for cleanup of ground or ambient surface water contamination. California’s Safe Drinking Water Act, codified at Health and Safety Code Section 116365 et seq., requires that OEHHA perform risk assessments and publish PHGs for contaminants in drinking water based exclusively on public health considerations. Section 116365 specifies that the PHG is to be based exclusively on public health considerations without regard to cost impacts. Section 116365(c). OEHHA develops PHGs to determine concentrations of drinking water contaminants that pose no significant health risk if consumed for a lifetime, based on current risk assessment principles and practices.
The Department of Public Health (DPH) is charged with developing primary drinking water standards, or maximum contaminant levels (MCL), for contaminants in drinking water. In that process, DPH must take into account PHGs developed by OEHHA, among other factors, but may also consider technical and economic feasibility in setting MCLs. Health and Safety Code Section 116365(a), (b). Thus, whereas PHGs developed by OEHHA are to be based solely on scientific and public health considerations without regard to economic cost considerations, MCLs adopted by DPH are to consider economic factors and technical feasibility, and are to be set at a level that is as close as feasible to the corresponding PHG, placing emphasis on the protection of public health.
The December 2012 technical support document is a further step in OEHHA’s process of revising the perchlorate PHG, which began with its January 7, 2011, announcement (pdf) and issuance of the prior iteration of the technical support document (pdf). OEHHA accepted public comments on the proposed PHG and subjected it to peer review, providing responses to the peer reviewers’ comments in conjunction with the release of the December 2012 document (pdf). Further public comments will be accepted until January 22, 2013, and should be addressed to OEHHA as directed here.
This is not the first time this week that perchlorate has been in the news in California. On December 5, the Environmental Protection Agency (EPA) announced a settlement worth more than $50 million at the B.F. Goodrich Superfund Site in Rialto, California. One of the primary contaminants of concern at the site is perchlorate associated with testing and manufacturing of fireworks, munitions, rocket motors, and pyrotechnics over several decades. Cleanup of the site is anticipated to take 30 years at a cost of $43 million.