EPA Seeks Advice on Perchlorate in Drinking Water, Issues Interim Health Advisory

January 23, 2009 // Published as a news service by IHS

The agency is also issuing an interim health advisory of 15 parts per billion (ppb) to assist state and local officials in addressing local contamination of perchlorate in drinking water and making a corresponding change to the factors it considers in cleaning up Superfund sites.

States have the right to establish and enforce drinking water standards and the EPA encourages state-specific situations to be addressed at the local level. The EPA expects to issue a final health advisory concurrent with the final regulatory determination for perchlorate.

On Oct. 10, 2008, the agency issued a preliminary regulatory determination for public comment in the Federal Register. The notice described the agency's decision that there is not a "meaningful opportunity for health risk reduction" through a national drinking water regulation for perchlorate. The agency received more than 32,000 comments on the notice.

After considering public comments, as well as recommendations from EPA advisory groups and offices, the EPA is asking the NAS to provide additional insight on various issues. Specifically, the EPA is asking the NAS to evaluate its derivation of the health reference level of 15 ppb, the use of modeling to evaluate impacts on infants and young children and the implication of recent biomonitoring studies.

The agency is also asking the NAS how it should consider the role of perchlorate relative to other iodide uptake inhibiting compounds and if there are other public health strategies to address this aspect of thyroid health.

As a result of the publication of the interim health advisory for perchlorate, the EPA will formally withdraw the Jan. 26, 2006 guidance it issued regarding perchlorate and sites addressed under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the National Oil and Hazardous Substances Contingency Plan (National Contingency Plan or NCP).

The January 2006 guidance recommended that regions consider using a preliminary remediation goal (PRG) of 24.5 ppb (or µg/L). In its place, the EPA recommends that regions consider using the interim health advisory level of 15 µg/L as a PRG; consistent with the NCP, the EPA often considers health advisories as "to be considered" (TBC) values for setting cleanup levels.

Also, where state regulations establish applicable or relevant and appropriate requirements (ARARs) for perchlorate, these standards should be used as the cleanup level at Superfund sites, unless the ARAR is waived at the site.

A regulatory determination is a formal decision by the EPA as to whether it should initiate development of a national primary drinking water regulation for a specific contaminant under the Safe Drinking Water Act.

Every five years, the EPA develops a contaminant candidate list to consider for regulation and then makes regulatory determinations on some of the contaminants based on scientific information on health effects, occurrence in drinking water and the opportunity for risk reduction.

A health advisory provides technical guidance to federal, state and other public health officials on health effects, analytical methods and treatment technologies associated with drinking water contamination.

Health advisories also contain guidance values that are concentrations of a contaminant in drinking water that are likely to be without adverse health effects.

More information on the perchlorate health advisory is available at the EPA.

Source: U.S. Environmental Protection Agency (EPA).