EPA Issues Health Advisory For Perchlorate; Defers Regulation

Jan 8: U.S. EPA announced that it is seeking advice from the National Academy of Sciences (NAS) before making a final determination on whether to issue a national regulation for perchlorate in drinking water. EPA's action follows a December 30, 2008, release of a major 213-page report from EPA's Office of Inspector General (OIG) entitled, General Scientific Analysis of Perchlorate [See WIMS 1/6/09].

EPA also issued 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 EPA encourages state-specific situations to be addressed at the local level. EPA said it expects to issue a final health advisory concurrent with the final regulatory determination for perchlorate. Benjamin Grumbles, EPA’s assistant administrator for water said, "This is a sensible step for protecting public health and preserving regulatory options as the science of perchlorate is reviewed."

On October 10, 2008, EPA issued a preliminary regulatory determination for public comment in the Federal Register. The Agency announced its intention on October 3, prior to the official Federal Register notice. 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. On October 3, environmental advocates [Earthjustice, representing the Environmental Working Group (EWG)] announced they planned to sue the Agency, saying, the decision would benefit weapons makers at the expense of millions of Americans' drinking water "spiked with rocket fuel." They said they would "fight in court to make sure this toxin is regulated under the Safe Drinking Water Act." [See WIMS 10/6/08].

EPA said that after considering public comments, as well as recommendations from EPA advisory groups and offices, it was asking the NAS to provide additional insight on various issues. Specifically, 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 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.

EPA said it is replacing the existing preliminary remediation goal of 24.5 ppb with the interim health advisory value of 15 ppb. They said the goal will be used as a consideration when establishing cleanup levels for perchlorate at Superfund sites. The OIG reported that on February 18, 2005, EPA established a perchlorate reference dose (RfD) that corresponds to a drinking water equivalent level of 24.5 parts per billion (ppb). The OIG said that unlike EPA it used a cumulative risk assessment to analyze the risk from the multiple sodium iodide symporter (NIS) stressors and said that approach "is required to identify potential actions that will effectively lower the risk to public health."

OIG concluded that despite the fact that EPA did not use the proper cumulative risk assessment, "EPA’s perchlorate RfD is conservative and protective of human health, but limiting perchlorate exposure does not effectively address this public health issue. Potentially lowering the perchlorate drinking water limit from 24.5 ppb to 6 ppb does not provide a meaningful opportunity to lower the public’s risk."

EPA noted in its latest announcement that a "regulatory determination" is a formal decision by 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. 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.

Access a release from EPA (click here). Access more information on EPA's health advisory (click here). Access multiple WIMS-eNewsUSA blog posts on the perchlorate issue (click here). [*Drink, *Toxics]