[CPEO-BIF] NRC perc study released

[Lenny Siegel <lsiegel@cpeo.org>]

The National Research Council (of the National Academies of Sciences) 
has just released its "Review of the Environmental Protection Agency's 
Draft IRIS Assessment of Tetrachloroethylene." See 
http://www.nap.edu/catalog.php?record_id=12863. Tetrachloroethylene, the 
principal "dry-cleaning" chemical used in the U.S., is also known at 
perchloroethylene, perc, or PCE, and it is one of the most widely found 
groundwater and soil contaminants in the U.S., particularly in populated 
areas. The June 2008 EPA assessment that the NRC Committee reviewed 
found that existing (and already protective) standards for perc 
exposure, particularly for the inhalation pathway, were not protective 
enough.

The NRC wrote, "the committee has identified concerns about some of the 
approaches that EPA used to evaluate the data on tetrachloroethylene and 
subjects about which inadequate information or rationales are used to 
support its risk assessment - factors that call into question the 
soundness and reliability of EPA's proposed reference values and cancer 
risk estimates for tetrachloroethylene."

It also concluded, "The committee found several parts of the draft IRIS 
assessment that could be improved on in the future. Such changes are not 
necessary for completing the current assessment but should be considered 
 when tetrachloroethylene is re-evaluated in the future."

Finally, the document reports important divisions among the committee 
members, including an unusual dissenting statement and rebuttal.

LS

--


Lenny Siegel
Executive Director, Center for Public Environmental Oversight
a project of the Pacific Studies Center
278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org



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