[CPEO-MEF] States critique perchlorate reference dose

[Lenny Siegel <lsiegel@cpeo.org>]

Environmental Health Perspectives has published a commentary, "The NAS
Perchlorate Review: Questions Remain about the Perchlorate RfD,"
critical of the National Academy of Sciences perchlorate assessment and
EPA's quick acceptance of its findings. It was written by Gary Ginsberg,
of the Connecticut Department of Public Health and
Deborah Rice of the Maine Bureau of Health.

Abstract

Human exposure to perchlorate is commonplace because it is a contaminant
of drinking water, certain foods, and breast milk. USEPA conducted a
perchlorate risk assessment in 2002 which yielded an RfD based upon both
the animal and human toxicology data. This assessment has been
superceded by a recent National Academy of Science (NAS) review that
derived a perchlorate reference dose (RfD) that is 20 fold greater (less
stringent) than that derived by USEPA in 2002. The NAS-derived RfD has
been put on USEPA's IRIS database very quickly and with no further
public review. This commentary raises concerns about the NAS approach to
RfD development in three areas of toxicity assessment: the dose which
NAS described as a NOAEL is actually associated with perchlorate-induced
effects, that consideration of uncertainties was insufficient, and that
NAS considered the inhibition of iodine uptake to be a non-adverse
effect. The commentary concludes that risk assessors should carefully
evaluate whether the IRIS RfD is the most appropriate value for
assessing perchlorate risk.

To download the PDF version or the 16-page document, go to
http://ehp.niehs.nih.gov/members/2005/8254/8254.pdf



-- 


Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 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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