[CPEO-MEF] NAS Perchlorate Study

[Lenny Siegel <lsiegel@cpeo.org>]

Information on the National Research Council (National Academy of
Sciences) perchlorate study is now available at 
http://www4.nas.edu/webcr.nsf/5c50571a75df494485256a95007a091e/4c13dcaf6487bb0f85256d640064525b?OpenDocument&Highlight=0,perchlorate
To read the original, you'll probably need to cut and paste the URL, but
I have pasted the entire task statement below.

Biographical sketches for the members of the NRC Committee to Assess the
Health Implications of Perchlorate Ingestion may be found at
http://www4.nas.edu/webcr.nsf/CommitteeDisplay/BEST-K-03-05-A?OpenDocument.

The Committee's first meeting will be October 27, 2003 at the Academy's
new building at
 500 5th Street, N.W., Washington, DC.

The announcement says, "If you would like to attend the sessions of this
meeting that are open to the public or need more information please contact:
Contact Name: Jennifer Saunders
Email: jsaunder@nas.edu
Phone: 202-334-2616
Fax: 202-334-1393"

Lenny

***

Project Title: Committee to Assess the Health Implications of
Perchlorate Ingestion

Date Posted: <Posted: 07/14/2003>

Project Identification Number: BEST-K-03-05-A

Major Unit: 
Division on Earth and Life Studies 
Institute of Medicine 

Sub Unit: 
Board on Environmental Studies and Toxicology
Board on Health Sciences Policy

Project Scope:

A committee of the National Academies will assess the adverse health
effects resulting from ingestion of perchlorate from a clinical,
toxicological, medical, and public health perspective. The committee
will critically evaluate the scientific literature, including both human
and animal data, and will assess the key studies underlying EPA's 2002
Draft Toxicological Review and Risk Characterization for Perchlorate in
terms of quality, reliability, and relevance to draw conclusions about
the health implications of exposure to low levels of perchlorate in
drinking water.

In conducting its assessment, the committee will first address the
following basic scientific issues:

1. The current state of the science regarding potential adverse effects
resulting from disruption of thyroid function in humans and laboratory
animals at various stages of life. Specifically, the committee will
evaluate whether science supports the model that predicts potential
adverse neurodevelopmental and neoplastic effects from changes in
thyroid hormone regulation resulting from disruption of iodide uptake by
the thyroid gland. The committee will indicate its level of confidence
in the model.

2. The levels at which chronic inhibition of iodide uptake may lead to
adverse (not just adaptive) health effects in humans, especially
sensitive subpopulations. The committee will consider the influence of
iodine in the diet on the levels at which adverse effects would be
observed, especially in sensitive subpopulations, and will indicate its
degree of confidence in the levels that it proposes.

3. The levels at which changes in thyroid hormones may lead to adverse
(not just adaptive) health effects in humans, especially sensitive
subpopulations. The committee will indicate its confidence in these values.

The committee will evaluate the animal studies used to assess human
health effects from ingestion of perchlorate with particular attention
to key endpoints, including changes in brain morphometry, behavior,
thyroid hormone levels, and thyroid histopathology. The committee will
indicate its level of confidence in the relevance of the adverse effects
observed in the animal studies to human health, especially sensitive
subpopulations, and will specifically address the validity of the models
that extrapolate changes in brain morphometry in rats to adverse effects
in the human population, especially sensitive subpopulations. The
committee will also indicate whether adverse effects, other than those
associated with iodide update inhibition, may result from daily
ingestion of low levels of perchlorate.

Based on the above review, the committee will determine whether EPA's
findings in its 2002 Draft Toxicological Review and Risk
Characterization for Perchlorate are consistent with the current
scientific evidence. Specifically, the committee will determine whether
EPA considered all relevant literature (both supporting and
non-supporting), consistently critiqued that literature, and then used
appropriate scientific studies to develop its health risk assessment. If
the committee finds deficiencies in EPA's analysis, such as lack of
consideration of a key study, the committee will provide suggestions as
to how EPA might modify its assessment. The committee will provide a
range of values consistent with scientific evidence for percent iodide
uptake that would be protective of individuals at various life stages
and thyroid status. The committee will also provide information on the
basis of the scientific evidence that can be used to inform the
selection of uncertainty factors used in the approximation of a safe
lifetime exposure for humans, especially sensitive subpopulations.

As a final task, the committee will suggest specific scientific research
that could reduce the uncertainty in the current understanding of human
health effects associated with low-level perchlorate ingestion.
Specifically, it will suggest research that could clarify safe levels of
exposure for sensitive subpopulations. Rough estimates for timeframe,
costs, and potential to reduce overall uncertainty will be provided for
the specific research studies suggested.

The project sponsor is the Environmental Project Agency. Co-sponsorship
anticipated from Department of Defense, Department of Energy, and
National Aeronautics and Space Administration. 

The approximate starting date for the project is 06/05/2003.

One report will be issued in approximately 15 months. Project Duration:
15 months


-- 


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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