[Federal Register Volume 63, Number 188 (Tuesday, September 29, 1998)]
[Notices]
[Pages 51918-51919]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26007]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6170-1]


Nominations for Peer Reviewers for Perchlorate Toxicological 
Review

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

ACTION: Request for nominations.

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SUMMARY: EPA's Office of Solid Waste and Emergency Response has 
retained Research Triangle Institute, Inc. (RTI) to coordinate a 
scientific peer review of the Toxicological Review document for 
perchlorate, including the revised provisional reference dose (RfD), 
cancer assessment and ecological assessment. The peer review workshop 
is tentatively scheduled to be held in late 1998 or early 1999, in 
Ontario, California, and will be open to members of the public as 
observers. The peer review will be conducted in accordance with EPA's 
1998 Peer Review Handbook, and is being organized to assist in 
completing EPA's evaluation of the effects on human health and the 
environment of perchlorate. RTI is seeking nominations of highly 
qualified scientists with expertise in general toxicology, thyroid 
function and toxicology, developmental toxicology, neurotoxicology, 
immunotoxicology, pharmacology, genetic toxicology, medical 
endocrinology with an emphasis on thyroid function, biostatistics, 
assessment of risks due to non-cancer and cancer health effects, and 
assessment of risks due to ecological effects. RTI will select 
approximately 10 objective peer reviewers based upon demonstrated 
expertise of the scientists and the need for balance in affiliation 
among the peer reviewers. RTI will consider potential conflicts of 
interest in screening nominees for suitability as peer reviewers. All 
nominations will be carefully considered, but the source of peer 
reviewer nominations will not be a factor in the selection of peer 
reviewers and stakeholders are not guaranteed that any of their 
nominees will be selected. The peer review will cover the protocols and 
results of ongoing studies of perchlorate toxicity to human health and 
the environment, as well as the Toxicological Review document, 
including the revised provisional RfD, cancer assessment, and 
ecological assessment for perchlorate prepared by EPA's National Center 
for Environmental Assessment (NCEA).

DATES: Nominations for peer reviewers must be submitted by October 29, 
1998. A detailed resume for each nominated scientist should be included 
with the submission. The projected date for the peer review workshop is 
late 1998 or early 1999, depending on the availability of the peer 
reviewers.

ADDRESSES: Peer reviewer nominations should be sent to Susan Goldhaber 
at Research Triangle Institute, Inc., P.O. Box 12194, Research Triangle 
Park, North Carolina, 27709. Peer reviewer nominations may also be 
submitted by facsimile at 919-541-7155, or by E-mail at [email protected]. 
The peer review workshop will be held in Ontario, California.

FOR FURTHER INFORMATION CONTACT: For technical and logistical inquires, 
contact Susan Goldhaber, Research Triangle Institute, by telephone, at 
919-541-5965, by facsimile, at 919-541-7155, or by E-mail, at 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    EPA is in the process of developing a toxicological review document 
for perchlorate, including a revised provisional RfD, cancer 
assessment, and ecological assessment. An RfD is an estimate of a daily 
oral human exposure that will result in no deleterious noncancer 
effects over a lifetime. Ideally, an RfD is based on an array of 
endpoints that address potential toxicity during various critical life 
stages, from developing fetus through adult and reproductive stages. 
The noncancer, cancer and ecological assessments may be used to support 
development of a health advisory and/or drinking water regulations and 
cleanup decisions at hazardous waste sites. In accordance with EPA's 
1998 Peer Review Handbook, a key step in the development of the 
Toxicological Review document for perchlorate will be an external peer 
review, in the form of a workshop, of the recently completed toxicity 
studies, the Toxicological Review document, and the revised provisional 
RfD, cancer assessment and ecological assessment in that document.
    EPA's Superfund Technical Support Center issued a provisional RfD 
for perchlorate in 1992 and a revised provisional RfD in 1995. The 
provisional RfD values (1992 and 1995) were based on an acute study in 
which

[[Page 51919]]

single doses of potassium perchlorate caused the release of iodide from 
the thyroids of patients with Graves' Disease. The provisional RfD 
values did not undergo internal Agency or external peer review. In 
March of 1997 a peer review panel convened by an independent 
organization, Toxicology Excellence for Risk Assessment (TERA), 
determined that the health effects and toxicity data for perchlorate 
were insufficient to generate a credible RfD for risk assessment 
purposes. The reviewers were concerned that developmental toxicity, 
notably neurological development due to hypothyroidism during 
pregnancy, could be a critical effect of perchlorate that has not been 
adequately examined in studies to date. They also concluded that 
insufficient data were available on potential effects of perchlorate on 
organs and tissues other than the thyroid.

New Health Effects/Toxicology Studies Underway

    A set of toxicological and ecological studies is underway to 
address key data gaps and provide a comprehensive database related to 
the toxicity of perchlorate. The studies are being funded and overseen 
by a variety of organizations with potential responsibility for 
perchlorate contamination in the environment including the United 
States Air Force, the National Aeronautics and Space Administration and 
the Perchlorate Study Group (PSG).1
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    \1\ The PSG is a consortium of defense contractors and 
manufacturers including: Aerojet, Alliant Techsystems, American 
Pacific/Western Electrochemical Company, Atlantic Research 
Corporation, Kerr-McGee Chemical Corp. Lockheed Martin, Thiokol 
Propulsion Group, and United Technologies Chemical Systems.
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    To date, a 90-day subchronic oral study, a neurobehavioral 
developmental toxicity study, and a genotoxicity study have been 
completed. Currently ongoing studies include a segment II developmental 
toxicity study, a two-generation reproductive toxicity study, 
absorption, distribution, metabolism, and elimination (ADME) studies, 
perchlorate mechanistic studies, and immunotoxicity studies. 
Ecotoxicity studies in Daphnia, earthworms, lettuce and fathead minnow 
are also being performed. The results of most of these studies will be 
available for discussion in the Toxicological Review document and for 
development of the revised RfD, cancer, and ecological assessment for 
perchlorate.
    The peer review will focus on the scientific data, methods, and 
analyses, along with the assumptions and uncertainties that are 
associated with the revised provisional RfD, cancer assessment, and 
ecological assessment for perchlorate. Following the peer review 
workshop, RTI will issue a report summarizing the workshop. EPA will 
consider the results of the workshop prior to issuing the revised 
Toxicological Review document for perchlorate. Although the completed 
risk assessment will be one of the factors considered in making future 
decisions regarding perchlorate contamination in the environment, these 
decisions and other risk management issues will not be a part of the 
peer review process.

    Dated: September 23, 1998.
Timothy Fields, Jr.,
Acting Assistant Administrator, Office of Solid Waste and Emergency 
Response.
[FR Doc. 98-26007 Filed 9-28-98; 8:45 am]
BILLING CODE 6560-50-P