[Federal Register Volume 64, Number 9 (Thursday, January 14, 1999)]
[Notices]
[Pages 2492-2493]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-890]
[[Page 2492]]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-6219-3]
Technical Workshop on Perchlorate Risk Issues
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of meeting.
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SUMMARY: EPA is announcing a workshop convened by the Research Triangle
Institute (RTI), an EPA contractor, for external scientific peer review
of the EPA draft document entitled ``Perchlorate Environmental
Contamination: Toxicological Review and Risk Characterization Based on
Emerging Information.'' The workshop will be held in San Bernardino,
California, and will be open to members of the public as observers. The
peer review, to be conducted by scientists from outside EPA, is being
organized to assist in completing the toxicological review and risk
characterization of perchlorate, and will include the protocols and
reports of recent studies on perchlorate, as well as EPA's draft
Toxicological Review document. Stakeholders in the perchlorate issue
who have additional information which is relevant to the assessment of
the potential health and ecological effects of perchlorate are invited
to make a short presentation of this information at the peer review
workshop.
DATES: The workshop will begin on Wednesday, February 10, 1999 at 8:30
a.m. and end on Thursday, February 11, 1999 at 12:30 p.m. Members of
the public may attend as observers.
ADDRESSES: The meeting will be held at the San Bernardino City Council
Chambers, 300 North D Street, San Bernardino, California 92418. Since
seating capacity is limited, please contact Ella Darden of RTI, by
telephone, at 919-541-7026; by facsimile, at 919-541-7155; or by E-
mail, at ejd@rti.org, by January 31, 1999 to attend the workshop as an
observer. Observers who wish to make a short presentation of
information which may be relevant to the assessment of potential health
and ecological effects of perchlorate should register to do so with RTI
by January 31, 1999.
FOR FURTHER INFORMATION CONTACT: For technical and logistical inquires,
contact Ella Darden, Research Triangle Institute, by telephone, at 919-
541-7026; by facsimile, at 919-541-7155; or by E-mail, at ejd@rti.org.
Copies of the draft Toxicological Review document will be available for
inspection on EPA's National Center for Environmental Assessment web
site (http://www.epa.gov/ncea/), at EPA's Regional Superfund Records
Centers, and at the EPA Headquarters Information Resources Center,
Washington DC. Inquiries concerning additional opportunities for
document review should be directed to Ella Darden at Research Triangle
Institute.
SUPPLEMENTARY INFORMATION:
Background
EPA is in the process of conducting a toxicological review for
perchlorate, including the development of a revised provisional
reference dose (RfD), a cancer assessment, and an 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 is the upcoming external peer review, in the
form of a workshop, which will cover protocols for and reports of the
recently completed toxicity studies, the Toxicological Review document,
and the proposed 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 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 health 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
As a result of that peer review, a set of toxicological and
ecological studies was undertaken 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, genotoxicity studies, a segment II
developmental toxicity study, and ecotoxicity studies in Daphnia,
earthworms, lettuce and fathead minnow have been completed. Currently
ongoing studies include a two-generation reproductive toxicity study,
absorption, distribution, metabolism, and elimination (ADME) studies,
perchlorate mechanistic studies, and immunotoxicity studies. The
results of most of these studies will be discussed in the Toxicological
Review document and utilized for development of the proposed revised
RfD, and cancer and ecological assessment for perchlorate.
Ten independent scientists from the fields of 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 will review
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. These
scientists were selected by RTI from among the experts nominated by
stakeholders for possible service as external peer reviewers. Following
the peer review workshop, RTI will issue a
[[Page 2493]]
report summarizing the workshop. EPA will address the comments of the
peer reviewers in finalizing the Toxicological Review document for
perchlorate and adopting the revised perchlorate RfD. The RfD will be
utilized in performing risk assessments of perchlorate contamination in
the environment. Although such risk assessments will be one of the
factors considered in making future decisions regarding perchlorate
contamination, these decisions and other risk management issues will
not be a part of the peer review process.
Dated: January 7, 1999.
Timothy Fields, Jr.,
Acting Assistant Administrator, Office of Solid Waste and Emergency
Response.
[FR Doc. 99-890 Filed 1-13-99; 8:45 am]
BILLING CODE 6560-50-P
