[Federal Register Volume 67, Number 1 (Wednesday, January 2, 2002)]
[Pages 75-76]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-32088]




Peer Review of EPA Draft Human Health and Ecological Risk 
Assessment of Perchlorate

AGENCY: Environmental Protection Agency.

ACTION: Notice of Peer Review Workshop and public comment period.


SUMMARY: The U.S. Environmental Protection Agency (EPA) Office of 
Research and Development is announcing an external peer review workshop 
to review the revised draft document entitled, ``Perchlorate 
Environmental Contamination: Toxicological Review and Risk 
Characterization'' (NCEA-I-0503). The EPA is also announcing a public 
comment period for this draft document. The workshop is being organized 
and convened by the Eastern Research Group, Inc. (ERG), an EPA 

DATES: The two-day peer review workshop will begin on Tuesday, March 5, 
2002, at 9 a.m. and will end on Wednesday, March 6, 2002, at 4:30 p.m. 
The 30-day public review and comment period will begin January 9, 2002, 
and will end February 11, 2002.

ADDRESSES: The external peer review meeting will be held at a facility 
in Sacramento, California. To attend the meeting as an observer, please 
register with ERG via the Internet by visiting [email protected]. 
You may also register by calling ERG's conference registration line at 
781-674-7374 or by faxing a registration request to 781-674-2906. Upon 
registering, you will be sent an agenda and a logistical fact sheet 
containing information on the meeting site, overnight accommodations, 
and ground transportation. The deadline for pre-registration is 
February 25, 2002. Space is limited, and reservations will be accepted 
on a first-come, first-served basis. There will be a limited time for 
oral comments on the revised draft document during the meeting. When 
registering, please let ERG know if you

[[Page 76]]

wish to make a brief statement not to exceed five minutes.
    Document Availability: The external review draft of the perchlorate 
document will be available by January 9, 2002, on EPA's National Center 
for Environmental Assessment (NCEA) Web site at http://www.epa.gov/ncea. In addition, a compact disk (CD) containing documents cited in 
the ``Perchlorate Environmental Contamination: Toxicological Review and 
Risk Characterization'' report that cannot be readily obtained from the 
open literature will be available by request as of January 9, 2002. To 
obtain a copy of the CD, you may contact the EPA Superfund Records 
Center in San Francisco, California. A shipping and handling fee may 
apply. The circulation desk phone number for the Superfund Records 
Center is 415-536-2000. Copies of the perchlorate document and CD are 
not available from ERG.
    Comment Submission: Written comments should be submitted to ERG, 
Inc., 110 Hartwell Avenue, Lexington, Massachusetts 02421. Comments 
under 50 pages may be sent via e-mail attachment (in Word, Word 
Perfect, or PDF) to [email protected]. Written comments must be 
postmarked by the end of the public comment period (February 11, 2002). 
Please note that all technical comments received in response to this 
notice will be placed in a public record. For that reason, commentors 
should not submit personal information (such as medical data or home 
address), Confidential Business Information, or information protected 
by copyright. Due to limited resources, acknowledgments will not be 

FOR FURTHER INFORMATION CONTACT: Questions regarding registration and 
logistics should be directed to EPA's contractor, ERG, Inc., at 781-
674-7374. For technical inquiries, please contact: Annie Jarabek, U.S. 
Environmental Protection Agency (MD 52), USEPA Mailroom, Research 
Triangle Park, NC 27711; telephone 919-541-4847; facsimile 919-541-
1818; e-mail [email protected].

SUPPLEMENTARY INFORMATION: Perchlorate (ClO4) is an anion 
that originates as a contaminant in groundwater and surface waters from 
the dissolution of ammonium, potassium, magnesium, or sodium salts. 
Perchlorate is exceedingly mobile in aqueous systems and can persist 
for many decades under typical groundwater and surface water 
conditions. A major source of perchlorate contamination is the 
manufacture of ammonium perchlorate for use as the oxidizer component 
and primary ingredient in solid propellant for rockets, missiles, and 
    EPA's Superfund Technical Support Center issued a provisional 
reference dose (RfD) for perchlorate in 1992 and a revised provisional 
RfD in 1995 based on the effects of potassium perchlorate in patients 
with Graves' disease (an autoimmune disease that results in 
hyperthyroidism). (An RfD is an estimate of a daily oral human exposure 
that is anticipated to be without adverse noncancer health effects over 
a lifetime.) In March 1997, the existing toxicologic database on 
perchlorate was determined to be inadequate for quantitative human 
health risk assessment by an external peer review panel. A lack of data 
on the ecotoxicological effects was also noted. In May 1997, a testing 
strategy was developed based on the known mode-of-action for 
perchlorate toxicity (the inhibition of iodide uptake in the thyroid 
and subsequent perturbations of thyroid hormone homeostasis), and an 
accelerated research program was initiated to gain a better 
understanding of the human health effects of perchlorate, examine 
possible ecological impacts, refine analytical methods, develop 
treatment technologies, and better characterize the occurrence of 
perchlorate in groundwater and surface waters.
    In December 1998, the National Center for Environmental Assessment 
(NCEA) developed an external peer review draft document that assessed 
the human health and ecological risk of perchlorate (``Perchlorate 
Environmental Contamination: Toxicology Review and Risk 
Characterization Based on Emerging Information,'' NCEA-I-0503). This 
document presented an updated human health risk assessment that 
incorporated results of the newly performed health effects studies 
available as of November 1998 and a screening-level ecological 
assessment. The human health risk assessment model utilized a mode-of-
action approach that harmonized noncancer and cancer approaches to 
derive a single oral risk benchmark based on precursor effects for both 
neurodevelopmental and thyroid neoplasia. A workshop was convened in 
February 1999 in San Bernardino, California, to provide external peer 
review of that document. Peer reviewers endorsed the conceptual 
approach proposed by NCEA, but recommended that new analyses be 
conducted and that several additional studies be planned and performed. 
NCEA has prepared a revised perchlorate assessment that addresses 
comments from the 1999 external peer review workshop and incorporates 
data from additional studies that were either nearing completion at the 
time of the 1999 review or were recommended at that time. This revised 
draft document is the subject of the external peer review workshop 
announced in today's Federal Register notice.
    The external peer review panel will consist of a panel of 
independent scientists selected by EPA's contractor, ERG, from the 
fields of developmental toxicology, reproductive toxicology, 
neurotoxicology, immunotoxicology, pharmacokinetics, genetic 
toxicology, endocrinology, pathology, epidemiology, statistics, 
ecotoxicology, and environmental transport and biotransformation. Peer 
reviewers will review the revised human health and ecological risk 
assessment for perchlorate as well as new studies performed since the 
1999 external peer review. Following the external peer review workshop, 
ERG will prepare a report summarizing the workshop. EPA will address 
the comments of the external peer reviewers in finalizing the 
perchlorate risk assessment document and in developing revised toxicity 
values. The human health and ecological risk assessment may be used in 
the future to support development of a health advisory or possible 
drinking water regulations and cleanup decisions at hazardous waste 
sites. However, any such future decisions would be subject to all 
applicable statutory and regulatory requirements and policy 
considerations for use of the assessments under those programs.

    Dated: December 20, 2001.
George W. Alapas,
Acting Director, National Center for Environmental Assessment.
[FR Doc. 01-32088 Filed 12-31-01; 8:45 am]