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Reference Dose for Methylmercury

 


[Federal Register: October 30, 2000 (Volume 65, Number 210)]
[Notices]
[Page 64702-64703]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30oc00-81]

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ENVIRONMENTAL PROTECTION AGENCY

[FRL-6893-4]


Reference Dose for Methylmercury

AGENCY: Environmental Protection Agency.

ACTION: Notice of peer-review workshop and public comment period.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing
that Versar, Inc., an EPA contractor for external scientific peer
review, will convene a panel of experts and organize and conduct an
external peer-review workshop to review the draft document titled,
Reference Dose for Methylmercury (NCEA-S-0930). The EPA is also
announcing a 30-day public comment period for the draft document. The
document was prepared by the EPA's National Center for Environmental
Assessment-Washington Office (NCEA-W) within the Office of Research and
Development. NCEA will consider the peer-review advice and public
comment submissions in revising the document.

DATES: The peer-review workshop will begin on Wednesday, November 15,
2000, at 9 a.m. and end at 5 p.m. Members of the public may attend as
observers, and there will be a limited time for comments from the
public in the afternoon. The 30-day public comment period begins
October 30, 2000, and ends November 29, 2000.

ADDRESSES: The external peer-review panel workshop will be held at the
Marriott Crystal Gateway Hotel, 1700 Jefferson Davis Highway,
Arlington, Virginia 22202, (703) 920-3230. Versar, Inc., an EPA
contractor, is organizing, convening, and conducting the peer-review
workshop. To attend the workshop, register by November 6, 2000, by
calling Versar, Inc. (Ms. Marit Espevik) at (703) 750-3000, ext. 460,
or send a facsimile to (703) 642-6954. You also can register via e-mail
at espevmar@versar.com. Space is limited, and reservations will be
accepted on a first-come, first-served basis. There will be a limited
time for comments from the public during the afternoon of the workshop.
Please let Versar, Inc. know if you wish to make comments.
    The external review draft is available primarily via the Internet
on the National Center for Environmental Assessment's home page at
http://www.epa.gov/ncea under the What's New and Publications menus. A
limited number of paper copies are available from NCEA's Technical
Information Staff; telephone: (202) 564-3261; facsimile: (202) 565-
0050. If you are

[[Page 64703]]

requesting a paper copy, please provide your name, mailing address, and
the document title, Reference Dose for Methylmercury (NCEA-S-0930).
Copies are not available from Versar, Inc.
    Comments may be mailed to the Technical Information Staff (8623D),
NCEA-W, U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue,
NW., Washington, DC 20460, or delivered to the Technical Information
Staff at 808 17th Street, NW., 5th Floor, Washington, DC 20006;
telephone: (202) 564-3261; facsimile: (202) 565-0050. Comments should
be in writing and must be postmarked by November 29, 2000. Please
submit one unbound original with pages numbered consecutively, and
three copies of the comments. For attachments, provide an index, number
pages consecutively with the comments, and submit an unbound original
and three copies. Electronic comments may be e-mailed to: nceadc-
comment@epa.gov.
    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 sent.

FOR FURTHER INFORMATION CONTACT: For workshop information,
registration, and logistics, contact Versar Inc., (Ms. Marit Espevik,
telephone: (703) 750-3000, ext. 460; facsimile: (703) 642-6954).
    For information about the draft document, contact the Technical
Information Staff, NCEA-Washington Office; telephone: (202) 564-3261;
facsimile: (202) 565-0050; or e-mail: nceadc-comment@epa.gov.

SUPPLEMENTARY INFORMATION: In 1997, U.S. EPA issued the Mercury Study
Report to Congress (MSRC). Among the assessments in the MSRC was a
state-of-the-science evaluation of the health effects of methylmercury.
There has been considerable discussion within the scientific community
regarding the level of exposure to methylmercury that is likely to be
without appreciable risk of adverse health effects. Congress directed
EPA through the House Appropriations Report for FY99 to contract with
the National Research Council to evaluate the body of data on the
health effects of methylmercury, with particular emphasis on new data
since the 1997 Mercury Study Report to Congress, and provide
recommendations regarding issues relevant to the derivation of an
appropriate RfD for methylmercury. EPA has thoroughly reviewed this
document, and concurs with the NRC findings and recommendations. The
NRC document is used as the basis for the current EPA derivation of the
RfD for methylmercury.
    Methylmercury is a highly toxic substance; there are a number of
adverse health effects associated with methylmercury exposure. Most
extensive are the data for neurotoxicity, particularly in developing
organisms. Therefore the brain is considered to be the most sensitive
target organ for which there are data suitable for derivation of an
RfD. The NRC considered three epidemiological longitudinal
developmental studies suitable for quantitative risk assessment: the
Seychelles Islands, the Faroe Islands, and New Zealand. The Seychelles
study has yielded no evidence of impairment related to methylmercury
exposure, while both the other studies have found dose-related adverse
effects on a number of neuropsychological endpoints. The Faroe Islands
study, the larger of the latter two studies, has been extensively peer-
reviewed and is used for the derivation of the RfD. The NRC's major
finding is that the results of the Faroe Islands study provide a
scientifically credible basis on which to base EPA's RfD.
    The RfD derived in this assessment is 0.1 ug/kg per day. This is
the same as the RfD derived by EPA in 1995 based on an earlier study of
a poisoning episode in Iraq, in which data on adverse neurological
effects in infants was used as the point of departure for derivation of
the RfD.

    Dated: October 24, 2000.
William H. Farland,
Director, National Center for Environmental Assessment.
[FR Doc. 00-27781 Filed 10-27-00; 8:45 am]
BILLING CODE 6560-50-U

 
 

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