Harmonization in Interspecies Extrapolation: Use of BW\3/4\ as
Default Method in Derivation of the Oral RfD
[Federal Register: February 15, 2006 (Volume 71, Number 31)]
[Notices]
[Page 7958-7959]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15fe06-63]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
[FRL-8031-9; EPA-HQ-Docket ID No. ORD-2006-0116]
Harmonization in Interspecies Extrapolation: Use of BW\3/4\ as
Default Method in Derivation of the Oral RfD
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of public comment period.
-----------------------------------------------------------------------
SUMMARY: EPA is announcing a 60-day public comment period for the draft
document titled, ``Harmonization in Interspecies Extrapolation: Use of
BW\3/4\ as Default Method in Derivation of the Oral RfD'' (EPA/630/R-
06/001), which was prepared by the EPA's Risk Assessment Forum (Forum).
EPA is releasing this draft document solely for the purpose of pre-
dissemination peer review under applicable information quality
guidelines. This document has not been formally disseminated by EPA. It
does not represent and should not be construed to represent any Agency
policy or determination. EPA will consider any public comments
submitted in accordance with this notice when revising the document.
DATES: The 60-day public comment period begins February 15, 2006, and
ends April 17, 2006. Technical comments should be in writing and must
be received by EPA by April 17, 2006.
ADDRESSES: The draft, ``Harmonization in Interspecies Extrapolation:
Use of BW\3/4\ as Default Method in Derivation of the Oral RfD,'' is
available primarily via the Internet on the Risk Assessment Forum's
home page at http://cfpub.epa.gov/ncea/raf/index.cfm. A limited number
of paper copies are available from the Technical Information Staff,
NCEA-W; telephone: 202-564-3261; facsimile: 202-565-0050. If you are
requesting a paper copy, please provide your name, your mailing
address, and the document title, ``Harmonization in Interspecies
Extrapolation: Use of BW\3/4\ as Default Method in Derivation of the
Oral RfD.''
Comments may be submitted electronically, by mail, by facsimile, or
by hand delivery/courier. Please follow the detailed instructions
provided in the SUPPLEMENTARY INFORMATION section of this notice.
FOR FURTHER INFORMATION CONTACT: For information on the public comment
period, contact the Office of Environmental Information Docket;
telephone: 202-566-1752; facsimile: 202-566-1753; or e-mail:
ORD.Docket@epa.gov.
For technical information, please contact Resha M. Putzrath, Risk
Assessment Forum; telephone: 202-564-3229; facsimile: 202-565-0062; or
e-mail: putzrath.resha@epa.gov.
SUPPLEMENTARY INFORMATION:
I. Information About the Document
The Agency endorses a hierarchy of approaches to derive human
equivalent oral exposures from data from laboratory animals, with the
preferred approach being physiologically based toxicokinetic modeling.
Intermediate approaches include using some chemical-specific
information. In lieu of data to support either of these approaches,
body weight scaling to the 3/4 power (BW\3/4\) would be endorsed as a
general default procedure to extrapolate toxicologically equivalent
doses of chronic orally administered agents from laboratory animals to
humans for the purpose of deriving an oral Reference Dose (RfD). Use of
BW\3/4\ in derivation of RfD values would be parallel with current
Agency use in derivation of cancer oral slope factors. Thus, this paper
would harmonize the two main Agency oral dose-response extrapolation
procedures. This generalized default procedure is viewed as an
informed, species-specific, dosimetric adjustment factor (DAF) that
addresses predominantly toxicokinetic and some toxicodynamic aspects of
the interspecies uncertainty factor UFA. Use of this
procedure would result in derivation of a human equivalent exposure,
specifically a human equivalent dose (HED) that is to be used in
derivation of the oral RfD in a manner parallel to the human equivalent
concentration (HEC) in derivation of an inhalation RfC.
II. How to Submit Technical Comments to the Docket
Submit your comments, identified by Docket ID No. EPA-HQ-ORD 2006-
0116, by one of the following methods:
? http://www.regulations.gov: 
Follow the on-line
instructions for submitting comments.
? E-mail: ORD.Docket@epa.gov.
? Fax: 202-566-1753.
? Mail: Office of Environmental Information Docket (Mail
Code: 28221T), U.S. Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460. The phone number is 202-566-1752;
facsimile: 202-566-1753.
If you provide comments in writing, 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.
? Hand delivery/courier: The Office of Environmental
Information (OEI) Docket is located in the Headquarters EPA Docket
Center (EPA/DC), EPA West Building, Room B102, 1301 Constitution Ave.,
NW., Washington, DC. The EPA Docket Center Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The telephone number for the Public Reading Room is 202-566-
1744, and the telephone number for the OEI Docket is 202-566-1752;
facsimile: 202-566-1753; or e-mail: ORD.Docket@epa.gov. Such deliveries
[[Page 7959]]
are only accepted during the Docket's normal hours of operation, and
special arrangements should be made for deliveries of boxed information.
Instructions: Direct your comments to Docket ID No. EPA-HQ-ORD-
2006-0116. EPA's policy is that all comments received will be included
in the public docket without change and may be made available online at
http://www.regulations.gov, including any personal information
provided, unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to be
CBI or otherwise protected through http://www.regulations.gov
or e-mail. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov, your e-mail address
will be automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit the EPA Docket Center home page at
http://www.epa.gov/epahome/dockets.htm.
Docket: All documents in the docket are listed in the
http://www.regulations.gov index. Although listed in the index,
some information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Office of
Environmental Information (OEI) Docket (EPA/DC), EPA West Building,
Room B102, 1301 Constitution Ave., NW., Washington, DC. The Public
Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is 202-566-1744, and the telephone number for the OEI
Docket is 202-566-1752; facsimile 202-566-1753.
Dated: February 7, 2006
Peter W. Preuss,
Director, National Center for Environmental Assessment.
[FR Doc. E6-2146 Filed 2-14-06; 8:45 am]
BILLING CODE 6560-50-P
![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}