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Harmonization in Interspecies Extrapolation: Use of BW3/4

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Information about this document as published in the Federal Register.

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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 BW3/4 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 BW3/4 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 BW3/4 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.

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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.

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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 (BW3/4) 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 BW3/4 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 Start Printed Page 7959are 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.

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Dated: February 7, 2006

Peter W. Preuss,

Director, National Center for Environmental Assessment.

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[FR Doc. E6-2146 Filed 2-14-06; 8:45 am]

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