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###### Environmental Protection Agency

          - [FRL-8291-2; Docket ID No. ORD-2005-0001] 

# AGENCY:

Environmental Protection Agency (EPA). 

# ACTION:

Notice of External Review Draft for Public Review and Comment. 

# SUMMARY:

The U.S. Environmental Protection Agency is announcing a 30-day public review and comment period for the external review draft of Part 2 of the 2007 release of the EPA Web site titled, “Causal Analysis/Diagnosis Decision Information System (CADDIS).” The CADDIS Web site was developed and prepared by EPA's National Center for Environmental Assessment (NCEA) in the Office of Research and Development (ORD). NCEA will consider public comments received in accordance with this notice when revising the CADDIS Web site. 

EPA is releasing the draft CADDIS 2007 Web site solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. The draft CADDIS 2007 Web site 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 30-day public comment period begins March 23, 2007, and ends April 23, 2007. Technical comments should be in writing and must be submitted electronically or postmarked by April 23, 2007. 

# ADDRESSES:

                        The draft CADDIS 2007 Web site can be accessed via the Internet at                         *http://caddis.tetratech-ffx.com*. Enter the username “public” and the password “public.” Comments may be submitted electronically to the EPA's e-docket, by mail, by facsimile, or by hand delivery/courier. Additional instructions for providing comments and a description of the portions of the Web site that are available for review are provided at the top of the home page of the CADDIS Web site and in the section of this notice entitled,                         **SUPPLEMENTARY INFORMATION**                        .                     

# 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, contact Vic Serveiss, NCEA, via phone: 202-564-3251, facsimile: 202-564-2018, or e-mail:                         *serveiss.victor@epa.gov.*

# SUPPLEMENTARY INFORMATION:

## I. Information About the Project/Document 

                    Over 2800 water bodies in the United States are listed by states as biologically impaired. For many of these sites, the cause of impairment is reported as “unknown.” To formulate appropriate management actions for impaired water bodies, it is important to identify the causes of biological impairment (                    *e.g.*, excess fine sediments, nutrients, or toxic substances). Effective causal analyses call for knowledge of the mechanisms, symptoms, and stressor-response relationships for various stressors, as well as the ability to use that knowledge to draw appropriate, defensible conclusions. To aid in these causal analyses, NCEA developed CADDIS. CADDIS is a Web-based decision support system that will help regional, State, and tribal scientists find, access, organize, and share information useful for causal evaluations of impairment in aquatic systems. It is based on EPA's Stressor Identification process, which is an EPA-recommended method for identifying causes of impairments in aquatic environments. EPA released the first version of CADDIS earlier in 2006, after addressing comments from the public and independently selected peer reviewers. Current features of CADDIS include a step-by-step guide to conducting causal analysis, downloadable worksheets and examples, a library of conceptual models, and links to useful information sources.                 

Two sets of modules are being added to the CADDIS Web site in preparation for release of a major revision in September 2007 (CADDIS 2007). On January 17, 2007, the draft of the first of the two sets of modules was released for external peer review and public comment. This first set of draft modules included information on six candidate causes: metals, sediments, nutrients, dissolved oxygen, thermal alteration, and ionic strength. 

This notice invites comment on the second set of draft modules being developed for CADDIS 2007. Specifically, comment is invited on two additional candidate cause models, altered flow rates and toxic substances; an interactive conceptual model for phosphorus; and added analytical methods, tools, and databases. Descriptive information on ten analytical methods have been added to CADDIS 2007 including scatter plots, linear regression, predicting environmental conditions from biological observations, and species sensitivity distributions. The principal analytical tool added to CADDIS is CADStat; a downloadable software package for analyzing data using a variety of exploratory and statistical approaches. New analytical databases include a stressor-response gallery for metals and a tolerance value database. These additions improve the capability of CADDIS to diagnose the causes of biological impairments in streams. 

## II. How to Submit Technical Comments to the Docket at www.regulations.gov

Submit your comments, identified by Docket ID No. EPA-HQ-ORD-2005-0001 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 (OEI) Docket (Mail Code: 2822T), U.S. Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460. The phone number is 202-566-1752.                 
    -  Hand Delivery:                      The OEI Docket is located in the EPA Headquarters Docket Center, EPA West Building, Room 3334,                            ( print page 13790)                          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. Such deliveries are only accepted during the docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.                 

If you provide comments by mail or hand delivery, please submit three copies of the comments. For attachments, provide an index, number pages consecutively with the comments, and submit an unbound original and three copies. 

*Instructions:*                     Direct your comments to Docket ID No. EPA-HQ-ORD-2005-0001. Please ensure that your comments are submitted within the specified comment period. Comments received after the closing date will be marked “late,” and may only be considered if time permits. It is EPA's policy to include all comments it receives in the public docket without change and to make the comments available online at                     *http://www.regulations.gov*, including any personal information provided, unless a 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                     *www.regulations.gov*                     or e-mail. The                     *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                     *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 homepage at                     *http://www.epa.gov/​epahome/​dockets.htm.*

*Docket:*                     Documents in the docket are listed in the                     *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 materials, such as copyrighted material, are publicly available only in hard copy. Publicly available docket materials are available either electronically in                     *www.regulations.gov*                     or in hard copy at the OEI Docket in the EPA Headquarters Docket Center.                 

Dated: March 20, 2007. 

George Alapas, 

Director, National Center for Environmental Assessment.

[FR Doc. E7-5358 Filed 3-22-07; 8:45 am] 

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