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###### Environmental Protection Agency

          - [FRL-7824-8] 

# AGENCY:

Environmental Protection Agency. 

# ACTION:

Notice of availability of a final document.

# SUMMARY:

This notice announces the availability of a final report titled, Rapid Processing of Turner Designs Model 10-AU-005 Internally Logged Fluorescence Data (EPA/600/R-04/053, August 2004), which was prepared by the U.S. Environmental Protection Agency's (EPA) National Center for Environmental Assessment (NCEA) of the Office of Research and Development (ORD). 

# ADDRESSES:

                        The document will be made available electronically through the NCEA Web site (                        *http://www.epa.gov/​ncea*). A limited number of copies of the printed and CD-ROM version of the document will be available from the EPA's National Service Center for Environmental Publications (NSCEP), PO Box 42419, Cincinnati, OH 45242; telephone: 1-800-490-9198 or 513-489-8190; facsimile: 513-489-8695. Please provide your name, your mailing address, the title and the EPA number of the requested publication.                     

# FOR FURTHER INFORMATION CONTACT:

                        The Technical Information Staff, National Center for Environmental Assessment/Washington Office (8623D), U.S. Environmental Protection Agency, 1200 Pennsylvania Avenue, NW., Washington, DC 20460. Telephone: 202-564-3261; fax: 202-565-0050; e-mail:                         *nceadc.comment@epa.gov.*

# SUPPLEMENTARY INFORMATION:

The U.S. EPA has used field fluorometers to measure dye fluorescence when such dyes are injected into ground water to trace groundwater flow. Typically, the data output from these off the shelf fluorometers are not optimized for field use or subsequential analysis. EPA has developed a methodology to enhance the usability of fluorometer data and is sharing that information with the user community. 

This document and the related computer program, FLOWTHRU, provide a method for rewriting data internally logged by a fluorometer used by EPA (Turner Designs Model 10-AU-005 Field Fluorometer), thus optimizing the utility of the instrument's stored data. Application of the methodology provides the information necessary for rapid examination of tracer test results and preparation of data sets for numerical analysis. The new computer program bypasses block headers, reads the downloaded data, identifies the time-concentration units used, and relates the data to injection time. All preinjection time-concentration data are accorded background data status and are written to a background file with average temperature values included. All time values recorded after injection time are rewritten into decimal time using time units chosen by user. Additional features include options for processing selected percentages, averaged time values, and a smoothing routine that may be applied to the time-concentration data. FLOWTHRU also allows users to view the data converted to decimal time directly on the computer monitor without program interruption or to go directly to a data plotting routine. Data plotting is rapid and clear with a smooth line connecting each data point, and each data plot may be saved as a file in a common format. 

Dated: September 27, 2004. 

Peter Preuss, 

Director, National Center for Environmental Assessment. 

[FR Doc. 04-22486 Filed 10-5-04; 8:45 am] 

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