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What Does ReachScan Do?

. Estimates surface water chemical concentrations at drinking water utilities downstream from industrial facilities.
. Estimates the populations served by those drinking water utilities.
. Serves as a database for the identification of facilities and utilities.
. Estimates the number of days per year that an aquatic ecotoxicological concern concentration will be exceeded in the subject stream or stream segment. A chemical's aquatic ecotoxicological concern concentration is the estimated concentration at which the chemical may adversely affect aquatic organisms.
. Provides stream flow statistics on a daily average basis.
. Determines the presence of endangered species or critical habitats in the county of the releasing facility.

How Does ReachScan Work?

. Operates as an integrated software package, with links to other computer-based programs developed by the U.S. Environmental Protection Agency (EPA), including the Probabilistic Dilution Model (PDM3) and the Endangered Species Data Base.
. Estimates chemical concentrations in single or multiple stream (segments) reaches by simple dilution or using simple fate algorithms.
. Instructions to install and run the model are not presented here.

What Do I Need to Use ReachScan?

. Facility information, such as:
. National Pollution Discharge Elimination System (NPDES) number.
. Facility name.
. Standard Industry Classification (SIC) code.
. Reach number (an 11-digit number that identifies a specific section of a stream).
. Distance up- or downstream to consider.
. Amount of chemical released to stream.
. Chemical properties (if chemical fate is to be considered), including:
. Molecular weight, Solubility, Vapor pressure, Soil Adsorption Coefficient (Koc), Half-life.

How Are ReachScan Data Used?

Risk assessors use data on chemical concentrations in streams surrounding an industrial or utility discharge to estimate fish bioconcentration rates and potential dose rates for humans exposed via ingestion of drinking water and fish.
ReachScan can also be used to determine how a release may affect endangered species or critical habitats surrounding an industrial facility or utility.

What Type of Computer System Do I Need?

Hardware: Personal computer with 640K memory and 18 MB hard disk space.
Software: MS-DOS 3.0 or higher.

What Is ReachScan's Status and Availability?

This program is currently in a DOS format. A Windows-based version of this model is under development. ReachScan has not been peer reviewed in accordance with EPA Peer Review Guidance but will be scheduled for peer review upon completion of the Windows-based version. ReachScan was developed under contract by Versar Inc. for the EPA Office of Pollution Prevention and Toxics, Economics, Exposure, and Technology Division, Exposure Assessment Branch (EAB).

For more information about the model, contact:
David Lynch
US Environmental Protection Agency
1200 Pennsylvania Avenue N.W.
Washington, DC 20460
Mail Code 7406M
Phone #: (202) 564-8532
e-mail:David Lynch


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