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Model Report

Estimation Program Interface Suite

Last Revision Date: 07/11/2011 View as PDF
General Information Back to Top
Model Abbreviated Name:

Model Extended Name:

Estimation Program Interface Suite
Model Overview/Abstract:
The EPI (Estimation Program Interface) SuiteTM is a Windows based suite of physical/chemical property and environmental fate estimation models developed by the EPA's Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC). EPI SuiteTM uses a single input to run the following estimation models:


Keywords: Chemical, property, fate, estimation, degradation, structure-activity relationships, QSAR, transport, distribution, screening
Model Technical Contact Information:
Dr. Robert Boethling
U.S. Environmental Protection Agency
1200 Pennsylvania Ave., N.W. (Mail Code 7406M)
Washington, DC 20460
Phone # (202) 564-8533

For Technical Support and Training on EPI SuiteTMplease contact:
Dr. Philip Howard
Syracuse Research Corporation
6225 Running Ridge Road
North Syracuse, NY 13212
Phone: (315) 452-8417
e-mail: howardp@syrres.com

Model Homepage: http://www.epa.gov/oppt/exposure/pubs/episuite.htm
Substantive Changes from Prior Version: EPA’s Science Advisory Board (SAB) reviewed the software in 2006 and made many recommendations, which EPA has now implemented. These fall into three general categories:
  1. Functionality: user interface updated and features added
  2. Transparency: more information provided on methodology, validation, statistics, domain
  3. Core methods: many data sets updated and models re-regressed.
Item 3 includes major upgrades to the KOCWIN, HYDROWIN and BCFBAF (formerly, BCFWIN) programs. Item 2 includes enhancement of all Help files to provide more information on domain, accuracy and validation. Examples of functionality improvements include redesign of the user interface, and numerous new features such as ability to launch programs from the main screen; automatic creation of Microsoft Word documents; and full citations for PHYSPROP references. This new version of and publicly available for free download.
Plans for further model development: SAB recommendations have not yet been fully implemented. Model development is an ongoing process and implementation of the recommendations is expected to continue.

User Information Back to Top
Technical Requirements
Computer Hardware
  • Windows 3.1X,
  • Windows 95/98 or
  • Windows NT.
Compatible Operating Systems
EPI SuiteTM (v4.00) is compatible with Windows Vista®. It also runs on Windows® 3.1X, Windows® 95/98,Windows NT® and Windows XP/XP Professional®.
Download Information
EPI SuiteTM (v4.00) is provided as a zip file. If you do not have unzip software in your computer, you may not successfully install the program. By downloading this software, you agree to the Terms and Conditions of Use. More detailed instructions are given at the download website:http://www.epa.gov/oppt/exposure/pubs/episuite.htm
Using the Model
Basic Model Inputs
EPI Suite requires only a representation of the chemical structure via its SMILES notation. SMILES is "Simplified Molecular Information and Line Entry System". A description of this system is available in the Help files of the program. Entry of SMILES via a linked file of CAS numbers included within the SMILECAS file in EPI Suite is also possible; as is entry of only the chemical name using the Name Lookup utility.
Basic Model Outputs
EPI Suite provides users with screening level estimates of physical/chemical and environmental fate properties. These properties are the building blocks of exposure assessment. EPI Suite includes estimation programs for Log KOW, KOC, KOA, atmospheric oxidation potential, Henry's Law constant, water solubility, melting point, boiling point, vapor pressure, biodegradation, sorption to aerosols, bioconcentration factor, bioaccumulation factor, ecotoxicity (via ECOSAR), hydrolysis, sewage treatment plant removal, and multimedia distribution.
User Support
User's Guide Available?
Extensive documentation for the

? Basic Model Inputs

? Basic Model Outputs

? User's Guide

can be found in the Help Files in the EPI Suite download:


Availability of User Support
Agency or developer contact
User Qualifications
EPI Suite is intended to be used by scientists and engineers familiar with exposure assessment principles. Generally, users should have at least a bachelor’s degree level of education. In addition, a clear understanding of the estimation methods and their appropriate application is important. More information on the methods and models in EPI Suite is available in the program Help files, but appropriate use is the responsibility of the user. EPI Suite is a screening level tool and should not be used if measured property values are available.

Model Science Back to Top
Problem Identification
The Office of Pollution Prevention and Toxics (OPPT) has developed exposure assessment methods, databases, and predictive models to help in evaluating what happens to chemicals when they are used and released to the environment; and how workers, the general public, consumers and the aquatic ecosystems may be exposed to chemicals. These models and tools may be helpful when appropriate monitoring data are not available or need to be supplemented; in considering potential exposure when designing and selecting products and processes; and in evaluating pollution prevention opportunities. There is a high demand for screening-level tools in chemical assessment as a result of the lack of availability of data for many chemicals. EPI Suite is such a tool and is intended for use in applications such as to quickly screen chemicals for release potential and "bin" chemicals by priority for future work.
Summary of Model Structure and Methods
EPI Suite operates via an interface program that transfers a single SMILES notation to separate estimation programs that require chemical structure input. The 13 separate estimation programs are:
  • AOPWIN - estimates atmospheric oxidation rates
  • BCFBAF - estimates bioconcentration factor (BCF) and bioaccumulation factor (BAF)
  • BioHCwin - estimates biodegradation of hydrocarbons
  • BIOWIN - estimates biodegradation probability
  • ECOSAR - estimates aquatic toxicity (LD50, LC50)
  • HENRYWIN - estimates Henry’s law constant
  • HYDROWIN - estimates aqueous hydrolysis rates
  • KOAWIN - estimates octanol-air partition coefficient
  • KOWWIN - estimates octanol-water partition coefficient
  • MPBPWIN - estimates melting point, boiling point and vapor pressure
  • PCKOCWIN - estimates soil sorption coefficient (Koc)
  • WSKOWWIN - estimates water solubility (from log octanol-water partition coefficient)
  • WATERNT - estimates water solubility (using atom-fragment methodology)

They do not require the interface program (Epiwinnt.exe) to run. The EPI Suite interface program is designed specifically to execute these programs and capture their output. The interface program is a convenience for users because it automatically executes each program in succession without user interaction. In addition, the interface program executes the WVOLWIN (Volatilization Rate from Water), STPWIN (Sewage Treatment Plant Fugacity Model), AEROWIN (sorption to atmospheric particulates) and LEVEL3NT (Level III Fugacity Model) programs by transferring the Molecular Weight, the Henry's Law Constant, log octanol-water partition coefficient and various volatilization parameters to these programs.
Model Evaluation
Individual estimation programs and/or their underlying predictive methods and equations have been described in numerous journal articles in peer-reviewed technical journals. The full reference citations are given in the EPI Suite™ Help files. In addition, EPI Suite™ has undergone detailed review by a panel of EPA’s independent Science Advisory Board (SAB), and the September 2007 report (PDF) (60pp, 473KB) can be downloaded from the SAB website. In addition, as indicated above, v4.00 includes enhancement of all Help files to provide more information on domain, accuracy and validation.
Key Limitations to Model Scope
EPI Suite™ is a screening-level tool and cannot be used for all chemical substances. Like other such tools, it is intended for use in screening level applications such as to quickly screen chemicals for release potential and "bin" chemicals by priority for future work. Estimated values should not be used when experimental (measured) values are available. Important information on the performance, development and application of the individual estimation programs within EPI Suite™ is included in the User's Guide. Except for the BioHCwin and KOAWIN models, EPI Suite™ and the individual models included within the software are owned by the U.S. Environmental Protection Agency and are protected by copyright throughout the world. Permission is granted for individuals to download and use the software on their personal and business computers. Users may not alter, modify, merge, adapt, distribute, or prepare derivative works from the software. Users may not remove or obscure copyright, trademark, or proprietary notices on the program or related documentation.
Case Studies
EPI Suite™ has thousands of users worldwide. Journal articles and reports describing applications appear daily in the technical and regulatory literature. Validation studies on selected estimation programs are cited in the Help files.

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