The EPI Suite is now available from the U.S. Environmental Protection Agency via free Internet download.

In 1988, SRC developed its first estimation program, Henry, to aid its environmental scientists in the preparation of chemical profiles for the National Library of Medicine's Hazardous Substance Data Bank. Since that time, SRC has developed many new methodologies to meet the needs of our sponsors, some of which are represented in the following suite of environmental and physical/ chemical property estimation programs.

SRC's estimation programs contain common features to simplify their use. Recent enhancements have increased the convenience of entering a chemical structure by allowing users to import structures that were produced in popular chemical drawing programs.

Estimation Software

	KowWin	KowWin estimates the log octanol-water partition coefficient, log P, of chemicals using an atom/fragment contribution method developed at SRC. Use our Online LogKow Demoto test the program's estimation ability and experimental log P database retrieval.
	AopWin	The gas-phase reaction rate for the most prevalent atmospheric oxidant, hydroxyl radicals, with chemical compounds is estimated by AOP. Gas-phase ozone and nitrate radical reaction rates are also estimated, as appropriate. Atmospheric half-lives for each reaction are automatically determined.
	HenryWin	This program calculates the Henry's Law constant (air/water partition coefficient) using both the group contribution and the bond contribution methods.
	MPBPVP	Melting point, boiling point, and vapor pressure of organic chemicals are estimated using a number of techniques.
	BioWin	BioWin, the biodegradation probability program, calculates the probability that an organic chemical will biodegrade rapidly (or slowly) under aerobic conditions.
	PcKoc	The ability of a chemical to adsorb to soil and sediment, its soil adsorption coefficient (Koc), is estimated by this program.
	WsKow	WsKow estimates an octanol/water partition coefficient using the algorithms in SRC's LogKow program and estimates a chemical's water solubility from this value.
	Hydro	Hydrolysis rate constants for specific organic classes are estimated by Hydro. A chemical's half-live under typical environmental conditions is also determined.
	EPI Suite	EPI (estimation program interface) integrates SRC's suite of estimation software by allowing a single input to obtain the above environmental/chemical properties. It also estimates a chemical's rate of volatilization from a model river and lake to the atmosphere as well as its expected fate in a sewage treatment plant and level III fugacity model.
	DermWin	This program estimates the dermal permeability coefficent (Kp); an indicator of the potential for a chemical to be absorbed through the skin.
	ECOSAR	The ECOSAR Class Program is a computerized version of the ECOSAR analysis as currently practiced by EPA's Office of Pollution Prevention and Toxics (OPPT). This analysis involves the application of SARs (Structure Activity Relationships) to predict the aquatic toxicity of chemicals (LC50, EC50, chronic, etc.) for various aquatic organisms (fish, daphnid, algae, etc.). To date, over 150 SARs have been developed for more than 50 chemical classes.
	BcfWin	This program estimates the bioconcentration factor (BCF) based upon chemical structure and log octanol-water partition coefficient.
SMILESCAS Database		This is a separate product sold by SRC that contains SMILES notations, chemical names and CAS numbers for 110,000 compounds which can be used as input for the suite of estimation software.
Read Me Notes Windows Versions of the EPI Suite are now available for free from the US EPA.   SMILES Description Online - The SRC document "A Brief Description of SMILES Notation" is now online with all figures. It describes what a SMILES notation is and how to write a SMILES notation manually. A list of Example SMILES is also available.   All Windows programs have the ability to run "batch files" using SDFiles as input. Commercial database programs such as ISIS/Base (MDL Inc), CS ChemFinder (CambridgeSoft Corp), and Accord (Synopsys Scientific) can export their data to SDFiles which can then be used as SRC input files. All SRC programs can also run batches using files of SMILES strings or CAS numbers.   The SMILECAS database has been expanded to more than 103,000 SMILES notations (indexed by CAS number). Many SMILES strings (especially metals) have been modified.