Home Environmental Software Ecological Structure Activity Relationships
Ecological Structure Activity Relationships PDF Print E-mail
User Rating: / 101

 Our rating:          License:  Free

What is ECOSAR?

ECOSAR (Ecological Structure Activity Relationships) is a personal computer software program that is used to estimate the toxicity of chemicals used in industry and discharged into water. The program predicts the toxicity of industrial chemicals to aquatic organisms such as fish, invertebrates, and algae by using Structure Activity Relationships (SARs). The program estimates a chemical's acute (short-term) toxicity and, when available, chronic (long-term or delayed) toxicity.

What is a Structure Activity Relationship (SAR)?

Structure Activity Relationships, or SAR, is a technique routinely used by EPA to estimate aquatic toxicity of chemicals being reviewed by the EPA in response to Pre-Manufacture Notices mandated by Section 5 of the Toxic Substances Control Act (TSCA). ECOSAR makes EPA's SAR methods for aquatic toxicity conveniently available through an easy-to-use computer program.

How Does ECOSAR Work?

ECOSAR uses SARs to predict the aquatic toxicity of chemicals based on their structural similarity to chemicals for which aquatic toxicity data is available. SARs express the correlations between a compound's physicochemical properties and its aquatic toxicity. SARs measured for one compound can be used to predict the toxicity of similar compounds belonging to the same chemical class. ECOSAR also allows access to over 100 SARs developed for 42 chemical classes. The SARs contained within the program are based on test data. Many of the SAR predictions have been validated.

What Information Do I Need to Use ECOSAR?

  • Octanol/water partitioning coefficient (KOW) and molecular weight.
  • Charge density and other information may also be required for some chemical classes.
  • Descriptions of chemical structures, using Simplified Molecular Input Line Entry System (SMILES) notation. SMILES is a widely used language for describing chemical structures.

With this information, ECOSAR can perform a SAR analysis and automatically estimate standard toxicity values for the chemical.

How Are ECOSAR Data Used?

The U.S. Environmental Protection Agency (EPA) uses SARs to predict the aquatic toxicity of new industrial chemicals in the absence of test data. The use of SARs is an accepted practice for estimating ecotoxicity for many chemicals. Environmental assessors and others use ECOSAR data to develop quantitative toxicity profiles for fish, invertebrates, and aquatic green algae.

How can community groups use ECOSAR?

Community groups can use ECOSAR in ways similar to those listed above: to estimate aquatic toxicity, although technical assistance from specialists is advisable. In addition, ECOSAR can be used as a reference resource.

What Type of Computer System Do I Need?

  • Hardware: Minimum requirements are an IBM-compatible computer with an 80386 or 80286 processor and 640 KB RAM. At least 512 to 550 KB RAM must be free for acceptable performance, and expanded memory will improve performance.
  • Software: Microsoft Windows 3.1, 95, or NT.

What Type of Training Do I Need to Run the Program and Interpret Data?

The program requires a basic understanding of organic chemistry, ecotoxicology, SARs, and SMILES notation. Users must also know how to estimate OW for situations where measured or estimated data are not available. Most SARs in ECOSAR were developed using KOW values predicted using ClogP which is a computer program available from BioByte Corp., 201 W. Fourth St., Suite #204, Claremont, CA 91711-4707, tel: 909-624-5992, fax: 909-624-1398. Syracuse Research Corporation offers two programs, EPIWIN© and KOWWIN©, for estimating KOW. Contact Philip H. Howard (contact information below) for pricing and ordering information.

Download the ECOSAR User Manual (187 Kb PDF). This file requires the Acrobat Reader which is available below.

Download the last ECOSAR Technical Reference manual (470 Kb PDF).

Download Now