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OncoLogic™, ECOSAR and AQUATOX
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A Tribute to Vince Nabholz
We honor Vince Nabholz--a cherished member of the OPPT family for over 25 years--who died in February 2008. Vince made significant contributions to the cause of protecting the environment as an expert environmental toxicologist and quantitative structure activity relationships analyst. Vince will be remembered as a trusted colleague and friend with a great sense of humor and passion for his work.
Tools and models are used in the hazard, exposure and risk assessment processes to evaluate both new and existing chemicals under TSCA when certain data are missing. OPPT uses and promotes the use of these models, including OncoLogic™ for health hazard evaluation, and ECOSAR and AQUATOX for environmental effects and fate.
OncoLogic™ is a stand alone computer program that evaluates the potential that a chemical may cause cancer. OncoLogic, which provides the scientific rationale for each evaluation along with the results, has been peer reviewed and runs on a Windows® PC. EPA's Web site provides a downloadable version of OncoLogic™ along with extensive information on proper use of the method. OncoLogic analyzes a chemical structure to determine the likelihood that it may cause cancer by applying the rules of structure activity relationship (SAR) analysis and incorporating knowledge of how chemicals cause cancer in animals and humans. OncoLogic is comprised of four subsystems that evaluate fibers, metals, polymers, and organic chemicals of diverse chemical structures.
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. ECOSAR also allows access to hundreds of SARs developed for 48 chemical classes. The SARs contained within the program are developed using test data. Many of the SAR predictions have been validated.
AQUATOX is a simulation model for aquatic systems. AQUATOX predicts the fate of various pollutants, such as nutrients and organic chemicals, and their effects on the ecosystem, including fish, invertebrates, and aquatic plants. This model is a valuable tool for ecologists, biologists, water quality modelers, and anyone involved in performing ecological risk assessments for aquatic ecosystems.
Accomplishments
- OncoLogic™: OPPT is now providing a downloadable version of OncoLogic™, a powerful predictive screening method, at no cost to interested users wishing to evaluate cancer potential of chemicals. The U.S. Food and Drug Administration OncoLogic™ recently published a study affirming the model’s predictive capability
.OPPT shared OncoLogic™ with the European Union. In addition, the method has been selected for future inclusion in the Organization for Economic Cooperation and Development (OECD) Quantitative Structure Activity Relationships ((Q)SAR) Application Toolbox
for cancer.
- ECOSAR: OPPT scientists are working to make numerous improvements to ECOSAR including the addition of new SARs (inorganic and organometallic chemicals, and 20 new chemical classes with excess toxicity), and enhancements for existing SARs:
- All SARs for excess toxicity have been recalculated using the Kow value from EPI Suite™.
- All classes now have at least six SARs for freshwater organisms.
- Test data have been added to existing SARs.
OPPT scientists improved the ECOSAR decision tree which selects SAR(s) from “structure” and they have added “Help” screens for every SAR showing data used in SAR regression equations, data used in SAR but not in regression equations, and data for chemicals which fit the SAR class but are not used.
OPPT shared ECOSAR with the OECD, which added the method to the (Q)SAR Application Toolbox for aquatic toxicity. Work in progress includes the addition of structural alerts for herbicides, insecticides, fungicides, and other pesticides. ECOSAR version 0.99g is available as a stand-alone model and version 0.99h has been incorporated into the EPI Suite of models. The next version of ECOSAR is expected to have over 2,000 SARs.
- AQUATOX: During 2005, 2006, and 2007, OPPT funded the development of a version of AQUATOX relating to estuaries, and a comparison of predictions of AQUATOX on the fate and effects of nonylphenol and pefluoralkylated surfactants. In addition, EPA's Office of Water (OW) and OPPT jointly funded the inclusion of the Office of Research and Development - Gulf Breeze Lab "Interspecies Correlation Estimations (ICE) for Acute Toxicity to Aquatic Organisms and Wildlife" into AQUATOX. These enhancements have been included in Release 3 of AQUATOX, which has been beta tested and is scheduled to be peer reviewed and released in 2008.
Read more information on OncoLogic™, ECOSAR, and AQUATOX and other OPPT exposure assessment tools and models.