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Predicting transformation products from the direct photolysis of organic compounds in aquatic systems
Yuan, C., C. Stevens, AND E. Weber. Predicting transformation products from the direct photolysis of organic compounds in aquatic systems. ACS Spring 2018 National Meeting, LA, New Orleans, March 18 - 22, 2018.
This presentation describes the development of a reaction library to predict the molecular structure of transformation products formed due to direct photolysis of organic chemicals in aquatic ecosystems. The library will be implemented in the Chemical Transformation Simulator (CTS), a web- based software tool under development in ORD/NERL. The predictions from CTS will support the application of environmental fate and transport models to assess the potential environmental exposure of vulnerable organisms to toxic organic chemicals dissolved in groundwater, surface water, and runoff.
Direct photolysis is an important degradation pathway for organic compounds bearing sunlight-absorbing chromophores in aquatic systems. An ever-growing body of process science underlying direct photolysis transformation pathways provides the basis for the development of predictive tools for identifying likely phototransformation products. In this study, we identified various chromophores, reaction sites, and pathways of organic chemicals and have encoded this information into a reaction library using a cheminformatics-based software. The execution of this reaction library can be used to predict intermediate phototransformation products that have not been completely mineralized. Reaction rates were approximated with parent degradation rates if product formation rates were unavailable. Challenges exist such as capturing dramatic changes in reactivity due to slight modification of chemical structure, lack of knowledge concerning the photomineralization processes, and accurately addressing photochemical transformation in the field.
Record Details:Record Type: DOCUMENT (PRESENTATION/SLIDE)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
SYSTEMS EXPOSURE DIVISION