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Chemical Transformation Simulator (CTS): Predicting PFAS Metabolites and Environmental Transformation Products
Citation:
Stevens, C. AND E. Weber. Chemical Transformation Simulator (CTS): Predicting PFAS Metabolites and Environmental Transformation Products. EPA Tools & Resources Training Webinar, Virtual, October 07, 2021.
Impact/Purpose:
By expanding chemical assessments to consider the formation of transformation products, CTS helps provide a more holistic evaluation of the potential impacts to humans and ecological species from the manufacture and use of an organic chemical product. Chemical exposure and risk assessors can use CTS to address data gaps associated with chemical registration and assessment and to support alternative assessment activities for manufactured chemicals. Environmental exposure assessment modelers can use CTS as a parameterization tool for models that simulate/predict environmental fate, transport, bioaccumulation and dose estimation. Laboratory scientists can use CTS predictions to help interpret the results of field and laboratory studies.
Description:
The Chemical Transformation Simulator (CTS) is a publicly available web-based application that predicts how organic chemicals will transform in environmental and biological systems. Traditional exposure and risk assessments for human-made organic chemicals have only focused on chemicals in their manufactured form, but it is well known that many organic chemicals can be transformed in the environment. Organic chemicals can also be metabolized into new molecules when they are ingested by humans or ecological species. These transformation products may differ from the parent in toxicity and tendency to bioaccumulate or persist in the environment. CTS Reaction Libraries predict the products that form from various environmental transformation processes. Reaction Libraries have recently been developed to predict transformations of Per- and Polyfluoroalkyl Substances (PFAS), based on PFAS transformation products and kinetics reported in peer-reviewed literature. The enhanced predictive capabilities of CTS can help states identify and anticipate potential PFAS metabolites and environmental transformation products to which humans and ecosystems may be exposed. This training webinar will provide an overview of CTS, including a demonstration of the CTS workflows for predicting transformation pathways and physicochemical properties of organic chemicals. The presentation will also highlight how CTS predictions can help identify transformation products detected during nontargeted analysis of environmental samples, particularly for novel PFAS chemicals.