Web-based access to data for >600 disinfection by-products via the EPA CompTox Chemicals Dashboard

The US EPA’s CompTox Chemicals Dashboard (https://comptox.epa.gov/dashboard) is a freely available web-based application providing access to data for ~900,000 chemical substances, the majority of these represented as chemical structures. The Dashboard also provides access to segregated lists of chemicals that are of specific interest to relevant stakeholders and, in particular, a list of hundreds of disinfection by-product (DBP) chemicals reported in the literature and detected in the laboratory using mass spectrometric techniques. Many of these chemicals are explicit chemical structures whose structures have been confirmed using purchased or synthesized reference standards. However, some of these chemicals may be ambiguous in nature with no explicit positional isomers being possible to define but the formula and mass spec fragmentation sufficient to define a class of chemicals (e.g. dichlorophenol). Such chemicals may be represented with ambiguous chemical structure forms, so-called Markush structures, and mapped to the individual class members. Chemicals accessible via the Dashboard can include access to a wide array of computed and measured physicochemical properties, in vitro high-throughput screening data and in vivo toxicity data, product use information extracted from safety data sheets, and integrated chemical linkages to a growing list of literature, toxicology, and analytical chemistry websites. Since DBP chemicals are primarily identified using mass spectrometric techniques specific search types have been developed to directly support the non-targeted screening community, enabling cohesive workflows to support data generation for the detection and assessment of environmental exposures to chemicals contained within the database. This presentation will provide an overview of the Dashboard, the ongoing expansion of the DBP chemical list and specific functionality supporting identification of DBPs by mass spectrometry. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.