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Exposure pathway forensics for chemical source identification in non-targeted analysis
Citation:
Isaacs, K., J. Sobus, S. Newton, J. Sloop, AND K. Phillips. Exposure pathway forensics for chemical source identification in non-targeted analysis. ISES, Chicago, IL, August 27 - 31, 2023. https://doi.org/10.23645/epacomptox.24001947
Impact/Purpose:
This is an abstract for a proposed ISES 2023 meeting presentation.
Description:
Non-targeted analysis (NTA) technologies and supporting data analysis platforms hold great potential for identifying thousands of chemicals in environmental and biological samples. However, challenges in linking identified chemical substances with upstream exogenous exposure sources must be addressed. Here, a method was developed for exploring exposure pathways that integrated available chemical use and monitoring data with mining of chemical co-occurrence patterns within NTA samples. A fingerprinting approach was developed that encoded available exposure pathway information from U.S. Environmental Protection Agency (EPA) Office of Research and Development chemical use and monitoring databases as hierarchical binary descriptor sets. These descriptors can be queried for enrichment for subsets of chemicals co-occurring in biological or environmental samples using NTA to provide evidence of exposure source. Descriptors represented occurrence of chemicals in commercial, industrial, consumer, and functional categories, as well as known occurrence in the environment. In a proof-of-concept case study, an enrichment analysis was applied to a set of chemicals tentatively identified using NTA in 46 geospatially diverse drinking water samples collected in California. A clustering approach was used to identify chemical groups co-occuring across subsets of multiple samples. The approach identified unique chemical clusters reflecting pharmaceutical, manufacturing, and consumer uses. These use patterns may be indicative of unique sources impacting specific sampling locations. However, use information was missing for 75% of the identified chemicals, highlighting the need for improved use data and annotation of degradants of commercial chemicals. These approaches have the potential to inform exposure sources associated with NTA samples.
URLs/Downloads:
DOI: Exposure pathway forensics for chemical source identification in non-targeted analysis
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