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Characterizing pathways of exposure for risk-based chemical prioritization
Citation:
Ring, C., P. Kruse, J. Wambaugh, AND K. Isaacs. Characterizing pathways of exposure for risk-based chemical prioritization. SOT, Nashville, TN, March 19 - 23, 2023. https://doi.org/10.23645/epacomptox.22266229
Impact/Purpose:
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Description:
We categorized 64,413 chemical substances by broad pathways of exposure: consumer, industrial, pesticide, food, pharmaceuticals, and other pathways. These pathway categorizations can be used as a training set for automated read-across of chemical exposure pathways to better inform rapid exposure modeling as part of risk-based chemical prioritization. Pathway categorizations integrated multiple heterogeneous data streams that reported chemical use and/or occurrence. Data streams included large public inventories of chemicals—for example, lists of consumer product ingredients; lists of substances added to food; and lists of pharmaceutical active ingredients as well as government inventories of chemicals with reported use in industrial and consumer sectors. Chemical use and occurrence information from each data stream was organized into 19 harmonized, hierarchical categories for pathways of exposure and 3 aggregated pathways. Each chemical was categorized for each pathway as positive, negative, or unknown (no data), depending on the use/occurrence data available. We explored patterns in pathway categories and in the data streams underpinning the pathway categories. These analyses revealed common signatures or “fingerprints” for chemicals along exposure pathway categories and data streams. In addition, we explored correlations between pathway categories and chemical class, using the ClassyFire tool for structure-based chemical classification according to the ChemOnt ontology, and a newly-developed software package to visualize the ChemOnt ontology as a “tree of life”. These results can be used to characterize evidence availability by pathway and by chemical class.One case study to be presented concerns more than 25,000 chemicals categorized with respect to the food pathway. These chemicals were both positive and known negative examples of the food use pathway. The majority of these chemicals also had data informing other pathway classifications (primarily consumer, industrial, and pesticide). However, more than six thousand chemicals had data only for the food pathway,with no data available for other pathways. These “food data only” chemicals were identified primarily from two data sources: the VCF (Volatile Compounds in Food) database and a Food Packaging Forum Foundation database of intentionally-used food-contact chemicals. Chemical classes for these chemicals were primarily mixture/UVCB (unknown or variable composition, complex reaction product, or biological materials), fatty acyls, organooxygen compounds, and prenol lipids. The views expressed in this presentation are those of the authors and do not necessarily reflect the views or policies of the U.S. EPA
URLs/Downloads:
DOI: Characterizing pathways of exposure for risk-based chemical prioritization
RING_SOT2023_PATHWAYS.PDF (PDF, NA pp, 1419.222 KB, about PDF)