U.S. Environmental Protection Agency Office of Research and Development A Cheminformatics Workflow for Higher-Throughput Modeling of Chemical Exposures From Biosolids Paul M. Kruse1,2, Caroline L. Ring2 1. Oak Ridge Institute for Science and Education; Oak Ridge, TN 2. Center for Computational Toxicology and Exposure, United States Environmental Protection Agency; Research Triangle Park, NC Introduction Methods Workflows Results and Discussion Conclusion Paul Kruse l kruse.paul@epa.gov l 0000-0001-5516-9717 Abstract number: 4397 Poster number: P184 • Biosolids are treated sewage sludge produced as a byproduct of the wastewater treatment process • Under the Clean Water Act, the US EPA Office of Water (OW) has the responsibility to protect human health and the environment from adverse effects of pollutants that may be present in biosolids • EPA has identified over 700 chemicals found in previous National Sewage Sludge Surveys (NSSS) and Biennial Reviews (BR) [1, 2] • OW has developed a Biosolids Screening Tool (BST), a software tool implementing a model for risk screening for potential human and ecological exposures to biosolids chemicals • The BST models two disposal pathways: land application of biosolids and landfilling of sewage sludge • The BST requires many chemical-specific input parameters, including physico-chemical and fate and transport property data • We created the R package ccdR to access and retrieve data from the Center for Computational Toxicology and Exposure (CCTE) APIs • We developed an automated workflow to collect and process the input parameters the BST requires to run for each chemical. This new R-based workflow: o Integrates chemical information from publicly available cheminformatics databases and tools  EPA CompTox Chemicals Dashboard (CCD) [3]  OPEn (quantitative) structure-activity/property Relationship App (OPERA) [4]  ClassyFire chemical-classification tool [5]  Httk R package [6] o Interfaces with the existing Microsoft Access implementation of the BST via Microsoft Excel input/output References • 591 of the 623 Biosolids chemicals with ClassyFire classifications and concentration data had available physico-chemical property data. An additional three chemicals were removed due to incomplete physico- chemical property data or property data values outside the range of applicability for the BST, leaving 588 • Removed 222 Dioxin-like compounds from this list since they require cumulative exposure assessment and cannot be modeled appropriately using the BST, leaving 366 chemicals • Removed chemicals missing sufficient biosolids concentration data, leaving 339 remaining chemicals for mean concentration and 345 for 95th percentile concentration simulations • The workflow for collecting physico-chemical property data, filtering out chemicals missing necessary values for running the BST, and correctly formatting data for use within the BST takes under 15 minutes to execute for roughly 700 chemicals • The BST takes about 30 hours to run all possible scenarios for roughly 340 chemicals (average/wet/dry climate types, surface disposal/land applied use, mean/95th percentile biosolids concentration) • The workflow is easily adjusted to accommodate high-throughput screening efforts, and the BST runs on the output of the R-based workflow • This workflow combines several publicly available cheminformatics tools and databases to prepare chemicals for screening using the BST • This high-throughput workflow is easily adaptable for facilitating rapid chemical prioritization under other chemical fate scenarios • The workflow leverages the ccdR R package we developed, which can be deployed rapidly and easily in a variety of data pipeline workflows Biennial Reviews & Sewage Sludge Surveys Prioritization of Chemicals for Assessment Risk Screening Exceeds EPA level of concern? Low Priority Risk Assessment Exceeds EPA level of concern? Low Priority Consider Regulation If chemical may harm human health or the environment