In recent years, the growth of scientific data and the increasing need for data sharing and collaboration in the field of environmental chemistry has led to the creation of various software and databases that facilitate research and development into the safety and toxicity of chemicals. The US-EPA Center for Computational Toxicology and Exposure has been developing software and databases that serve the chemistry community for many years. This presentation will focus on several web-based software applications which have been developed at the US-EPA and made available to the community. While the primary software application from the Center is the CompTox Chemicals Dashboard almost a dozen proof-of-concept applications have been built serving various capabilities. The publicly accessible Cheminformatics Modules (https://www.epa.gov/chemical-research/cheminformatics) provides access to six individual modules to allow for hazard comparison for sets of chemicals, structure-substructure-similarity searching, structure alerts and batch QSAR prediction of both physicochemical and toxicity endpoints. Each of these depends on the underlying DSSTox chemicals database, a rich source of chemistry data for over 1.2 million chemical substances. This presentation will provide an overview of all tools in development and the integrated nature of the applications based on the underlying chemistry data. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency

1. Utilizing US-EPA Data Dashboards to
Support Exposomics research
Human Health Exposure Analysis Resource (HHEAR) Webinar
http://www.orcid.org/0000-0002-2668-4821
The views expressed in this presentation are those of the author and do not necessarily reflect the views or policies of the U.S. EPA
Antony Williams
Center for Computational Toxicology and Exposure, US-EPA, RTP, NC

2. The role of cheminformatics at EPA
• Our branch is in the Center for Computational
Toxicology and Exposure (CCTE)
• We develop curated chemistry data streams to
support our applications and models
• We develop prediction models, web-based
applications and data streams to support others
• Today’s presentation: how do our efforts
support Exposomics and especially NTA efforts
– What’s public and what’s in development?
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3. Everything is underpinned by the
DSSTox Database
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• >1.2M substances
• Highly curated data
• Mapped relationships
• The data are made
available via the
Dashboard…

4. Accessing DSSTox chemistry:
CompTox Chemicals Dashboard
• A publicly accessible website delivering:
– 1.2M chemicals with related property data
– Experimental/predicted physicochemical property data
– Experimental Human and Ecological hazard data
– Integration to “biological assay data” (ToxCast/Tox21)
– Information regarding chemicals in consumer products
– Links to other agency websites and public data resources
– Related substances: transformation products, metabolites
– “Batch searching” for tens to thousands of chemicals
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5. CompTox Chemicals Dashboard
https://comptox.epa.gov/dashboard
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6. Detailed Chemical Pages
• Chemical page: intrinsic properties, structural identifiers,
linked substances, navigation to Hazard and Exposure data

7. 6
SEARCH
TOX DATA
BIOACTIVITY
SIMILARITY
READ-ACROSS
PUBMED
BATCH SEARCH
CompTox Chemicals Dashboard
https://comptox.epa.gov/dashboard

8. Batch Search

9. Batch Search – Excel, CSV, SDF file

10. Batch Search

11. Chemical Lists
• Chemical lists are focused on regulations,
specific research efforts and categories
• 425 lists and growing
– TSCA Inventory
– Clean Water Act Hazardous Substances
– Consumer Products database
– Chemicals of Emerging Concern
– PFAS lists
– Extractables and Leachables
– …lists are versioned and updated and new lists added
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12. The ELSIE Database
https://comptox.epa.gov/dashboard/chemical-lists/ELSIE
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13. Tire Crumb Rubber (298)
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14. Hydraulic Fracturing (1640)
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15. Disinfection By-Products
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16. PFAS lists of Chemicals
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17. Why Does EPA Need Measurement Data?
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• Measurement data are needed to ensure chemical safety
• Characterize risk
• Regulate use & disposal
• Manage human & ecological exposures
• Ensure compliance under federal statutes
Chemical Monitoring Needs
Exposure
Assessment
Dose-
Response
Assessment
Risk
Characterization
Hazard
Identification

18. “MS-Ready Chemicals”
• MS-Ready chemical standardization is ESSENTIAL to our
support of Non-Targeted Analysis
• It links chemicals across the Dashboard and facilitates
detection linking back to products in commerce
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https://jcheminf.biomedcentral.com/articles/
10.1186/s13321-018-0299-2

19. Predicted Mass Spectra
http://cfmid.wishartlab.com/
• MS/MS spectra prediction for ESI+, ESI-, and EI
• Predictions generated for MS-Ready structures
• Use experimental vs predicted spectral searches
for candidate identification
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20. We have proven the value…
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21. CASMI
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22. CASMI
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23. Candidate Identification is only
PART of the process
• Whatever the approach for candidate
identification, chemical hazard is important
• Hazard Comparison Profiling is important
https://www.epa.gov/chemical-research/cheminformatics
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24. Applications of Exposomics at EPA
• We have ongoing efforts applying NTA
to exposomics challenges including
– PFAS identification
– Pesticides in various matrices
– CECs in water
– Biosolids
• Examples include…
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25. Example 1: Consumer Product Analysis
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26. Example 2: Recycled Product Analysis
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27. Example 3: Placental Tissue Analysis
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28. Conclusions
• Our data resources underpin our research
efforts – data quality and curation is key
• Our web-based applications deliver our data
to the community for multiple use cases
• Our support for Exposomics is multi-fold
– Curated chemistry data streams
– Experimental and predicted properties, toxicity, etc.
• The NTA WebApp in development will use
all of these data streams to support analysis
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29. Acknowledgments
• The work presented here represents the
collective work of dozens of our scientists
• Our team of DSSTox curators
• Our Dashboard development team
• Our mass spectrometry team
• Our student service contractors and postdocs
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30. Contact Information
• Contact info: williams.antony@epa.gov
• Slides available at: https://www.slideshare.net/AntonyWilliams/
• Obtain articles from Google Scholar Profile
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