Incorporating new technologies and High Throughput Screening in the design and selection of chemical alternatives
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Tens of thousands of chemicals are currently in commerce, and hundreds more are introduced every year. Because current chemical testing is resource intensive, only a small fraction of chemicals have been adequately evaluated for potential human health effects. New technologies and computational tools have shown promise for closing this knowledge gap. In the U.S. EPA’s ToxCast effort, the use of ~700 high-throughput in vitro assays has broadly characterized the biological activity and potential mechanisms of ~1,800 chemicals. Coupling the high-throughput in vitro assays with additional in vitro pharmacokinetic assays and in vitro-to-in vivo extrapolation modeling allows conversion of in vitro bioactive concentrations to estimates to an administered dose (mg/kg/day). High throughput exposure models are generating exposure estimates based on key aspects of chemical production, fate, transport, and personal use. The path for incorporating new approach methods and technologies for prioritization and assessment of chemical alternatives poses multiple scientific challenges. These challenges include sufficient coverage of toxicological mechanisms to meaningfully interpret negative test results, development of increasingly relevant test systems, computational modeling to integrate experimental data, characterizing uncertainty, and efficient validation of the test systems and computational models. The presentation will cover progress at the U.S. EPA in the development and application of these technologies and approaches in evaluating alternatives and systematically addressing each of these challenges. This abstract does not necessarily reflect U.S. EPA policy.
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This presentation highlights known challenges with the production of high quality chemical databases and outline recent efforts made to address these challenges. Specific examples will be provided illustrating these challenges within the U.S. Environmental Protection Agency (EPA) Computational Toxicology Program. This includes consolidating EPA’s ACToR and DSSTox databases, augmenting computed properties and list search features, and introducing quality metrics to assess confidence in chemical structure assignments across hundreds of thousands of chemical substance records. The past decade has seen enormous investments in the generation and release of data from studies of chemicals and their toxicological effects. There is, however, commonly little concern given to provenance and, more generally, to the quality of the data. The presentation will emphasize the importance of rigorous data review procedures, progress in web-based public access to accurate chemical data sets for use in predictive modeling, and the benefits that these efforts will deliver to toxicologists to embrace the “Big Data” era.
This abstract does not necessarily represent the views of the U.S. Environmental Protection Agency.
Does bigger mean better in the world of chemistry databases?
Does bigger mean better in the world of chemistry databases? US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The internet has changed the way we access chemistry data as well as providing access to data that can quickly proliferate and becomes referenceable. Web access to chemical structures and their integration with biological data has become massively enabling with numbers for UniChem, PubChem and ChemSpider reaching 157, 97 and 71 million respectively (at the time of writing). A range of specialist databases small enough to be curated have stand-alone utility and synergies when integrated into the larger collections. These include DrugBank, BindingDB, ChEBI, and many others. Databases of any size have inherent quality challenges but at large scale various forms of “noise” accumulate to problematic levels. The unfortunate consequence is that “bigger gets worse”. This is particularly associated with large uncurated submissions from vendors and automated document extractions (even though these are high-value). Virtual enumerations and circularity between overlapping sources add to the problem. As a result of some of the noise in the larger databases the value becomes highly dependent on the specific applications. An example includes using the databases to support non-targeted analysis. This presentation covers examples of these noise and quality issues and suggests at least some options to ameliorate the problem. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency. The EPA CompTox Dashboard as a Data Integration Hub for Environmental Chemist...
The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program integrates advances in biology, chemistry, and computer science to help prioritize chemicals for further research based on potential human health risks. This involves computational and data-driven approaches that integrate chemistry, exposure and biological data. The National Center for Computational Toxicology (NCCT) has measured, assembled and delivered an enormous quantity and diversity of data for the environmental sciences, including high-throughput in vitro screening data, in vivo and functional use data, exposure models and chemical databases with associated properties. The CompTox Chemistry Dashboard is a web-based application providing access to data associated with ~760,000 chemical substances. New data are continuously added to the database on an ongoing basis, along with registration of new and emerging chemicals. This includes data extracted from the literature, identified by our analytical labs, and otherwise of interest to support specific research projects to the agency. By adding these data, with their associated chemical identifiers (names and CAS Registry Numbers), the dashboard uses linking approaches to allow for automated searching of PubMed, Google Scholar and an array of public databases. This presentation will provide an overview of the Dashboard, how it has developed into an integrated data hub for environmental data, and how it can be used for the analysis of emerging chemicals in terms of sourcing related chemicals of interest, and deriving read-across as well as QSAR predictions in real time. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.
Mining 'Bigger' Datasets to Create, Validate and Share Machine Learning Models
Talk given to computational toxicology group at the EPA 23 Sept 2015 - Alex Clark co-author
Structure identification by Mass Spectrometry Non-Targeted Analysis using the...
Structure identification by Mass Spectrometry Non-Targeted Analysis using the...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Identification of unknowns in mass spectrometry based non-targeted analyses (NTA) requires the integration of complementary pieces of data to arrive at a confident, consensus structure. Researchers use chemical reference databases, spectral matching, fragment prediction tools, retention time prediction tools, and a variety of other data to arrive at tentative, probable, and confirmed, if possible, identifications. With the diverse, robust data contained within the US EPA’s CompTox Chemistry Dashboard (https://comptox.epa.gov), the goal of this research is to identify and implement a harmonized identification tool and workflow using previously generated chemistry data. Data has been compiled from product use, functional use prediction models, environmental media occurrence prediction models, and PubMed references, among other sources. We will report on our development of a visualization tool whereby users can visualize the relative contribution of identification-based metrics on a list of candidate structures and observe the greatest likelihood of occurrence. These data and visualization tools support NTA identification via the Dashboard and demonstrate an open, accessible tool for all users of HRMS data. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Development of a Tool for Systematic Integration of Traditional and New Appro...
Development of a Tool for Systematic Integration of Traditional and New Appro...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Multiple regulatory bodies (EPA, ECHA, Health Canada) are currently tasked with prioritizing chemicals for data collection and risk assessments. These prioritization efforts are in response to regulatory mandates to identify chemicals for further assessment. We have developed a web-based application that enables a rapid, flexible and transparent prioritization process. The tool includes multiple data streams related to human and ecological hazard, exposure, and physicochemical properties (persistence and bioaccumulation). For human hazard, the data streams include quantitative points of departure (PODs) that are compiled from multiple sources such as EPA ToxRefDB, ECHA, COSMOS; estimated PODs from high-throughput in vitro screening assays and computational models; and qualitative measurements and predictions of specific endpoints (e.g., genotoxicity, endocrine activity). For ecological hazard, quantitative PODs are taken from the EPA ECOTOX database. Exposure information includes production volume, quantitative predictions using the EPA ExpoCast and SHEDS models, biomonitoring data, and qualitative information such as media occurrence, use profiles and likelihood of consumer and childhood exposures. The use of the tool is illustrated by prioritizing chemicals related to TSCA and the Safer Choice Ingredient List. The underpinning data streams for this application are already available in the EPA CompTox Chemistry Dashboard and have been repurposed to deliver this application. This is in keeping with our overarching software development methodology of providing multiple “building blocks” in the form of databases, web services and visualization components to deliver fit-for purpose applications to the relevant audiences. This abstract does not necessarily represent U.S. EPA policy.The importance of data curation on QSAR Modeling: PHYSPROP open data as a cas...
This presentation highlighted how data curation impacts the reliability of QSAR models. We examined key datasets related to environmental endpoints to validate across chemical structure representations (e.g., mol file and SMILES) and identifiers (chemical names and registry numbers), and approaches to standardize data into QSAR-ready formats prior to modeling procedures. This allowed us to quantify and segregate data into quality categories. This improved our ability to evaluate the resulting models that can be developed from these data slices, and to quantify to what extent efforts developing high-quality datasets have the expected pay-off in terms of predicting performance. The most accurate models that we build will be accessible via our public-facing platform and will be used for screening and prioritizing chemicals for further testing.
Using the US EPA’s CompTox Chemistry Dashboard for structure identification a...
Using the US EPA’s CompTox Chemistry Dashboard for structure identification a...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
High resolution mass spectrometry (HRMS) and non-targeted analysis (NTA) are advancing the identification of emerging contaminants in environmental matrices, improving the means by which exposure analyses can be conducted. However, confidence in structure identification of unknowns in NTA presents challenges to analytical chemists. Structure identification requires integration of complementary data types such as reference databases, fragmentation prediction tools, and retention time prediction models. The goal of this research is to optimize and implement structure identification functionality within the US EPA’s CompTox Chemistry Dashboard, an open chemistry resource and web application containing data for ~760,000 substances. Rank-ordering the number of sources associated with chemical records within the Dashboard (Data Source Ranking) improves the identification of unknowns by bringing the most likely candidate structures to the top of a search results list. Database searching has been further optimized with the generation of MS-Ready Structures. MS-Ready structures are de-salted, stripped of stereochemistry, and mixture separated to replicate the form of a chemical observed via HRMS. Functionality to conduct batch searching of molecular formulae and monoisotopic masses was designed and released to improve searching efforts. Finally, a scoring-based identification scheme was developed, optimized, and surfaced via the Dashboard using multiple data streams contained within the database underlying the Dashboard. The scoring-based identification scheme improved the identification of unknowns over previous efforts using data source ranking alone. Combining these steps within an open chemistry resource provides a freely available software tool for structure identification and NTA. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.New developments in delivering public access to data from the National Center...
New developments in delivering public access to data from the National Center...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Researchers at EPA’s National Center for Computational Toxicology integrate advances in biology, chemistry, and computer science to examine the toxicity of chemicals and help prioritize chemicals for further research based on potential human health risks. The goal of this research program is to quickly evaluate thousands of chemicals, but at a much reduced cost and shorter time frame relative to traditional approaches. The data generated by the Center includes characterization of thousands of chemicals across hundreds of high-throughput screening assays, consumer use and production information, pharmacokinetic properties, literature data, physical-chemical properties as well as the predictive computational modeling of toxicity and exposure. We have developed a number of databases and applications to deliver the data to the public, academic community, industry stakeholders, and regulators. This presentation will provide an overview of our work to develop an architecture that integrates diverse large-scale data from the chemical and biological domains, our approaches to disseminate these data, and the delivery of models supporting predictive computational toxicology. In particular, this presentation will review our new CompTox Chemistry Dashboard and the developing architecture to support real-time property and toxicity endpoint prediction. This abstract does not reflect U.S. EPA policy.Accessing Environmental Chemistry Data via Data Dashboards
Accessing Environmental Chemistry Data via Data Dashboards US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
As part of its mission the Center for Computational Toxicology and Exposure (CCTE) delivers access to chemicals related data via online Dashboards. The CompTox Chemicals Dashboard (available at https://comptox.epa.gov/dashboard) provides access to >900,000 chemicals and associated data including experimental and predicted property data, in vivo hazard data, in vitro bioactivity data, exposure data, and various other data types. The application provides a set of flexible searches allowing for search, visualization and downloads of the data to the desktop for further interrogation. This presentation will provide an overview of the Dashboard and other proof-of-concept applications that are now publicly available (https://www.epa.gov/chemical-research/cheminformatics). For example, the Hazard Comparison module (shown in the figure below) allows profiling of chemicals based on toxicity types (https://doi.org/10.1007/s10098-019-01795-w). This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Progress in Using Big Data in Chemical Toxicity Research at the National Cent...
Progress in Using Big Data in Chemical Toxicity Research at the National Cent...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at Proctor and Gamble in Mason, OH, in June 2017 in a symposium regarding "Big Data: Perspectives from Diverse Fields on How to Extract, Filter and Manipulate Large Data Sets to Answer Scientific Questions"More Related Content
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Accessing information for chemicals in hydraulic fracturing fluids using the ...
Accessing information for chemicals in hydraulic fracturing fluids using the ...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
EPA’s National Center for Computational Toxicology is developing automated workflows for curating large databases and providing accurate linkages of data to chemical structures, exposure and hazard information. The data are being made available via the EPA’s CompTox Chemistry Dashboard (https://comptox.epa.gov/dashboard), a publicly accessible website providing access to data for almost 760,000 chemical substances, the majority of these represented as chemical structures. The web application delivers a wide array of computed and measured physicochemical properties, in vitro high-throughput screening data and in vivo toxicity data as well as integrated chemical linkages to a growing list of literature, toxicology, and analytical chemistry websites. In addition, several specific search types are in development to directly support the mass spectroscopy non-targeted screening community, who are generating important data for detecting and assessing environmental exposures to chemicals contained within DSSTox. The application provides access to segregated lists of chemicals that are of specific interests to relevant stakeholders including, for example, scientists interested in algal toxins and hydraulic fracturing chemicals. This presentation will provide an overview of the challenges associated with the curation of data from EPA’s December 2016 Hydraulic Fracturing Drinking Water Assessment Report that represented chemicals reported to be used in hydraulic fracturing fluids and those found in produced water. The data have been integrated into the dashboard with a number of resulting benefits: a searchable database of chemical properties, with hazard and exposure predictions, and open literature. The application of the dashboard to support mass spectrometry non-targeted analysis studies will also be reviewed. This abstract does not reflect U.S. EPA policy.New Approach Methods - What is That?
New Approach Methods - What is That?US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Presentation for Texas A&M Superfund Research Center virtual learning series, Big Data in Environmental Science and Toxicology. More details at https://superfund.tamu.edu/big-data-session-2-aug-18-2021/The EPA iCSS Chemistry Dashboard to Support Compound Identification Using Hig...
The EPA iCSS Chemistry Dashboard to Support Compound Identification Using Hig...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
There is a growing need for rapid chemical screening and prioritization to inform regulatory decision-making on thousands of chemicals in the environment. We have previously used high-resolution mass spectrometry to examine household vacuum dust samples using liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). Using a combination of exact mass, isotope distribution, and isotope spacing, molecular features were matched with a list of chemical formulas from the EPA’s Distributed Structure-Searchable Toxicity (DSSTox) database. This has further developed our understanding of how openly available chemical databases, together with the appropriate searches, could be used for the purpose of compound identification. We report here on the utility of the EPA’s iCSS Chemistry Dashboard for the purpose of compound identification using searches against a database of over 720,000 chemicals. We also examine the benefits of QSAR prediction for the purpose of retention time prediction to allow for alignment of both chromatographic and mass spectral properties. This abstract does not reflect U.S. EPA policy.Structure Identification Using High Resolution Mass Spectrometry Data and the...
Structure Identification Using High Resolution Mass Spectrometry Data and the...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The iCSS Chemistry Dashboard is a publicly accessible dashboard provided by the National Center for Computation Toxicology at the US-EPA. It serves a number of purposes, including providing a chemistry database underpinning many of our public-facing projects (e.g. ToxCast and ExpoCast). The available data and searches provide a valuable path to structure identification using mass spectrometry as the source data. With an underlying database of over 720,000 chemicals, the dashboard has already been used to assist in identifying chemicals present in house dust. However, it can also be applied to many other purposes, e.g., the identification of agrochemicals in waste streams. This presentation will provide a review of the EPA’s platform and underlying algorithms used for the purpose of compound identification using high-resolution mass spectrometry data. We will also discuss progress towards a high-throughput non-targeted analysis platform for use by the mass spectrometry community. This abstract does not reflect U.S. EPA policy.An examination of data quality on QSAR Modeling in regards to the environment...
An examination of data quality on QSAR Modeling in regards to the environment...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The development of QSAR models is critically dependent on the quality of available data. As part of our efforts to develop public platforms to provide access to predictive models, we have attempted to discriminate the influence of the quality versus quantity of data available to develop and validate QSAR models. We have focused our efforts on the widely used EPISuite software that was initially developed over two decades ago and, specifically, on the PHYSPROP dataset used to train the EPISuite prediction models. This presentation will review our approaches to examining key datasets, the delivery of curated data and the development of machine-learning models for thirteen separate property endpoints of interest to environmental science. We will also review how these data will be made freely accessible to the community via a new “chemistry dashboard”. This abstract does not reflect U.S. EPA policyEnvironmental Chemistry Compound Identification Using High Resolution Mass Sp...
Environmental Chemistry Compound Identification Using High Resolution Mass Sp...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
There is a growing need for rapid chemical screening and prioritization to inform regulatory decision-making on thousands of chemicals in the environment. We have previously used high-resolution mass spectrometry to examine household vacuum dust samples using liquid chromatography time-of-flight mass spectrometry (LC-TOF/MS). Using a combination of exact mass, isotope distribution, and isotope spacing, molecular features were matched with a list of chemical formulas from the EPA’s Distributed Structure-Searchable Toxicity (DSSTox) database. This has further developed our understanding of how openly available chemical databases, together with the appropriate searches, could be used for the purpose of compound identification. We report here on the utility of the EPA’s iCSS Chemistry Dashboard for the purpose of compound identification using searches against a database of over 720,000 chemicals. We also examine the benefits of QSAR prediction for the purpose of retention time prediction to allow for alignment of both chromatographic and mass spectral properties. This abstract does not reflect U.S. EPA policy.How to place your research questions or results into the context of the "Lega...
How to place your research questions or results into the context of the "Lega...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Presentation for Texas A&M Superfund Research Center virtual learning series, Big Data in Environmental Science and Toxicology. More details at https://superfund.tamu.edu/big-data-session-1-july-14-2021/ The influence of data curation on QSAR Modeling – examining issues of qualit...
The influence of data curation on QSAR Modeling – examining issues of qualit...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The construction of QSAR models is critically dependent on the quality of available data. As part of our efforts to develop public platforms to provide access to predictive models, we have attempted to discriminate the influence of the quality versus quantity of data available to develop and validate QSAR models. We have focused our efforts on the widely used EPISuite software that was initially developed over two decades ago. Specific examples of quality issues for the EPISuite data include multiple records for the same chemical structure with different measured property values, inconsistency between the structure, chemical name and CAS registry number for single records, the inability to convert the SMILES strings into chemical structures, hypervalency in the chemical structures and the absence of stereochemistry for thousands of data records. Relative to the era of EPISuite development, modern cheminformatics tools allow for more advanced capabilities in terms of chemical structure representation and storage, as well as enabling automated data validation and standardization approaches to examine data quality. This presentation will review both our manual and automated approaches to examining key datasets related to the EPISuite training and test data. This includes approaches to validate between chemical structure representations (e.g. molfile and SMILES) and identifiers (chemical names and registry numbers), as well as approaches to standardize the data into QSAR-consumable formats for modeling. We have quantified and segregated the data into various quality categories to allow us to thoroughly investigate the resulting models that can be developed from these data slices and to examine to what extent efforts into the development of large high-quality datasets have the expected pay-off in terms of prediction performance. This abstract does not reflect U.S. EPA policy.Structure Identification Using High Resolution Mass Spectrometry Data and the...
Structure Identification Using High Resolution Mass Spectrometry Data and the...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The iCSS CompTox Chemistry Dashboard is a publicly accessible dashboard provided by the National Center for Computation Toxicology at the US-EPA. It serves a number of purposes, including providing a chemistry database underpinning many of our public-facing projects (e.g. ToxCast and ExpoCast). The available data and searches provide a valuable path to structure identification using mass spectrometry as the source data. With an underlying database of over 720,000 chemicals, the dashboard has already been used to assist in identifying chemicals present in house dust. This poster reviews the benefits of the EPA’s platform and underlying algorithms used for the purpose of compound identification using high-resolution mass spectrometry data. Standard approaches for both mass and formula lookup are available but the dashboard delivers a novel approach for hit ranking based on functional use of the chemicals. The focus on high-quality data, novel ranking approaches and integration to other resources of value to mass spectrometrists makes the CompTox Dashboard a valuable resource for the identification of environmental chemicals. This abstract does not reflect U.S. EPA policy.US EPA CompTox Chemistry Dashboard as a source of data to fill data gaps for ...
US EPA CompTox Chemistry Dashboard as a source of data to fill data gaps for ...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Chemical risk assessment is both time-consuming and difficult because it requires the assembly of data for chemicals generally distributed across multiple sources. The US EPA CompTox Chemistry Dashboard is a publicly accessible web-based application providing access to various data streams on ~760,000 chemical substances. These data include experimental and predicted physicochemical property data, bioassay screening data associated with the ToxCast program, consumer product and functional use information and a myriad of related data of value to environmental scientists and toxicologists. At this stage of development, the public dashboard provides access to almost 20 predicted physicochemical and environmental fate and transport endpoints with full transparency in terms of model performance. Experimental and predicted human and ecological toxicity data are also available, as are in vitro to in vivo extrapolation dosimetry predictions and predicted exposure and functional use. In parallel to the CompTox Chemistry Dashboard we are developing RapidTox, a web-based application that enables a rapid, flexible and transparent prioritization process for sets of chemicals using several previously used workflows focused on scoring of traditional risk metrics and the inclusion of alternative hazard and exposure estimates. This presentation will give an overview of the CompTox Chemistry Dashboard, RapidTox, our approaches to building transparent and open prediction models, and our efforts to provide access to real time predictions. This abstract does not necessarily represent U.S. EPA policy.Web-based access to data for >600 disinfection by-products via the EPA CompTo...
Web-based access to data for >600 disinfection by-products via the EPA CompTo...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
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.The needs for chemistry standards, database tools and data curation at the ch...
The needs for chemistry standards, database tools and data curation at the ch...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation highlights known challenges with the production of high quality chemical databases and outline recent efforts made to address these challenges. Specific examples will be provided illustrating these challenges within the U.S. Environmental Protection Agency (EPA) Computational Toxicology Program. This includes consolidating EPA’s ACToR and DSSTox databases, augmenting computed properties and list search features, and introducing quality metrics to assess confidence in chemical structure assignments across hundreds of thousands of chemical substance records. The past decade has seen enormous investments in the generation and release of data from studies of chemicals and their toxicological effects. There is, however, commonly little concern given to provenance and, more generally, to the quality of the data. The presentation will emphasize the importance of rigorous data review procedures, progress in web-based public access to accurate chemical data sets for use in predictive modeling, and the benefits that these efforts will deliver to toxicologists to embrace the “Big Data” era.
This abstract does not necessarily represent the views of the U.S. Environmental Protection Agency.
Does bigger mean better in the world of chemistry databases?
Does bigger mean better in the world of chemistry databases? US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The internet has changed the way we access chemistry data as well as providing access to data that can quickly proliferate and becomes referenceable. Web access to chemical structures and their integration with biological data has become massively enabling with numbers for UniChem, PubChem and ChemSpider reaching 157, 97 and 71 million respectively (at the time of writing). A range of specialist databases small enough to be curated have stand-alone utility and synergies when integrated into the larger collections. These include DrugBank, BindingDB, ChEBI, and many others. Databases of any size have inherent quality challenges but at large scale various forms of “noise” accumulate to problematic levels. The unfortunate consequence is that “bigger gets worse”. This is particularly associated with large uncurated submissions from vendors and automated document extractions (even though these are high-value). Virtual enumerations and circularity between overlapping sources add to the problem. As a result of some of the noise in the larger databases the value becomes highly dependent on the specific applications. An example includes using the databases to support non-targeted analysis. This presentation covers examples of these noise and quality issues and suggests at least some options to ameliorate the problem. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency. The EPA CompTox Dashboard as a Data Integration Hub for Environmental Chemist...
The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program integrates advances in biology, chemistry, and computer science to help prioritize chemicals for further research based on potential human health risks. This involves computational and data-driven approaches that integrate chemistry, exposure and biological data. The National Center for Computational Toxicology (NCCT) has measured, assembled and delivered an enormous quantity and diversity of data for the environmental sciences, including high-throughput in vitro screening data, in vivo and functional use data, exposure models and chemical databases with associated properties. The CompTox Chemistry Dashboard is a web-based application providing access to data associated with ~760,000 chemical substances. New data are continuously added to the database on an ongoing basis, along with registration of new and emerging chemicals. This includes data extracted from the literature, identified by our analytical labs, and otherwise of interest to support specific research projects to the agency. By adding these data, with their associated chemical identifiers (names and CAS Registry Numbers), the dashboard uses linking approaches to allow for automated searching of PubMed, Google Scholar and an array of public databases. This presentation will provide an overview of the Dashboard, how it has developed into an integrated data hub for environmental data, and how it can be used for the analysis of emerging chemicals in terms of sourcing related chemicals of interest, and deriving read-across as well as QSAR predictions in real time. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.
Mining 'Bigger' Datasets to Create, Validate and Share Machine Learning Models
Talk given to computational toxicology group at the EPA 23 Sept 2015 - Alex Clark co-author
Structure identification by Mass Spectrometry Non-Targeted Analysis using the...
Structure identification by Mass Spectrometry Non-Targeted Analysis using the...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Identification of unknowns in mass spectrometry based non-targeted analyses (NTA) requires the integration of complementary pieces of data to arrive at a confident, consensus structure. Researchers use chemical reference databases, spectral matching, fragment prediction tools, retention time prediction tools, and a variety of other data to arrive at tentative, probable, and confirmed, if possible, identifications. With the diverse, robust data contained within the US EPA’s CompTox Chemistry Dashboard (https://comptox.epa.gov), the goal of this research is to identify and implement a harmonized identification tool and workflow using previously generated chemistry data. Data has been compiled from product use, functional use prediction models, environmental media occurrence prediction models, and PubMed references, among other sources. We will report on our development of a visualization tool whereby users can visualize the relative contribution of identification-based metrics on a list of candidate structures and observe the greatest likelihood of occurrence. These data and visualization tools support NTA identification via the Dashboard and demonstrate an open, accessible tool for all users of HRMS data. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Development of a Tool for Systematic Integration of Traditional and New Appro...
Development of a Tool for Systematic Integration of Traditional and New Appro...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Multiple regulatory bodies (EPA, ECHA, Health Canada) are currently tasked with prioritizing chemicals for data collection and risk assessments. These prioritization efforts are in response to regulatory mandates to identify chemicals for further assessment. We have developed a web-based application that enables a rapid, flexible and transparent prioritization process. The tool includes multiple data streams related to human and ecological hazard, exposure, and physicochemical properties (persistence and bioaccumulation). For human hazard, the data streams include quantitative points of departure (PODs) that are compiled from multiple sources such as EPA ToxRefDB, ECHA, COSMOS; estimated PODs from high-throughput in vitro screening assays and computational models; and qualitative measurements and predictions of specific endpoints (e.g., genotoxicity, endocrine activity). For ecological hazard, quantitative PODs are taken from the EPA ECOTOX database. Exposure information includes production volume, quantitative predictions using the EPA ExpoCast and SHEDS models, biomonitoring data, and qualitative information such as media occurrence, use profiles and likelihood of consumer and childhood exposures. The use of the tool is illustrated by prioritizing chemicals related to TSCA and the Safer Choice Ingredient List. The underpinning data streams for this application are already available in the EPA CompTox Chemistry Dashboard and have been repurposed to deliver this application. This is in keeping with our overarching software development methodology of providing multiple “building blocks” in the form of databases, web services and visualization components to deliver fit-for purpose applications to the relevant audiences. This abstract does not necessarily represent U.S. EPA policy.The importance of data curation on QSAR Modeling: PHYSPROP open data as a cas...
This presentation highlighted how data curation impacts the reliability of QSAR models. We examined key datasets related to environmental endpoints to validate across chemical structure representations (e.g., mol file and SMILES) and identifiers (chemical names and registry numbers), and approaches to standardize data into QSAR-ready formats prior to modeling procedures. This allowed us to quantify and segregate data into quality categories. This improved our ability to evaluate the resulting models that can be developed from these data slices, and to quantify to what extent efforts developing high-quality datasets have the expected pay-off in terms of predicting performance. The most accurate models that we build will be accessible via our public-facing platform and will be used for screening and prioritizing chemicals for further testing.
Using the US EPA’s CompTox Chemistry Dashboard for structure identification a...
Using the US EPA’s CompTox Chemistry Dashboard for structure identification a...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
High resolution mass spectrometry (HRMS) and non-targeted analysis (NTA) are advancing the identification of emerging contaminants in environmental matrices, improving the means by which exposure analyses can be conducted. However, confidence in structure identification of unknowns in NTA presents challenges to analytical chemists. Structure identification requires integration of complementary data types such as reference databases, fragmentation prediction tools, and retention time prediction models. The goal of this research is to optimize and implement structure identification functionality within the US EPA’s CompTox Chemistry Dashboard, an open chemistry resource and web application containing data for ~760,000 substances. Rank-ordering the number of sources associated with chemical records within the Dashboard (Data Source Ranking) improves the identification of unknowns by bringing the most likely candidate structures to the top of a search results list. Database searching has been further optimized with the generation of MS-Ready Structures. MS-Ready structures are de-salted, stripped of stereochemistry, and mixture separated to replicate the form of a chemical observed via HRMS. Functionality to conduct batch searching of molecular formulae and monoisotopic masses was designed and released to improve searching efforts. Finally, a scoring-based identification scheme was developed, optimized, and surfaced via the Dashboard using multiple data streams contained within the database underlying the Dashboard. The scoring-based identification scheme improved the identification of unknowns over previous efforts using data source ranking alone. Combining these steps within an open chemistry resource provides a freely available software tool for structure identification and NTA. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.New developments in delivering public access to data from the National Center...
New developments in delivering public access to data from the National Center...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Researchers at EPA’s National Center for Computational Toxicology integrate advances in biology, chemistry, and computer science to examine the toxicity of chemicals and help prioritize chemicals for further research based on potential human health risks. The goal of this research program is to quickly evaluate thousands of chemicals, but at a much reduced cost and shorter time frame relative to traditional approaches. The data generated by the Center includes characterization of thousands of chemicals across hundreds of high-throughput screening assays, consumer use and production information, pharmacokinetic properties, literature data, physical-chemical properties as well as the predictive computational modeling of toxicity and exposure. We have developed a number of databases and applications to deliver the data to the public, academic community, industry stakeholders, and regulators. This presentation will provide an overview of our work to develop an architecture that integrates diverse large-scale data from the chemical and biological domains, our approaches to disseminate these data, and the delivery of models supporting predictive computational toxicology. In particular, this presentation will review our new CompTox Chemistry Dashboard and the developing architecture to support real-time property and toxicity endpoint prediction. This abstract does not reflect U.S. EPA policy.What's hot (20)
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Accessing Environmental Chemistry Data via Data Dashboards US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
As part of its mission the Center for Computational Toxicology and Exposure (CCTE) delivers access to chemicals related data via online Dashboards. The CompTox Chemicals Dashboard (available at https://comptox.epa.gov/dashboard) provides access to >900,000 chemicals and associated data including experimental and predicted property data, in vivo hazard data, in vitro bioactivity data, exposure data, and various other data types. The application provides a set of flexible searches allowing for search, visualization and downloads of the data to the desktop for further interrogation. This presentation will provide an overview of the Dashboard and other proof-of-concept applications that are now publicly available (https://www.epa.gov/chemical-research/cheminformatics). For example, the Hazard Comparison module (shown in the figure below) allows profiling of chemicals based on toxicity types (https://doi.org/10.1007/s10098-019-01795-w). This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Progress in Using Big Data in Chemical Toxicity Research at the National Cent...
Progress in Using Big Data in Chemical Toxicity Research at the National Cent...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at Proctor and Gamble in Mason, OH, in June 2017 in a symposium regarding "Big Data: Perspectives from Diverse Fields on How to Extract, Filter and Manipulate Large Data Sets to Answer Scientific Questions"Accessing Environmental Chemistry Data via Data Dashboards and Applications t...
Accessing Environmental Chemistry Data via Data Dashboards and Applications t...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The Center for Computational Toxicology and Exposure (CCTE) is part of the Office of Research and Development at the US Environmental Protection Agency. As part of its mission the center delivers access to chemicals related data via web-based freely accessible online Dashboards to disseminate data generated within the center as well as harvested and integrated from open databases around the world. The CompTox Chemicals Dashboard (available at https://comptox.epa.gov/dashboard) provides access to >1.2 million chemicals and associated data including experimental and predicted property data, in vivo hazard data, in vitro bioactivity data, exposure data, and various other data types. The curation of the chemicals dataset has included the development of over 400 segregated lists of chemicals that represent specific research areas of interest including disinfectant by-products, per- and polyfluoroalkyl substances (PFAS), extractables and leachables, and chemicals of emerging concern. The chemicals collection, the associated data, the lists and searches for mass and formulae makes the Dashboard an ideal foundation technology to support our colleagues working in the field of mass spectrometry, especially in targeted and non-targeted analysis. This presentation will provide an overview of the Dashboard, its value to the community in terms of providing access to the integrated and highly curated data, and its utility to support researchers in the field of mass spectrometry. New proof-of-concept projects will also be introduced including the development of a cheminformatics enabled methods database. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.US EPA CompTox Chemicals Dashboard Data Integration Hub to Support Environmen...
US EPA CompTox Chemicals Dashboard Data Integration Hub to Support Environmen...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
A presentation given at the Global Marine Summit at UNC Wilmington on October 9th 2019. The focus of the presentation was an overview of the EPA CompTox Chemicals Dashboard with a specific focus on providing access to data to chemicals such as algal toxins and mycotoxins. Cheminformatics tools and chemistry data underpinning mass spectrometry analy...
Cheminformatics tools and chemistry data underpinning mass spectrometry analy...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Mass spectrometry analyses at the US-EPA, especially non-targeted analysis studies, are highly dependent on the cheminformatics efforts which have been underway within the agency for almost a decade. These research efforts have resulted in a rich data infrastructure based on the DSSTox database, data integration approaches based on a structure standardization approach to produce “MS-ready” structures, and a number of supporting data types to facilitate ranking of non-targeted analysis candidates. 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 includes the development of the underlying chemistry database of >1.2 million chemical substances (DSSTox), approaches to structure standardization to facilitate structure-substance mapping, development of a spectral database of >150,000 spectra for >25,000 chemicals, a database of >3000 analytical methods, prediction models for LCMS amenability, and an application for the profiling of toxicity hazards for batches of chemical substances. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Accessing information for Per- & Polyfluoroalkyl Substances using the US EPA ...
Accessing information for Per- & Polyfluoroalkyl Substances using the US EPA ...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
EPA’s National Center for Computational Toxicology is developing automated workflows for curating large databases within the DSSTox project, and providing accurate linkages of data to chemical structures, exposure and hazard information. The data are made available via the EPA’s CompTox Chemistry Dashboard (https://comptox.epa.gov/dashboard), a publicly accessible website providing access to data for ~760,000 chemical substances, the majority of these represented as chemical structures. The web application delivers a wide array of computed and measured physicochemical properties, in vitro high-throughput screening data and in vivo toxicity data, as well as integrated chemical linkages to a growing list of literature, toxicology, and analytical chemistry websites. In addition, several specific search types are in development to directly support the mass spectrometry non-targeted screening community, enabling cohesive workflows to support data generation for the detection and assessment of environmental exposures to chemicals contained within DSSTox. The application provides access to segregated lists of chemicals that are of specific interest to relevant stakeholders, including, for example, scientists interested in Per- & Polyfluoroalkyl Substances (PFAS). Added lists include those sourced from the European Union as well as developed in-house and now containing thousands of chemicals. A procured testing library of hundreds of PFAS chemicals annotated into chemical categories has been integrated into the dashboard with a number of resulting benefits: a searchable database of chemical properties, with hazard and exposure predictions, and links to the open literature. This presentation will provide an overview of the dashboard, the developing library of PFAS chemicals and associated categorization, and new physicochemical property and environmental fate and transport QSAR prediction models developed for these chemicals. The application of the dashboard to support mass spectrometry non-targeted analysis studies for the identification of PFAS chemicals will also be reviewed. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Data delivery from the US-EPA Center for Computational Toxicology and Exposur...
Data delivery from the US-EPA Center for Computational Toxicology and Exposur...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
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 have served the chemistry community for many years. Several web-based software applications have been developed at the US-EPA and made available to the community to provide access to information regarding mycotoxins. This includes related structures, experimental and predicted properties, hazard data and mass spectrometry analytical data and methods. 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 modules to allow for hazard comparison for sets of chemicals, structure-substructure-similarity searching and batch QSAR prediction of both physicochemical and toxicity endpoints. This presentation will provide an overview of all tools in development that provide access to mycotoxin related data and the integrated nature of the applications based on the underlying chemistry data set. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Delivering web-based access to data and algorithms to support computational t...
Delivering web-based access to data and algorithms to support computational t...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The US-EPA National Center for Computational Toxicity (NCCT) has been generating data and building software applications and web-based chemistry databases for over a decade. During this period the center has analyzed thousands of chemicals in hundreds of bioassays, has researched high-throughput physicochemical property measurements and investigated approaches for high throughput toxicokinetics. NCCT continues to expand the battery of assays and number of chemicals under examination and is now investigating the application of transcriptomics. In parallel to these experimental efforts, and to support our efforts to develop new approaches to prioritize chemicals based on potential human health risks, we aggregate and curate data streams of various types to support prediction models. Over the past few years some of the data have been delivered through prototype web-based “dashboards” for public consumption. The latest of these web applications, the CompTox Chemicals Dashboard, is an integrated access point to obtain information associated with 875,000 chemical substances and providing experimental and predicted data of various types. This includes physicochemical and fate and transport data, bioactivity data, exposure data and integrated literature searches. Real-time predictions and generalized read-across are possible and advanced search capabilities are available to support EPA-related projects including mass spectrometry non-targeted analysis. This presentation will provide an overview of the CompTox Chemicals Dashboard and the its role in delivering access to the outputs of NCCT. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Cheminformatics Support for MS Supporting Exposomics
Cheminformatics Support for MS Supporting ExposomicsUS Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
A presentation given at the 5th Metabolomics of North America webinar on September 8th 2023. Provides an overview of the cheminformatics support provided by the DSSTox database, CompTox Chemicals Dashboard and multiple other web-based applications in development TRIANGLE AREA MASS SPECTOMETRY MEETING: Structure Identification Approaches U...
TRIANGLE AREA MASS SPECTOMETRY MEETING: Structure Identification Approaches U...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at a TRIANGLE AREA MASS SPECTOMETRY meeting on 01/29/2019 in Research Triangle Park, North Carolina to provide a general overview of the CompTox Chemicals Dashboard to an audience of mass spectrometrists and people interested in the capabilities of the dashboard for chemical forensics, structure identification etc.The EPA CompTox Chemistry Dashboard and Underpinning Software Architecture
The EPA CompTox Chemistry Dashboard and Underpinning Software Architecture US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The CompTox Chemistry Dashboard was developed by the Environmental Protection Agency’s National Center for Computational Toxicology. This dashboard has been architected in a manner that allows for the deployment of multiple “applications”, both as publicly available databases, and for deployment under the constraints of confidential business information (CBI). The public dashboard provide access to multiple types of data for ~750,000 chemicals. This includes, when available for a chemical substance, physicochemical parameters, toxicity and bioassay data, consumer use and analytical data. Fate, exposure, and hazard calculations can benefit from access to the data aggregation and curation efforts that underpin the public dashboard. Also, regulators can benefit from the integration of their own data within their closed infrastructure environments. This presentation will provide a review of the chemistry dashboard architecture and its present application providing access to data to the research and regulatory communities. We will also review present developments in the area of delivering an application programming interface, web services, and software components for integration into third party applications providing access to the data exposed via the dashboard. This abstract does not reflect U.S. EPA policy.The US-EPA CompTox Chemicals Dashboard to support Non-Targeted Analysis
The US-EPA CompTox Chemicals Dashboard to support Non-Targeted AnalysisUS Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at the ASMS Sanibel Conference "Unraveling the Exposome" and provided a general overview of the dashboard and how it integrates to many of the projects that we support but with a special focus on list generation, mass and formula searching based on MS-Ready structures and some of the prototypes that we have been developing to support non-targeted analysis.US-EPA Cheminformatics Support for Delivering Data Related to Chemicals of E...
US-EPA Cheminformatics Support for Delivering Data Related to Chemicals of E...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at the "Department of Defense's (DoD) Energy and Environment Innovation Symposium" in Arlington, Virginia on December 1st 2023 (https://serdp-estcp.org/events/details/04d444f1-aa19-4e66-bb5c-5163964cc4dd/symposium-2023)Non-targeted analysis supported by data and cheminformatics delivered via the...
Non-targeted analysis supported by data and cheminformatics delivered via the...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
Non-targeted analysis (NTA) uses high-resolution mass spectrometry to better understand the identity of a wide variety of chemicals present in environmental samples (and other matrices). However, data processing remains challenging due to the vast number of chemicals detected in samples, software and computational requirements of data processing, and inherent uncertainty in confidently identifying chemicals from candidate lists. Analysis of the resultant mass spectrometry information relies on cheminformatics to identify and rank chemicals and the US EPA has developed functionality within the CompTox Chemicals Dashboard (https://comptox.epa.gov/dashboard) to address challenges related to this analysis. These tools include the generation of “MS-Ready” structures to optimize database searching, retention time prediction for candidate reduction, consensus ranking using chemical metadata, and in silico MS/MS fragmentation prediction for spectral matching. Combining these tools into a comprehensive workflow improves certainty in candidate identification. This presentation will review how the CompTox Chemicals Dashboard via its flexible search capabilities, rich data for ~875,000 chemical substances, and visualization approaches within this open chemistry resource provides a freely available software tool to support structure identification and NTA. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Delivering chemical-associated data via EPA web applications
Delivering chemical-associated data via EPA web applicationsUS Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
This presentation was given at the conference: "Cheminformatics Resources of U.S. Governmental Organizations" and focuses on the CompTox Chemicals Dashboard and the sharing of our data https://www.fda.gov/news-events/fda-meetings-conferences-and-workshops/cheminformatics-resources-us-governmental-organizations-05092022#event-information Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...
Chemistry Data Delivery from the US-EPA Center for Computational Toxicology a...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
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 USEPA 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/chemicalresearch/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. A number of other applications in development include a chemical transformations database (ChET) and a database of analytical methods and open mass spectral data (AMOS). Each of these depends on the underlying DSSTox chemicals database, a rich source of chemistry data for over 1.2 million chemical substances. I 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.Web-based access to experimental and predicted data for environmental fate, t...
Web-based access to experimental and predicted data for environmental fate, t...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The EPA CompTox Chemistry Dashboard provides access to data associated with ~760,000 chemical substances. The available data includes experimental and predicted physicochemical properties, environmental fate and transport data, in vivo and in silico toxicity data, in vitro bioassay data, exposure data and a variety of other types of information. The data are under continuous expansion and curation and the experimental data have been used to develop QSAR and QSPR models. A number of these models are available via a web interface so that users can submit a chemical structure and predict properties in real time. The dashboard also provides access to pre-compiled chemical lists and categories, including pesticides, and chemicals detected in the environment via non-targeted mass spectrometry analysis. The data are searchable using chemical identifiers (systematic names, trade names, CAS Registry Numbers), by structure, mass and formula. Batch searches allow for data associated with thousands of chemicals to be obtained in a few seconds, with just a few button clicks, and downloaded to the desktop. This presentation will provide an overview of the Dashboard and its applications to accessing source data associated with agriculturally related chemicals. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Crofton Evolution of Toxicology
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Applications of the US EPA’s CompTox Chemistry Dashboard to support structure...
Applications of the US EPA’s CompTox Chemistry Dashboard to support structure...US Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
High resolution mass spectrometry (HRMS) and non-targeted analysis (NTA) are of increasing interest in chemical forensics for the identification of emerging contaminants and chemical signatures of interest. At the US Environmental Protection Agency, our research using HRMS for non-targeted and suspect screening analyses utilizes databases and cheminformatics approaches that are applicable to chemical forensics. The CompTox Chemistry Dashboard is an open chemistry resource and web-based application containing data for ~760,000 substances. Basic functionality for searching through the data is provided through identifier searches, such as systematic name, trade names and CAS Registry Numbers. Advanced Search capabilities supporting mass spectrometry include mass and formula-based searches, combined substructure-mass searches and searching experimental mass spectral data against predicted fragmentation spectra. A specific type of data mapping in the underpinning database, using “MS-Ready” structures, has proven to be a valuable approach for structure identification that links structures that can be identified via HRMS with related substances in the form of salts, and other multi-component mixtures that are available in commerce. This presentation will provide an overview of the CompTox Chemistry Dashboard and demonstrate its utility for supporting structure identification and NTA in chemical forensics. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.US-EPA Chemicals Dashboard – an integrated data hub for environmental science
US-EPA Chemicals Dashboard – an integrated data hub for environmental scienceUS Environmental Protection Agency (EPA), Center for Computational Toxicology and Exposure
The U.S. Environmental Protection Agency (EPA) Computational Toxicology Program utilizes computational and data-driven approaches that integrate chemistry, exposure and biological data to help characterize potential risks from chemical exposure. The National Center for Computational Toxicology (NCCT) has measured, assembled and delivered an enormous quantity and diversity of data for the environmental sciences, including high-throughput in vitro screening data, in vivo and functional use data, exposure models and chemical databases with associated properties. The CompTox Chemicals Dashboard website provides access to data associated with ~900,000 chemical substances. New data are added on an ongoing basis, including the registration of new and emerging chemicals, data extracted from the literature, chemicals studied in our labs, and data of interest to specific research projects at the EPA. Hazard and exposure data have been assembled from a large number of public databases and as a result the dashboard surfaces hundreds of thousands of data points. Other data includes experimental and predicted physicochemical property data, in vitro bioassay data for over 4000 chemicals and ~1500 assays, and millions of chemical identifiers (names and CAS Registry Numbers) to facilitate searching. Other integrated modules include an interactive read-across module, real-time physicochemical and toxicity endpoint prediction and an integrated search to PubMed. This presentation will provide an overview of the CompTox Chemicals Dashboard and how it has developed into an integrated data hub for environmental data. This abstract does not necessarily represent the views or policies of the U.S. Environmental Protection Agency.Similar to Incorporating new technologies and High Throughput Screening in the design and selection of chemical alternatives (20)
Accessing Environmental Chemistry Data via Data Dashboards
Accessing Environmental Chemistry Data via Data Dashboards
Progress in Using Big Data in Chemical Toxicity Research at the National Cent...
Progress in Using Big Data in Chemical Toxicity Research at the National Cent...
Accessing Environmental Chemistry Data via Data Dashboards and Applications t...
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US EPA CompTox Chemicals Dashboard Data Integration Hub to Support Environmen...
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US-EPA Cheminformatics Support for Delivering Data Related to Chemicals of E...
US-EPA Cheminformatics Support for Delivering Data Related to Chemicals of E...
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Web-based access to experimental and predicted data for environmental fate, t...
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Applications of the US EPA’s CompTox Chemistry Dashboard to support structure...
Applications of the US EPA’s CompTox Chemistry Dashboard to support structure...
US-EPA Chemicals Dashboard – an integrated data hub for environmental science
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Incorporating new technologies and High Throughput Screening in the design and selection of chemical alternatives
- 1. Incorporating new technologies and high- throughput approaches in the design and selection of chemical alternatives Antony Williams U.S. Environmental Protection Agency, RTP, NC June 15th, 2017 21st Annual Green Chemistry & Engineering Conference, Reston, VA This work was reviewed by the U.S. EPA and approved for presentation but does not necessarily reflect official Agency policy. http://www.orcid.org/0000-0002-2668-4821
- 2. Paradigm Shift in Chemical Design (especially in regards to toxicology) • Chemical Design in the future – High-throughput modeling – SAR/QSAR/QSTR models – Retrosynthetic analysis algorithms for synthesis • Toxicology – FEWER animal studies. Maybe NONE?? – Openness in data sharing – More confidence in computational predictive models that link chemical structures to adverse outcomes 1
- 3. It will depend on lots of DATA 2
- 4. What we need to progress • Adequate information on potential bioactivity for as many chemicals as possible • Read-across, QSAR and QSTR models from large high-quality curated datasets 3
- 5. • National Center for Computational Toxicology established in 2005 to integrate: – High-throughput and high-content technologies – Modern molecular biology – Data mining and statistical modeling – Computational biology and chemistry • Currently staffed by ~60 employees as part of EPA’s Office of Research and Development • Home of ToxCast & ExpoCast research efforts • Key partner in U.S. Tox21 federal consortium • Multiple cross-division collaborations National Center for Computational Toxicology
- 6. What we need to progress • Adequate information on potential bioactivity for as many chemicals as possible • High Throughput Screening ToxCast/Tox21 generating and making available bioactivity data • GREAT progress to date – more to come! • Read-across, QSAR and QSTR models from large high-quality curated datasets • Chemistry data gathering and high-throughput bioassays are providing the necessary data to generate these models 5
- 7. Data and Modeling Efforts to Date ToxCast ExpoCast Predictive Models Comp Chemistry HTTK • High-throughput in vitro screening of ~4,000 chemicals across ~1200 assay endpoints (ToxCast) and ~8,000 chemicals in ~60 assay endpoints (Tox21) • High quality, curated chemical structure and physical chemical properties database of ~750,000 chemicals • High-throughput exposure estimates with uncertainty for ~ 7,000 chemicals based on production volume and chemical use
- 8. Data and Modeling Efforts to Date • High-throughput in vitro screening of ~4,000 chemicals across ~1200 assay endpoints (ToxCast) and ~8,000 chemicals in ~60 assay endpoints (Tox21) • High quality, curated chemical structure and physical chemical properties database of ~750,000 chemicals • High-throughput exposure estimates with uncertainty for ~ 7,000 chemicals based on production volume and chemical use • Legacy in vivo data from ~6,000 animal toxicology studies on ~1,110 unique chemicals • High-throughput toxicokinetic (HTTK) models for ~700 chemicals based on in vitro measurements • AOPs and virtual tissue models for broad range of developmental toxicities ToxCast ExpoCast Comp Chemistry HTTK ToxRef Predictive Models
- 10. Approximately 15 Years of Data… Growing with daily curation DSSTox_v2 PublicCurated 5. Low 2. Low 6. Untrusted 1. High 3. High 4. Med 7. Incomplete Public_Untrusted Public_Low Public_Medium Public_High DSSTox_Low DSSTox_High 4535 16K 33K 101K 584K ~ 310K pending ~ 150K pending
- 11. Features Properties Chemotypes, fingerprints, physchem properties, ... Chemical representation levels supporting data integration 10 Structure Generic Substance Test Sample Chemical Name CASRN Supplier, Lot/Batch, physical description SMILES InChI
- 12. Features Properties Chemotypes, fingerprints, physchem properties, ... Chemical analogs, Read-across, SAR modeling Chemical representation levels supporting data integration 11 Structure Generic Substance Test Sample Chemical Name CASRN Supplier, Lot/Batch, physical description SMILES InChI Experimental Endpoint Data Public toxicity datasets Structure searching & modeling
- 13. Integrating in vitro and in vivo data HTS-In vitro ToxRef COSMOS ToxCast Tox21 Chemicals DSSTox Measured Properties Chemical KB Biological Data Biological activities
- 14. Adding Product Use and Exposure HTS-In vitro ToxRef COSMOS ToxCast Tox21 Chemicals DSSTox Measured Properties Product Use & Exposure Chemical KB Biological Data Biological activities
- 15. High Throughput Measurement to Characterize Exposure 14
- 16. Building Models from the data HTS-In vitro ToxRef COSMOS ToxCast Tox21 Chemicals DSSTox Biological Data Fate & Transport ADME Reactivity Biotransformation Physchem properties Biological activities Measured Properties ModelsExposure Data Toxicity Predictions Structure-alerts Chemical KB Product Use & Exposure
- 17. Access to Our Data and Models 16
- 18. What we have learned… • Data curation, standardization and versioning is essential • Prototype application development suffices for research projects but production development requires managed processes • ODOSOS (Open Data, Open Source and Open Standards) endows many benefits • With this in mind… 17
- 20. Bisphenol A 19
- 22. Chemical Properties 21 • Consuming and producing open data
- 23. Data Distribution 22 • Consuming and producing open data
- 25. Modeling Details 24 Calculation Result for a chemical Model Performance with full QMRF Nearest Neighbors from Training Set 24
- 26. Prediction Details and QMRF Report 25
- 27. Developing “NCCT Models” • Our approach to modeling: – Obtain high quality training sets – Apply appropriate modeling approaches – Validate performance of models – Define the applicability domain and model limitations – Use models to predict properties across our full datasets • Release as Open Data and Open Models
- 28. Workflow Details and Data 27 OPERA Models: https://github.com/kmansouri/OPERA
- 29. Making Toxicity Value Data available 28
- 30. Exposure 29
- 31. Consumer Product data 30 • Data gathered from multiple online data sources – text mining and data downloads • CASRN and name mappings to produce curated structure set with functional uses • Produce Functional Use (FuseDB) and build predicted functional use models
- 32. NHANES Exposure data 31 Environ. Sci. Technol., 2013, 47 (15), pp 8479–8488
- 33. ToxCast and Tox21 Bioassays 32
- 34. ToxCast and Tox21 Bioassays 33
- 35. PubChem Bioassay Data Integration 34
- 36. PubMed: BIG DATA Literature Search Integration 35
- 37. Linked Directly to PubMed 36
- 38. Literature Search Integration Google Scholar 37
- 39. Batch Data Searching • I have a 5000 CAS Numbers (or Names) – is there data available? – Has any Toxcast data been run? – Are there Toxicity Data values available? – Are there predicted exposure data? – Can I get predicted physchem data for my model? 38
- 40. We get lots of user feedback.. • Online since April 2016 • Feedback welcomed! 39
- 41. “RapidTox” in Development • Semi-automated decision support tool for high-throughput risk assessments • Use Dashboard “architecture”, existing data streams and add new data – e.g. Global Hazard Summary and ECHA data • Combine data streams into quantitative toxicity values with uncertainty estimates
- 42. Risk Assessments Generally Contain a Standard Set of Components We are assembling these components to deliver RapidTox Phys Chem Exposure Hazard Dose Response, PK, and PODs Risk Summary Uncertainty Variability
- 43. Quantifying Uncertainty & Assessing Performance of Read-Across - GenRA • “Chemical-Biological Read-Across” - predict toxicity as a similarity-weighted activity of nearest neighbors • Evaluates read-across performance and uncertainty using available data
- 45. We’re not done yet… HTS-In vitro ToxRef COSMOS ToxCast Tox21 Chemicals DSSTox Biological Data Fate & Transport ADME Reactivity Biotransformation Phys-chem properties Biological activities Measured Properties ModelsExposure Data Toxicity Predictions Structure-alerts Chemical KB Product Use & Exposure
- 46. Acknowledgements EPA-RTP Russell Thomas Kevin Crofton Chris Grulke Ann Richard Richard Judson John Cowden John Wambaugh Imran Shah Grace Patlewicz and… Many other contributors from across EPA-ORD
- 47. Contact Antony Williams US EPA Office of Research and Development National Center for Computational Toxicology (NCCT) Williams.Antony@epa.gov ORCID: https://orcid.org/0000-0002-2668-4821 46