Events

Innovations in Exposure and Mixture Assessment Approaches

Hosted by: The SOT Risk Assessment and Exposure Specialty Sections and The International Society of Exposure Science

Speaker(s):
Zach Stanfield, PhD, US Envirsonmental Protection Agency
Kyle P. Messier, PhD, National Institute of Environmental Health Sciences

“Using Biomonitoring Data to Infer Chemical Exposures and Inform High-Throughput Exposure Predictions”
Zach Stanfield, PhD, US Environmental Protection Agency
[ Presentations ]

Abstract:
Knowing which environmental chemicals contribute to metabolites observed in humans is necessary for meaningful estimates of exposure and risk from biomonitoring data. In this work, we set out to employ a high-throughput, chemical-independent modeling approach to estimate chemical daily intake rates with well-quantified uncertainty. Bayesian methodology was used to infer ranges of exposure for parent chemicals of biomarkers measured in urine samples from the National Health and Nutrition Examination Survey (NHANES). Metabolites were probabilistically linked to parent chemicals using the NHANES reports and text mining of PubMed abstracts. Chemical exposures were estimated for various population groups and translated to a risk-based metric for prioritization using toxicokinetic (TK) modeling and experimental data. Exposure estimates were investigated more closely for children aged 3 to 5 years, a population group that debuted with the 2015–2016 NHANES cohort. The methods described here have been compiled into an R package called bayesmarker and made publicly available on GitHub. These inferred exposures can help aid in the identification of public health priority chemicals and be used to evaluate high-throughput exposure models.

“GeoTox and RGCA: Developing Extensible Software for Geospatial Exposure and Risk Assessment of Chemical Mixtures”
Kyle P. Messier, PhD, National Institute of Environmental Health Sciences
[ Presentations ]

Abstract:
Comprehensive environmental risk characterization, encompassing physical, chemical, social, ecological, and lifestyle stressors, necessitates innovative approaches to handle the near infinite complexity. Individual and population-level variability in biological response to real-world exposures further magnifies the combinatorial challenges. In this seminar, we’ll discuss the development of two software packages to support environmental exposure and risk assessment for individuals and populations. First, we introduce GeoTox, an open-source R software package in development for characterizing the risk of perturbing molecular targets involved in adverse human health outcomes based on exposure to spatially-referenced stressor mixtures1. Second, a key step of mixture risk characterization is predicting the combined response, which is typically derived from sparse information on individual stressor responses. RGCA, Reflected Generalized Concentration Addition2, is a software and statistical approach that extends the Generalized Concentration Addition3 method for mixtures predictions to allow for 3+ parameter sigmoidal concentration-response models. With an objective towards software extensibility, we demonstrate the GeoTox usage in building computational workflows for individual and population-level exposure and risk assessment. The GeoTox package represents a significant advancement in environmental risk characterization, providing modular software to facilitate the application and further development of the GeoTox framework for quantifying the relationship between environmental exposures and health outcomes. RGCA will be interoperable with GeoTox, allowing a flexible approach for the combined mixture prediction step in the risk characterization. By integrating geospatial methods with cutting-edge exposure and toxicological frameworks, GeoTox and RGCA offer robust tools for assessing individual and population-level risks from combined environmental stressors.

Webinar Recording

Risk Assessment Syllabus: Basics of Exposure Assessment

Hosted by: Risk Assessment Specialty Section

Speaker(s):
Nicolle Tulve, PhD, US EPA
Dan Vallero, PhD, US EPA [ Presentations ]

Moderator:
Linda Birnbaum, PhD, DABT, ATS, NIEHS, Retired

Panelists:
Paul Price, PhD, Risk Sciences International
Sharada Balakrishnan, MSc, PhD, DABT, California EPA-DTSC
Ruthann Rudel, MS, Silent Spring Institute

Abstract:
Risk assessment is a multidisciplinary approach used to underpin decision making processes in human and environmental health sciences. Risk assessment combines risk characterization, informed by hazard identification, dose-response, and exposure assessment, with risk communication and provides critical input informing risk management decisions. While these fundamentals remain unchanged, the discipline is evolving in scope and methodology. Unlike other scientific disciplines, contemporary challenges of the risk assessment community are not strictly technical in nature, but often situated at the interface between science and regulation/policy.
Given its inherent complexity and often specific focus, key concepts in risk assessment are frequently not comprehensively addressed in educational programs of individual disciplines such as exposure sciences, toxicology, and epidemiology. As a result, current trainees and post-graduate professionals can benefit from educational opportunities that convey both fundamental concepts of risk assessment sciences and knowledge on applying these concepts to health evaluations. The Society of Toxicology Risk Assessment Specialty Section (SOT RASS) has developed this “Risk Assessment Syllabus” as a semi-regular opportunity for members of the SOT to enhance their understanding of essential concepts and contemporary topics in the risk assessment sciences.
In this presentation on the "Basics of Exposure Assessment," participants will be provided with a basic foundation in the concepts and principles of human exposure assessment. Participants will be introduced to the various components of an exposure assessment as well as relevant key terminology. Fundamentals that will be covered include: intake, uptake, and dose; applied, potential, internal, and biologically effective dose; acute dose, average daily dose, and average lifetime dose; and dermal, oral, and respiratory dose.

Webinar Recording

An Introduction to Chemical Exposure Estimation

Hosted by: Exposure and Risk Assessment Specialty Sections

Speaker(s):
Jon Arnot, PhD, [ Presentation ]
Arnot Research and Consulting Inc.

Abstract:
Exposure data are required for chemical risk and safety assessment for the general population, consumers, and workers. It is not feasible to measure all chemicals in all exposure scenarios and exposure models are necessarily required to address data gaps and integrate existing measurements. This webinar introduces general exposure estimation concepts, required data, data sources and models. A systematic method for addressing uncertainty in exposure characterization is described and case examples for applying models and data to obtain exposure estimates are presented.

Webinar Recording

Silicone Wristbands: Personal Exposure Monitors to Help Support Research on the Exposome

Co-Hosted by: SOT Risk Assessment Specialty Section, SOT Exposure Specialty Section, and The International Society of Exposure Science

Speaker:
Heather M. Stapleton, PhD [ Presentation ]
Ronie-Richele Garcia-Johnson Distinguished Professor of Environmental Health, Nicholas School of the Environment, Duke University

Abstract:
This talk will highlight current research that utilizes silicone wristbands to measure the external exposome, discussing the strengths and weaknesses of these wearable sensors. In addition, this talk will highlight research that has used silicone wristbands to understand associations with internal dose, exposures over different life stages, to support One Health, and in occupational and non-occupational settings.

Webinar Recording

Beyond the Bench: Using Exposure Science to Promote Toxicology in Policy, Decision-Making, and Public Health

Speakers:
Tom Luben, PhD, Epidemiologist, [ Presentation ]
US EPA Jane Clougherty, ScD, Associate Professor,
Drexel University

Abstract:
In this webinar, scientists from Drexel University Dornsife School of Public Health and the US Environmental Protection Agency (US EPA) will share some basic tools and methods of exposure science, the reasons for using these methods, and how the inclusion of exposure science tenets may increase what we learn from toxicology research.

The presenters will discuss:

• The usefulness of exposure science in linking toxicological research results to human populations
• Improving the applicability of exposure science to regulatory decision-making to enhance public health protections
• The iterative process by which toxicological research can inform other scientific disciplines (and vice versa) by highlighting exposure science as a common link

The presentations also will include examples of toxicological evidence successfully informing regulatory decisions and indicate useful resources from the US EPA and other federal agencies that can aid in designing future experiments.

Webinar Recording

Climate Change and Vulnerable Populations: Complementary Approaches for Assessing Extreme Heat and Health

Speakers:
Dr. Madeleine Scammel, PhD [ Presentation ]
Department of Environmental Health, Boston University School of Public Health, Boston, MA

Dr. Gregory Wellenius, PhD [ Presentation ]
Department of Environmental Health, Boston University School of Public Health, Boston, MA

Abstract:
Climate change is increasing the frequency, intensity, and geographic expanse of extreme heat events. Not everyone is equally vulnerable to the effects of extreme heat. Drs. Wellenius and Scammell will take turns in this session sharing examples from their own work studying the effects of extreme heat. Dr. Wellenius will discuss the use of “big data” and approaches for analyzing health care claims and hospitalization records in cities across the United States in relation to ambient temperatures- drawing on his studies examining mental health, reproductive and pediatric outcomes, and heat related illness, renal disease, cardiovascular disease, respiratory disease. Dr. Scammell will share her experience conducting participatory monitoring of ambient and personal heat in urban and rural communities with environmental justice concerns in the US and in Central America. These include analyses of exposure in relation to health, as well as coping strategies during extreme heat events.

Webinar Recording

Exposures Specialty Section Award Winners

Speakers:
Darryl B. Hood, PhD, Ohio State University, Associate Professor
David Hines, PhD, Integrated Laboratory Systems, LLC (ILS), Senior Computational Toxicologist

Description:
Exposures Specialty Section is excited to launch its webinar series where the first webinar will focus on awards winners from 2019 and 2020 whom we did not get a chance to meet in 2020 and hear about their research.

In this webinar, Dr. David E. Hines, recipient of the Best Paper of 2019 Award will present on “A Quantitative Source-to-Outcome Case Study to Demonstrate the Integration of Human Health and Ecological End Points Using the Aggregate Exposure Pathway and Adverse Outcome Pathway Framework.”

David Hines Abstract and Bio

Presentation

Dr. Darryl Hood, who received the Best Abstract of 2020 Award, will present his work titled “Big Data to Knowledge Analytics Reveals the Zika Virus Epidemic as Only One of Multiple Factors Contributing to a Year-over-Year 28-Fold Increase in Microcephaly Incidence.”

Darryl Hood Abstract and Bio

Presentation

Webinar Recording

ExpoSS Webinar—Co-sponsored with the International Society for Exposure Science (ISES) and RASS

Speaker: Marc Chadeau-Hyam, PhD

Presentation

Webinar Recording