EPA Workshop on Temporal Exposure Issues for Environmental Pollutants: Health Effects and Methodologies for Estimating Risk (January 2016)
Background
EPA’s Human Health Risk Assessment (HHRA) Program and the National Center for Environmental Assessment (NCEA) are holding a workshop on Temporal Exposure Issues for Environmental Pollutants: Health Effects and Methodologies for Estimating Risk. The purpose of the workshop is to explore the state-of-the-science with respect to varying temporal exposures to environmental pollutants, the observed associations with health effects, and opportunities to utilize current or future scientific data.
EPA strives to stay abreast of current and up-to-date science that informs human health risk assessments. One avenue to accomplish this goal is to engage scientific experts in public discussions to explore how the most current research informs science decisions in human health risk assessments. Estimating human health risk from varying temporal exposures to environmental pollutants represents an important challenge for the EPA’s HHRA program and NCEA. Primarily, the fields of environmental epidemiology and toxicology have focused on continuous, chronic exposures to pollutants and not fully evaluated how varying patterns of exposure may be associated with health effects (both cancer and noncancer effects) especially for specific lifestages and susceptible populations. Exposure scenarios range from a single exposure during a critical lifestage to chronic exposures, or a combination thereof which may be associated with health effects that occur in a relatively short time period or have a long latency. This workshop will focus on how our understanding of temporal exposure scenarios and the range of resulting health effects can better inform human health risk assessment.
Dates
The workshop was held on January 27-29, 2016.
Location
The workshop was held in Conference Room C111A-C at EPA's Research Triangle Park (RTP) campus located at 109 TW Alexander Drive, Research Triangle Park, NC 27711. The workshop was also available by webinar/teleconference.
EPA hosted a workshop to explore the state-of-the-science regarding the influence of duration and time-dependent concentrations or doses on a range of endpoints (health effects) and best practices for estimating risk. Additionally, the agency sought to advance the development of methods for addressing the differences between dose regimens in animal testing and temporal patterns of human exposures in the human health risk assessment process.
The workshop included presentations and discussions by scientific experts and risk assessors in areas pertaining to exposure science, physiologically-based pharmacokinetic modeling, health effects resulting from exposure to environmental pollutants, and regulatory risk assessment. The workshop was structured to include opportunities for comments, questions, and engagement from stakeholders and members of the public.
- Session I: Defining Temporal Exposure Issues in Risk Assessment. Current practices for estimating human health risk in the context of various temporal exposure scenarios and how these exposures for environmental chemicals are measured and characterized will be discussed. Additionally, health effects associated with varying temporal exposures will be discussed.
- Session II: Critical Topics Related to Temporal Exposures of Environmental Pollutants. The current scientific evidence associated with varying temporal exposures including how other scientific organizations are addressing these types of exposures will be explored. These discussions will include consideration of critical factors in exposure characterization and identification of susceptible populations and lifestages.
- Session III: Case Studies and Best Practices for Estimating Risk from Temporal Exposure Scenarios. Considerations associated with evaluating varying temporal exposures of environmental chemicals including, but not limited to, factors such as duration and pattern of exposures, peak short-term exposures versus chronic lifetime exposures, and acute exposures leading to latent effects will be discussed.
- Session IV: Advancing the Characterization of Temporal Exposure Scenarios and Health Effects. Exposure sources, temporal patterns, durations and latency of effects in the context of epidemiological and toxicological studies in consideration of development and utilization of new data sources will be explored.
Final agenda from the workshop.
- Temporal Exposure Issues Workshop (Final Agenda) (PDF) (5 pp, 401 KB, about PDF)
- Temporal Exposure Issues Workshop - Final Agenda (PDF) (5 pp, 401 KB, about PDF)
- Session 1: Overview of temporal considerations for risk assessment of acute scenarios (PDF) (20 pp, 575 KB, about PDF)
- Session 1: Understanding temporal variations in exposure to chemicals (PDF) (25 pp, 918 KB, about PDF)
- Session 1: Understanding risks for non-constant exposure patterns: experimentation and defining dose metrics (PDF) (23 pp, 1 MB, about PDF)
- Session 1: Addressing temporally varying exposures in toxicity characterizations (PDF) (27 pp, 872 KB, about PDF)
- Session 2: Dose-time-response implications of the approach to saturation for metabolism- and receptor-mediated end-effects (PDF) (15 pp, 147 KB, about PDF)
- Session 2: Biomonitoring and temporality in environmental epidemiology: The data we collect versus the data we need (PDF) (26 pp, 464 KB, about PDF)
- Session 2: Improving the use of spot biomarker data for environmental Epi. and Population Risk Assessment (PDF) (28 pp, 1 MB, about PDF)
- Session 2: Chronically Underestimated: the impact of high early life water intake rates and short-term effects for deriving health-protective drinking water criteria (PDF) (24 pp, 338 KB, about PDF)
- Session 3: Temporality Best Practices: Case Study with N-Methylpyrrolidone (PDF) (39 pp, 731 KB, about PDF)
- Session 3: EPA Temporal Issues for Environmental Pollutants: Prenatal and Early life Exposure to Arsenic (PDF) (44 pp, 3 MB, about PDF)
- Session 3: Perspectives on Timing of Exposure in an Epidemiologic study of Arsenic: Temporal Measures, Exposure Lifelines, Exposure Error, and Uncertainty (PDF) (31 pp, 1 MB, about PDF)
- Session 4: Incorporating modernized approaches and data sources to assess temporal exposures: considerations across the source to outcome continuum (PDF) (26 pp, 3 MB, about PDF)
- Session 4: What a difference a day makes: Critical exposure periods for adverse birth outcomes (PDF) (32 pp, 2 MB, about PDF)
- Session 4: Advantages and implications of using adverse outcome pathways (AOPs) for disease outcomes resulting from temporal exposures (PDF) (36 pp, 3 MB, about PDF)
- Session 4: Temporal Exposures to Obesogens and Transgenerational Inheritance (PDF) (29 pp, 2 MB, about PDF)