EPA Workshop on Temporal Exposure Issues for Environmental Pollutants: Health Effects and Methodologies for Estimating Risk (January 2016)

UPDATE: EPA hosted a workshop on Temporal Exposure Issues on January 27-29, 2016. EPA has released the presentations that were given during this workshop, see the workshop materials tab.


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.


The workshop was held on January 27-29, 2016.


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.

Top of Page

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.

Top of Page