Bridging Exposure Science into Future Human Health Risk Assessment

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By Yu Syuan Luo posted 03-14-2018 04:28

  

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Human health risk assessment has four critical components: hazard identification, exposure assessment, dose-response assessment, and risk characterization. However, human health risk assessment is traditionally hazard driven because the exposure data is limited at the initial stage and usually is being considered retrospectively. In the "Toxicology’s Next Grand Challenge: Embracing Exposure Science for Effective Public Health Protection" workshop, the speakers suggested a paradigm shift toward exposure-driven assessment, so-called “exposome,” by applying several advanced technologies/alternative approaches, including advanced analytical chemistry, computational tools, and a novel framework to describe environmental exposures.

The advancement of analytical instruments makes “exposome” possible. The improved sensitivity of analytical instruments refines the targeted analysis and provides the biomonitoring data with higher quality. On the other hand, the development of non-targeted analyses further creates a venue to understand the exposures to unknown chemicals, which in turn facilitates the exposure-driven health risk assessment.

Computational tools, such as physiologically-based pharmacokinetic modeling and in vitro to in vivo extrapolation, can help translate the internal marker measurements into the external measure of exposure, predict the repeated dosing scenario, and bridge the in vitro testing concentrations into the in vivo target site concentrations. In addition, the evolvement of computational tools can also help deal with the “big data” generated during the process, i.e. metabolomics, transcriptomics, and proteomics data. 

Aside from the advanced technologies, Dr. David Hines, US Environmental Protection Agency, introduced an approach combining aggregated exposure pathway (AEP) and adverse outcome pathway (AOP) to refine the cumulative risk assessment. This approach presents a detailed framework from the external exposure to the target site exposure and then further reach out to a specific adverse outcome. However, the existing data gaps for some chemicals may hinder the risk assessors from doing a complete AEP-AOP framework.

With the promising progress in technology and exposure science, scientists are trying to shift the paradigm of human health risk assessment from “hazard driven” towards “exposure driven.” Incorporating the exposure information at the early stage of human health risk assessment could save considerable time, effort, and animal use. Scientists are working even more closely together to expedite this paradigm shift—for better human health.

This blog was prepared by an SOT Reporter. SOT Reporters are SOT members who volunteer to write about sessions and events they attend during the SOT Annual Meeting and ToxExpo. If you are interested in participating in the SOT Reporter program in the future, please email SOT Communications Director Michelle Werts.

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