Citation:

Teeguarden, J. AND C. Tan. The Aggregate Exposure Pathway (AEP): A conceptual framework for advancing exposure science research and applications. Joint ISES-SOT webinar, NA, December 14, 2016.

Impact/Purpose:

The Aggregate Exposure Pathway (AEP) framework is developed to answer the National Research Council's call for a systems-based approach to exposure science that considers exposures from source to internal exposure, and at multiple levels of integration. This presentation will introduce the AEP concept to the audiences, as well as possible applications of AEPs. The purpose is to promote an integrated AEP-Adverse Outcome Pathway (AOP) framework to inform a flexible decision making framework that can be applied to risk-based, hazard-based, or exposure-based decisions.

Description:

Historically, risk assessment has relied upon toxicological data to obtain hazard-based reference levels, which are subsequently compared to exposure estimates to determine whether an unacceptable risk to public health may exist. Recent advances in analytical methods, biomarker discovery, computational tools, and sensor/monitoring technologies have enabled new streams of data to be generated at higher volumes and speed, thus allowing risk assessment to be driven by these new exposure data. For example, untargeted analysis of environmental/biological samples may identify chemicals with significant exposure potentials, which in turn can inform toxicity testing priorities. In addition, through these techniques, exposure science now offers new opportunities to transition risk assessment approaches from investigating a certain source of exposure to a single chemical that leads to a certain disease, to one that contributes understanding of cumulative risk, characterizing the intricate interactions among chemical and non-chemical stressors, the environment, and biology in the real world. To enable these opportunities, a conceptual framework, Aggregate Exposure Pathway (AEP), is proposed to 1) organize the increasing flow of dispersed exposure information; 2) provide common nomenclature to facilitate communications and innovations; and 3) support the integration of exposure information with other environmental health communities, e.g., toxicology and epidemiology. The AEP framework adapts the conceptual structure of the maturing Adverse Outcome Pathway (AOP) framework, which organizes knowledge on biologically plausible and empirically supported links between perturbations of a biological system at the molecular level and the resulting adverse outcome(s). Similarly, the AEP framework organizes exposure data and predictions, linking them from sources to internal target sites. In this presentation, we will introduce the AEP framework and its potential applications, such as identifying primary exposure sources, informing toxicity testing strategies, and supporting cumulative risk assessment. Disclaimer: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

Record Details: