Process-Related Contaminants as an Example for Holistic Dosimetry of Endogenous and Exogenous Exposures

Background & Objectives
In modern risk assessment, deriving accurate exposure estimates can present serious challenges and uncertainties. To some extent, this is due to the fact that today’s consumer exposure is multifactorial, including exposure from exogenous environmental, occupational and food related sources; while in some cases also endogenous exposure adds to the aggregate exposure. For some compounds it has already been well established that endogenous exposure may add substantially to the total exposure. For instance, methanol and ethanol and their oxidative metabolites formaldehyde and acetaldehyde are ingested with food when consuming fruits and certain beverages. Those compounds are, however, also continuously formed endogenously in the course of physiological intermediary energy metabolism. In cases where endogenous exposure is proven to add substantially to the exposome, it becomes essential to better understand the contribution of in vivo background occurrence, as compared to the ingestion from exogenous sources, to arrive at a comprehensive risk assessment.

A peer-reviewed publication providing an overview of the state-of-the-art with respect to understanding the contribution of endogenous exposure to the overall exposure of those process-related contaminants that also occur as constitutive physiological components of mammalian intermediary energy metabolism or other processes in the organism.