Integration of the exposome concept into health risk assessments: a challenge for health safety agencies.

The exposome is a concept that aims to study the environmental factors to which individuals are exposed during their lifetime and the role of these factors in the development of chronic diseases. Since the concept emerged in 2005, new data, methods, and tools have been generated by the scientific community to assess the different components of the exposome and their impacts on human health. Currently, one of the main challenges is accounting for the diversity and complexity of exposures and their effects on health in risk assessment, which might be accomplished by integrating the exposome into this process. To this end, a working group was constituted by Anses to develop a strategy to integrate the exposome concept in risk assessment and more generally in the work produced by health safety agencies. We present the principal challenges to be addressed by considering 8 themes covering relevant aspects of the exposome and we made recommendations for each theme: 1) characterization of the exposome in epidemiological surveys; 2) exposome data; 3) risk assessment of chemical mixtures; 4) aggregation of multiple sources and routes of exposure; 5) dynamics of the exposure in the context of time, space, and social factors; 6) establishment of reference values; 7) multiple factors in risk, benefit and health impact assessment; and 8) eco-exposome. Then, we propose practical recommendations with short-, medium-, and long-term time scales to progressively operationalize the exposome into risk assessments implemented by health safety agencies. We also discuss how providing broader exposome input into risk assessment can support risk regulators to incorporate exposome input into risk management.