5. Challenges and prospects

5.1 Uncertainties

The overall health risk assessment process compiles and processes a certain amount of information and data, characteristic of a source, a substance, an environment or a population, which are inevitably accompanied by uncertainties.

Uncertainties are presented at every stage of the assessment, in particular when defining scenarios (emission, exposure, etc.), using models (which cannot accurately represent reality), or measurements (uncertainties linked to metrological performance and spatial and temporal heterogeneity).

The concept of uncertainty can be divided into two categories:

• true" uncertainty, linked to the absence of scientific data. It reflects the total or partial...