Biomonitoring indicators serve as a complement to environmental monitoring for documenting, controlling and preventing worker exposure to chemical contaminants, and vary with factors related to the worker and his environment. In a previous study, the authors examined the individual conditions responsible for this variability. In this publication, they document the effect of variation in exposure levels on the measurement of these indicators. The objective: to propose a model for the mathematical calculation of the total variability while taking the different sources into account. As a complement to previous research in this field, this study provides Québec occupational health professionals with essential information on the total variability that can affect biomonitoring data. The results will be used to compare expected variations in environmental surveillance parameters to the variation in biological indicators, according to different exposure scenarios. This information will be added to the IRSST's biomonitoring guide. The institute's various clienteles will thus have a decision tool applicable to biomonitoring strategies. This research will also yield a computer tool that facilitates calculation of the number of samples required.
