106 Variability of within- and between-worker exposure to chemical agents in France: information from the Colchic occupational exposure database

The well-cited work of Kromhout et al. (1993) was the first large-scale study reporting workplace exposure variability and its within- and between-worker components. Few other studies are available on this central topic of exposure assessment. Here we present information on workplace exposure variability obtained from the Colchic occupational exposure database, which contains more than one million measurements for over 700 chemicals, collected since 1987 in French workplaces. We defined Similar Exposure Groups (SEGs) on the basis of occupation, task, and chemical agent and we evaluated the within- and between-worker components of exposure variability on a “by establishment” basis for the period 2010-2022. Data selection criteria included at least two workers per establishment and at least three personal measurements per worker, including measurements taken in the same or in different days. Measurements duration was comprised between 30 and 540 minutes. We evaluated variability using the total worker geometric standard deviation (GSDt) and its within- (GSDw) and between- (GSDb) components, as estimated by ANOVA. In addition, we calculated the rho heterogeneity coefficient and the R ratio. Median values for GSDt, GSDw and GSDb were 2.27, 1.92, and 1.28, respectively. Rho values were comprised between 0 and 0.92, with a median of 0.18. The R ratio was comprised between 1 and 1627, with a median of 3 and a 75th percentile of 10. Our results are similar to those published by Kromhout et al. (1993) and show that “monomorphic groups” with an R ratio ≤ 2 represent 42% of the 383 SEGs identified.