Impact of multiple exposures on chemical risk assessment

In occupational area, the workers can be exposed to several chemical substances simultaneously. Most exposure assessment procedures are limited to deciding if the levels are acceptable with regards to the occupational exposure limit. However, the adverse effects on the health of the operators potentially are additive, because of the so called cocktail effect. This study proposes innovative prevention solutions to better take into account the multi-exposures assessment.
Nearly 30,000 work situations, identified in two French exposure databases COLCHIC and SCOLA between 2005 and 2014, were subjected to analysis using the algorithms of Mixie software. Mixie can identify classes of toxicological effects shared by one or several substances present in the mixture, and Mixie also quantifies the exposure ratio of the mixture. The results of this retrospective analysis show that almost 20% additional risk situations were identified by comparison to a classical single-substance approach. These work situations cannot be identified without taking into account the potential additive effect of the substances.
Thus, it shows that considering the multi-exposures is an important issue for occupational health. For industrial hygienists, the best manner to introduce this is to improve the early stages of chemical risk assessment. All substances present in products need to be carefully identified and the sampling strategy should be designed to take into account the potential additive effects of these substances.