In an opinion article published on August 9, 2023, in the journal Current Opinion in Toxicology, Olwenn V. Martin from the University College London, UK, calls for more research on the synergistic action of chemicals in real-life mixtures before assuming that this interaction is rare.
The context for her statement is the EU’s Chemicals Strategy for Sustainability, which was published in October 2020 (FPF reported). The Strategy acknowledges the risks associated with chemical mixtures and suggests the use of a Mixture Assessment Factor (MAF) for evaluation. Currently, the MAF applied in environmental and health risk assessments, operates under the assumption of additive behavior among chemicals in mixtures. Consequently, it neglects synergistic interactions. This assumption is based on an examination of eight reviews published in the past 30 years, revealing that “synergistic deviations from additivity greater than two-fold were observed in approximately 5% of the examined mixtures.”
Certainly, the additive approach serves as a good approximation (FPF reported). However, Martin asks, “[h]ow frequent is rare?” given the limited amount of representative mixture toxicological studies and their transferability to the real-world scenario. Therefore, she emphasizes performing further research to arrive at a more reliable estimate of how frequent synergism occurs under real-world exposure and to not leave out potential synergism in current debates.
Reference
Martin, O. V. (2023). “Synergistic effects of chemical mixtures: How frequent is rare?” Current Opinion in Toxicology. DOI: 10.1016/j.cotox.2023.100424
