The underestimated and important role of thiol moieties in predicting the fate of toxic metals in the environment

Studying the interactions between metals and thiol moieties in natural systems is challenging, although they are of major importance for some (ultra)trace elements (e.g., Hg, Cu, Pt). A major current bottleneck is the development of accurate preservation and detection methods. Based on our current knowledge, thiol moieties are abundant in reduced organic waters, where thiolation of natural organic matter (NOM) occurs, as well as in metal-enriched environments, where organisms secrete thiol moieties. Depending on their affinity and their redox potential, metals complexed to thiolated NOM, can be reduced, and even transformed into sulphur nanoparticles over time. Such mechanisms are not properly considered in currently used biogeochemical models, explaining why the fate of metals in the environment is not well predicted.