The role of thiols on trace metals phytoavailability in agricultural soils

Zinc (Zn) is essential for all biota, while cadmium (Cd) is non-essential for most biota and poses a health risk at relatively low concentrations for humans. While reduced sulfur groups (R-SH, thiols) can separate chemically these trace metals in plants, the role of thiols in agricultural soils on the phytoavailability of these metals is largely unexplored. We expect that soil thiols can selectively reduce the transfer of Cd from soils to crops. To this end, we will determine S speciation in a large variety of agricultural soils using XANES. The XANES data will be combined with phytoavailability data of Zn and Cd (i.e. soil extracts) and soil properties that are known to control the phytoavailability of these trace metals (e.g., soil pH). Finally, multivariate statistics will be applied to determine the importance of thiols on the phytoavailability of Zn and Cd. With this unprecedented dataset we seek to provide novel knowledge that will help to improve the quality of staple crops.