Phytostabilization of As, Sb and Pb by two willow species (S. viminalis and S. purpurea) on former mine technosols

It is becoming increasingly popular to use phytoremediation methods for the reclamation of mine sites containing metal(loid)s. This study aims to assess the phytostabilization ability of two willow species (Salix viminalis and Salix purpurea) on technosols from a former gold mining site presenting polymetallic contamination (As, Sb and Pb). Different reconstituted soils using a mixture of the litter and the technosol collected on this previously mined site and a non-contaminated control garden soil were investigated in a 2 laboratory mesocosm. The physico-chemical soil parameters and the total metal(loid)s content in pore water were determined. After 45 days of growth, roots, leaves and stems from the two willow species were harvested. The biomass, metal(loid) concentrations and the mineral mass were determined for the different plant organs. Both Salix species were able to develop root systems on the different reconstituted soils and a variable aboveground biomass according to the soil composition. As, Sb and Pb accumulated mainly in the Salix rhizosphere. S. purpurea was more efficient in accumulating As in the plant's upper parts than S. viminalis. S. viminalis showed an ability to transfer Pb and Sb to its shoots whereas S. purpurea did not translocate these elements.