Lead Uptake and Translocation by Willows in Pot and Field Experiments

Plant growth and lead (Pb) uptake by seven willow varieties were investigated in pot and field experiments to assess the suitability of willows for phytoremediation of Pb at heavily contaminated sites such as skeet ranges. Differences in uptake and translocation of Pb in Salix were observed between pot and field experiments. In the pot experiment, willows grown in Pb-contaminated field soil for 6 months showed tolerance to very high soil Pb concentration (21360 mg kg-1), and with the addition of EDTA were able to take up and translocate more than 1000 mg kg-1 Pb into above-ground tissues. In the field experiment, all willow varieties showed tolerance to heterogeneously high soil Pb concentrations. Plants were also able to take up and translocate Pb into above-ground tissues. However, after 4.5 months, the lead concentration in the above-ground tissues of willows grown in soil amended with EDTA was less than 200 mg kg-1. The results from the pot experiment suggest that Salix varieties have the potential to take up and translocate significant amounts of Pb into above-ground tissues using EDTA. However, to verify the phytoextraction abilities of Salix in the field, additional research is needed.