Lead phytoremediation capacity of Puccinellia distans (Jacq.) Parl. using EDTA and DTPA and associated potential leaching risk

This study was conducted to determine phytoextraction efficiency of Puccinellia distans (Jacq.) Parl. for Pb (450 mg kg-1 Pb(NO3)2) and the application of EDTA and DTPA (2.5DTPA, 5DTPA, 2.5EDTA, 5EDTA, 2.5EDTA+2.5DTPA, 2.5EDTA+5DTPA, 5EDTA+2.5DTPA, 5EDTA+5DTPA) on the Pb uptake and the potential for leaching of Pb during the phytoextraction process. Bioconcentration factor (BCF), translocation factor (TF) and tolerance index (TI) were calculated to determine Pb phytoextraction efficiency. Results showed that DTPA appeared to be more toxic to the plant than EDTA. Plants with combined treatments of EDTA and DTPA exhibited higher decrease in biomass compared to those that had received a treatment of EDTA and DTPA alone. 5DTPA and 5EDTA were the most efficient ratio for increasing concentrations of Pb in the shoots. DTPA showed much higher efficiency than EDTA. BCF of the shoot was relatively higher than the BCF of root. Thus, the plant would be applicable for Pb phytoextraction. Addition of chelates had virtually significant effect on Pb uptake by the plant and elevated Pb concentration in the soil and plant parts. Optimum phytoextraction was observed when 5mg kg−1 EDTA and DTPA was added alone in single dosage to reduce the Pb–chelates leaching risk.