An incubation greenhouse study was conducted to determine the efficiency of vetiver grass in lead phytoremediation. The objectives of this phase I study is to determine:
1. Examine the relationship between geochemical and phytoavailable lead as a function of soil properties.
2. To evaluate EDDS as a potential environmentally friendly chelating agent.
3. Identify the biochemical mechanisms behind vetiver’s tolerance to lead contamination.
4.Evaluate the use of vetiver grass to reduce human bioavailable lead.
This study demonstrated the efficiency of EDDS as an environmentally safe chelating agent. EDDS at 15 mmol kg-1 soil increased lead concentrations in the roots and increased translocation. Vetiver showed a tolerance to lead by forming phytochelatins, which bound lead. Lead was shown to increase stress enzymes in the vetiver plant. Plants with the chelating agent were shown to mask the lead stress and decrease stress enzyme activities (Datta, Sarkar, and Andra).
This study also demonstrates the impact soil properties have on phytoavailability. The majority of lead was bound to Fe-Mn oxides and carbonates. At the end of the study, the addition of chelating agents increased the phytoavailable lead. Vetiver, in one cycle, was able to accumulate 14.0% and 24.0% of lead from San Antonio and Baltimore soil. According to calculations, 4-6 cycles of vetiver would be needed to reduce lead concentrations to EPA permissible levels (Datta, Sarkar, and Andra).