Vetiver grass: An environment clean-up tool for heavy metal contaminated iron ore mine-soil

• Vetiver grass can grow on iron mine spoil-dump with the development of dense mesh like root system.
• The roots accumulate higher concentrations of heavy metals than the shoots.
• Vetiver can withstand the adverse effects of mine-soil by enhancing the activities of major antioxidant enzymes.
• Absence of damage in nuclear DNA makes it a suitable candidate for reclamation of iron mine spoil-dump sites.

AimsVetiver grass – Chyrsopogon zizanioides (L.) Roberty is a known plant tolerant to heavy metals and its use as an alternative method for rehabilitation of iron ore mine-soil has been investigated.MethodsA pot experiment was performed over a period of three months and the performance of vetiver grass on heavy metal-rich soil from iron ore mine was assessed. The presence of the following heavy metals – Fe, Mn, Zn, Cu, Pb, Ni, Cr and Al were assessed in mine-soil and their uptake by vetiver grass system was evaluated. In addition, oxidative and genotoxic stress were used to monitor the changes over the period.ResultsPhysico-chemical characterization and metal analysis revealed that vetiver plant is a good phytostabilizer. The plant is a potential accumulator of heavy metals and the root parts of the plant accumulated higher metal concentrations than the shoot. The high proportions of metals inhibited the chlorophyll content of leaves, but stimulated the accumulation of proline and lipid peroxidation. Enhanced activities of catalase (CAT), guaiacol peroxidase (GPOD) and glutathione (GSH) implied that different mechanisms existed to detoxify reactive oxygen species (ROS) in the shoot of the plants. Genotoxicity assays demonstrated the absence of genetic instability or DNA damage in the plants.ConclusionVetiver can be used as an excellent candidate for remediation and restoration of iron-ore mine spoil-dumps.

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