Evaluation of Phytoremediation Potential of Vetiver Grass (Chrysopogon Zizanioides L.) Grown on Contaminated Soils in Bulgaria

Abstract

This research investigated the potential for using vetiver grass (Chrysopogon zizanioides L.) to remediate metal-polluted sites in Bulgaria. In the second year of the experiment, the vetiver grass was gathered. The heavy metal (Pb, Cd, Hg), micro (Fe, Cu, Zn, Mn), and macro (P, K, Ca, Mg) element contents in vetiver roots and shoots were determined by ICP after microwave miner-alisation. The essential oil of the ground vetiver roots was obtained by steam distillation in laboratory conditions. Gas chromatography-mass spectrometry identified fifteen compounds in the oil, mainly sesquiterpenes. The vetiver grass is tolerant to heavy metals with no signs of toxicity (chlorosis and necrosis) and can be grown on heavy metal polluted soils (37.7 mg/kg Cd, 1238.7 mg/kg Pb and 1676.4 mg/kg Zn). Bioaccumulation factor and translocation factor values (BAF and TF < 1) were less than one suggesting low accumulation in the shoot. This crop can be referred to as a non-accumulating plant for Pb, Cd and Zn and can be used for the phytostabilisation of contaminated soils in situ. Cultivating vetiver on soils contaminated with heavy metals has a beneficial effect on the yield and production of oil of high commercial value (high in khusimol).