Biomass Growth and Remediation Efficiency of Chrysopogon zizanioides (L.) Nash for artificially contaminated Alluvial soil

Though Chrysopogon zizanioides (vetiver grass) has potential characteristics for remediation of contaminated soils, sediments, and water, but it has very limited application for the remediation of contaminated alluvial soil. The vetiver was planted to evaluate its biomass growth in artificially contaminated alluvial soil in Prayagraj, India for the purpose of its remediation. The vetiver was planted on alluvial soil mass artificially contaminated by two heavy metal salts, lead nitrate (Pb(II)) and potassium dichromate (Cr(VI)), for a period of 150 days. The vetiver grass, having 10cm root and 20cm shoot length, was planted in total 30 treatment boxes of dimensions 45cm x 45cm x 90cm, made of GI sheets. Four replicates (100, 300, 500, and 700mg/kg) of lead (Pb(NO3)2), four replicates (50, 100, 200, and 400mg/kg) of chromium (K2Cr2O7), one mixed replicate (Cr100+Pb-300), and one control have been selected. With increasing Cr-concentration in soil, vetiver shows a higher toxic effect, resulting in reduced biomass production with increased Cr-accumulation in roots. Whereas increasing Pb-concentration in soil, biomass production increases with minimum toxic effects. 65-75% of Cr and Pb were found to accumulate in root tissues and only 10-15% were translocated to aerial parts from roots tissues. The findings reveal that vetiver has good potential for rhizostabilization of Pb and Cr from polluted soils, minimizing the risk to contaminate groundwater and entering into the food chain as well as enhanced biomass of vetiver would be utilized for slope stabilization of embankments constructed on erodible soils and as a potential renewable energy source.