Phytoextraction of Zinc, Cadmium and Lead from Contaminated Soil by Vetiver Grass

Abstract

Phytoextraction of heavy metals is an environmental remediation method that uses plants to transport and accumulate the metals into harvestable growth. The ability of two vetiver ecotypes for phytoextraction of heavy metals (Zn, Cd and Pb) was studied using a 2 × 4 factorial pot experiment in a completely randomized design with three replications. The two factors were the vetiver ecotype and heavy metal concentration level in the soil. The Ratchaburi vetiver ecotype (Chrysopogon nemoralis) and the Surat Thani vetiver ecotype (Chrysopogon zizanioides) were grown in contaminated soils with four levels of Zn, Cd and Pb. The results indicated that vetiver could grow well in the contaminated soil without any heavy metal toxicity symptoms. The Ratchaburi ecotype had a significantly better plant height and shoot dry weight than the Surat Thani ecotype. Vetiver plants grown in soil highly contaminated with heavy metals decreased in growth and accumulated more heavy metals. Two vetiver ecotypes gave
different translocation factors of heavy metals. In general, vetiver accumulated more heavy metals in the roots than in the shoots. However, the Ratchaburi ecotype accumulated significantly more Zn in its shoots than roots, indicating its potential for use in the phytoextraction of Zn from contaminated soil.