PHYTOREMEDIATION POTENTIAL OF Jatropha curcas and Cassia occidentalis ON SELECTED HEAVY METALS IN THE SOIL

Abstract

The potential of Cassia occidentalis and Jatropha curcas to remediate the heavy metals: Pb, Mn, Zn, Cr and Cu in polluted soil was studied. The seedlings of the plants, Cassia occidentalis and Jatropha curcas were obtained and planted in six pots which were spiked with aqueous solution of each metal. The matured plants were harvested and separated into roots, stem and leaves. Standard operating procedures was used to extract the metals from the plant parts. Results revealed uptake of the metals through the roots, stem and leaves of the plants. Cassia occidentalis and Jatropha curcas grown in the spiked soil showed relatively higher values for the uptake of the analysed metals as compared to those grown on the control soil. The order of metal accumulation in the parts of the plant are: Pb, leaves > root > stem; Mn, roots > leaves > stem; Zn, roots > leaves > stem; Cr, roots > leaves > stem and Cu, leaves > roots > stem, for C. occidentalis, while for J. cucas metals accumulation was found to be in the order: Pb, stem > roots > leaves; Mn, stem > roots > leaves; Zn, roots > stem > leaves; Cr, stem > roots > leaves and Cu, stem > roots > leaves. The Translocation Factor (TF) revealed that Pb (1.52) and Cu (1.41) are highly accumulated in the leaves of C. occidentalis plant, while a TF of Pb (1.53), Mn (1.31), Cr (1.27) and Cu (1.19) was observed in the stem of J. curcas. The high remediation potential observed in this study as occasioned by the Bioconcentration Factor (BCF) value recorded indicates that C. occidentalis and J. curcas have vital characteristics that can be used for phytoextaction of the analysed metals.