Assessing the potential of Khayasenegalensis in phytoremediation of heavy metals under borehole water and tannery effluent irrigation

Abstract

Khayasenegalensis was planted on soil irrigated with tannery effluent and borehole water for duration of three months. Plant samples were collected after harvest and soil samples were collected before planting and after harvesting. Atomic Absorption Spectroscopy (AAS) was used to determine the concentration of heavy metals in the planting media and plant tissues. The aim was to establish the phytoremediation potential of Khayasenegalensis under these conditions. After harvesting, a noticeable decrease in the concentrations of Cd, Cr, Cu Ni, Pb and Zn in the media was observed from the initial values. The highest levels of Cd (5.53±0.56mg/kg), Cr (13.99±0.82mg/kg), Pb(10.6110.61±0.57mg/kg, Ni (8.33±2.78mg/kg)and Zn(25.72±0.00 mg/kg) accumulation were found in the roots, whereas the highest Cu (7.29±1.80mg/kg) concentrations was observed in the shoot. The roots of Khayasenegalensis were found to be suitable for the phytostabilization heavy metals in both the tannery effluent and borehole water irrigated media. In addition, Cd, Cr, Cu, Ni and Pb mainly accumulated in the Khayasenegalensisroots. The results of translocation factors (TF) and bioconcentration factors (BCF) of Khayasenegalensis for heavy metals revealed that Khayasenegalensis is an excluder plant for Cd, Cr, Pb, Ni and Zn and a potential accumulator plant for Cu serving as an ideal remediation plant for this metal. Furthermore, the increasing heavy metal contents in soil that have been irrigated with tannery effluent resulted in the accumulation of these metals inKhayasenegalensis.