Determination of bio-accumulated Cd, Cr, Cu, Ni and Pb in a wild plant Lantana camara L. Verbenaceae, grown on waste dump site and assessment of its phyto-extraction potential for studied metals

The inputs of chemical fertilizers, street runoffs and regular use of heavy metal contaminated water to irrigate farm crops may result in elevated levels of heavy metals in agri-soil. The food crops growing on such soils may selectively bio-accumulate these metals, which usually depend on the concerned plant’s bio- accumulation potential for concerned metal and characteristics of the soil. This study was aimed to evaluate the bio-accumulation of Cd, Cr, Cu, Ni and Pb in the root, stem and leaves of the wild plant Lantana camara L., Verbenaceae, grown on waste dump site, by analyzing levels of studied metals in soil and plant parts. The bio-concentration factors (BCFs) and translocation factors (TFs) for metals under study were also evaluated, to find out the suitability of Lantana plant for phytoextration of the tested metals. The observed order of metal concentrations in soil samples was Pb (8.91± 0.54) > Cr (6.42 ±0.43) >Cu (1.91± 0.17) > Ni (1.42± 0.13) > Cd (0.86± 0.09, mg/Kg). The observed levels of studied metals in roots, stem and leaves of Lantana were, Pb(8.73±0.32)> Cr (2.96± 0.18)> Cu (2.16±0.15)> Ni (1.38±0.12)>Cd (0.54±0.03mg/kg); Pb(5.18±0.24)>Cr (3.18±0.18)>Cu (2.42±0.17) >Ni (1.49±0.12) >Cd (0.28±0.02, mg/Kg) and Pb (6.07±0.27)> Cr (1.30±0.13) >Cu (0.88±0.07) Ni (0.16±0.02) >Cd (0.10 ±0.01, mg/Kg), respectively. The bio-concentration factors for Lantana from soil to roots (BCFRoot) and from roots to shoots (BCFShoot) for Cd, Cr, Cu, Ni and Pb were 0.63, 0.46, 1.13, 0.97 (~ 1.00) and 0.98 (~ 1.00) and 0.70, 1.51, 1.49, 1.20 and 1.29, respectively. The translocation factors from root to stem (TFStem) and from stem to leaves (TFLeaf) for tested metals in Lantana camara were, 0.52, 1.07, 1.12, 1.08, 0.59 and 0.36, 0.41, 0.36, 0.11, 1.17, respectively. Thus, the recorded BCF values, mostly being >1, makes Lantana suitable for phyto-extraction of tested metals from agri-soil and medium to good translocation factors (TF) suggested the potential of the plant to translocate the tested metals into the stem and leaves.