Phytoremediation efficacy of Nerium oleander L. for removal of Cd, Ni, and Pb- contaminated soil

Abstract

A pot experiment was conducted to assess the effectiveness of Nerium oleander L. in phytoremediation of cadmium (Cd), nickel (Ni), and lead (Pb)- contaminated soil. This evaluation included the application of ethylene diamine tetra-acetic acid (EDTA) and a nutrient solution containing NPK. The results revealed that the inclusion of EDTA and NPK, in combination with varying metal concentrations, significantly increased the dry weight of the plants. The results demonstrated that oleander, when aided by EDTA and NPK, exhibited a high capacity to efficiently absorb and accumulate Pb without any amendments. The addition of EDTA increased Pb concentrations in both aerial parts and roots (84.9 mg kg-1 and 80.2 mg kg-1, respectively). For Nickel, in the presence of NPK, the concentration in roots was 80,2 mg kg-1. Cd accumulation was highest in the treatment with 100 mg kg-1 EDTA, reaching 72.9 mg kg-1 in the aerial parts. Particularly, NPK reduced Ni levels in aerial parts, while EDTA enhanced root metal uptake. The Translocation Factor (TF) was greater than 1 for Cd and Ni treatments, indicating oleander's remarkable ability to absorb and accumulate these heavy elements. The treatment involving Pb50+EDTA displayed the highest Bioaccumulation Factor (BAF) value at 1.7. Furthermore, for Pb50, Ni50 and Cd50, the NPK treatment exhibited the highest Bioconcentration Factor (BCF) values, ranging from 0.3 to 1.69. Nerium oleander L. exhibits promise for both Ni phytoextraction and Cd and Pb phytostabilization, suggesting its potential as an effective phytoremediation agent. Future research should focus on optimizing metal uptake conditions and investigating long-term plant health and soil impacts to refine sustainable strategies for mitigating metal pollution in contaminated environments.