The phytoremediation of heavy metals (cadmium, chromium, copper and lead) by Phaseolus vulgaris and Arachis hypogaea were investigated using standard techniques. The heavy metal polluted soil samples were collected from Crush Rock Industries Ishiagu, Ebonyi State, Nigeria, while heavy metal free control soil samples were obtained from Ebonyi State Ministry of Agriculture, Ishiagu Station. The seeds of the two plants were collected from the Enugu State Ministry of Agriculture. The experimental setup consists of 4 contaminated potted soils each of Z. mays and S. bicolor. Another 4 potted soils not contaminated with heavy metals served as control. Soil sample analysis was carried out prior to planting (of which the polluted soil sample had slightly acidic pH (pH was 6.34Â±0.29), higher Cation Exchange Capacity (21.80Â±0.33), higher Cd (25.18Â±0.34), Cr (10.20Â±0.21), Cu (28.54Â±0.49), and Pb (9.92Â±0.36), levels but lesser soil organic carbon (0.87Â±0.10). After the duration of 62 days, the plants were harvested and their leaves and roots were digested and subjected to experimental tests (Metal determination, transfer factor and bioaccumulation factor (BAF)). A. hypogaea showed highest Cd translocation factor 1.63Â±0.08, TF<1 was observed in all the plants examined for Cr. A. hypogaea showed the highest BAF for Cd, (1.16Â±0.08). BAF<1 was observed for Cr and Cu in the two plants examined while A. hypogaea showed the highest BAF (1.05Â±0.10). The BAF of A. hypogaea was higher than that of P. vulgaris. Plants from the control showed zero to very minute concentration of heavy metals in their tissues. Although, consumption of these plants may likely result to metal toxicity in man, these plants can be useful in cleaning up contaminated soil.
Keywords: Contamination, Phaseolus vulgaris, Arachis hypogaea, Nigeria