Despite being an essential element, at higher concentrations, Cu is highly toxic to plants, microorganisms, and invertebrates. Phytoremediation is a low-cost and effective strategy to clean up contaminated soils. This study was conducted to evaluate the potential of Jatropha curcas; Acacia mangium, Dyera costulata and H. odorata for remediation of soils contaminated with Cu. Seedlings were planted in growth media treated with Cu in amount of 0, 50, 100, 200, 300 and 400 mg kg-1 (Cu0, Cu1, Cu2, Cu3, Cu4 and Cu5) for a period of five months. The results revealed that among the seedlings exposed to Cu5, J. curcas exhibited the highest basal stem diameter (14.81 mm), whereas the maximum height (76.25 cm) and number of leaves (49) were observed in A. mangium and H. odorata, respectively. The total dry biomass (dry biomass of leaves+stems+roots) was significantly decreased (pâ‰¤0.05) with increase in the Cu concentration applied to the growth media. The highest total dry biomass (44.3 g) under Cu5 was achieved by A. mangium. However, total Cu concentration increased significantly (pâ‰¤0.05) with increase in the Cu concentration added to the growth media. J. curcas showed the highest total Cu concentration (665.04 mg kg-1) under Cu5. In order to evaluate the potential of species selected as phytoremediator, three indicators were used namely, biocentration factor (BCF, metal concentration ratio of plant roots to soil), translocation factor (TF, metal concentration ratio of plant shoots to roots) and removal efficiency (RE, total concentrations of metal and dry biomass of plants to total loaded metal in growth media). The BCFs of Cu were >1 within each level of Cu and in control media. Plant species grown in control media showed TFs >1, whereas plant species grown in the media treated with various concentrations of Cu exhibited very small TFs (<1). Among seedlings exposed to Cu5, the highest RE (0.23 %), BCF (1.76) and TF (0.33) were attained by J. curcas. Hence, it may be inferred that J. curcas has a potential to be used in phytoremediation of Cu-contaminated soil.
Keywords: Phytoremediation, Jatropha curcas, Acacia mangium, Dyera costulata, Hopea odorata, Heavy metals, Soil pollution, Removal efficiency