Heavy metals uptake of Ricinus communis L. grown in soil irrigated with industrial waste water

Abstract

This study assessed the potential of Ricinus communis for heavy metals uptake in soils irrigated with industrial waste water to reduce their toxicity impact on the environment. Pot experiments consisting 2 kg of top soil irrigated with different proportion of borehole water and industrial waste water (100% borehole water, 75% borehole water+25 % industrial waste water, 50% borehole water + 50% industrial waste water, 25% borehole water+75% industrial waste water and100% industrial waste water were replicated five times in a completely randomized design in this study. Physicochemical properties of the soils, borehole and industrial waste water; before the experiment as well the concentrations in soils and seedlings (roots and shoots) after the experiment were determined using standard instrumentation methods.Growth parameters, bioaccumulation and translocations factors at the end of twelve weeks after transplanting were used to assess the potential of the plants for heavy metal uptake. Significant seedling heights (11.02-18.22cm), leaf area (92.11-137.19 cm2), stem diameter (0.90-2.11mm) and leaf production (12.84-26.10) were observed in Ricinus communis at P≤0.05 The concentrations of heavy metals in the growing media after the experiment were Fe (89.87 - 95.81 mg/kg), Zn (28.98 – 35.69mg/kg), Cu (22.51- 27.99mg/kg), Pb (16.21 – 20.95mg/kg), Co (6.01 – 8.99 mg/kg) and Cr (3.01 – 5.01mg/kg). The trend of Fe>Cu>Zn>Pb>Co> Cr uptake was observed in different parts of the seedlings. Respective bioaccumulation factor values of 0.20-0.88 classified the plants as accumulator while translocation factor values of 1.09 -1.82 for heavy metals, classified Ricinus communis as high efficiency phytoextractor plant. This study has shown the efficacy of Ricinus communis to uptake heavy metals and transfers it into its tissue parts.