Phytoremediation of Heavy Metals in Spent Engine Oil-polluted Soil by Senna alata L.

摘要

Background and Objective: Indiscriminate disposal of spent engine oil (SEO) pose adverse effects on the ecosystem, due to build-up of heavy metals and hydrocarbons in the environment. Therefore, the objective of this study is to determine the impact of different concentrations of SEO on the uptake and accumulation of heavy metals by Senna alata L. Materials and Methods: Polythene bags (120) filled with 20 kg of soil each were separated into part A and B. Part A contained S. alata seedlings while part B had no plant. To simulate spillage, 0.15, 0.75 and 3.75% v/w concentrations of SEO were used to pollute the soil-bags, 57 days after planting. Control had no pollution. Heavy metal content of the SEO, soil and vegetative parts of S. alata were analyzed 106 days after pollution. Vegetative and reproductive parameters were also determined. Results: Cu, Pb, Zn, Fe and Al were detected in SEO. Concentrations of heavy metals in vegetated soil were significantly (p0.05) less than those in non-vegetated soil. Cu accumulated most in the stem while Zn and Al were highest in the root. Fe and Pb accumulated most in the leaf. Aerial roots were formed and plant height, leaf area, stem circumference and number of pinnules and roots increased after pollution but the number of inflorescence and dry weight of seeds decreased. Conclusion: Hence, S. alata is suitable for phytoremediation and particularly, phytoaccumulation of heavy metals in SEO contaminated soil.