Phytoremediation Enhancement of Kenaf Plant (Hibiscus cannabinus L.) Grown on Spent Oil Polluted Soil

Abstract

Oil pollution especially Spent Lubricating Oil is a wide environmental problem in Nigeria. It constitutes potential toxic effects on soil, flora, fauna and humans and also making the environment unsightly. This study assessed the potential of kenaf plant as a phytoremediator grown in spent oil polluted soil for a period of 84 days (12 weeks). Pot experiment was conducted in the Nursery site of the Moist Forest Research Station, Forestry Research Institute of Nigeria (FRIN), Ibadan, Oyo State, Nigeria. The treatments: amended (with organic manure) and unamended (without organic manure) soils and three pollution levels (0, 3 and 6%) of spent engine oil, each filled in eight-liter plastic pots with 6 kg soil. Growth parameters: plant height, stem diameter and number of leaves were collected and Total Petroleum Hydrocarbon (TPH) in soil was determined. Data were analyzed using descriptive statistics and ANOVA. Results at 12 weeks (84 days) showed amended (control 0%) treatment having highest plant height (112.17 cm), stem diameter (8.92 cm) and number of leaves (178.43), while 6% unamended level of pollution had the lowest plant height (26.78 cm), stem height (1.62 cm) and number of leaves (8.06). Amended soil had the highest total percentage reduction of TPH (75.90, 90.05 and 90.30%), when compared with unamended soil with lowest values (76.88, 85.18 and 82.36%) at 0, 3 and 6 pollution levels, respectively. Reduction of TPH in the phytoremediation process was in this order of pollution levels 6%> 3%> 0%. This study revealed effectiveness of kenaf with organic amendment in remediating Total Petroleum Hydrocarbon in oil polluted soil, hence a good potential phytoremediator.