Eco-toxicity assessment of fossil fuel tainted soil before phytoremediation trial

The research objective was to assess the extent of fossil fuel toxicity in the contaminated soil for an improved appraisal before phytoremediation trial and eco-safety of the soil. We used Bonny light fossil fuel to contaminate soil at different percentage levels of concentrations (5%, 3%, 1% and 0%). We assessed earthworm weight change and survival rate and plant response of Zea mays to the various treatments. Our results show that soil treated at concentration level of 5% had the highest earthworm mortality rate while the control soils had the highest earthworm survival rate. In addition, there was a noticeable change in the body weight of surviving earthworms in the 5% and 3% treated soil. Germination, shoot length and root length of the experimental plant was not totally inhibited in all the different concentrations. There was greater germination percentage obtained in 3%, 1% and 0% fossil fuel concentrations. The study verifies that high fossil fuel contamination percentage affects the biota of the soil by inhibiting plant germination and growth as well as reducing the survival and body mass of earthworms in the soil. The petroleum oil percentages utilized in this investigation can support phytoremediation trial and proposes that petroleum oil soil contamination ≤ 3% is ecologically safe for plants and animals’ survival as well as development.