Abstract

The study was aimed at evaluating ecotoxicity of remediated crude oil contaminated soil in Rivers State using maize (Zea mays) and okra (Abelmoshus esculentus) plants in order to ascertain the bioremediation approaches adopted. Research was designed to evaluate the bioaugumentation efficiency of hydrocarbon degrading bacteria and the biostimulation efficiency of organic nutrients in bioremediation, thereafter, the strength of the remediated soil was evaluated using okra and maize plants in the Rivers State University agricultural farm, Port Harcourt, Nigeria. The experiment was conducted for a period of 98 days, from May to August 2022. Analyses were carried out after 2 weeks of planting and afterwards, at weekly intervals. Thirty-six (36) experimental pots were employed, each having about 1000g of farm soil which was prepared according to six different percentages of the remediated soil in triplicates each, for okra and maize plants. These experimental setups were left for acclimatization before planting viable okra and maize seeds. The grown plants were analyzed for their physical growth parameters and statistically compared using statistical package for service solutions (SPSS). Ecotoxicity assessment of the remediated soil revealed that the bioremediated soils supported plant growth as there were no significant differences (P>0.05) observed between the plants grown on the control soil, on the different percentages of remediated soil and on the remediated soil. Results showed that the bioremediation protocols employed in this study could restore the initial status of the soil for agricultural sustainability purposes, thereby, boosting the economy and local content of the States affected by oil spills. It is therefore, recommended that, soils and environments contaminated with crude oil hydrocarbons in the Niger Delta can be bioremediated and the soil quality restored for agricultural  purposes to improve agricultural sustainability.