Bioremediation of a crude-oil polluted agricultural-soil at Port Harcourt, Nigeria.

A combination of treatments, consisting of the application of fertilizers and oxygen exposure, was evaluated in situ during a period of six weeks. Conditions of a major spill were simulated by sprinkling crude-oil on experimental cells containing agricultural soil. The remedial treatments were then applied and the soil characteristics analyzed after set periods. Soil physicochemical parameters, such as moisture content, pH value, electrical conductivity as well as organic-carbon and total-nitrogen contents, showed distinct variations with time. The total heterotrophic-bacteria (THB) count in all the treatment cells increased with time. The control cell, O (which was not treated) indicated no signs of remediation within the study period. The hydrocarbon losses (50–95%) experienced in the five other treatment-cells revealed the effectiveness in degrading the hydrocarbon contaminant. The results of this study indicate that the application of increased concentrations of nutrients (by the application of fertilizers) lead to greater rates of biodegradation of petroleum-polluted agricultural soils.