Soil quality assessment 33 months after crude oil spillage and clean-up

Abstract

A post-impact assessment, 33 months after oil spillage and initial clean-up, was conducted on selected soil quality indices. The ultimate aim of the study was to ascertain whether there was any need for further clean-up or remediation options. The results obtained showed that the mean soil pH in the oil contaminated area was 5.93±0.18, (electrical conductivity 123.15± 1.60μScm−1) total petroleum hydrocarbons (TPH, 581.02 mg kg−1) oil and grease (492.55 mg kg−1), polynuclear aromatic hydrocarbons (PAH, 20.41 mg kg−1). Pb (2.34 mg kg−1), Cd (1.93 mg kg−1) significant correlation exists between TPH, and oil and grease (0.97), TPH and PAH (0.64), TPH and hydrocarbon degrading bacteria (0.72). All these values were significantly higher than the uncontaminated (control) soils. The investigation revealed that there were significantly high levels of diffuse petroleum hydrocarbons in the contaminated area. Further monitoring and characteristics of the hydrocarbon levels is recommended while a synergistic bioremedia-tion approach should be the first step in the reclamation process.