Affiliations: Department of Chemistry and Biochemistry, University
of Uyo, Nigeria | Department of Botany and Microbiology, University of
Uyo, Nigeria
Abstract: The effect of organic amendments on the oil content,heavy metals
concentration and pH of petroleum contaminated sandy loam ultisol obtained from
Rumuekpe oil field in Emohua Local Government Area of Rivers State, Nigeria was
determined. Petroleum contaminated soils were treated with wood ash, compost
and sawdust. The addition of organic amendments resulted in a significant(at
95% probability level) decrease in oil content by 92% for composting,81% for
soil treated with sawdust and 58% for soil with ash supplementation, over 6
months. The effect of treatments on the iron(Fe), copper(Cu) and lead(Pb)
concentration was significant at P<0.001. The remediation also affected the
pH of soil. This initial pH of 5.6 was depressed by the application of compost
and sawdust supplements respectively to a final pH of 5.2 and 5.3. On the other
hand, amending the soil with wood ash raised the pH from 5.6 to 6.2. Increased
acidity caused a decrease in the heavy metals concentration in the contaminated
soil. Soil treatment with compost generally gave the best remediation results,
followed by sawdust and then ash. Adjusting the pH of oil contaminated soil to
high acidic levels may promote the availability and migration of heavy metals
in remediated soils and not necessarily the rate of oil mineralization.