Crude oil remediation potentials of Pennisetum purpureum in oil producing communities of Akwa Ibom State, Nigeria

Abstract

The phytoremediation of hydrocarbon impacted soil using selected plant species (Pennisetum purpureum) in oil producing communities of Akwa Ibom State, Nigeria was investigated using standard techniques. The selected plant species were cultivated on soils from Mbo, Ikot Abasi and Esit Eket contaminated with graded concentration (5, 10, 15 and 20%) of crude oil. Analyses of the crude oil remediating potential of the test plants revealed that at 5% contamination, the concentration of residual hydrocarbon in the rhizosphere soil of P. purpureum reduced from between 1928 – 1934 mg/kg to between 114.60 – 114.63 mg/kgafter 90 days. At 10% contamination, the concentration reduced from between 3124 – 3127 mg/kg and between 482.49 – 482.51 mg/kgafter 90 days. At 15% contamination, the concentration of the residual hydrocarbon, in the Control as well P. purpureum rhizosphere reduced from between 5146 – 5151 mg/kg to between 511.60 – 511.59 mg/kgafter 90 days. Similarly, at 20% contamination, the concentration of the residual hydrocarbon, in the Control as well as P. purpureum rhizosphere soil reduced from between 6021 – 6025 mg/kg to between 1131.21 – 1133.2 mg/kgafter 90 days. P. purpureum exhibited high hydrocarbon remediating potentials. Contamination of the soil samples with crude oil increased the organic matter and hydrocarbon content in the soil while decreasing the soil total nitrogen and phosphorous contents. The pH of the soil samples tended towards acidity as the concentration of the crude oil increased. The potentials of P. purpureumto phytoremediate hydrocarbon contaminated soil as reported in this study can be explored for broader use in remediating crude oil polluted environment.