Impact assessment of petroleum depot wastewater on agricultural soil: a case study of Suleja, Niger state

Abstract

Though petroleum is a vital resource of great economic importance, it is also among the leading pollutants of soil, freshwater and ecosystems. This study aims at assessing the impact of petroleum depot wastewater on agricultural soil in Suleja, Niger state. Soil and water samples around the petroleum depot were collected and analysed for selected heavy metals (Mn, Cr, Cu, Zn and Pb) and the results were compared with World Health Organization (WHO) and Federal Environmental Protection Agency (FEPA) standards. The result of the soil analysis indicates that the control soil sample contained 0.06±0.002 mg/kg of Mn, 0.10±0.001 mg/kg of Cu, 0.04±0.001 mg/kg of Cr, 0.13±0.002 mg/kg of Zn and Pb was not detected. The mean concentration of Mn, Cu, Cr, Zn and Pb from the soil samples taken from polluted sites were 0.23±0.05 mg/kg, 0.22±0.004 mg/kg, 0.16±0.03 mg/kg and 0.33±0.04 mg/kg and 0.004±0.03 mg/kg respectively. Also, the metals were detected in the surface water. The relatively high values of some of the metals in soil and surface water when compared to the control and the established standards imply the probable influence of the depot activities on the resources and a threat to agricultural activities and man. Hence, to ensure food security and safety there is a need for remediation.