Assessment of Some Heavy Metals in Groundwater in the Vicinity of an Oil Depot in Nigeria

Abstract

Assessment of heavy metals in groundwater located around refined petroleum products depot in Ibadan, Nigeria were carried out using Atomic Absorption Spectrophotometry (AAS) technique. Water samples were collected and analyzed for copper (Cu), cadmium (Cd), chromium (Cr), lead (Pb) and zinc (Zn). The mean concentrations (range) of 0.0064±0.005 mg/l (ND – 0.019 mg/l), 0.0014±0.002 mg/l (ND – 0.005 mg/l), 0.45±0.3 mg/l (0.06 – 0.96 mg/l) and 0.042±0.08 mg/l (0.018 – 0.389 mg/l) were obtained for Cu, Cr, Pb and Zn, respectively. Cd was not detected in all the water samples analyzed. All the heavy metals investigated in the water samples except Pb were generally below the recommended limits set by regulatory bodies such as World Health Organization (WHO) and Nigerian Industrial Standards/Standard Organization of Nigeria (NIS/SON) for drinking or potable water. There was elevation of Pb concentrations in all the water samples in the area which were significantly above the recommended limit. This suggests that source of Pb contamination could be from anthropogenic activities such as loading and offloading of petroleum products. This pollution of groundwater in the vicinity of the oil depot caused by Pb contamination is a potential threat to the people living in the area as groundwater is their major source of potable water. Therefore, government should provide good drinking water for people located in the area while remediation process of the heavy metal should be carried out on the site.