The effects of petroleum exploration and production operations on the heavy metals contents of soil and groundwater in the Niger Delta

Abstract

Soil and water samples obtained from four sampling points; around an oil well head, flare site, waste pit and effluent discharge point in an exploration area in the Niger Delta were analysed for their heavy metals contents. The results showed that the amount of lead present in the soil ranges from 3.40 – 99.40 mg/kg, copper values were in the range of 5.10 – 49.30 mg/kg, Nickel concentration vary from 1.60 – 13.80 mg/kg, values for cadmium, iron, zinc, and chromium were 0.04 – 0.95 mg/kg, 536.00 – 12,872.00 mg/kg, 11.1 – 274.00 mg/kg and 1.30 – 165.00 mg/kg respectively. Apart from zinc and nickel, all other heavy metals were higher than the toxicity limits for heavy metals in natural soil; this implies pollution of the soil by heavy metals. Also the waters were found to be polluted by lead, the pH of the water samples was found to deviate significantly from DPR limits and W.H.O. standard for potable water. This also implies pollution. Remediation measures were suggested so as to render the soil and ground water fit for use. Key words: Soil, water, heavy metals, pollution, exploration area, Niger Delta.