Heavy metal analysis of groundwater from Warri, Nigeria.

The levels of some ions of heavy metals known to be associated with petroleum industry operations, including Pb, Ni, V, Cr, Cd, Zn and Fe, were studied in untreated groundwater from Warri area, Nigeria by atomic absorption spectroscopy. Warri area is characterized by petroleum industry activities including a Refinery. With this in mind, the residential area was divided into Effurun junction, Waterside Ekpan village and the Refinery's vicinity. The concentrations of Pb, Ni and Fe measured (in mg x l(-1)) in the groundwater samples of all areas studied ranged from 0.06 to 0.44, 0.008 to 0.19 and 0.315 to 2.753 respectively, while V, Cr, Zn and Cd were present in very low concentrations, 0-0.85 x 10 (-3). The levels of Pb, Ni and Fe exceeded the threshold limits (0.01, 0.02 and 0.3 mg x l(-1), respectively) set by the WHO health-based guideline for drinking water and this could portend environmental hazards.