Concentrations of some heavy metals in underground water samples from a Nigerian crude oil producing community.

Pollution due to oil exploration activities in the Niger Delta region of Nigeria and government under-investments in potable water infrastructure has led to the dependence of the population on personal boreholes. Yet, there are little quality or surveillance reports on such waters. The concentrations of heavy metals in underground water samples from an oil producing area, Umuebulu, in the Niger Delta were therefore investigated. Water samples were collected from three test points, each approximately 300 m from (1) wellhead area (WHA), (2) flare area (FA) and (3) effluent discharge area (EDA), and one control point located 10 km away from any oil-related activity. The concentrations of lead, arsenic and cadmium were determined in the samples using atomic absorption spectrophotometry. All three heavy metals were present in the test, and control water samples at concentrations significantly (P < 0.05) exceeding the maximum contaminant levels recommended by the World Health Organization. The total hazard index of the water samples showed that their consumption constituted significant health risks in the order EDA > FA > WHA > Control. Appropriate water treatment and surveillance is warranted and therefore recommended for underground water resources of the studied community.