The Quality of Groundwater in Benin City: A baseline study on inorganic chemicals and microbial contaminants of health importance in boreholes and open wells.

Purpose: Inorganic chemicals and microorganisms are common in human environments and at high levels poisoning from the chronic effects have occasionally occurred. The purpose of this study was therefore to investigate whether the levels of inorganic chemicals and microbial contaminants in boreholes and open wells in selected Districts in Benin City are sufficient to affect the health of the inhabitants of the areas under investigation. Method: Six (6) boreholes and three (3) open wells were randomly selected from two Districts (Okhoro and Teboga) in Benin City. Water samples were collected from the boreholes and open wells using standard techniques. Lead (Pb), chromium (Cr), zinc (Zn), and cadmium (Cd) concentrations as well as aerobic bacteria, presumptive faecal coliform, E. coli, faecal Streptococci and fungi in the water samples were determined using standard procedures. World Health Organisation acceptable limits for drinking water were used in the evaluation. Result: All the boreholes and open wells were contaminated with abnormal levels of Pb. High levels of Cr and Cd were found in the borehole and open wells at Okhoro. Abnormal levels of Zn concentrations were detected in almost all the boreholes and open wells. All the boreholes at Teboga were contaminated with unacceptable levels of aerobic bacteria and fungi. Presumptive faecal colifom, E.coli and faecal Streptococci were seen in all the boreholes. Conclusion: Some boreholes and open wells in Okhoro and Teboga Districts in Benin City are contaminated with abnormal levels of metals and microorganisms capable of causing health hazards to the consumers of boreholes and open wells. Keywords: Benin City, boreholes, inorganic chemicals, microorganisms, open wells. Tropical Journal of Pharmaceutical Research 2002; 1(2):75-8