Quality Assessment of Groundwater in Mowe, Ogun State, Nigeria

Abstract

Drinking water contamination by heavy metals and microbes is increasingly implicated in a variety of diseases around the world, prompting quality assessment of all drinking water sources. This study evaluated the safety of borehole and well water in Mowe metropolis, Ogun State, Nigeria. The levels of heavy metals, namely copper (Cu), nickel (Ni), lead (Pb), cadmium (Cd), iron (Fe), and chromium (Cr), as well as microorganisms were determined in the samples of the water using conventional procedures. The mean of the values obtained for each parameter was then compared with the World Health Organization (WHO) permissible limits. In addition, the average daily ingestion (ADI) and hazard quotients (HQ) of the heavy metals were estimated. The heavy metal analysis revealed that both the borehole and well water samples had non-tolerable concentrations of Pb and Fe, while Ni, Cd, Cr, and Cu were within the tolerable limits. The ADI and HQ of the heavy metals were within the recommended limits. However, the cumulative HQ (health risk index) of the heavy metals in the well water was higher than the threshold of 1. The microbiological examinations indicated that the borehole and well water samples contained non-permissible levels of bacterial and yeast colonies, while only the well water had non-permissible concentrations of coliforms. Heavy metals and microbiological contaminants in well water samples were higher in comparison. These findings indicate that the water may pose some health hazards if consumed in its current form. As such, consumers are advised to treat groundwater before consuming it.