ORHIONMWON LOCAL GOVERNMENT AREA

In Orhionmwon Local Government Area, many residents depend on untreated surface and groundwater sources such as wells, boreholes, and rivers for drinking and domestic use. The quality of these sources had not been scientifically assessed, raising concerns about their suitability for human consumption. The area faces growing contamination from agricultural runoff, poor waste disposal. These factors can introduce harmful substances like nitrates, phosphates, and heavy metals into drinking water sources. Consuming contaminated drinking water can cause diseases such as cholera, typhoid, and diarrhea, and long-term exposure to toxic metals like lead orchromium can result in neurological and kidney damage. Hence, there was a need to determine if water from these sources posed such health risks. This study assessed the physicochemical quality of drinking water from selected sources in Orhionmwon Local Government Area, Edo State, Nigeria. Water samples were collected from five sites comprising two boreholes, two hand-dug wells, and one river. A total of twenty-three physicochemical parameters were analysed, including pH, turbidity, electrical conductivity, total dissolved solids (TDS), total suspended solids (TSS), nitrate, sulphate, phosphate, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total hardness, alkalinity, and several heavy metals (Fe, Cu, Zn, Ni, Pb, Mn, Cr, etc.). Analytical methods were based on APHA standard procedures and results were compared with Nigerian Industrial Standard (NIS 977:2017) and WHO permissible limits. The findings revealed that pH values across all water sources were below the acceptable range (6.5–8.5), indicating acidic water with potential for corrosiveness and metal leaching. River water showed elevated turbidity, BOD (3.8 mg/L), and COD (38.0 mg/L), suggesting organic pollution. Lead and chromium levels in the river exceeded regulatory limits, posing potential health risks. Borehole water generally exhibited the best quality, while the river was the most contaminated source. Most other parameters, including nitrate, sulphate, chloride, and iron, were within permissible limits.These results
indicate that while some water sources are suitable for consumption, others, particularly the river, require urgent intervention and treatment. The study recommends regular monitoring, pH correction, community sensitization, and infrastructure improvement to ensure the provision of safe drinking water in Orhionmwon.