Assessment of variability in physicochemical water parameters of Lake Nyabihoko, Western Uganda

This study evaluates the spatial and seasonal variations in the physicochemical water quality parameters of Lake Nyabihoko. To assess the physicochemical quality, fifty-four (54) water samples were collected from nine sampling stations during the wet and dry seasons. On-site measurements included water temperature, dissolved oxygen (DO), turbidity, electrical conductivity (EC), and pH. Additionally, parameters such as hardness, alkalinity, chloride, calcium, magnesium, phosphates, and nitrates were determined. Variance analysis revealed that the mean values of all measured parameters did not significantly differ (p > 0.05) among the sampling stations, except for magnesium. The average values of DO, EC, turbidity, TDS, chloride, and phosphates showed significant differences between seasons, while temperature, pH, hardness, alkalinity, calcium, magnesium, and nitrates did not. The lake’s water quality index (WQI) was calculated according to WHO (Guidelines for drinking-water quality: incorporating the first and second addenda, 2022) standards for drinking water, using the mean value for each parameter at each station, month, and season. WQI values ranged from 82.9 to 88.8, with an overall mean of 86.1, placing the water in the “very poor” category according to WQI classification. Seasonal variation was evident, with the WQI higher in the wet season (81.0) than in the dry season (76.8). The study recommends implementing a community catchment management plan and proper monitoring by local authorities to prevent further deterioration of water quality, thereby protecting public health and livelihoods in the vicinity of the lake.