Anthropogenic and Domestic Waste Impacts on Surface Water Quality of Asa River, Ilorin, Nigeria

Asa River, a vital freshwater source for Ilorin, faces increasing pressure from anthropogenic activities such as industrial effluents, agricultural runoff, and domestic waste discharges This study examined spatial and temporal variations in water quality across wet and dry seasons using field surveys, laboratory analyses, and statistical tests. While most physicochemical parameters were within limits, microbial indicators consistently exceeded thresholds, posing serious health risks. Water Quality Index (WQI) assessments classified the river as poor and unsuitable for domestic use without treatment. Independent samples t-tests indicated significant upstream–downstream differences, highlighting localized pollution hotspots, while paired samples t-tests confirmed greater deterioration during the dry season due to reduced dilution. Two-way Analysis of Variance revealed significant season–location interactions for parameters such as nitrate, dissolved oxygen, and biological oxygen demand, reflecting complex pollution dynamics. Overall, the findings demonstrate severe human-driven pollution of Asa River and underscore the urgent need for stricter regulation, improved monitoring, and sustainable waste management to protect environmental and public health.