ANALYSIS OF WATER QUALITY AROUND DUMPSITES USING GIS AND REGRESSION APPROACH

This study investigates the environmental impact of the Ekosodin dumpsite in Benin City, Edo State, on surrounding groundwater quality, specifically addressing the risks of leachate infiltration. The research aim was to evaluate twenty-two physicochemical and microbial parameters across eight sampling locations to determine the spatial extent of contamination and assess the suitability of local water resources for domestic use. By benchmarking these parameters against World Health Organization (WHO) and Nigerian Industrial Standards (NIS), the study provides a comprehensive overview of how inadequate waste management practices threaten the availability of safe potable water for the community. The methodology integrated systematic laboratory analysis with advanced geospatial modeling using ArcGIS 10.8. Groundwater samples were collected from eight borehole locations and analyzed for various physical, chemical, and biological properties, including heavy metals like Lead (Pb) and Cadmium (Cd). A Water Quality Index (WQI) was calculated for each site to classify water quality, while Inverse Distance Weighting (IDW) interpolation was applied to map the spatial distribution of pollutants. Furthermore, a Multiple Linear Regression (MLR) model was developed to quantify the relationship between five key parameters—including Electrical Conductivity (EC) and Iron (Fe)—and the calculated WQI, achieving a high predictive accuracy with an R 2 value of 0.9983. Results revealed a significant degradation gradient, with WQI values ranging from 27.20% to 130.05% (and up to 945.24% in specific computations), indicating that boreholes closest to the dumpsite possess very poor water quality unsuitable for drinking. Spatial analysis confirmed the dumpsite as the primary source of elevated heavy metals and organic contaminants, though quality generally improves as the distance from the waste source increases. The study concludes that leachate from the Ekosodin dumpsite severely impairs groundwater safety, leading to the recommendation that future boreholes be sited at least 400 meters away from disposal areas. These findings emphasize the urgent need for modernized waste management strategies and continuous groundwater monitoring to protect public health and ensure a sustainable water supply.