ASSESSMENT OF THE IMPACT OF LANDFILL LEACHATE ON GROUNDWATER QUALITY IN OWERRI WEST LOCAL GOVERNMENT AREA, IMO STATE, NIGERIA

Groundwater contamination resulting from landfill leachate has become a major environmental concern inmany developing countries due to indiscriminate solid waste disposal practices. This study assessed theimpact of landfill leachate on groundwater quality around the Umuchima landfill site in Ihiagwa, OwerriWest Local Government Area, Imo State, Nigeria. Four leachate samples and four groundwater samples fromboreholes located within 12–30 m of the dumpsite were collected and analyzed alongside two controlgroundwater samples located away from the landfill. Standard analytical procedures involvingspectrophotometric and titrimetric methods were employed to determine selected physicochemical parametersincluding pH, temperature, turbidity, total dissolved solids (TDS), total suspended solids (TSS), electricalconductivity, nitrate, sulphate, chloride, total hardness, bicarbonate, carbonate, sodium, calcium, magnesium,iron, and copper. The results showed that leachate contained elevated concentrations of dissolved solids,suspended solids, conductivity, chloride, hardness, bicarbonate, and other dissolved constituents.Groundwater samples collected near the landfill exhibited considerably higher values of turbidity, TDS, TSS,electrical conductivity, chloride, nitrate, sulphate, and total hardness than the control samples, indicating theinfluence of leachate migration into the surrounding aquifer. These findings agree with previous studies thatidentified landfill leachate as a major source of groundwater pollution. Although heavy metal concentrationsremained relatively low, the elevated physicochemical parameters demonstrate deterioration in groundwaterquality associated with landfill activities. The study concludes that landfill leachate has adversely affectedgroundwater quality in the study area and recommends continuous groundwater monitoring, improved landfillengineering with leachate collection systems, and regular environmental assessment to safeguard publichealth and groundwater resources