Geoenvironmental evaluation of leachate and soil pollution potential of an open dumpsite

Abstract

This study assessed leachate and soil contamination at the Igbatoro dumpsite, Akure, Nigeria. Leachate samples were analyzed for heavy metals, BOD, and other physicochemical parameters. Soil samples were collected at depths of 0.5, 1.0, and 1.5 m to evaluate twenty-five (25) parameters, including pH, TDS, DO, COD, and heavy metals. Statistical analyses, including two-way ANOVA and correlation analysis, were performed. Leachate Pollution Index (LPI), revised LPI (r-LPI), Geo-accumulation Index (Igeo), Metal Pollution Index (MPI), Pollution Load Index (PLI), Degree of Contamination (Cdeg), and Potential Ecological Risk Factor (RI) were used to evaluate contamination levels of Igbatoro dumpsite. Results showed that Leachate pH ranged from 5.44 to 6.45 (mean 6.01), and metals like As and Cu exceeded the Federal Environmental Protection Agency (FEPA) limits. Strong negative correlations were observed between pH and most parameters, while temperature showed positive correlations with nitrate and Ni. An LPI of 13.65 and r-LPI of 40.39 exceeded pollution thresholds, indicating significant contamination. Soil analysis revealed elevated metal concentrations compared to the control, with Cd showing the highest Igeo value (-0.60). Location 6 recorded the highest MPI values for Cu and Cr, while most heavy metals fell within pollution classes, reflecting severe contamination. The potential ecological risk factor (RI) value of 174.70 indicates moderate ecological risk, with Cd posing a particularly high risk (Eir = 98.34). Overall, the study highlights considerable environmental and public health risks, underscoring the urgent need for remediation and adoption of sustainable waste management practices.