Assessment of physicochemical properties and heavy metal contamination of soil at a central dumpsite in Effurun, Delta State, Nigeria

This study assessed the physicochemical characteristics and heavy metal contamination of soil at a central dumpsite in Effurun, Delta State, Nigeria. Soil samples were collected from three locations within the dumpsite and analyzed for parameters such as pH, nitrogen, phosphorus, particle size distribution, bulk density, pore size, and concentrations of heavy metals (Cr, Zn, Cd, Pb, Mn, Fe, Ni). Results revealed a predominantly sandy texture (mean sand content: 72.40%) with low clay content (10.41%), contributing to high infiltration and leaching potential. The pH was slightly acidic (mean: 5.5), enhancing the mobility of heavy metals. Nitrogen (3.15%) and phosphorus (1.49 mg/kg) levels were elevated, likely due to organic waste decomposition. Heavy metal concentrations varied widely, with chromium (25.72 mg/kg), cadmium (9.21 mg/kg), and lead (36.64 mg/kg) exceeding WHO and FEPA limits, indicating potential risks to groundwater and human health. Spatial analysis showed significant variability among sampling locations, and correlation analysis revealed strong associations between clay content and metal accumulation. Compared to a control site, dumpsite soils showed elevated levels of organic matter, electrical conductivity, and metal concentrations. The findings underscore the environmental impact of improper waste disposal and highlight the need for regular monitoring and remediation strategies to safeguard soil and water resources.