Comprehensive Groundwater Quality Assessment of a Municipal Solid Waste Site Using Vertical Electrical Soundings and Hydrochemical Analysis

This study employed a geophysical and hydrogeochemical approach to investigate groundwater contamination at a municipal solid waste (MSW) site. The geophysical technique (vertical electrical sounding) was primarily applied to map variations in subsurface resistivity, identifying a leachate contaminant plume between 7 and 30 m below ground level at multiple locations close to the MSW site. Based on these findings, groundwater samples were collected and analyzed for various physicochemical properties and heavy metal (HM) concentrations. The results revealed that nitrate (NO3−) levels ranged from below the detection limit to 289.28 mg/L, with 61.5% of the samples exceeding the permissible limit of 45 mg/L set by the Bureau of Indian Standards. HMs such as Mn, Ni, Cu, Zn, As, Se, Mo, Cd, and Pb with a mean value of 0.115 mg L−1 (Mn), 0.077 mg L−1 (Ni), 0.127 mg L−1 (Cu), 0.848 mg L−1 (Zn), 0.102 mg L−1 (As), 0.004 mg L−1 (Se), 0.007 mg L−1 (Mo), 0.001 mg L−1 (Cd), and 0.045 mg L−1 (Pb), respectively, were observed in the collected samples. This suggests the clear influence of leachate contamination in this region. The groundwater quality index was computed by integrating 22 parameters, which include total hardness, total dissolved solid, major ions (Ca2+, Mg2+, Na+, K+, SO42−, NO3−, HCO3−, F−, and Cl−), and HMs (As, Cu, Zn, Cd, Ni, Pb, Al, Cr, Mn, Se, and Mo), suggest that 84% of the samples were excessively polluted for domestic use. The geophysical data aligned with the spatial distribution of nitrate contamination, confirming the significant impact of landfill leachate on groundwater quality. This study highlights the effectiveness of this integrated approach in providing a comprehensive assessment of groundwater quality near MSW sites. The findings offer valuable insights for groundwater resource management and the development of remediation strategies for similar contamination-prone areas.