Assessing the environmental impacts of municipal solid waste landfill leachate on groundwater and soil contamination in western Saudi Arabia

Potential environmental risks associated with leachate from a municipal solid waste landfill located at Al-Hamra Al-Assad, Al-Madinah City, Saudi Arabia, were reported in this study. Three leachate samples from the landfill, 54 groundwater samples, and 44 surface soil samples were collected from the surroundings. The collected samples were analyzed for toxic trace elements (As, Cd, Cr, Co, Mo, Cu, Fe, Mn, Ni, Pb, and Zn), pH, EC, NO3–, and E. coli. Results revealed that the concentrations of Fe, Mn, and Zn in the leachate were higher than other metals. Based on Food and Agricultural Organization (FAO) guidelines, 59.3% of the water samples were found to inappropriate for irrigation. Likewise, the majority of the groundwater samples were unsuitable for drinking-water purposes owing to the higher concentrations of NO3−, As, Cd, Cr, Fe, Mo, Ni, and Pb. Enrichment factors (EF) indicated an extreme soil contamination with Mo, strong Cd and As pollution, significant pollution for Pb, Zn, and Co, moderate Cu and Ni pollution, and minimal Cr and Mn pollution. Further, EF values of > 2.0 depicted the anthropogenic origin of trace elements, suggesting their possible introduction from an adjacent landfill. Therefore, proper management of the landfills is recommended to temper the adverse impacts on the surrounding environment.