Agronomic Benefits and Contaminant Risks of Municipal Solid Waste Leachate Irrigation: An in-situ Analysis

Abstract

Municipal solid waste (MSW) leachate is increasingly being explored as a low-cost soil amendment due to its high nutrient content. This study evaluated the effects of MSW leachate (MSWL) application on soil properties and heavy metal accumulation in some cereals and millets. The leachate was characterized by acidic pH and high electrical conductivity, with substantial concentrations of potassium, calcium, and phosphorus. Results indicated enhanced uptake of essential micronutrients such as zinc (Zn) and copper (Cu), with concentrations remaining within FAO/WHO permissible limits. In contrast, toxic metals such as cadmium (Cd) and nickel (Ni) were present at low levels across all crops. However, lead (Pb) concentrations in leaves exceeded recommended limits, while chromium (Cr) showed moderate accumulation, occasionally surpassing reference values. Transfer factor (TF) and bioconcentration factor (BCF) analyses revealed that Zn and Cu were readily translocated to aerial parts, whereas Cr and Ni were largely retained in roots. Crop-specific variations indicated higher accumulation in ragi and restricted uptake in green gram. The findings suggest that MSW leachate can improve soil fertility and plant nutrition, but its application requires careful consideration to mitigate potential risks associated with heavy metal accumulation.