Evaluation of the effect of landfill leachate on soil and surface water quality: a case study of the Lamdeng landfill site, Manipur, Northeast India.

Environmental pollution due to leachate infiltration from Municipal Solid Waste (MSW) landfill is a grave problem in many developing countries. A pioneer study was undertaken to assess the impact of the Lamdeng Municipal Solid Waste Management Plant in Manipur, Northeast India on the soil and surface water quality of the surrounding areas and its associated human health risk. For the study, leachate, soil, and surface water physico-chemical characteristics were assessed during 2022-2023. Heavy metals such as Fe, Cu, Zn, and Cd concentrations in leachate, soil and surface water from the surrounding areas were quantified. The surface water characteristics such as EC, TDS, turbidity, DO, alkalinity, total hardness, Ca2+, Mg2+, Na+, NO3-, and PO43- showed values beyond WHO thresholds. The Water Quality Index (WQI) values calculated for surface water in the surrounding areas ranged from 130.56 to 511.74, which is in the unsuitable category for drinking. Moreover, the crops cultivated in the agricultural fields near the facility are exposed to high EC, TDS, salinity, and magnesium ions. The health risk assessment of locals via metal exposure from the landfill leachate showed that the carcinogenic risk due to cadmium was 1.77 × 10-6 for adults and 7.08 × 10-6 for children, which is > 1 per 1,000,000 inhabitants, indicating an acceptable carcinogenic risk. However, the locals, oblivious of the current scenario, practice agriculture and fishing, extract wild edibles, and depend on the surface water from the surrounding areas of the waste management facility.