Post-reclamation changes in radiation dose equivalent rate and leachate properties: a case study of the Lviv municipal landfill

Abstract

Reclamation of municipal solid waste landfills is a critical environmental measure aimed at reducing radiological and hydrochemical risks associated with long-term waste disposal. This study evaluates post-reclamation changes in radiation dose equivalent rates and the physicochemical characteristics of raw landfill leachate at the Lviv Municipal Landfill (Ukraine), one of the most environmentally hazardous waste disposal sites in the region. Ambient equivalent dose rates were measured in 2025 at the landfill summit and along the main cardinal directions and compared with pre-reclamation data from 2012. The results indicate a substantial decrease in equivalent dose rate following reclamation measures, with current values ranging from 0.089 to 0.101 μSv/h, remaining well below the regulatory limit of 0.3 μSv/h and significantly lower than pre-reclamation levels of 0.41–0.42 μSv/h. At the same time, pronounced spatial heterogeneity of radiation levels persists, with the highest values recorded in the western sector of the landfill. In parallel, the chemical composition of raw landfill leachate collected from a dedicated leachate accumulation pond was analyzed. This pond receives leachate generated by drainage from the waste body and serves as temporary storage prior to treatment by an on-site reverse osmosis system implemented as part of the landfill reclamation project. The leachate is characterized by extremely high concentrations of ammonium nitrogen (3844 mg/l), chemical oxygen demand (8960 mg O₂/l), chlorides (4000 mg/l), phosphates (88 mg/l), and total dissolved solids (14,625 mg/l), indicating severe organic and mineral contamination typical of mature landfill leachate. The results demonstrate that, despite the effectiveness of reclamation measures in mitigating radiological hazards, the generation of highly concentrated raw leachate remains a significant environmental challenge. The chemical composition of the leachate clearly confirms the necessity of its advanced treatment, which provides a scientific justification for the implementation of a reverse osmosis- based leachate treatment system at the landfill. The findings emphasize the importance of continuous monitoring of both radiation dose equivalent rate and leachate quality to ensure long-term environmental safety during and after landfill reclamation.