Environmental Impact of Uncontrolled Sites in the Central Region of Mexico: A Life Cycle Assessment

Abstract

The increase in municipal solid waste (MSW) generation and its inefficient management have caused significant environmental impacts, particularly in developing countries such as Mexico. In the central region, final disposal in uncontrolled sites (UCSs) remains a common practice despite its negative effects on the environment and public health. These impacts have been underestimated due to the scarcity of studies and the lack of technological alternatives aimed at mitigating them. In response to this problem, Life Cycle Assessment (LCA) emerges as a strategic tool to quantify these effects and to guide decision-making toward more sustainable management. The objective of this study was to evaluate the environmental impacts of a UCS using LCA, considering four scenarios: a baseline (E0) representing the current system conditions and three alternative scenarios (E1, E2, and E3) designed to explore potential improvements in environmental performance and to identify a feasible option under the socioeconomic conditions of a municipality in central Mexico. The functional unit was defined as the treatment of one tonne of MSW. The system boundaries included the separation of recyclable inorganic waste (RIW), the treatment of organic waste (OW) through composting and anaerobic digestion (AD), and the final disposal of mixed waste (MW) in UCSs and sanitary landfills. The assessment was performed using SimaPro Analyst v9.6 software and the ReCiPe methodology. The E0 scenario exhibited the highest environmental burdens, whereas E2 and E3 reduced the disposal of MW from 85.92% to 52.57% and emissions by 78.9%. E3 showed the lowest overall impact by integrating mechanical separation, AD, and controlled landfill disposal. E2, which employed composting instead of AD, proved to be a viable alternative for resource-constrained contexts. The results support the closure of uncontrolled sites and encourage the transition toward integrated systems that incorporate valorization technologies, which are urgently needed to achieve the Sustainable Development Goals.