Evolution and associated environmental pollution risks of micro- and nanoplastics through landfill processes

Plastic pollution has garnered increasing global attention, with secondary micro- and nanoplastics (MNPs) being recognized as emerging contaminants and becoming growing environmental challenges. Due to their ubiquity and persistence, MNPs pose a significant risk to ecosystems and human health. Landfills are the main sink for waste plastics and have become important a source of MNP generation. This review synthesized existing research on the distribution, impact, and toxicity of MNPs across diverse environments. Focusing on the complex environment in landfills, the fragmentation pathways of waste plastics and the occurrence of MNPs were reviewed, with particular attention to the analytical challenges posed by their detection. By analysing the evolution, leakage, and migration behaviours of waste plastics in landfills, their potential implications for the global carbon cycle as carbon-rich materials were revealed. Furthermore, this review also discussed MNP release risks during landfill remediation, such as landfill mining, providing insights for pollution control strategies for landfills.