Aging of disposable face masks in landfill leachate poses cyto-genotoxic risks to Allium cepa: Perils of uncontrolled disposal of medical waste

The accumulation of disposable face masks (DFMs) has become a significant threat to the environment due to extensive use during the COVID-19 pandemic. In this research, we investigated the degradation of DFMs after their disposal in landfills. We replicated the potential degradation process of DFMs, including exposure to sunlight before subjecting them to synthetic landfill leachate (LL). After exposure to UV radiation, all three layers of the DFMs displayed surface abrasions and fractures, becoming less stable with increased UV exposure duration, indicating an aging process. Changes in the surface morphology of the DFMs and carbonyl index after UV exposure confirmed this aging process. DFM aging in LL accelerated by 11% compared to deionized (DI) water after 28 days. Different analytical techniques, including microscopy, FT-IR, Raman spectroscopy, and ICP-MS were used to detect microplastics and metals in the leachates. The microfibers collected from the leachates were primarily made of polypropylene, and the abundance of smaller microfibers (<40 μm) increased with the aging time of DFMs in leachate. Additionally, this study examines the toxicity of UV-weathered DFM leachates collected at different periods on Allium cepa, a model terrestrial plant. Leachates from DFM aged in landfill caused 15% more harm to A. cepa root cells due to increased oxidative stress (66%) compared to leachates aged in DI water. Additionally, DFM leachates aged in landfills showed a 29% increase in heavy metal content over time compared to those aged in DI water, potentially leading to significant phytotoxicity. In summary, this report highlights the impact of disposing DFMs in landfills and their biological effects on a model plant.