Post COVID-19 pandemic: Biofragmentation and soil ecotoxicological effects of microplastics derived from face masks

Because of the COVID-19 pandemic, used face masks have increasingly littered the environment and are causes for concern since they are commonly made of plastics such as polypropylene. Understanding production of microplastics from face masks is essential for predicting the post COVID-19 pandemic impact on the soil ecosystem. We investigated the generation of nanofibers from meltblown face mask filters (MB filters) and their adverse effects on soil species, particularly the earthworm and springtail. Results of MB filter soil bioassays at a high concentration (1000 mg/kg dry soil) suggest inhibited reproduction and stunted growth in springtails, decreased intracellular esterase activity in earthworm coelomocytes, and inhibited spermatogenesis in male earthworm reproductive tissues. Moreover, it was estimated that generation of nanofibers from microfibers and fragments of MB filters might occur in the soil ecosystem post COVID-19. This study does not oppose the use of face masks but aims to encourage appropriate disposal of the masks. Preservation of human health and the ecosystem should be prioritized even amidst the COVID-19 pandemic.