Toxicological Effects of Microplastic Fibers from Different Disposable Face Masks on Soil Nematodes

Abstract

Since the COVID-19 outbreak, disposable masks have been widely implemented as a primary preventive measure to minimize virus transmission. Despite their high usage, there has been limited research on the impact of disposable masks on soil ecosystems. This study aims to investigate the toxicological effects of microplastics from masks on Caenorhabditis. elegans (C. elegans) in the soil media. The toxic effects of microplastics from three types of disposable masks (KF94 mask, medical mask, and particulate respirator) and a polypropylene (PP) reference material on the growth and number of offspring of C. elegans were evaluated. The results showed that the growth of C. elegans was not affected by microplastic exposure. However, significant decreases in the number of C. elegans offspring were observed in KF94 masks and particulate masks when exposed to 0.3% (microplastics/soil, w/w) microplastics. Mass spectrometry (MS)-based metabolome analysis revealed distinct metabolic changes between the masks, which were not detectable in phenotype. Alterations in the polyamine biosynthetic pathway, which is involved in reproductive function in C. elegans, were commonly observed in the KF94 mask- and particulate respirator-exposed groups. On the contrary, the pattern of quantitative changes in metabolites was not identical between the two groups. Analysis of mask extracts using ultra-high resolution MS revealed plastic additives that can be reproductively toxic to C. elegans such as phthalates, suggesting that various plastic additives may be responsible for the reproductive toxicity in C. elegans.