Investigating the effects of disposable face masks leaching compounds on marine biota: a toxicogenomic approach using stress indices and transcriptomics in tissues of mussel Mytilus galloprovincialis.

The present study provides integrated evidence that Disposable Face Masks (DFMs) leaching process could adversely affect marine bivalves, such as the mussel species Mytilus galloprovincialis. Specifically, cellular (through lysosomal membrane stability, using the Neutral Red Retention Time/NRRT), oxidative (by measuring superoxide anions/O2.-, nitric oxides/NO, and lipid peroxidation, via malondialdehyde/MDA content), and genotoxic (by measuring micronucleus/MN formation) effects were determined in hemolymph/hemocytes of mussels exposed for 96 h to artificial seawater containing DFM leaching compounds (DFMASW), generated during a laboratory controlled 20-day leaching period (DFMtreated), compared to control (DFMfree) mussels. In parallel, whole-transcriptome analysis was conducted in gills of DFMtreated and DFMfree mussels to investigate gene expression patterns and underlying molecular mechanisms. Although O2.- and NO levels were not significantly altered, the pronounced lysosomal membrane impairment, the increased MDA content, and the elevated MN formation in hemocytes of DFMtreated mussels indicate the disturbance of mussels' health status due to DFM-derived leaching compounds. Moreover, the transcriptomic analysis revealed a pronounced gene expression remodeling in gills of DFMtreated mussels, with upregulation of genes related to key cellular defense and homeostasis-related pathways. On the other hand, DFMfree mussels exhibited gene activation primarily related to basal metabolic and biomineralization/shell matrix processes. This pattern suggests a trade-off between normal physiological functions and stress-adaptation mechanisms during DFM exposure. To our knowledge, this is the first study to identify multi-endpoint stress responses and molecular pathways triggered by DFM leachates in marine mussels, thus highlighting the importance of toxicogenomic approaches in assessing aquatic chemical threats.