Unveiling the toxic release: kinetics and comparative effects of microplastic fibers, organic, and metal leachates from disposable surgical face masks on two aquatic trophic levels: algae and crustaceans

The unprecedented and widespread use of disposable face masks and their improper disposal poses a significant risk of escalating the already alarming problem of plastic pollution. This study presents a comparative analysis of the leachates from surgical masks, focusing on the differential impacts of microplastic fibres, organic compounds, and metal ions on two aquatic organisms: the microalga Chlorella variabilis and the crustacean Artemia salina. The facemasks were kept in water under stirring conditions for various time points (24, 48, 72, 96, 120, and 144 h), and the mask leachate (concentrations: 1.48 × 104 ± 0.04, 1.64 × 104 ± 0.04, 1.90 × 104 ± 0.06, 2.42 × 104 ± 0.29, 4.32 × 104 ± 0.19, and 4.87 × 104 ± 0.16 particles mL−1) was obtained. Experimental results indicated that disposable surgical masks leach out polypropylene microplastic fibres, alongside detectable levels of organic compounds (e.g., phthalates) and trace metals (e.g., Cu, Ni, Zn). When these microplastic rich-leachates came into contact with algae, it resulted in reduced cell viability, elevated levels of oxidative stress, and increased activity of antioxidant enzymes. A. salina exhibited increased mortality rates upon exposure to the leachates from the mask. Organic and heavy metal leachates induced minor biochemical stress responses. Moreover, our study also observed the entanglement and accumulation of mask microplastic fibers on the surface and in the digestive tract of A. salina, resulting in an increased mortality rate for the organism. This comparative study highlights the multifaceted toxicity of face mask leachates and underscores the distinctive threat posed by microplastic fibres, which exert both chemical and physical stress. Our investigation validates that the leachates from disposable surgical face masks present a significant risk to marine organisms, with subsequent consequences that would detrimentally impact aquatic ecosystems.