Products Released from Surgical Face Masks Can Provoke Cytotoxicity in the Marine Diatom Phaeodactylum Tricornutum

Surgical face masks are more present than ever as personal protective equipment due to the COVID-19 pandemic.  In this work, we show that the contents of regular surgical masks: i) polypropylene microfibres and ii) some added metals such as: Al, Fe, Cu, Mn, Zn and Ba, may be toxic to some marine life. This work has two objectives: i) to study the release rate of the products from face masks in marine water and ii) to assess the toxicity to Phaeodactylum tricornutum of these by-products. To achieve these two objectives, we performed release kinetic experiments by adding masks in different stages of fragmentation to marine water (i.e. whole face masks and fragments of them 1.52±0.86 mm). After one month of the face mask, or fragments, being in marine water, the microfibres released were collected; 0.33±0.24 and 21.13±13.19 fibres·mL-1 from the whole and fragmented face masks respectively. Significant amounts of dissolved (<0.22 µm) metals released, such as Mn, Zn and Ni were detected, as well as functional groups only in the water containing the face mask fragments.Water from both treatments was employed to study its toxicity on the marine diatom. Only the water from the face mask fragments showed a significant, dose-dependent, decrease in cell density in P. tricornutum; 53.09 % lower than in the controls. Although the water from the face mask fragments showed greater effects on the microalgae population than the water from the complete face mask, the latter treatment did show significant changes in the photosynthetic apparatus and intrinsic properties of the cells. These results indicate that during the first phases of fragmentation and degradation face masks may leave a significant number of microfibres and an inorganic and organic chemical print in the marine environment.