Old Dominion University

Michaela Bonner

BIOL 293: Cell Biology

Professor K. Dillard-Wilkins

9 April 2023

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During the Covid-19 pandemic of 2020, the use of masks, gloves, disposable gowns, and other pieces of PPE dramatically increased as both hospital workers and the public tried to avoid infection. According to the World Health Organization, around 89 million masks were used per month due to Covid-19 (Chaib, 2020). Those discarded masks (typically single use only) put a strain on our society that lacks environmentally sustainable infrastructure to handle normal waste output. As a result, the Covid-related PPE ended up where a lot of our trash typically does—in the ocean. In the years since the first spikes in PPE use, researchers have studied marine PPE pollution, the breakdown of face masks, and their impact on a diatom called Phaeodactylum tricornutum.

One measure of how much solid pollution exists in ocean water is how much trash washes up on beaches. By studying both the volume of trash and the state of decomposition the trash is in, researchers are able to learn about what is floating in our oceans. One study looked at the face masks that washed up on the shores of several beaches in Morocco. The researchers photographed the masks in various stages of decomposition, and they also found that a single decomposing mask released over 16 million microplastic fibers (Mghili, 2022). They were also able to correlate higher rates of mask pollution to months with higher human activity (for instance, during the fast of Ramadan, fewer masks were found along the beach) (Mghili, 2022). As restrictions lifted worldwide and more masks polluted the ocean, researchers became concerned about the biological impact of microplastics from masks on the environment.

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More in-depth research about mask breakdown and the environmental role it played was conducted in 2022 with a study simulating the breakdown of mask microplastics and those effects on diatoms (specifically Phaeodactylum tricornutum). In the study, researchers placed both whole masks and mask fragments in marine water containers, and shook the containers for a month to simulate the movement of ocean tides (Sendra, et. al., 2022). After the month was up, P. tricornutum diatoms were placed in both water samples, and the results were compared: not only did the microplastics released by the masks impact the diatoms, but the samples with the fragmented masks released significantly more particles (Sendra, et. al., 2022). As a result, the P. tricornutum suffered much more toxic damage than the samples with whole face masks, which researchers determined was evidence of the danger of degrading face masks on the environment (Sendra, et. al., 2022). While the impact to the marine species would be concerning on its own, there are bottom-up effects on the rest of the environment that the toxicity of face mask pollution impacts.

P. tricornutum is a common research diatom, and its presence in the ocean serves as a primary producer; the toxicity of the mask microplastics in the test water damaged the diatom’s ability to create a photosynthesis reaction (Sendra, et. al., 2022). Further research could be conducted to see further impacts on the broader ecosystem, but the takeaway is that proper disposal of face masks is critical to protect our oceans.

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The biomedical assays used for this study were made of P. tricornutum that was grown for two weeks and then placed in 100 mL Erlenmeyer flasks with filtered marine water (Sendra, et. al., 2022). One of the methods used to measure the impact of the face mask particles on the microalgae was comparing initial cell density counts to final cell density counts after the experiment; the researchers also documented the initial and final reactive oxygen species produced by the microalgae (Sendra, et. al., 2022). To ensure accuracy, the researchers completed three tests of controls and treatments (Sendra, et. al., 2022). These preparatory methods allowed researchers to attribute cell density and ROS changes in the microalgae to the mask particles. Furthermore, efforts to control the purity of the materials used included cleaning the scissors used to cut the masks, ensuring the marine water was from an uncontaminated area, and cleaning the Erlenmeyer flasks with acid prior to use (Sendra, et. al., 2022).

The results of this study showed a cytotoxic response in the microalgae due to the level of metal particles released into the water (Sendra, et. al., 2022). The metals released included copper, barium, and iron; while the white parts of the masks had a lower amount of metal overall, both the white and blue masks were found to release metal (Sendra, et. al., 2022). When both the fragmented mask water and whole mask mater was compared, there were more particles (including microplastics) from masks in the fragmented sample (Sendra, et. al., 2022). This implies that masks that have degraded contaminate the environment more. The data shown in Figure 3A illustrates the poor cell density in affected P. tricornutum populations: there is little difference between the degraded masks and the whole masks when the contamination level is low, but as the contamination increases, the difference decreases (Sendra, et. al., 2022). The figure implies that degraded masks contaminate the water faster, but both sources affect the cell density of the microalgae.

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The research discussion centered around the new perspectives this study shows about pollution and face masks. The discussion notes that previous studies have center around the microplastics released by ropes, discarded fishing gear, etc., but no quantifiable research had included face masks as a measured impact on the environment (Sendra, et. al., 2022). The discussion also briefly touches on the possibility that sediment or other factors not present in a controlled lab setting might increase the amount of microplastics released from the masks (Sendra, et. al., 2022). Finally, the discussion ends with concerns that the increased ROS and decreased cell density in microalgae may impact the algae’s ability to photosynthesize, thereby producing harmful effects to the rest of the food chain (Sendra, et. al., (2022).

Future research expanding off this study could include better disposal of medical waste and biodegradable mask options. Pandit, et. al., (2021) suggests that the next concern should be creating a biodegradable variety of face mask that will not leach toxicity into the environment. Another article by Walker (2021) brings up the lack of availability for sustainable waste disposal in all areas (e.g., some areas do not have high-temperature incinerators); when this is the case, biodegradable masks might be the more feasible option for short-term mask waste management. In the future, it would be prudent to research ways to ensure that masks are disposed of through incineration so that particles do not end up in the ocean.

References:

Chaib, Fadela. “Shortage of personal protective equipment endangering health workers worldwide” World Health Organization, 2020, https://www.who.int/news/item/03-03-2020-shortage-of-personal-protective-equipment-endangering-health-workers-worldwide. 

Mghili, Bilal, et al.. “Face masks related to COVID-19 in the beaches of the Moroccan Mediterranean: An emerging source of plastic pollution” Marine Pollution Bulletin, vol. 174, 2022, pp. 113181, https://doi.org/10.1016/j.marpolbul.2021.113181.

Pandit, Pintu, et al.. “Potential biodegradable face mask to counter environmental impact of Covid-19” Cleaner Engineering and Technology, vol. 4, 2021, pp. 100218, https://doi.org/10.1016/j.clet.2021.100218.

Sendra, Marta, et al.. “Products released from surgical face masks can provoke cytotoxicity in the marine diatom Phaeodactylum tricornutum” Science of The Total Environment, vol. 841, 2022, pp. 156611, https://doi.org/10.1016/j.scitotenv.2022.156611.

Walker, Tony R. “Why are we still polluting the marine environment with personal protective equipment?” Marine Pollution Bulletin, vol. 169, 2021, pp. 112528, https://doi.org/10.1016/j.marpolbul.2021.112528.