Surgical masks flood the ocean: another wave of the pandemic

Sendra, M., Rodriguez-Romero, A., Yeste, M. P., Blasco, J., & Tovar-Sánchez, A. (2022). Products released from surgical face masks can provoke cytotoxicity in the marine diatom Phaeodactylum tricornutum. Science of The Total Environment, 841, 156611. https://doi.org/10.1016/j.scitotenv.2022.156611

Pandemic plastic

Plastics enter the ocean a variety of ways: boats, littering, rivers, and illegal dumping. Photo from NOAA Ocean Services.

With the persistence of the Covid-19 pandemic, it is unlikely that the common use of surgical facemasks will ever go away. Between 2019 and 2020 the demand for personal protective equipment (PPE) has increased more than 200 times with 129 billion disposable face masks used per month around the world in 2020. After they are used, those face masks must go somewhere, not all of which is disposed of properly. While most face masks simply go to landfills, many are accidentally washed into waterways or illegally dumped in the ocean. During the first year of the pandemic, 150,000 to 390,000 tons of PPE waste entered the ocean; that’s about 56,000 school buses worth of trash. Pandemic waste adds to the substantial amounts of trash already in the ocean, such as the Great Pacific Garbage Patch, which is now larger than the state of Texas. While larger wildlife might mistake masks for a tasty snack, how might tiny algae that form the base of the ocean’s food webs be affected by the pandemic’s waste?

Face mask hazards

Face masks are comprised of three different layers, each made of a plastic known as polypropylene. Image from WHO.

Face masks are made up of plastics and a slew of chemicals, such as flame retardants, artificial colors, antioxidants, and metals that could be released into the ocean when degraded. These byproducts not only alter the biological processes of larger organisms like fish, but they also change how micro-organisms in the ocean function. A team of scientists in Spain looked at how face masks in the ocean can affect diatoms, a microscopic algae at the base of many marine food webs. These microorganisms photosynthesize just like plants do on land and provide food to other, larger animals like snails or fish. The researchers mimicked the degradation of face masks in the ocean by taking face masks and shaking them in seawater for a month before sampling the water. They found the masks had released metals such as iron, copper, zinc, and nickel, as well as microplastics, into the water. In the open ocean, it is highly likely that face masks do not remain whole as they as they get broken down by the sunlight, waves, or sand. Unfortunately, these fragmented face masks tend to release more chemicals and create more microplastics, posing increased danger to marine animals.

Death of the diatom

Diatoms are a common type of phytoplankton, which produce a significant potion of the oxygen we breath every day. The microalgae used in this study is Phaeodactylum tricornutum commonly known as the “lab rat of diatoms”. Image from Dr. Ansgar Gruber, Universität Konstanz, Wikimedia commons.

After a month of soaking the face masks, the seawater had been contaminated with hazardous chemicals and microplastics. This water was then placed in a container with the diatoms, to see how they would react. Unfortunately, the face masks blocked the sunlight hindering the ability of the diatoms to photosynthesize. Over time the shading would make it difficult for the diatoms to make food to survive. Chemicals and microplastics released from the masks also made it difficult for the diatom to function properly in the short term as the diatom population significantly decreased. After being exposed for a longer period of time the diatoms seemed to have been able to adjust and make a partial recovery. The recovery of the diatoms gives hopes to these tiny organisms and all the animals that rely on them. Our best hope is to ensure that any trash we use, especially PPE, makes it into trash bins, instead of the ocean.


Cover image from dronepicr on Flickr.


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