In a pilot study, researchers found that chewing gum can release hundreds to thousands of microplastics per piece into saliva and potentially be ingested.
Scientists estimate that humans consume tens of thousands of microplastics (between 1 micrometer and 5 millimeters wide) annually through foods, drinks, plastic packaging, coatings, and production or manufacturing processes.
Yet, despite the candy’s worldwide popularity, chewing gum as a potential source of microplastics hasn’t been widely studied. So, scientists wanted to identify how many microplastics a person could potentially ingest from chewing natural and synthetic gums.
Chewing gum is made from a rubbery base, sweeteners, and flavorings. Natural gums use plant-based polymers like tree sap for chewiness, while others use synthetic, petroleum-based rubber.
Lisa Lowe, who started the project as an undergraduate intern at UCLA and is the presenter of this research, said, “Our initial hypothesis was that the synthetic gums would have a lot more microplastics because the base is a type of plastic.”
Researchers tested five commercially available synthetic and natural gum brands. To reduce variation, one person chewed seven pieces from each brand for 4 minutes. Saliva samples were collected every 30 seconds and combined with a final mouth rinse.
Another experiment studied microplastic release over 20 minutes. Microplastics were stained and counted under a microscope or analyzed using infrared spectroscopy to determine their polymer composition.
On average, Lowe found that chewing gum releases 100 microplastics per gram, with some pieces releasing up to 600 microplastics per gram. A typical piece of gum weighs 2–6 grams, so a more significant piece could release as many as 3,000 plastic particles.
If someone chews 160–180 sticks of gum annually, they could ingest around 30,000 additional microplastics, significantly increasing the yearly total microplastic consumption.
Lowe said, “Surprisingly, both synthetic and natural gums had similar amounts of microplastics released when we chewed them.”
Both synthetic and natural gums contained similar polymers, with polyolefins being the most common. Most microplastics flake off within the first 2 minutes due to the abrasive action of chewing, not saliva enzymes. After 8 minutes, 94% of the plastic particles had been released.
People can chew one piece longer to reduce microplastic exposure instead of switching to a new one. The study focused on 20 micrometers or larger microplastics, leaving smaller particles undetected and requiring further research.
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Mohanty said, “The plastic released into saliva is a small fraction of the plastic in the gum. So, be mindful of the environment and don’t just throw it outside or stick it to a gum wall. If used gum isn’t properly thrown away, it’s another source of plastic pollution to the environment, too.”
The researchers will present their results at the American Chemical Society (ACS) spring meeting.
Source: Tech Explorist
