Researchers from Canada’s McGill University found that the commonly used teabags were shedding micro- and nano-sized particles of plastic.
New research published the last week of September has found that a single plastic teabag releases about 11.6 billion microplastic and 3.1 billion nanoplastic particles into the water at brewing temperature.
Published in the American Chemical Society journal , the study finds that heating emptied teabags in water to simulate brewing tea releases levels of microplastics thousands of times higher than those reported previously in other foods.
To conduct their analysis, the researchers purchased four different commercial teas packaged in plastic teabags. The researchers cut open the bags and removed the tea leaves so that they wouldn’t interfere with the analysis.
Then, they heated the emptied teabags in water to simulate brewing tea. Using electron microscopy, the team found that a single plastic teabag at brewing temperature released about 11.6 billion microplastic and 3.1 billion nanoplastic particles into the water.
The research team also explored the effects of the released particles on small aquatic organisms called Daphnia magna, or water fleas, which are model organisms often used in environmental studies.
They treated water fleas with various doses of the micro- and nanoplastics released from the teabags and found that although the animals survived, they did show some “anatomical and behavioural abnormalities”.
The first author of the study, PhD student Laura Hernandez says more research is needed to determine if the plastics could have more subtle or chronic effects on humans.