Canada's McGill University finds plastic traces in teabags

Teabags have been found to emit micro- and nano-plastics, underscoring the need for research into plastic's health impacts

Some teabags contain traces of plastic [representational].
Some teabags contain traces of plastic [representational].

New research published in the American Chemical Society's journal, Environmental Science & Technology, suggests has provided insights on the experiment conducted by Canada's McGill University to gauge the safety of plastic teabags. 

Over time, plastic breaks down into tiny microplastics and even smaller nanoplastics, the latter being less than 100 nanometres (nm) in size – for scale, remember that a human hair has a diameter of about 75,000nm.

While scientists have previously detected microplastics in the environment, tap and bottled waters, and some foods, McGill’s professor of chemical engineering, Nathalie Tufenkji, and her colleagues wondered whether recently introduced plastic teabags could be releasing micro- and nano-plastics into beverages during brewing.

Consequently, a research programme was kicked off, funded by Canada Research Chairs Program, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation, and McGill University, according to Construction Week's sister title Refining & Petrochemicals Middle East.

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 would not 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. These levels were thousands of times higher than those reported previously in other foods.

The 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. The researchers treated water fleas with various doses of the micro- and nanoplastics released from the teabags.

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.

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