Plastic teabags release billions of tiny particles into tea – research

Plastic teabags can release billions of microplastic particles into a cup of tea, according to researchers at McGill University in Canada.

Over time, plastic breaks down into tiny microplastics and smaller nanoplastics, the latter being less than 100 nanometers in size.

While scientists have previously detected microplastics in the environment, tap and bottled water and some foods, McGill professor of chemical engineering Nathalie Tufenkji and colleagues decided to investigate whether recently introduced plastic teabags could be releasing micro- and nanoplastics into beverages during brewing.

To conduct their analysis, the team purchased four different commercial teas packaged in plastic teabags. They cut open the bags and removed the tea leaves so they wouldn’t interfere with the analysis. Then, they heated the emptied teabags in water to simulate brewing tea.

Using electron microscopy, the researchers found that a single plastic teabag at brewing temperature released about 11.6 billion microplastic and 3.1 billion nanoplastic particles into the water.

According to the team, these levels were “thousands of times higher” than those reported previously in other foods.

While the possible health effects of ingesting these particles are currently unknown, the new research published in the American Chemical Society journal Environmental Science & Technology suggests further investigation is needed.

The World Health Organization (WHO) recently called for further research into microplastics and their potential effects on human health.

According to a WHO analysis, microplastics larger than 150 micrometres are not likely to be absorbed in the human body and uptake of smaller particles is expected to be limited.

However, absorption and distribution of very small microplastic particles including in the nano size range may be higher, although the data is “extremely limited”.