Some teabags shed billions of micro- and nano-sized plastics, Canadian researchers warned this week.
While scientists have previously detected microplastics in the environment, tap and bottled waters and some foods, a team from McGill University in Montreal wondered whether recently introduced plastic teabags could be releasing tiny plastic particles into beverages during brewing.
To find out, the researchers tested four different types of tea bags from shops and cafes in Montreal. 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 McGill team noted.
“…levels were ‘thousands of times higher than those reported previously in other foods,’ the McGill team noted”
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 researchers say more research is needed to determine if the plastics could have more subtle or chronic effects on humans.
A number of natural and organic tea brands have recently switched to plastic-free bags, following concern that many widely used paper teabags contain small quantities of plastic (mainly at the point at which the bags are sealed), making them problematic in recycling. In October last year, Wessanen organic and Fairtrade tea brand Clipper launched what it said was the “world’s first plastic-free, non-GM and unbleached heat-sealed teabag.