Microplastics in your tea, from the teabag.

New Scientist has the less-than-cheerful discovery that a plastic-based teabag will release *billions* of microplastic particles as it steeps:

A Canadian team found that steeping a single plastic teabag at a brewing temperature of 95°C releases around 11.6 billion microplastics – tiny pieces of plastic between 100 nanometres and 5 millimetres in size – in a single cup. That is several orders of magnitude higher than other food and drink.

Nathalie Tufenkji of McGill University says: “We think that it is a lot when compared to other foods that contain microplastics. Table salt, which has a relatively high microplastic content, has been reported to contain approximately 0.005 micrograms plastic per gram salt. A cup of tea contains thousands of times greater mass of plastic, at 16 micrograms per cup.”

Her team bought four different teas from shops and cafes in Montreal, cut them open and washed them, steeped them in 95°C water, and analysed the water with electron microscopes and spectroscopy. A control of uncut teabags was used to check it was not the cutting that was causing the leaching of microplastics.

To test the potential toxicity of the particles released by plastic teabags, Tufenkji and colleagues exposed water fleas to the contaminated water.

“The particles did not kill the water fleas, but did cause significant behavioral effects and developmental malformations,” she says.