SIPP ING GOURMET TEA COULD MEAN A MOUTHFUL OF PLASTIC.

Study suggests ‘silken’ tea bags are to blame

EDMONTON• When you take a sip of your tea in the morning, you may be slurping down more than you thought, as new Canadian research suggests there could be high quantities of microplastics in that cup — if it was made with a “silken” tea bag.

Unlike regular tea bags — which are made of paper, similar to coffee filters — “silken” or “silky” tea bags are made of food grade plastics. They are often pyramid- shaped, which is supposed to give tea leaves more room to expand. Like regular tea bags, they’re discarded after use.

Researchers at Mcgill University found that when a plastic tea bag is steeped in hot water, 11.6 billion microplastic particles and 3.1 billion nanoplastic particles are released into the tea.

That, the study notes, is “thousands of times higher than those reported previously in other foods.” For example, table salt has quite a high concentration of microplastics, at 0.005 micrograms per gram of salt.

A cup of tea, in comparison, has between 13 and 16 micrograms of microplastics, according to results for the four different tea bags tested in the study, which was published in the journal Environmental Science & Technology on Wednesday.

Laura Hernandez, a PHD student and first author of the study, said the idea came up when her supervisor, chemical engineering professor Nathalie Tufenkji, got a plastic tea bag in a Montreal coffee shop.

They had already been looking into microplastics at the time.

“I was not surprised to see there was plastic coming out,” Hernandez said. “I was surprised to see such a high concentration.”

The World Health Organization says, at this point, there’s little evidence to suggest microplastics in drinking water are harmful to human health, but that further study is needed as the data are limited.

The Mcgill researchers, though, “treated water fleas” with differing dosages of nanoplastics and microplastics and discovered anatomical and behavioural abnormalities, including some affecting the distance they could swim.

That said, the bugs, which filter the water they live in, didn’t die.

The Mcgill team went to coffee shops and grocery stores in Montreal and purchased four different brands of plastic tea bags.

The actual leaves were removed, to ensure the scientists were only testing plastic that leached from the bags.

The tea bags were then rinsed clean and heated in water, to simulate the process of brewing tea.

A process called electron microscopy measured the amount of minuscule plastics found in the heated water.

A set of unsliced control bags was used to make sure it wasn’t the removal of the leaves that caused the release of microplastics.

Microplastic particles measure about the diameter of a human hair. A nanoplastic is about 1,000 times smaller than that — about the size of a virus, Hernandez said.

While there’s no evidence of health problems linked to the tiny plastic particles, she said consumers might want to avoid single-use plastic at a time when politicians across Canada and around the world are pledging to tackle pollution.

“It would be a responsible consumer action ... to stop purchasing this, not only because of the plastic that it’s releasing, but because of the single- use plastic,” Hernandez said.

IT WOULD BE A RESPONSIBLE CONSUMER ACTION ... TO STOP PURCHASING THIS.