McGill University chemical engineering professor Nathalie Tufenkji decided to test tea bags after she was given one in a Montreal cafe that looked like it was made from plastic.
She asked her graduate student Laura Hernandez to purchase several tea bag brands from Montreal stores. The scientists then tested them to see if they left any plastic particles behind. The results, published in Environmental Science and Technology Wednesday, far surpassed the researchers' expectations.
"We were shocked when we saw billions of particles in a single cup of tea," Tufenkji told CBC News. In total, the researchers found that steeping a plastic tea bag at 95 degrees Celsius released around 11.6 billion microplastics and 3.1 billion nanoplastics into a single cup. That's much more than other foods and beverages commonly contaminated with plastics, Tufenkji told New Scientist. "We think that it is a lot when compared to other foods that contain microplastics," she said. "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."