In the study, which was published in the American Chemical Society's journal Environmental Science & Technology, researchers tested four different types of commercial tea bags constructed out of plastic.
The researchers opened the plastic bags, removed the tea leaves and washed the plastic bags, according to a September 25 press release by the American Chemical Society.
After heating the empty tea bags in water to “simulate brewing conditions,” the scientists used electron microscopy to find that a “single plastic teabag at brewing temperature released about 11.6 billion microplastic and 3.1 billion nonplastic particles into the water.”
The levels found in this experiment were “thousands of times higher than those reported previously in other foods,” the American Chemical Society’s statement says.
The researchers also “treated water fleas” with “various doses” of the microplastics and nanoplastics to determine the effects they have. The fleas did not die but did experience some “anatomical and behavioral abnormalities.” However, the researchers concluded that more research needs to be conducted to determine if consuming microplastics and nanoplastics has adverse effects on humans.
Researcher Laura Hernandez told BBC News that she was surprised by the study’s results, and she warned consumers to avoid plastic tea packaging, despite the fact that the effects of consuming plastics are currently unknown.
"The consumer should avoid plastic packaging, not a specific brand, and definitely not the tea that comes inside," Hernandez told BBC. "We encourage consumers to choose loose teas that is sold without packaging or other teas that come in paper tea bags.”
She also noted that there is “really no need” to place tea leaves in single-use plastic bags, and that doing so contributes to the “environmental burden of plastic.”