A recent study published by Laura Hernandez and co-authors in the journal Environmental Science and Technology found that plastic tea bags release 11.6 billion microplastic particles and 3.1 billion nanoparticles during brewing. The research team from McGill University purchased four different teas packaged in plastic brewing bags, removed the tea leaves, and then heated them in water at 95 °C to simulate brewing. The authors quantified the released particles with electron microscopy and used fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) to confirm that the particles were sourced from the tea bags investigated, which were made out of nylon and polyethylene terephthalate (PET).
The measured levels are reported to be “several orders of magnitude higher than plastic loads previously reported in other foods.” An “initial acute invertebrate toxicity assessment” performed in daphnia also “shows that exposure to only the particles released from the teabags caused dose-dependent behavioral and developmental effects.” The lead author commented that more research is necessary to determine if the particles could have subtle or longer-term effects on humans.
McGill University (September 25, 2019). “Some plastic with your tea?”
Kayla Epstein (September 27, 2019). “These tea bags release billions of plastic particles into your brew, study shows.” Washington Post
Rachel Arthur (September 30, 2019). “Plastic tea bags release microplastics into brew, says study.” Beverage Daily
Hernandez et al. (2019). “Plastic Teabags Release Billions of Microparticles and Nanoparticles into Tea.” Environmental Science and Technology (published September 25, 2019).