How do you like your tea? Milk, one sugar, and billions of microplastics.
A number of tea manufacturers have recently replaced their paper teabags with plastic or "silken" ones. Not least are these plastic teabags a real pain for the environment, a new study has highlighted that they release billions of microplastics (100 nanometers to 5 millimeters in size) and nano-sized plastics (100 nanometers or smaller) into the tea.
Reported in the journal Environmental Science & Technology, researchers from McGill University in Montreal steeped four different commercially available plastic teabags (with the actual tea removed) in water heated to 95°C (200°F). They used electron microscopes to analyze the contents of the water and teabags, concluding that an average of 11.6 billion microplastic and 3.1 billion nanoplastic particles had leached out of each bag into the water.
The teabags are often branded as “silken”, although they are actually made out of nylon and polyethylene terephthalate (PET), a form of plastic that’s found in water bottles. Even if the teabags aren’t explicitly listed as plastic, some manufacturers will use small amounts of plastic to reinforce their paper fiber bags too. The researchers on this project believe that the teabags shed so many microplastics because the PET is heated close to boiling point.
In the second part of this study, the researchers exposed water fleas (Daphnia magna) to water containing varying concentrations of microplastics. While the animals did not die, they did display some anatomical and behavioral abnormalities that could suggest the microplastics were having a toxic effect on them.
The potential effects on human health are not yet known. The World Health Organization recently concluded that microplastics in drinking water probably won't harm our bodies, however, that’s a big probably, which they said is “based on the limited information we have.”
“To date, the health effects of consuming micro- and nanoplastics to humans are still unknown, while the sublethal effects observed in the present study and in other animals (e.g., algae, zooplankton, fish, mice) give an early warning of both environmental risk and possible human health risk,” the researchers conclude in their new study.
“One of the main potential human exposure pathways of micro- and nanoplastics is likely via ingestion, and particle uptake may occur in the digestive tract. Once inside the digestive tract, cellular uptake and subcellular translocation or localization of the ingested particles may occur.”
It's worth bearing in mind that microplastics are everywhere – from America’s rainwater to the Arctic’s snow – and, chances are, there's most likely some in your digestive system right now, even if you're not a tea drinker. A study from earlier this year found that the average American consumes over 74,000 microplastic particles every year, while another recent piece of research showed that most of us have a load of microplastics in our poop.