If your favourite brand of tea is using plastic teabags, you are probably getting a gutful of microplastics.
A new study has found that a single plastic teabag steeped at a brewing temperature of 95 degrees Celsius releases around 11.6 billion microplastics and 3.1 billion nanoplastics into a single cup. Let that sink in for a moment.
Currently, we're estimated to consume over 74,000 particles of microplastics a year. According to this research, there's nearly 200,000 times that amount in a single cup of plastic teabag tea.
Microplastics are everywhere. So much of our food is wrapped in plastic, for a start, and often ends up in the food itself. In addition, it leaches out into the environment. We're making (painfully slow) headway eliminating useless plastic microbeads from body washes, and phasing out plastic straws and bags, but the damage has been done.
Plastic ends up in things like sea salt, canned fish, and honey, and chicken.
For many years, teabags have been made mostly out of paper, but recently some companies have been using plastic meshes instead.
This isn't just a problem for the environment. According to researchers at McGill University in Canada, temperatures greater than 40 degrees Celsius can degrade plastics immensely. Even food-grade plastics. So they set out to investigate.
The team took a bunch of plastic teabags from four tea brands, emptied out the tea, and rinsed them thoroughly. This was to make sure that anything they found in the water wasn't in the tea itself.
They also used several teabags that hadn't been emptied or rinsed as a control, to determine that cutting the teabag to empty the tea did not influence the number of particles released.
For each brand they tested, three emptied teabags were placed in a single clean glass vial, and steeped in 10 millilitres of 95-degree Celsius water for 5 minutes. Then, the teabags were removed, and the water decanted into another clean glass container.
Scanning electron microscope images were taken of the teabags before and after steeping, and their chemical composition analysed using Fourier-transform infrared spectroscopy (FTIR).
The water in which the teabags had been steeped was fixed to silicon wafers and dried, and Nanoparticle Tracking Analysis used to count the particles. FTIR was also used to determine their chemical composition.
They found that the teabags exhibited significant cracking and degradation after steeping, and that there were a lot of micro- and nanoparticles in the water, mostly between 1 and 150 micrometers for the microparticles, and 100 and 1,000 nanometres for the nanoparticles.
The chemical composition of these particles matched the teabags; a count of the particles led to an estimate of how many particles a tea-drinker would swallow with each cup - 2.3 million micron-sized, and 14.7 billion submicron particles.
But it gets worse. We don't know of any adverse effects in humans, but the researchers put water fleas (Daphnia magna) in 50 percent, 5 percent, and 0.5 percent dilutions of the teabag water, and it was not pretty.
"A number of micro-sized foreign particles were observed inside the bodies of 5 percent and 50 percent leachate-exposed D. magna but not in controls, and the shape and size of the particles were similar to those observed in the raw leachates," the researchers wrote in their paper.
More research is needed to determine if drinking your tea laced with plastic would exert an effect on humans, but one thing is certain: whether you tip the tea down the sink or drink it, those particles are going to eventually end up in the wider world.
The research has been published in Environmental Science & Technology.