Tea with plastic
Tea bags turned out to be a source of microplastics
Polina Gershberg, Naked Science
Disposable tea bags turned out to be a serious source of plastic pollution. An article about this was published in Environmental Science & Technology (Hernandez et al., Plastic Teabags Release Billions of Microparticles and Nanoparticles into Tea).
Recently, many manufacturers of packaged tea use synthetic substances for tea bags, not paper, for example, nylon or polyethylene terephthalate (PET). Scientists from the Canadian McGill University decided to check how these substances behave when brewing tea in boiling water and whether they are sources of pollution. To do this, the researchers purchased four types of packaged tea in Montreal stores, carefully removed all the tea leaves, and then placed the empty bags in boiling water at 95 ° C for five minutes.
The resulting liquid was then analyzed under a microscope. According to the data given in the article, when brewed for five minutes, about 11.6 billion microplastic particles (larger than 100 nm) and 3.1 billion nanoplastics particles (less than 100 nm) fall into the cup. This level of pollution is thousands of times higher than those previously reported in the study of other food products.
The researchers also tested how similar concentrations of small plastic particles would affect living creatures. Large daphnia – small crustaceans, which are often used as a model object in environmental studies, were selected as subjects. Although daphnia survived at high concentrations of microplastics, scientists observed numerous anatomical and behavioral abnormalities in animals.
For example, some crustaceans could not form an exuvium (a type of exoskeleton) and showed abnormal growth. Other daphnia began to swim at a much greater distance than the animals from the control group.
"We still do not have knowledge about the harmful effects of plastic particles on human health, and there is an urgent need to study the potential toxic mechanisms of [microplastics] in higher vertebrates and humans," the authors of the study write. Further work in this area should be important for assessing the risks of using plastic in food.
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