Researchers from Turkey calculated that when brewing tea from certain brands using mesh tea bags, one cup can contain from 555 to 2498 particles of microplastic. The scientists also found potentially hazardous amounts of bisphenol A and similar plasticizers that disrupt the human endocrine system in such cups. These substances seeped into the tea along with the plastic particles.

Chemical compounds are apparently added to plastic tea bags to increase their strength, elasticity, and resistance to high temperatures. However, as the scientists discovered, the latter task is likely not being accomplished.

Our study showed that the consumption of bisphenol A can reach 21.7% of the acceptable daily intake established by the European Food Safety Agency. This is a serious cause for concern, especially with regard to vulnerable population groups, such as pregnant women and children, the researchers wrote in their work.

For comparison, loose-leaf tea, which the researchers also tested for microplastic, contained from 146 to 1178 particles per kilogram - that is, to reach the level of microplastic observed in one plastic tea bag, about half a kilogram of loose-leaf tea would be needed.