UAB research has characterized in detail how polymer-based commercial tea bags release millions of nanoplastics and microplastics when infused. The study shows for the first time the capacity of these particles to be absorbed by human intestinal cells, and are thus able to reach the bloodstream and spread throughout the body.
This is the summary blurb at the top of the article.
I would be very skeptical of ingesting something and believing it harmless if the study finds that it eventually breaks down in the environment, let alone it’s clearly funded by a company with ‘bioplastics’ in the company name.