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Summary
A new study from Spain’s Autonomous University of Barcelona reveals that tea bags made from nylon, polypropylene, and cellulose release billions of micro- and nanoplastic particles when steeped in boiling water.
These particles, which can enter human intestinal cells, may pose health risks, potentially affecting the digestive, respiratory, endocrine, and immune systems.
Researchers urge regulatory action to mitigate plastic contamination in food packaging.
Consumers are advised to use loose-leaf tea with stainless steel infusers or biodegradable tea bags to minimize exposure.
I’m not totally sure what you mean by “get out more or less of the dissolved particles”, but I think I understand where your confusion lies. You keep referring to quantities, i.e. mass or particle counts. Their data is reporting these things as concentrations.
It should be obvious to you that 7.14g of salt dissolved in 2ml of water will produce a highly concentrated solution (saturated, in fact), whereas the same 7.14g dissolved in 350ml of water will produce a dilute solution. The concentration of the first one is 3.57g/ml, but the concentration of the second is 0.0204g/ml.
If somebody then turns around and says that 7.14g of salt dissolved in a mug of water will produce a concentration of 3.57g/ml, it should be readily apparent that they are incorrect. That is in effect what the authors are saying by reporting their results as particles/ml and then saying that those numbers are representative of what you might expect when brewing tea under normal conditions.
Does that all make sense?
Hmm, interesting. Maybe I’m being dense here. Let’s say that the teabag is that 7.14g of salt you mentioned - a chunk of salt, let’s say. They either A) try to dissolve 300 of those (each 7.14g) in 600 ml of water or B) they dissolve 1 chunk in 350 ml water. Like you said, they either report A) 3.57 g/ml or B) 0.204 g/ml.
I’m really just saying that either way, it’s still 7.14 g/chunk. Quite a lot of salt/particles per chunk/teabag.
I think maybe I don’t have an issue with them reporting the concentration because I didn’t interpret them as saying that they were saying there’s a billion particles per ml of a regular cup of brewed tea - it was always apparent to me that it was about the number of particles in a teabag (in this case, half a teabag with just a ml volume). I think we’re ultimately just arguing clarity of their language.
In a sense, but clarity of language can be the difference between accurate conclusions and misrepresentation. Just on data presentation alone, formal issuance of a correction is absolutely necessary.
Following on from that is where the issues with study design and methodology come in, and in my opinion they are both so flawed as to lead to spurious conclusions.
The other major problems I see so far:
as mentioned previously, their brewing methodology is so different from what would be done under normal conditions/at home that comparison between the two is meaningless. A good paper should discuss these differences and explain why some conclusions can still be drawn, but this one just makes a direct comparison.
the authors used empty mesh sleeves from an unnamed aliexpress vendor for their samples. We have no idea whether these sleeves are in use by any tea manufacturer, we don’t know anything about how they were made, and we don’t even know whether they were intended for food usage.
one of the three samples produced only cellulose particles, which a) isn’t a plastic and b) is a component of plant cell walls. I don’t know the cellulose particle concentration in a kale smoothie, but I’m certain that it’s higher. And yet the authors still just report this figure alongside the others.
Ultimately, the only thing this paper demonstrates is that certain types of thin-fibre plastic will, when handled roughly, shed nanoparticles. This isn’t a new conclusion, and doesn’t provide us with anything actionable with respect to our tea drinking habits.