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.
No it doesn’t. This study is unscientific garbage and should be retracted.
Their “simulation” of making tea involved 300 teabags boiled in 600ml of water at 95 C while being stirred at 750rpm for an unspecified amount of time. They then took counts using undiluted samples of that liquid.
It isn’t clear why they chose such an absurd methodology, but it is absolutely spurious to draw conclusions from this about teabags used under normal conditions.
I’ve worked in a lab before. You would do it this way for a bunch of reasons.
First it’s more reliable to measure something if there’s a lot than a little. The effects of your measurement uncertainties and your error professional goes down. So better to measure 300 teabags than just 1 if you can find out the same thing from doing it that way.
As others have said, 95 deg C is hot, but it is well short of a boil.
The magnetic stir bar doesn’t blend the water, it just moves it around into a swirl, even at 750 rpm because it’s small.
If the ideal study would be to steep 1000 teabags in teacups with just-boiled water and measure the micro plastics to see how much is released on average, I can see why they did it this way instead when their focus was on what type of plastic is released vs exactly how much. I’m not sure the food and wine journalist did a great job walking the reader through this though.
So can I still have my tea or what? I’m inclined to trusting you over some barcelonians
Yeah, just don’t put your teabag in a blender.
Gotchya
“got ya” or “gotcha” - make up your mind :D Although “got it” would be better here. From my non-native speaker understanding, “got ya” is more like “I got what you are saying”, whereas “gotcha” is more commonly used as “I got you there” - as in “I played a prank/practical joke on you and you fell for it”.
But this might just be something that varies with regional preference, or even from speaker group to speaker group.
“The study shows that, when brewing tea, polypropylene releases approximately 1.2 billion particles per milliliter, with an average size of 136.7 nanometres; cellulose releases about 135 million particles per milliliter, with an average size of 244 nanometres; while nylon-6 releases 8.18 million particles per milliliter, with an average size of 138.4 nanometres.”
What do you mean no it doesn’t?
So if you extrapolate the data, that’s 1 teabag per 2 ml water. Let’s be generous and say that 1 ml is about what you’d get in a cup of tea. That’s 8.18 million to 1.2 billion particles per teabag depending on the type. Let’s be generous and cut that in half due to the RPM of stirring. Maybe cut that in half again for that unspecified amount of time. Hell, let’s cut it in half again because maybe you brew at lower than 95 C. On the low end, we still have 1 million plastic microparticles per teabag. That’s insane.
I mean nothing about the methodology is even close to representing normal tea brewing behavior.
For starters, a typical cup of tea is around 300-350ml, not 2ml and certainly not 1, so the low end is already down to 23,371 particles even before accounting for the brewing technique.
Secondly, nobody holds their tea at an active boil while stirring it at 750 rpm. That’s virtually blending it. There isn’t a meaningful way to compare that to typical tea brewing behavior but I wouldn’t be surprised to learn that it produced 10,000x more particles.
Right. You still drink 300-350 ml per cup. It doesn’t matter if you did 1 teabag per 300 ml or 300 teabags per 300 ml. In the first instance, you would have to measure 300 ml to get the X particles per cup. In the second instance, you can get the X particles per ml which is effectively per cup, or more accordingly, per teabag. It’s the same. Please correct me if I’m wrong, but I think your math of 23k particles per teabag is not mathing.
Also, usually you don’t measure 1 teabag because of individual variability, so what they are doing is getting the average amount of particles from those 300 teabags. Much more accurate.
They likely are using a magnetic stir bar. 750 RPM will not virtually blend it. This video shows it going at 3000 RPM max for reference. (https://youtu.be/fzzV75aMM1c) In a large container, the water at the bottom will be swirling faster than the water at the top. And also, 95 C will not be at an active boil - that’s at 100 C. It suggests to me that they boiled water, then poured it into the teabag beaker.
I think that maybe you haven’t worked in a lab before, so it seems like the methodology isn’t right, but as a scientist, this passes the sniff test for me. Honestly, this part isn’t even the novel part of their study - the interesting part is that they found that intestinal cells took up the particles, but I digress.
I think you might have skimmed over the methods, but think what the OP was trying to say is:
Concentration: 300 tea bags / 600mL = 1 teabag per 2mL (175 tea bags in one 350mL cup of tea, doesnt appear typical?)
Mixing: 750rpm × [1m/60s] = 12.5 rotations a sec (Awfully fast to be stirring tea, constantly)
Incubation time: Not specified. (They could have left boiling overnight?)
There seems to be many points about the methodology that raise eyebrows. Maybe it’s ok if you want to use this method to purify particles for structural analysis or test toxicity on cells, but it doesn’t seem fair to present this as “release of micro/nanoplastics (MNPLs) from polymer-based teabags into the aqueous phase during typical usage”, as the amounts seem exaggerated.
Thanks for the clarification of the concerns.
For concentration, it’s not typical for 2 reasons. 1) their instrument may have a detection limit, so if they brewed 1 teabag per 300 ml, they’d have to concentrate it in another way. 2) they’re pooling a batch of teabags, which gives an average, reducing variability teabag to teabag.
Besides mimicking the exact real world scenarios, I think I don’t get what the issue is with concentration. If you boil something that’s dissolvable in a larger volume of water, you’ll typically get out more “pieces” than if you were to do it in a smaller volume. In the experiment, if anything, they may be underestimating the particle release.
For mixing, this method is super standard in the lab. I think that when the methods say 750 RPM, they’re talking about the speed of the stir bar - most definitely with the mass of the 300 wet teabags in that volume, the whole mixture isn’t actually going to get to 750 RPM. If it did, everything would spill out the side, over the top lol
Fair point about incubation time. Do we have a standard for how long people keep their teabags in hot water? I usually don’t take it out of the container when drinking it to go, and if it sits over a few hours and there’s stuff left over, I will usually finish the drink.
In any case, what’s the lowest amount of plastic microparticles we’re okay with? Above, the other commenter said 20k after every generous interpretation moving the number lower. Isn’t that still an insane amount for one drink?
I think my issue with the commenter’s first comment is that they call for the paper’s retraction over what is completely standard in lab science.
You can’t draw any real world conclusions from this methodology.
Apples are safe to eat even though the seeds contain arsenic. Take a bunch of seeds and put them in a blender and test it. That test will show them being toxic.
I would like to see a methodology that is closer to real world use. No way to know if it’s a real problem.
Eat the seeds. Your tolerance is going to spite your enemies.