this post was submitted on 23 Jun 2025
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The researchers found an average of around 100 microplastic particles per liter in glass bottles of soft drinks, lemonade, iced tea and beer. That was five to 50 times higher than the rate detected in plastic bottles or metal cans.

"We expected the opposite result," Ph.D. student Iseline Chaib, who conducted the research, told AFP.

"We then noticed that in the glass, the particles emerging from the samples were the same shape, color and polymer composition—so therefore the same plastic—as the paint on the outside of the caps that seal the glass bottles," she said.

The paint on the caps also had "tiny scratches, invisible to the naked eye, probably due to friction between the caps when there were stored," the agency said in a statement.

This could then "release particles onto the surface of the caps," it added.

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[–] be_gt@lemmy.world 160 points 3 weeks ago (3 children)

So nothing coupled to the glass but rather the cap having a extra plastic layer on the wet side.

[–] MrQuallzin@lemmy.world 118 points 3 weeks ago (3 children)

Sounds like we found the issue, now it's just a matter of producers improving the caps

[–] ieatpwns@lemmy.world 61 points 3 weeks ago (1 children)

Only if it doesn’t cut it to record profits

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[–] fluxion@lemmy.world 40 points 3 weeks ago (2 children)

Nah ill just spend $50 to have a Congress member introduce a bill to make regulating microplastics illegal

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[–] Infinite@lemmy.zip 53 points 3 weeks ago (1 children)

No, the paint on the outside.

[–] NoSpotOfGround@lemmy.world 25 points 3 weeks ago* (last edited 3 weeks ago)

Yes. So many people are misunderstanding this article... The microplastics are on the inside, in the drink, and they are bits of the paint from the exterior of bottle caps that stuck to the inside of other caps when the caps were all jumbled together in big bags before they were placed on the bottles.

[–] forrgott@lemmy.sdf.org 25 points 3 weeks ago

That would be far more intuitive, but it's not that - it's the painted logo on the outside.

[–] LovableSidekick@lemmy.world 109 points 3 weeks ago (2 children)

In a bizarre twist, plastic bottles have been found to contain alarming levels of microglass.

[–] creisel@lemmy.zip 22 points 3 weeks ago (1 children)
[–] Hupf@feddit.org 18 points 3 weeks ago (1 children)
[–] creisel@lemmy.zip 12 points 3 weeks ago* (last edited 3 weeks ago)

Yea it's coarse and everywhere

https://youtu.be/2tLf1JO5bvE

[–] copdeb@crazypeople.online 8 points 3 weeks ago

jajaajajajajajajajjjaaj

[–] Karyoplasma@discuss.tchncs.de 64 points 3 weeks ago

Step 1: Invent plastic bottles

Step 2: Pocket the cash

Step 3: Things got bad? Outsource the clean-up to the end user in the form of recycling

Step 4: Increase prices to account for recycling

Step 5: Laugh as the idiots actually recycle your shit

Step 6: Throw the whole shebang in the ocean or in landfills

Step 7: Pocket some more cash

Step 8: Pat yourself on your shoulder. You've done some capitalism.

[–] MTK@lemmy.world 46 points 3 weeks ago (2 children)
[–] Donjuanme@lemmy.world 19 points 3 weeks ago (3 children)

As someone in a cork industry, you really don't want that.

[–] MTK@lemmy.world 27 points 3 weeks ago (1 children)

What is this teasing? Elaborate.

[–] londos@lemmy.world 7 points 3 weeks ago (1 children)

It takes a lot of effort to soak the corks.

[–] Agent641@lemmy.world 12 points 3 weeks ago (1 children)

Its really hard to soak my own cork, so I just get my girlfriend to soak my cork instead.

[–] robocall@lemmy.world 8 points 3 weeks ago (2 children)

I also get this guy's girlfriend to soak my cork

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[–] piranhaconda@mander.xyz 12 points 3 weeks ago (1 children)

Care to expand on why? I've had corks dissolve and break if I didn't finish the drink quickly enough, just on liquor bottles that went unused for a year or so. Any other reason?

[–] ramielrowe@lemmy.world 30 points 3 weeks ago (1 children)

Slightly educated guess. True organic cork is produced by cutting the bark off specific trees. There are limited climates it grows. I would guess the scale with which we produce bottled drinks would require significantly more trees and labor that we currently have. And thus cork prices would skyrocket.

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[–] 6nk06@sh.itjust.works 9 points 3 weeks ago

Corka Cola.

[–] Bosht@lemmy.world 23 points 3 weeks ago (3 children)

Man on the surface this reeks of inside payoffs. I guess the technicality is plastic caps on glass bottles?? Which seems weird and nothing I've ever seen. Unless they're referencing the seal on the inside of some metal caps on glass bottles? Either way, seems suspect. I'd assume that overall drinking from glass is safer, as with plastic on any timeline you're dealing with the plastic breaking down and leaching chemicals and micro plastics into the liquid, which wouldn't be an issue with glass.

[–] Infinite@lemmy.zip 48 points 3 weeks ago (3 children)

Not plastic caps, plastic paint. The printing on bottlecaps is a polymer and it gets scuffed.

[–] NateNate60@lemmy.world 18 points 3 weeks ago (2 children)

Odd. I would have thought that the paint, being on the exterior, wouldn't leak into the beverage contained inside the glass.

But apparently, they found that blowing air over the caps reduced the amount of detected contamination by 60 per cent. So it seems like an easy fix that manufacturers can implement inexpensively (literally just an electric fan)

[–] MotoAsh@lemmy.world 15 points 3 weeks ago (1 children)

Or just not paint the caps, at least not with plastic.

[–] NateNate60@lemmy.world 9 points 3 weeks ago* (last edited 3 weeks ago) (5 children)

There is a real reason that the caps are painted. Glass beverage bottles are usually stored in a crate and grabbed from the top, so the design on the lid is what restaurant or store employees used to distinguish what drink is contained within it. This allows employees to distinguish similar-coloured drinks (e.g. Coca-Cola vs Pepsi or two different brands of beer) just from looking down at the top of the bottle.

But there probably is a way to paint them without using plastics

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[–] scrion@lemmy.world 8 points 3 weeks ago

Unfortunately, it's probably not going to be an electric fan, but compressed air. Even more unfortunately, compressed air turns out to be a major cost factor due to the cost of running compressors, which might prevent adoption.

The original paper mentions blowing the caps out with an "air bomb", which I'm pretty sure is a mistranslation stemming from the French term "Bombe d’Air Comprimé", i. e. an air duster, a can of compressed air. In an industrial setting, you'd use a compressor for this, naturally.

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[–] Cawifre@lemmy.world 14 points 3 weeks ago

The paint itself on the outside of the bottle cap. The ultra thin layer of (apparently polymer a.k.a. plastic) paint that make the cap not just metal colored.

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[–] BigBenis@lemmy.world 22 points 3 weeks ago

For the people in the comments who either won't or seemingly can't read the article: The paint on the top of the caps is plastic-based and before they're put on the bottle they're stored in a big jumbled up pile where the paint chips off and coats the caps in tiny flakes. When the cap gets put on the bottle, the flakes on the bottom of the cap get washed off into your drink. Studies show that washing the caps first dramatically reduces the micro-plastic contamination.

[–] Agent641@lemmy.world 21 points 3 weeks ago

Just pour it from the glass bottle to the plastic bottle. Problem solved

[–] daniskarma@lemmy.dbzer0.com 13 points 3 weeks ago* (last edited 3 weeks ago) (4 children)

Title seems misleading.

As the micro plastics were found on the paint outside the bottle cap. It seems complicate that that ended on the drink itself. Unless you are licking the bottle cap it doesn't seem that relevant.

[–] iglou@programming.dev 32 points 3 weeks ago

No, the microplastics were found in the content of the bottles. The cap thing is where they come from. As a reply to you explained, the microplastic from the top of a cap is scratched by another cap and ends up on the bottom of yet another cap.

[–] Gobbel2000@programming.dev 22 points 3 weeks ago* (last edited 3 weeks ago) (2 children)

The paint on the caps also had "tiny scratches, invisible to the naked eye, probably due to friction between the caps when there were stored," the agency said in a statement.

This could then "release particles onto the surface of the caps," it added.

Paint scratches off the outside, then sticks to the inside and makes it into the drink.

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[–] creisel@lemmy.zip 13 points 3 weeks ago

Wait...we not licking bottle caps anymore?!

[–] Smoogs@lemmy.world 7 points 3 weeks ago* (last edited 3 weeks ago)

I think because there is a helix twist that glass would grind away the plastic every time it’s recapped. Hence why at the end of the article it is urging manufacturers to use air and alcohol to clean the cap before fitting it to the bottle. Additionally using something other than a plastic cap to reseal the bottle when being used. And especially not one with a helix requiring a twist. You can use a wine reseal which requires no twisting

[–] Numenor@lemmy.world 13 points 3 weeks ago (5 children)

We just need glass caps then

[–] zaphod@sopuli.xyz 31 points 3 weeks ago (2 children)

Or just unpainted aluminium caps.

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[–] creisel@lemmy.zip 11 points 3 weeks ago (1 children)

When I was a kid they were made from metal

[–] SoleInvictus@lemmy.blahaj.zone 10 points 3 weeks ago (5 children)

When I was a kid they were made from cork.

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[–] Ledivin@lemmy.world 11 points 3 weeks ago (1 children)

...do plastic bottles not have caps? I'm confused.

[–] baronvonj@lemmy.world 11 points 3 weeks ago (7 children)

their caps are fully plastic, not painted metal. The non-screwtop metal caps need to be bent to release their grip on the bottle. That scrapes the paint off the metal cap.

[–] Damage@feddit.it 11 points 3 weeks ago

it's more likely that paint is scratched off by other caps, idk about metal caps but plastic ones are usually handled in bags, thrown into a cap feeder that aligns them and loads them into the capper. I expect metal caps to go through a similar process, and all that movement is bound to scratch it and send particles everywhere.

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[–] Evil_Shrubbery@lemm.ee 7 points 3 weeks ago* (last edited 3 weeks ago)

Ok, great find, we can simply switch the caps & solve the problem.
(The corps will do that, right??)

But I wander with such tests ... could there be any significant detection issues?

Did they have the proper equipment and processes? A methodological limitation to particle size maybe?
Coz some researches find higher concentrations than 100.

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