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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[–] [email protected] 13 points 3 days ago (7 children)

We just need glass caps then

[–] [email protected] 12 points 3 days ago (6 children)

When I was a kid they were made from metal

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[–] [email protected] 15 points 3 days ago* (last edited 3 days ago) (6 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.

[–] [email protected] 14 points 3 days ago

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

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[–] [email protected] 116 points 3 days ago (4 children)

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

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[–] [email protected] 21 points 3 days ago

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

[–] [email protected] 8 points 4 days ago* (last edited 4 days 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.

[–] [email protected] 47 points 4 days ago (2 children)
[–] [email protected] 19 points 4 days ago (3 children)

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

[–] [email protected] 27 points 3 days ago (1 children)

What is this teasing? Elaborate.

[–] [email protected] 8 points 3 days ago (1 children)

It takes a lot of effort to soak the corks.

[–] [email protected] 12 points 3 days ago (1 children)

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

[–] [email protected] 8 points 3 days ago (2 children)

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

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[–] [email protected] 7 points 4 days ago
[–] [email protected] 12 points 4 days 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?

[–] [email protected] 30 points 3 days 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.

[–] [email protected] 4 points 3 days ago

And you can't really close them again.

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[–] [email protected] 6 points 4 days ago

But the plastic bottle can still create a lot more, surely.

[–] [email protected] 11 points 4 days ago (1 children)

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

[–] [email protected] 11 points 4 days 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.

[–] [email protected] 11 points 4 days 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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[–] [email protected] 67 points 4 days ago (1 children)

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.

[–] [email protected] 39 points 4 days ago

You forgot the step where they invent a logo that looks almost the same as the recyclable logo and stick it on all plastics but it doesnt mean its recyclable but instead just says what kind of plastic it is.

[–] [email protected] 26 points 4 days 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.

[–] [email protected] 14 points 4 days 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.

[–] [email protected] 50 points 4 days ago (2 children)

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

[–] [email protected] 4 points 4 days ago (1 children)

How exactly would that happen if the cap is ON the bottle?

[–] [email protected] 22 points 4 days ago

You make a lot of them. They are flat. They get painted, they get punched out, (this is where the ‘magic’ happens) they get shuffled around to load into machines to put them on the bottles, they go through the machine and they get clamped to the bottles.

There! Instant plastics!

[–] [email protected] 19 points 4 days 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)

[–] [email protected] 7 points 3 days 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.

[–] [email protected] 16 points 4 days ago (1 children)

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

[–] [email protected] 9 points 4 days ago* (last edited 4 days ago) (3 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

[–] [email protected] 5 points 3 days ago (1 children)

Then stamp/engrave the caps paint isn’t needed

[–] [email protected] 1 points 3 days ago (1 children)

Which is easier? Squatting down to count how many caps say "Coca-Cola" or counting the number of bottles with red caps?

[–] [email protected] 1 points 3 days ago

Wholly and entirely dependent on the designs. Even barely two-tone patterns (as in low contrast) can be easily distinguishable.

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[–] [email protected] 171 points 4 days ago (3 children)

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

[–] [email protected] 26 points 4 days ago

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

[–] [email protected] 56 points 4 days ago (1 children)

No, the paint on the outside.

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[–] [email protected] 125 points 4 days ago (4 children)

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

[–] [email protected] 43 points 3 days 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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[–] [email protected] 3 points 3 days ago

Just use the plasticbottlecaps.

[–] [email protected] 20 points 4 days ago

Ha! Good one.

[–] [email protected] 67 points 4 days ago (1 children)

Only if it doesn’t cut it to record profits

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