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.
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.
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.
Not plastic caps, plastic paint. The printing on bottlecaps is a polymer and it gets scuffed.
How exactly would that happen if the cap is ON the bottle?
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!
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)
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.
Or just not paint the caps, at least not with plastic.
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
Put a sticker on it after it’s sealed.
Then stamp/engrave the caps paint isn’t needed
Which is easier? Squatting down to count how many caps say “Coca-Cola” or counting the number of bottles with red caps?