The number is apparently correct. Plastic caps/lids make for the 2nd most common item (by count) of SINGLE-USE plastic marine litter. Cigarette buds are number 1 with 19% though, and cotton bud sticks are 3rd with 10%. As a total of the whole (so not just single-use), plastic caps are 5%. Plastic string and cord from fishing makes up over 15% though.
Plastic bottles make up 5% of SUP marine waste, so apparently, people do throw away 2.5 times more caps than bottles. They’re also much easier to lose, when not attached.
So, if you reduce the number of bottlecap thrown away from 13% to 5% (as in, the same as bottles), that’s a pretty big drop in marine litter. And it’s probably a LOT easier than teacher smokers not to be fucking pigs.
Plastic caps/lids make for the 2nd most common item (by count)…
I know you didn’t create this data, but wouldn’t “by weight” or “by volume” have a more meaningful impact on reducing the amount of plastic in our oceans?
I feel like it’s like going into an ice cream shop and claiming that “sprinkles are the most common thing being sold, by count.”. Yeah, it is but it’s dwarfed in comparison to the volume of ice cream being sold.
They’re [the caps] also much easier to lose, when not attached.
I’ll certainly give you this. If I’m on a ship, with an open plastic bottle and a gust of wind comes along. It’ll certainly blow the cap into the ocean before I’d lose my bottle.
On the other hand, I’m currently in a land-locked region - so the chance the wind will blow my cap into the ocean is low.
I did a bit more homework, which gives me a bit of a reason to pause. According to The Ocean Cleanup Project:
There are two classifications: plastic that washes up on (or near the beaches) and plastic in “the rest of the ocean”.
Plastic closer to the beaches is “higher” (in volume, but it’s unclear exactly how much) than plastic in the middle of the ocean.
According to this study, most of the plastic in the ocean comes from nearby rivers and streams. The study has also identified 1000 streams that contribute up 80% of the total plastic that washes up on beaches.
80% of the plastic “floating in the middle of the oceans” consists of fishing equipment.
Other thing to note (from the link above):
If we take a PET bottle as an example; it is likely to sink as it fills up with water, but the cap, which is made of different type of plastic (HDPE), will stay afloat for much longer. High-density polyethylene (HDPE) products are most likely to travel long distances.
So, I guess the intention behind the tethering is that the PET bottle will sink, taking the cap with it, which means it won’t travel as far to get into the ocean (but is still sitting in in our waterways).
(rubbing my temples)… this seems like a really convoluted way to “fix” the problem and will only mitigate the issue, if you have these tethered cap near these 1000 rivers.
I know you didn’t create this data, but wouldn’t “by weight” or “by volume” have a more meaningful impact on reducing the amount of plastic in our oceans?
Yes, but that data is also harder to gather. It’s very easy to count pieces, it’s much harder to asses volume or dry weight. I’m also not entirely sure if that gives meaningful answers either, because a kilo of polystyrene is worse than a kilo of bottlecaps. If you’re working with a huge of different stuff, all measurements are kind of arbitrary.
If we take a PET bottle as an example; it is likely to sink as it fills up with water, but the cap, which is made of different type of plastic (HDPE), will stay afloat for much longer.
The marine litter in the paper is specifically about stuff that gets fished up. It covers floating AND seafloor debris, and floating stuff to a much lesser degree (since nets don’t drag over the water surface). So if the bottles are mostly on the floor and caps mostly float, we would expect to find many more bottles in marine litter.
this seems like a really convoluted way to “fix” the problem and will only mitigate the issue
Mitigation is good though. If you can reduce the volume of plastic in the ocean by a noticable fraction, by basically just very slightly changing the manufacturing process, that’s a good thing.
According to The Ocean Cleanup Project
Oh no… You’ve triggered one of my ecological pet peeves.
The Ocean Cleanup Project is a terrible fucking idea. It’s basically a scam that turns a HUGE amount of amount into a tiny amount of recovered plastic. The OCP reported on twitter in 2025 that they have, in total, removed 40.000 tons of plastic from all their activities. According to this they got about 300m in $A in funding since 2019. I’ll just pretend that’s all they’ve ever gotten, and conclude they spent 5300 USD to remove one ton of plastic waste.
So let me be extremely pessimistic and offer a vastly superior alternative to sailing around with boats and removing basically no waste:
Since OCP already knows where all the waste is coming from, what they SHOULD be doing is going there, buying up all the trash for 1000 USD per ton (which is an absolute fortune to most people there, so they will absolutely cooperate), shipping it to, I dunno, Australia for 100 USD/ton (which is again a fortune), and dispose of it for another 400 USD per ton (which is more than double what we pay here in Europe), and then they would still be 350% more efficient than what they’re doing, assuming the most impossibly generous terms for them.
I agree that it’s more efficient to reduce the amount of new waste from entering waterways than to remove what’s already there, but at this point we need to do both.
Getting it out of the oceans is just more expensive, ton for ton.
The number is apparently correct. Plastic caps/lids make for the 2nd most common item (by count) of SINGLE-USE plastic marine litter. Cigarette buds are number 1 with 19% though, and cotton bud sticks are 3rd with 10%. As a total of the whole (so not just single-use), plastic caps are 5%. Plastic string and cord from fishing makes up over 15% though.
Plastic bottles make up 5% of SUP marine waste, so apparently, people do throw away 2.5 times more caps than bottles. They’re also much easier to lose, when not attached.
source (in english, despite the link) from the EU, via google
So, if you reduce the number of bottlecap thrown away from 13% to 5% (as in, the same as bottles), that’s a pretty big drop in marine litter. And it’s probably a LOT easier than teacher smokers not to be fucking pigs.
Thank you for the well thought out response.
I know you didn’t create this data, but wouldn’t “by weight” or “by volume” have a more meaningful impact on reducing the amount of plastic in our oceans?
I feel like it’s like going into an ice cream shop and claiming that “sprinkles are the most common thing being sold, by count.”. Yeah, it is but it’s dwarfed in comparison to the volume of ice cream being sold.
I’ll certainly give you this. If I’m on a ship, with an open plastic bottle and a gust of wind comes along. It’ll certainly blow the cap into the ocean before I’d lose my bottle.
On the other hand, I’m currently in a land-locked region - so the chance the wind will blow my cap into the ocean is low.
I did a bit more homework, which gives me a bit of a reason to pause. According to The Ocean Cleanup Project:
Other thing to note (from the link above):
So, I guess the intention behind the tethering is that the PET bottle will sink, taking the cap with it, which means it won’t travel as far to get into the ocean (but is still sitting in in our waterways).
(rubbing my temples)… this seems like a really convoluted way to “fix” the problem and will only mitigate the issue, if you have these tethered cap near these 1000 rivers.
Yes, but that data is also harder to gather. It’s very easy to count pieces, it’s much harder to asses volume or dry weight. I’m also not entirely sure if that gives meaningful answers either, because a kilo of polystyrene is worse than a kilo of bottlecaps. If you’re working with a huge of different stuff, all measurements are kind of arbitrary.
The marine litter in the paper is specifically about stuff that gets fished up. It covers floating AND seafloor debris, and floating stuff to a much lesser degree (since nets don’t drag over the water surface). So if the bottles are mostly on the floor and caps mostly float, we would expect to find many more bottles in marine litter.
Mitigation is good though. If you can reduce the volume of plastic in the ocean by a noticable fraction, by basically just very slightly changing the manufacturing process, that’s a good thing.
Oh no… You’ve triggered one of my ecological pet peeves.
The Ocean Cleanup Project is a terrible fucking idea. It’s basically a scam that turns a HUGE amount of amount into a tiny amount of recovered plastic. The OCP reported on twitter in 2025 that they have, in total, removed 40.000 tons of plastic from all their activities. According to this they got about 300m in $A in funding since 2019. I’ll just pretend that’s all they’ve ever gotten, and conclude they spent 5300 USD to remove one ton of plastic waste.
So let me be extremely pessimistic and offer a vastly superior alternative to sailing around with boats and removing basically no waste:
Since OCP already knows where all the waste is coming from, what they SHOULD be doing is going there, buying up all the trash for 1000 USD per ton (which is an absolute fortune to most people there, so they will absolutely cooperate), shipping it to, I dunno, Australia for 100 USD/ton (which is again a fortune), and dispose of it for another 400 USD per ton (which is more than double what we pay here in Europe), and then they would still be 350% more efficient than what they’re doing, assuming the most impossibly generous terms for them.
I agree that it’s more efficient to reduce the amount of new waste from entering waterways than to remove what’s already there, but at this point we need to do both.
Getting it out of the oceans is just more expensive, ton for ton.