Research shows plant-based polymers can disappear within seven months
today.ucsd.edu
today.ucsd.edu
> Microplastics can take anywhere from 100 to 1,000 years to break down and, in the meantime, our planet and bodies are becoming more polluted with these materials every day
In general "biodegradable plastics" currently on the market should still be heavily scrutinized. So far it mostly has just meant it gets to the microplastics stage faster than other plastics. Not only does this have negative health consequences for us and fish, but it also makes it much more difficult to ever recycle and re-use these plastics
https://www.biopak.com/au/resources/biodegradable-plastic-pr...
Still, it's exciting to see progress on the possibility of an actually sustainable version of biodegradable plastic. Hopefully it can scale and doesn't lead to other micro pollutants
Are there any actual concerns with pure PLA?
https://en.wikipedia.org/wiki/Polylactic_acid#Degradation
No mention of its actual life cycle as it turns into a microplastic ie so it should be presumed dangerous in the same ways.
You really cant generalize “all industrial plastics” as “plastic” is way too broad a concept. Good engineering plastics like PEI/PEEK dont even need to use any additives like plasticizers, stabilizers, cross linkers etc.
Define "just fine". PLA microplastics can have strongly hormonal effects. In european perch, for example, they were even found to significantly alter social behavior.[0] MPs can cause tissue damage, oxidative stress, and changes in immune-related gene expression as well as antioxidant status in fish[1] and humans may experience oxidative stress, cytotoxicity, neurotoxicity, immune system disruption, and transfer of MPs to other tissues after being exposed to them.[1][2]
[0] https://www.sciencedirect.com/science/article/pii/S004896972...
[1] https://www.frontiersin.org/articles/10.3389/fenvs.2022.8272...
[2] https://www.undp.org/kosovo/blog/microplastics-human-health-...
Some other things can even go faster and easier, but you can use pla without feeling guilty of anything.
It doesn't do the world any good to make anyone wary of such a huge improvement.
> The last measurement involved chemical analysis via gas chromatography/mass spectrometry (GCMS), which detected the presence of the monomers used to make the plastic, indicating that the polymer was being broken to its starting plant materials. Scanning-electron microscopy further showed how microorganisms colonize the biodegradable microplastics during composting.
"Degradation and metabolism of synthetic plastics and associated products by Pseudomonas sp.: capabilities and challenges"
https://enviromicro-journals.onlinelibrary.wiley.com/doi/pdf...
Long-term exposure to sunlight and physical abrasion contributes to the formation of microplastics (<5 mm). Microplastics can be degraded further by microorganisms. Consequently, biological degradation and subsequent metabolism have the potential to eliminate plastics from contaminated environments.
...
With respect to plastic degradation, the species of the genus Pseudomonas are amongst the most cited degraders of various extents for a wide range of plastic polymers. Complete biologically mediated elimination of plastic polymers first requires breakdown of the polymer into smaller oligomers and, eventually, monomers that can pass through the cell membrane followed by assimilation and subsequent intracellular metabolism. Here, we present a review of the capabilities of species of the genus Pseudomonas to degrade and metabolize synthetic plastics.
Always this need to wait 5 years or so until European Union decide to fine them if they don't get their shit together.
[1] https://en.wikipedia.org/wiki/Carbon_disulfide#Health_effect...
i know intuitively they would be, but i haven’t actually found good evidence when i’ve gone searching
[1]. https://www.theguardian.com/environment/2024/mar/06/microsco...
Haven't seen any such studies, but I'm sure they're out there if you look hard enough.
...call it 5 or 10 years. But anything that gets us away from the functionally "forever" of current plastics would be a win
Sounds like a good avenue for (organic) material science research.
Materials science has come a long way, but some problems still are not solved and it isn't always clear if the problem can be solved.
I have found old buried plastic bags, from supermarkets - I remember the bag style from just a few years ago. The bags had severely degraded. When I tried to pick one up, it fell apart into small pieces, what integrity it had was gone. I've had the same experience with bags left in lofts - they degrade.
From my personal experience, I therefore assume that plastics already disintegrate after about 10 years, not 100 or 500 years, as you state.
The problem with plastic is that while the macroscopic structure can be altered in just a few years (depending on the conditions), the resulting parts aren't being metabolized away by micro-organisms and they remain as small plastic chunks, and then micro-plastic, then nano plastic, until they eventually break down entirely after decades, which is very unlike what happens with what we call biodegradable materials.
If I have understood your position correctly, this is certainly counterintuitive... because if there is not much plastic bag left, you'd think that whatever broke down the bag, would also be able to break down these smaller bits (microplastics). But you are saying that small bits of the bag remain for decades, even though I can't see them.. I just don't see why small bits of plastic bag would remain, when it is evident that something in the ground already degraded the plastic bag as a whole.
They are being degraded, just slowly.
> Is that a theory to you, or do you have first hand knowledge?
It's not a theory of mine, you can find the explanation in practically any explanation of what "microplastics" are.
> If I have understood your position correctly, this is certainly counterintuitive... because if there is not much plastic bag left, you'd think that whatever broke down the bag, would also be able to break down these smaller bits (microplastics)
That's correct, and it eventually happens, the process is just very slow, let me try explaining it to you:
Plastics are made of very long polymer chains, composed of the same small molecule (monomer) chained together millions of times. Let's assume we have a plastic for which half[1] of the connections break down in 50 years. If I'm not messing the math up, it means that every year you lose roughly 1% of the connections between the molecule. So, after one year, your chain of 1 million molecules have been cut in 10,000 smaller piece of 100 monomers. Then the next year, there's again 10,000 connections that will break (~1% of the remaining 990,000 connections), but this time it will just double the number of pieces (if you cut a piece 10 times, you and up with 11 pieces, if you have again 10 scissor hits on the next 11 pieces, you'll end up with 21 pieces).
Of course my model is not entirely accurate because I looked only at the 1D molecular structure, when plastics are actually 3D meshes of these chains, so multiple chains are holding one another and it slows down the macroscopic effect, but you should get the idea of why it first degrades relatively quickly at macro scale and then slower at smaller scale.
[1] half times are a good way to model degradations of chemical compounds, at least the “spontaneous” ones, but keep in mind it's a model: it's not flawless and it's not able to describe every degradation phenomenon (for instance it fails to describe degradation from microorganisms that can grow on a substrate they are degrading hence the “spontaneous” qualifier above).
I get how these connections are meant to break down, though not to the detail you provided. It could be like you say, though I don't why the degradation wouldn't be concurrent - ie I don't get why half times are a good way to model plastic degradation, when all of the plastic is exposed to 'scissor hits' all of the times. Ie, once the scissor hits start to impact the bag, I would think the bag would soon fully disintegrate.
Assuming it is like you say, if a plastic bag is brittle, going to dust after just 10 years after being in the ground, (I'm using supermarket bag design as a means to figure out the age of the bag,) that is far from 50 years to break down half the connections. This is too say the metric to measure degradation seems wrong to me... Or perhaps the metric is the case in artificial, sterile conditions, which the ground is not.
They are all exposed to scissor hits all the time, but it's a stochastic scissor. You can think of every connection rolling many dices every second, and whenever they all land on 1 the molecule breaks. This kind of behavior leads to exponential decay, which is subject to half life.
> Assuming it is like you say, if a plastic bag is brittle, going to dust after just 10 years after being in the ground, (I'm using supermarket bag design as a means to figure out the age of the bag,) that is far from 50 years to break down half the connections.
Why? You don't need to break all connections to break to dust. They are trillions of connections to break if you want to degrade the compound to its primitive molecule, but only thousands if you want to shred it to pieces. Keep in mind that if the monomer measures 1nm, a piece of plastic of 10um still has 10,000 connections. And if at the beginning you have a piece of plastic that's 10cm long (all reasoning are 1D here for simplicity), you just need to cut it 1000 times to get to 10um (so at 10um you're still much closer to the beginning than to the end, even though the plastic is now invisible).
> Or perhaps the metric is the case in artificial, sterile conditions, which the ground is not.
As I said before, it's a model and you're right it's not entirely accurate. Yet plastic doesn't have much enemies living in the ground, so it's pretty close to being sterile from the perspective of the plastic. And that's actually the problem we're facing right now.
> Yet plastic doesn't have much enemies living in the ground
But this is the very point I'm making in my first post in this thread - that I found a fairly recent plastic bag (~10 years old) that was badly degraded.
Perhaps there aren't adverse conditions in the lab. Or perhaps the measurements are wrong? Perhaps these micro plastics are too small to see... But the info we are given should correlate with one's personal verification, I hope you agree.
It's not linear, it's exponential! And, as I said before microbes are special and are not well represented by half-life models, but they aren't too relevant for plastics (and that's the reason we call plastics ”non-biodegradable”)
> that I found a fairly recent plastic bags (~10 years old) that was badly degraded
I've spent the past two comments explaining why this happens, and why the plastic bag can appear degraded even though there's little degradation overall in the material itself.
It's OK that you don't understand the phenomenon, I'm probably at fault here for not explaining it well enough although I did my best. But if you don't understand it, please at least admit that it's what happening even if it sounds counter-intuitive to you.
It's not the lab conditions that are at fault here, it's your understanding of the mechanism and my limited abilities to explain them to you.
If you are curious I'm pretty sure you can find much better explanation on YouTube or elsewhere, as the internet is crowded with extraordinary science teachers. And if you aren't that curious (that's OK, life is short we cannot learn everything) then at least please admit the result and move on. Do not assume that “everybody else is wrong including polymer scientists, and microplastics don't exist because once I've seen a bag that was in bad shape”. It's just your intuition is just wrong, and that's OK.
Not at all - I thank you. I am curious and want to understand. I simply don't accept counter-intuitive claims without good reason. I accept that such things as counter-intuitive claims exist. But, even so, I need to know how to verify things personally.
So, if I see plastics that are turned to dust after just 10 years, but another is saying that the dust continues to degrade for 500 years, I can consider the claim - but I want to know how it can be verified. Once you are talking about stuff you can't see or confirm, you are in thrall to experts. Unfortunately, when information or tools are not available to others, this provides cover of darkness for all sorts of poor ideas.
I can imagine all sorts of claims... but I'm after knowledge, not hearsay. And knowledge is not a communal endeavour - it is personal, based in personal verification. To me, even scientific claims are hearsay - you of course will know about the reproducibility crisis, and will no doubt have countless examples of how science presumed to know one thing, then changed position. Of course, this is the scientific method - nothing is set in stone. But science present monolithic conclusions that might be wrong. And its not like scientific endeavours cannot be steered by money.
The philosophical issue in play here relates to knowledge. What is it that knows - is it a group or an individual? Can it be that one part of science state this or that to be true, and everyone else must then uniformly accept that pronouncement? A pronouncement that cannot be verified personally? Even though we know that all science is the output of flawed humans? Etc.
Thanks for the exchange.
Science is a social thing, and as such it's far from an ethereal ideal of knowledge production. But at the same time, it's the best tool we have by far…
Maybe re-reading my explanation tomorrow or another day can help you grasp the phenomenon better ;).
Have a nice day.
Yet the general consensus seems to be that in a perfect world governments are democratic, and therefore beholden to the will of the people, not authoritarian like you suggest. But if the will of the people wants to see a change in the use of plastic, they don't need it to flow through government, they can simply change their buying habits.
And good packaging materials rarely make for good marketing.
Of course you can. Facilitating such a thing is Kickstarter's entire business model, as an example. You can also refrain from buying, communicating to other people that "I'm not buying your product unless you..." which gives really strong incentive to do things differently.
It's not like government is some kind of magical thing. It's just people. And in the case of democratic government, it's the very same people.
Day 56 after I refrained from buying food: I'm now dead.
No. Not sure why would you would choose to reply before reading the comments, but since you have... we are quite explicitly talking about at least one consumer expecting food packaging to degrade within a similar period as the food contained within, with a suggestion that an authoritarian government in a perfect world would recognize that as a good idea and force it upon the people.
But the general consensus seems to be that, in a perfect world, governments are democratic – a notion you do not seem to discount.
Under a democracy, if he stands alone in that desire of short-life packaging, nothing is going to change. No business is going to cater to his unique want (well, maybe if he's exceedingly rich and is willing to pay disproportionally for it) and government is not going to act on the wishes of one person (that would be undemocratic). If a majority of people share in that desire, though, then businesses would face pressure to provide when consumers make that choice clear. Any business that fails to comply will suffer the consequences of lost profits. The people can enact a law that prevents themselves from buying the product they already don't want to buy, but that doesn't accomplish anything. They've already decided they don't want to buy it!
Democratic government is useful for cleaning up minority groups who try to act against the wishes of the majority, but in this particular case you have not even made clear why the minority would be stuck on buying 'forever' packaging or what businesses would gain from catering to the minority. People don't care about food packaging that much. Once the majority are buying short-life packaging, the small number of people who want to watch the world burn will be priced out of the market anyway. As such, there is no need for government. The people can just do it...
...and if they don't, that's the end of it. Magic isn't going to swoop in and save the day. The democratic government is nothing other than the very same people who have already decided that, in this scenario, they don't want to do anything.
But maybe what you're really struggling to say is that democracy wouldn't be found in a perfect world? Fair enough, but I'm still not sure that's the general consensus.
Sure. And where am I supposed to find affordable food not wrapped in plastic? Ideally in my city and not 100kms away, and not 10 times the price. And now that you're at it, please tell me where I can buy food that is not already polluted by microplastics?
This kind of argument is a just a “blaming the victim” kind of reasoning.
The same place you expect to find it when you outlaw food wrapped in plastic. It's not going to disappear until people stop buying it. You can create a law to remind you to not buy food wrapped in plastic, or you can just not buy food wrapped in plastic. So long as the population is on board with the idea of not buying food wrapped in plastic, there is absolutely no difference.
If you are suggesting that the population isn't on board and everyone other than you is quite happy to keep buying food wrapped in plastic then a democratic government would never create such a law in the first place, rendering the entire discussion moot. That would not be in alignment with the will of the people. Democracy does not serve individual whims.
People aren't going to stop buying it as long as it's the only option!
> You can create a law to remind you to not buy food wrapped in plastic,
It's not about reminding you not to buy, it's about banning people from selling. You know, as they already do for dangerous stuff like Kinder Suprise in the US…
> or you can just not buy food wrapped in plastic.
You cannot because nobody is selling it.
> If you're suggesting that the population isn't on board, then a democratic government would never create such a law in the first place. It would not be the will of the people.
The population is on board, but population-wide synchronization don't happen for free you know. Here's a fun example: here in Europe the majority of people is against daylight saving time. Yet there is one. That's stupid you'd say, because they could actually collectively decide not to change their clocks' time and call it a day, DST is gone. But in fact, doing so would require an enormous amount of coordination, and this kind of amount of coordination is the exact reason why we've created the State in the first place! And it's actually its only power! (armed force: literally started as just a well synchronized militia, same for law enforcement, collecting taxes: just make sure to get a big enough group to raid the house of the people who refuse to pay, etc.)
Then that's it. Game over. Until buyers stop buying what's already out there, vendors don't have an avenue to sell any kind of replacement. Fortunately, your view is quite disconnected from reality. In the real world people talk, negotiate, and work to satisfy the buyer's wants and needs.
> It's not about reminding you not to buy, it's about banning people from selling. You know, as they already do for dangerous stuff like Kinder Suprise in the US…
Not to mention illicit drugs. They, of course, straight up vanished from the US as soon as it became illegal to sell them. Oh wait.
Let's be real: If someone is buying, there will be someone ready to sell. The law ultimately has to compel the buyer to back away. You can say the onus is on the seller, but you're just looking at the opposite side of the same coin.
> Yet there is one.
Meaning that if I decide to keep my clocks on a constant schedule it's straight to jail for me? If not, how does that relate to a law that would penalize you if you sell (or buy) plastic-wrapped food? In this part of the world, at least, if you want to ignore DST, go nuts. DST only exists because the people just do it, not because there is some legal threat that keeps them on the straight and narrow.
> and this kind of amount of coordination is the exact reason why we've created the State in the first place!
If the state is democratic, the people have to coordinate first. Without such coordination, there is no way for democracy to take place. Once the people have coordinated their will, they can just do it. Like you point out with DST – at least to the extent of its existence in my part of the world – you don't need a law to force people to do what they've already decided to do. They can just do it. Simple as that.
Such laws are useful for keeping the minority dissenters in line with the will of the majority, but in this case once the majority has stopped buying plastic-wrapped food, it is highly unlikely there will be a compelling business case to serve the small handful of people who want to see the world burn. I mean, even if you don't give a rat's ass about the environment, are you really going to go well out of your way to buy plastic-wrapped food? Not likely. You're just going to buy the food the same way everyone else is. It will be cheaper and much, much, much more convenient.
The previous commenter's idea of an authoritative higher power forcing the people to bend to his will is great and all, but doesn't work with democracy. If a perfect world sees that government be a democracy, as the prevailing consensus seems to indicate, then that idea is out the window in said perfect world.
That's pretty fascinating to see that you're reading literally everything backward, like not only the real world around you but even what I'm writing! I'm talking about the fact that nobody is offering the possibility to buy stuff that's not wrapped (and for legit business reasons, it's much easier on their supply-chain management to do so this way), and you're interpreting as if the problem was on the demand side.
And everything is in the same vein: I'm talking about a situation where the supply side is definitely not providing what the consumer want, at least a significant fraction of the population, and you insist in arguing as if plastic packaging was driven by consumer demand: it is not it's cost saving and supply chain ease of use on the supply side, not demand. And that's why you can't find any: why would a business bother doing what the customer want when they can get away with costs savings because customers have nowhere to go.
> Meaning that if I decide to keep my clocks on a constant schedule, it's straight to jail for me?
Chances are that you'll straight up lose your job after a couple days. Then you'll see how your freedom not to change your clock time is respected when you're being evicted because you could not pay your rents due to lack of revenue. By the way that's a good illustration of the difference between freedom in a vacuum, and the actual exercise of freedom in a socially interconnected world where your agency is in fact very constrained by material factors.
> If the state is democratic, the people have to coordinate first. Without such coordination, there is no way for democracy to take place.
Fascinatingly steady with backward-driven thinking indeed! You can't have democracy if you don't have a state entity that's able to run the elections and enforce them. The democratic character of the state comes later, once the people already in charge have been confirmed through the election, or when they decided to step down if they lose. Coordination comes from the state, which can then replicate itself thanks to this coordination. No state started with an election, at the very beginning was always somebody getting power through other means (be it a foreign invader, a previously ruling king, or a group of insurrectionist).
> Laws are useful for keeping the minority dissenters in line with the will of the majority, but in this case once the majority has stopped buying plastic-wrapped food, it is highly unlikely there will be a compelling business case to serve the small handful of people who want to see the world burn.
But without enforcement, nobody will ever be able to buy such food, because nobody has an incentive to sell it in the first place. It's cheaper to sell plastic wrapped food, and because the externalities come for free, the business isn't paying the cost of their behavior. Buyers, or at least a significant fraction of it, realize the cost, but they don't have any leverage on the business because there's nowhere to go. The same way I'm not buying a smartphone that's being manufactured in my country, because there isn't any.
> Laws are useful for keeping the minority dissenters in line with the will of the majority
Not only. Laws are also setting the state budget, the tax levels or food and drugs safety standards, your interpretation of what law is supposed to do is indeed very limited in comparison to what it actually is in the real world.
> he previous commenter's idea of a higher power forcing the people to bend to his will is great and all, but doesn't work with democracy.
No, there's no non-democratic high power in charge up there, it's just a matter of democratic state intervening to fix a market imperfection (negative externalities), but in your now infamous skill to misinterpret everything, you managed somehow invented some authoritarian power in the discussion. Well done.
Maybe you could try reading what other people are writing twice before commenting, or maybe three or four times, just to be sure you're not making things up in your head, because that's a recurring theme at that point.
Edit: oh I found this gem in another comment of yours (https://news.ycombinator.com/item?id=39783570)
Not sure why would you would choose to reply before reading the comments
The irony is absolutely delicious.
* One, the amount of carbon that get wasted if that sandwich goes bad is immense compared to the small amount of carbon it takes to make the plastic.
* Two, in places with decent waste management, what is wrong with the plastic sitting in a landfill.
* Three, assuming you are still going to protect food items, the alternatives are all heavier materials that will increase transportation costs and pollution.Given the people who are in the food supply chain are probably going to be sourcing the same packaging from maybe 2-3 vendors, I don’t see anyone able to differentiate themselves on packaging tech.
50 years ago many fruits and vegetables had a lot shorter shelf life, however that has been greatly extended due to selected breeding. For example tomatoes used to have a shelf life of around 3 days, but now it's 3 weeks or more.
The disadvantage of this is that now there are a few varieties that dominate what you can buy in supermarkets, and they are optimized for economic features. This means other features like taste and nutrient content are a lot worse than it was 50 years ago.
This is corporations 'socialising' the expense of their decisions via writing laws. Why should they pay?
Why make things last when you can have them "naturally" self-destruct and force you to buy again, under the guise of greenwashing?
It's cynical bordering on humor to look at the accumulation of forever trash in our oceans and blood and say "well at least we can build something that may last with all this poison". Nobody does that anyway.
PLA is stable enough in normal circumstances -- you need specific equipment to make it degrade -- but once broken down to microplastics it doesn't last long. Otherwise it's nearly an ideal plastic for printing; brittle, but strong and incredibly easy to print. With some additives you can get rid of the brittleness, though I'm not sure how those would degrade.
I see no reason you couldn't make plastic straws from PLA. Clothing might not last as long, but plastic clothing never lasts that long in any case; I prefer cotton.
Ssh - you will give the electronics industry ideas :)
Those are the least likely to degrade into microplastics anyway, unlike clothing fibers and the like, and that is already assuming you believe that microplastics have any actual effects.
nobody is trying to replace your iPad with a compostable version that disolves in humidity.
The article talks about phone cases and clothing.
(All clothing degrades; presumably you don’t object to wool or accuse wool sweaters of planned obsolescence.)
[1]: https://www.theguardian.com/global-development/2023/jun/05/y...
We could probably design washing machines to filter it better, granted.
https://ourworldindata.org/ocean-plastics
What we need to do is assist these few countries with better waste management, that is what by far would have the biggest impact. Not saying we shouldn't do other things too like trying to find new materials for fishing nets or reducing fishing but plastic bags in the west is not a significant source.
The same fires that poison the air we breathe also power life saving medical equipment so that we can keep breathing.
Micro plastics, endocrine disrupters and more have been unleashed. I am sure their effects will prove to be less than positive on both humans and wildlife.
But in trying to snuff out the next great environmental crisis, will we account for the benefits we've derived from the use of these materials when we do our cost-benefit analysis? The effects on innovation?
Did curiosity kill the cat, but save cats?
But I think looking around Times Square is not the best way to study this scientifically.
The studies that have been done in the Great Pacific Garbage Patch shows that it's majority from China, with Indonesia a strong seconds. US contributes < 1%.
This would be a more convincing post if I could point to sources. I don't have time to dig those up, so this data is from my memory. Take it for what it is...
Nothing lasts. Durable plastic and metal goods become damaged or worn. What then? When repair, reuse, or recycling is not socioeconomically attractive, having some sort of naturally sustainable cycle would be nice, wouldn't it?
Even if I have to buy a new phone case every seven months, if it's part of a sustainable cycle that becomes quite economical due to the massive scale -- wouldn't that be better than maintaining the current production of long-lived plastics?
This strikes me as an example of capitalism learning something from biology.
Degradable devices sounds like the sort of thing intended to assuage the consciences of very rich people who buy the newest iPhone every year.
That's capitalism taking a lesson from nature.