3mo ago

Starch-based bioplastic may be as toxic as petroleum-based plastic, study finds

www.theguardian.com

Starch-based bioplastic that is said to be biodegradable and sustainable is potentially as toxic as petroleum-based plastic, and can cause similar health problems, new peer-reviewed research finds.

Bioplastics have been heralded as the future of plastic because it breaks down quicker than petroleum-based plastic, and is often made from plant-based material such as corn starch, rice starch or sugar.

The material is often used in fast fashion clothing, wet wipes, straws, cutlery and a range of other products. The new research found damage to organs, changes to the metabolism, gut microbe imbalances that can lead to cardiovascular disease, and changes to glucose levels, among other health issues.

The authors say their study is the first to confirm “adverse effects of long-term exposure” in mice.

Study ... https://pubs.acs.org/doi/10.1021/acs.jafc.4c10855

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3mo ago

Starch-based bioplastic may be as toxic as petroleum-based plastic, study finds

www.theguardian.com /environment/2025/may/13/starch-based-bioplastic-petroleum-plastic-study

50 comments

AFAIK the claim was never that bioplastic are "healthy", the claim is that it breaks down way faster. Preventing a buildup as we have seen with mikroplastic.
Sensationalist headline IMO.
- It doesn't breakdown as fast as claimed, either. PLA needs high temperature composting to breakdown.
  It's not impossible to do, but nobody bothers. It's one of the more sustainable options for 3d printing, so we should get on that.
  
  I actually see it as weirdly counterproductive. When bioplastics degrade they release their carbon into the air as carbon dioxide. Whereas a properly landfilled piece of plastic takes its carbon permanently out of circulation, it's literally sequestered.
  Landfills get a bad rap. When they're done right they're a clean and reliable way to deal with waste. They're just easy to get wrong if you don't care, and they look so unphotogenic it's easy to campaign against them. But one of my favourite parks is a former landfill done right, aside from the occasional monitoring well scattered around the place there's no way to tell what it used to be.
- Don’t the still break down to microplastics since they are so resistant to being broken down?
  
  IDK how fast they break down, they are supposed to break down faster. But apparently not as fast as to makers claim.
Ok so what do we want? Toxic plastics that last forever or toxic plastics that break down in the environment after 3-5 years?
Because that is the gambit here. We're not going going to just get rid of plastics altogether.
Also, this article is setting off my BS meter by claiming plastics contain 16,000 toxic substances but not showing how much of that is realistically possible to get into your body. The dose makes the poison!
"This spider contains 1300 toxic substances—one of which will kill you if even a tiny droplet gets in your blood! And these spiders are out in the environment!"
- I think “no plastics” is actually what we want
  
  Are there any good alternatives though?
  
  Or maybe qualify that as "minimal plastics".
- I smell petroleum company money.
- Hm, depends how 'breaking down' is defined. Because it usually doesn't mean there's no toxic substance left. Instead, plastic degradation often IS the formation of micro or nano plastics. In this case, it's irrelevant how long this process takes without knowing how long it takes until there's no toxicity left.
  Also, if something is described as 'biodegradable', I wouldn't blame a consumer for composting it. And if it actually poisons the compost, that's net harm. So, it'd be actively harmful green washing.
  
  It is crucially relevant how long decay takes. That's why there's microplastics in your food and your body. Because plastic does not degrade for hundreds of years. Fucking Obviously, that is the single most important aspect of it.
- Unfortunately, most bioplastics are more like 300 years, which yes, is significantly better than 300 thousand years, and with industrial compost heaters you can push those 300 years down. But I've also had to come to terms that my failed 3D prints will likely outlive me (although I do collect the waste to hopefully recycle someday). I don't print that much compared to most in the hobby, but it is something I consider before I print things.
  That said, I'm not going to let perfect be the enemy of good, and the biodegradability of bioplastics is still exponentially better than petroleum plastic.
- Less plastic is what I want. The world is addicted and we need safe alternatives. Reduce and reuse come before recycle for a reason.
  Plastic is useful in a lot of applications, but does it really need to be in everything from our clothes to our shopping bags to our bodies?
Was the study funded by Big Oil?
. . . Just. Curious.
- I tried to access the study but can't find it at the usual mirrors (yet). They usually just have a line like 'the study authors and funding partners do not have any conflict of interest in this area of study' so it requires a journalist or some expert to dig into the funding sources. AFAIK.
“Starch based” plastic is just a way to greenwash PLA.
Just because the C, H, and O originally came from starch, does not automatically make the chemically synthesized product safe.
- It does mean no petroleum was used to make the plastic, which is one environmentally-friendly aspect.
  
  That's incorrect, making things from crops that use farms which could be wildlife habitat and use oil based fertilizers and pesticides isn't necessarily better or emit less net co2. It may in some cases be better but just like corn based ethanol it can also increase food shortages and depending on where it's grown be worse than just using oil.
  
  It barely makes it that far.
- The point of these plastics isn’t greenwashing, the point is to biodegrade. Petroleum plastics don’t break down in compost or a landfill.
Me looking at my shiny new 3D printer after all this stuff:
- Yup, this is why my printer is in an enclosure and always vents to outside no matter the filament I'm using.
  Even though I kinda like the sweet smell of melted PLA. :(
  
  It's a Prusa MK4, so I'll get it upgraded to the Core One to get it enclosed, and construct a vent.
  Based on what I'm reading, the glass transition isn't the issue, it's the plastic itself. PLA is brittle, and taking supports off creates an incredible mess. I also use ASA, and while it seems to be less brittle, there's still quite a mess. (Thankfully, ASA doesn't breakdown to release the styrene until it hits 400C, and the extrusion temp is 260C. That means the accumulation of the microplastic doesn't include the carcinogenic aspect, just the ones listed and suspected of micro plastics in general).
  I used to use an SLA printer since I like making minis, but the resin started irritating the shit out of me, was insanely difficult to clean, and apparently the UV reactant is carcinogenic. I stopped using that entirely 4+ years ago (maybe used it for 6 months irregularly). I want another, but not without a much better workspace and proper ventilation. Except it, as well, results in a resin copolymer that I would find extremely likely to cause the same micro plastic hazard.
Imagine that, plastics are dangerous

50 comments