It doesn't matter as long as they're actually "micro"?

May I remind you of the toxological properties of e.g. polyethylene, the world's most widely-used plastic:

https://pubmed.ncbi.nlm.nih.gov/17365139/

This applies to pure PET, but not chlorinated/fluorinated PET, which have been shown to contain PFAS.

I googled and fluorinated PET does not seem to exist. In fact one source said it's not even possible to do that.

And just adding fluorine to something does NOT make it a PFAS! PFAS is a very specific chemical, not everything with chlorine or fluorine is a PFAS.

Sorry I meant polyethylene, without the terephtalate. https://www.sciencedaily.com/releases/2023/03/230307114431.h...

According to the FDA such containers are not permitted for food use, only for chemical storage, such as pesticides.

Additionally they are very very rare (only used where the chemical can't be contained in simpler plastics), and are not really where your attention should be on the hazards of plastics.

The amounts of microplastics are ever-increasing and there could be a serious threat from their degradation into nanoplastics: https://www.sciencedirect.com/topics/chemistry/nanoplastics

A carbon-carbon bond is 0.154nm, and the polymer chain lengths of common plastics are in the few hundred to tens of thousands.

If those are a "serious threat", then I wonder what they think of petroleum jelly... which is basically the same structure with much shorter chains, and is even more reactive!

How much chemistry knowledge some of these fearmongers have is highly dubious.

below the dangerous amount

which concentration is that?

Not all substances have a threshold level.

One molecule will irreparably damage you?

In the right spot, yes.

What does it do?

Really? What spot would that be? I challenge you to come up with a spot where a single molecule will irreparably damage a human.

This is a fun game. Do I get to place it anywhere?

Single molecules of plastic getting involved in the process of rna transcription in cells resulting in genetic mutations or cancers.

That's the spot!

Would a single molecule causing a single cancerous cell be sufficient to trigger a cancer?

EDIT: Should have searched. https://www.cancerresearchuk.org/about-cancer/what-is-cancer...

It checks out that a single unchecked self-reproducing cell could rapidly create a lot of them. I just thought there'd be control mechanisms to cause other cells to attack them.

But it is realistic apparently! Welp!

Of course there are control mechanisms. The question is whether plastics are more or less carcinogenic than everything else we deliberately consume. All signs so far suggest less, far less.

Sure, sure. I was only interested in the no-minimum-threshold model and what were the causative things there. As always, I should have asked ChatGPT since it had a pretty good explanation.

The spot were it mutates a gene leading to cancer.

quantify it

> so what concentration of microplastics would you accept in your food?

As a rule of thumb, a tenth of empirically demonstrable toxicity. That's a good basis for thresholds, both legal and medicinal.