[fnordpiglet]

Plastic is generally defined by its mechanical and thermal properties and a dominance of polymers. There’s are lots and lots of different chemicals used as plastics today and they have wildly different chemical properties. It seems incredible to state that “all plastics” are endocrine disruptors. Many plastics are essentially chemically inert in a biological sense. In some ways DNA itself can be seen as a plastic being a biopolymer if it were handled properly and in enough quantity. As an uneducated layman my intuition, and the links you provide, is that the additives and monomers added to plastic to modulate their mechanical and chemical behaviors are most likely to be the chemically reactive part that can be disruptive to our biology. I didn’t find a reference to a single plastic in your references. This applies to the leaching comment as well - I suspect you mean ph and temp increase the leaching of the additives from the plastic.

Am I right?

[chordalkeyboard]

plasticizers are a component of plastic, characterizing one ingredient in plastic as an 'additive' in order to shift the blame from plastic to plastic ingredients doesn't change the basic fact that plastics are endocrine disruptors because they leach plasticizer into food.

[fnordpiglet]

Just because plasticizer has the word in its name doesn’t make it plastic. Nylon, PLA, PET, ABS, these are plastics. As far as I can tell they are not endocrine disruptors, and they are polymers - aka plastics. They require no other “ingredients” and can be used in an unadulterated form for many applications.

Phthalates are monomers (aka not plastics) that are added to plastics to change physical properties of a plastic, such as flexibility, durability, make them more transparent, etc. They’re in fact derived from alcohols to my memory, and have no relationship to plastic. But they are also called plasticizers because they make plastics behave more “plastic” (in the adjective sense not the chemical sense). They are also suspected of being endocrine disruptors. But they’re not “plastic ingredients” - their use is optional and there exist alternatives.

It is in fact an important distinction. There are other plasticizers that are not biologically active that can be used in place. Or, plasticizers don’t need to be used at all. Both of these options make the plastics benign.

It’s an important distinction because plastic isn’t the problem at all, it’s the regulatory framework around plastic additives, none of which are strictly necessary and there are almost always safer alternatives. Plus it’s important to distinguish because it’s simply false to say plastics are a an endocrine disruptor when they aren’t, even if it’s convenient to get your point across.

[coryrc]

ABS is only partially a plastic.

You can't avoid a plasticizer and still use i.e. PVC for the vast majority of its consumer use cases, which is what you are alluding to (I think) but you also can't just use the same molds and design with a different plastic. Of something's designed for UV resistance, you can't use the same design with an environmentally-friendly plastic. Like, it would have to be designed to be painted or metallized or something. At this point it's a different product: the products as currently made must be outlawed. No more aluminum cans with soda. No more lightweight waterproof jackets.

[fnordpiglet]

Goretex is made from PTFE which is pretty safe at normal environmental temperatures.

But, yes, the additives we use were picked for practical reasons and only later learned to be unsafe.

Phthalates are generally the most concerning plasticizer but they’re being phased out in favor of safer alternatives, and even safer alternatives are being intensely researched. According to this website [0] non phthalates account for 20% of all plasticizer today an expected to grow 4% in 2022.

What I find strange is the assertion that my cheap Chinese steel water bottle is somehow safer than a food grade PET water bottle from a reputable manufacturer.

[0] https://www.ceresana.com/en/market-studies/chemicals/plastic...

[klipt]

Right but in the absence of regulation, I would treat with suspicion e.g. fast food in any plastic container (or waterproofed "paper" container which usually means a plastic layer too).

I consider glass, stainless steel, and cast iron safe, and try to avoid almost anything non stick or plastic for cooking/food storage.

[fnordpiglet]

PTFE (nonstick coating marketed under Teflon) is safe unless you inhale a lot of its fumes by heating it to over 500F. And by a lot I mean cases of fume fever show up with people welding lots of ptfe. You are probably thinking of Perfluorooctanoic acid, which is carcinogenic but most exposure happens from fabric coatings. It was banned in the US in 2013 and none of it is manufactured or used in the US currently.

Which is an example of regulation of additives to plastics. The plastic itself (PTFE) isn’t the problem, it’s the additives.

I’d point out interestingly PTFE is what Goretex is made out of. You heat PTFE then jerk it hard and it foams into a fabric.

[klipt]

> The plastic itself (PTFE) isn’t the problem, it’s the additives

Yes and what additives are being added to the PTFE in your non stick pan now? Do you know? Are they proven safe or merely not banned yet?

[fnordpiglet]

In the absence of regulation I see no reason to believe that metal is stainless steel, that glass is unadulterated, or that iron doesn’t have toxic metals mixed in.

I would focus energy on advocating for regulation unless you smelt your own metals.

Edit: I’d be much more afraid of heavy metals from low quality steel, glass, and iron than modern plastic additives. Food grade plastics are heavily regulated, but metals and glass not really outside of a medical setting.

[klipt]

Toxic metals have been understood for a while so I would hope they are better regulated.

Plasticizers are clearly not well regulated yet, "BPA free" stuff just uses BPS which is just as bad.

[fnordpiglet]

Hope isn’t a strategy.

[philipkglass]

Not all plastics contain plasticizers, so I would say that fnordpiglet is correct. For example, low density polyethylene (commonly used for jugs holding milk and water) is flexible without addition of any plasticizers. For this reason it is also used in laboratory equipment where plasticizer contamination would interfere with experiments:

Low density polyethylene (LDPE) is a high molecular weight polyolefin material. Like all polyolefins, LDPE is nontoxic, non-contaminating and exhibits a high degree of break resistance.

The polymerization of polyethylene results in an essentially straight chain, high molecular weight hydrocarbon. The polyethylenes are classified according to the relative degree of branching (side chain formation) in their molecular structures, which can be controlled with selective catalysts. LDPE has more side branching than HDPE resulting in a less-dense 3-D structure. As a result, LDPE is naturally very flexible without the addition of plasticizers and melts at a relatively low temperature (85°C).

https://www.thermofisher.com/us/en/home/life-science/lab-pla...

[fnordpiglet]

You should say I’m correct more often, then I can reference that for my wife’s benefit.

[a1369209993]

> In some ways DNA itself can be seen as a plastic being a biopolymer if it were handled properly and in enough quantity.

To be fair, DNA absolutely disrupts all kinds of biological processes - that's why viruses do anything, for example. And random nonsense DNA that you'd see if someone was using it as a plastic would probably uncover new and exciting failure modes that existing biological systems haven't had to deal with before because nothing natural produces pure DNA in absurd enough quantities to make plastic bottles out of.

[tomp]

Not really, no. For obvious reasons, genetic material is very hard to get into a cell. The immune/digestive system fights it!

That’s why mRNA (BioNTech & Moderna) and DNA (J&J) vaccines took so long to develop!

[a1369209993]

> For obvious reasons, genetic material is very hard to get into a cell. The immune/digestive system fights it!

That's quite true, but it's true precisely because it's horrifically disruptive. (And the immune system has had more time to evolve protections against that disruption than it has for previously unheard of synthetic polymers.)

(Although to be clear, the new and exciting failure modes probably wouldn't involve the synthetic DNA actually getting inside of cells. (Sheer quantity might be sufficient to shove it's way through a phospholipid bilayer, but probably not.))

[fnordpiglet]

Next time you eat food realize it’s completely chock full of dna. Unless you eat a lot of non organic stuff, like plastic.