> PFAS are a special set of surfactants because, being perfluorinated, evolution is unlikely to have endowed us with effective ways to neutralize them.
I mean...maybe? That's a huge statement without any evidence. There are tons of other organic fluorines in common use, so while I'm not rushing out to bathe in firefighting foam, if I got hit with some while escaping a burning building, I'd be OK with it.
> I think our (the anti PFAS crowd) concern stems from being able to identify many chemical pathways that can make these very dangerous and therefore believe that they should be proven safe by studies
That's not how empiricism works. You can't prove that something has no bad effects. That's called "proving a negative", and it's an infinitely high bar. Remember: millions of people die from dihydrogen monoxide exposure every year! We must ban it until proven safe!
Also, this:
> stems from being able to identify many chemical pathways that can make these very dangerous
...is pseudoscience. Everything is resting on the "can make" part of that sentence. There are so many "chemical pathways" (most of which we know nothing about) that any claim about a particular chemical triggering a particular pathway to negative human outcome absolutely must be backed by solid empirical evidence, and not just speculation or theory.
See also: "the dose makes the poison." Even completely innocuous -- or beneficial! -- chemicals are harmful if you consume too much of them. There are "chemical pathways" that can absolutely kill you if you take too much Tylenol, or drink too much alcohol, or eat grapefruit when taking certain statins, or a large number of other innocent things.
My current summary of the state of evidence around PFAS is that there's a constellation of weak/bad studies suggesting that the water-soluble variants might have bad effects in some animals. Bioaccumulation clearly occurs, and therefore caution is warranted (particular with certain manufacturing processes or pollution), but the people who are extending that to egg pans and sandwich wrappers are way out over their skis.
I mean...maybe? That's a huge statement without any evidence. There are tons of other organic fluorines in common use, so while I'm not rushing out to bathe in firefighting foam, if I got hit with some while escaping a burning building, I'd be OK with it.
> I think our (the anti PFAS crowd) concern stems from being able to identify many chemical pathways that can make these very dangerous and therefore believe that they should be proven safe by studies
That's not how empiricism works. You can't prove that something has no bad effects. That's called "proving a negative", and it's an infinitely high bar. Remember: millions of people die from dihydrogen monoxide exposure every year! We must ban it until proven safe!
Also, this:
> stems from being able to identify many chemical pathways that can make these very dangerous
...is pseudoscience. Everything is resting on the "can make" part of that sentence. There are so many "chemical pathways" (most of which we know nothing about) that any claim about a particular chemical triggering a particular pathway to negative human outcome absolutely must be backed by solid empirical evidence, and not just speculation or theory.
See also: "the dose makes the poison." Even completely innocuous -- or beneficial! -- chemicals are harmful if you consume too much of them. There are "chemical pathways" that can absolutely kill you if you take too much Tylenol, or drink too much alcohol, or eat grapefruit when taking certain statins, or a large number of other innocent things.
My current summary of the state of evidence around PFAS is that there's a constellation of weak/bad studies suggesting that the water-soluble variants might have bad effects in some animals. Bioaccumulation clearly occurs, and therefore caution is warranted (particular with certain manufacturing processes or pollution), but the people who are extending that to egg pans and sandwich wrappers are way out over their skis.