5 ms·

PFAS are everywhere, but my understanding was that not every PFAS substance is unsafe for humans. (Maybe it's just wishful thinking?)

by m_a_g 2y ago

piskov 2y ago
It’s also in the article “The real issue is this stuff accumulates,” the professor said. “No chemical is totally innocuous, and it seems inconceivable that anything that accumulates would not eventually become toxic.” > man-made compounds from household products didn’t belong in the human body
- hcurtiss 2y ago
  These strike me as ideological, not scientific, positions.
timr 2y ago
You are correct. With regard to toxicity, PFAS is a term so broad that it is meaningless. It covers everything from Teflon (which is perhaps the most chemically inert substance ever created) fluorine-containing acids like PFOA, which are water soluble and bioavailable, and tend to accumulate in the environment. Because of this, you'll see all sorts of silly claims on every thread related to this topic, claiming that (for example) fry pans are toxic. This is silly, and driven by a poor understanding of chemistry, as well as some unfortunate hack scientists who continue to promote the idea that "alkyl-fluorine-containing = toxic", which isn't supported by evidence. You can see this hyperbole in the sibling comment, where the quote "man-made compounds from household products didn’t belong in the human body" is asserted as some kind of fact. Even if you're predisposed to believe this (extremely general) statement is true, this isn't a claim that you can really defend with an evidence-based argument.
- tedivm 2y ago
  Are you really claiming that perfluorooctanoic acid (PFOA) is safe? I'm not going to quote the whole "toxicology" section of wikipedia on that chemical but strongly recommend you read it: https://en.wikipedia.org/wiki/Perfluorooctanoic_acid#Toxicology https://en.wikipedia.org/wiki/Perfluorooctanoic_acid#Toxicol... PFOA was explicitly banned in the US in 2014, after being phased out the year before, due to it's toxicity. Teflon changed their manufacturing process so it's made with polytetrafluoroethylene instead. So yes, pans made with teflon before 2014 absolutely due contain a toxic chemical.
  - idunnoman1222 2y ago
    Manufactured with a toxic chemical
  - timr 2y ago
    No. I literally said the opposite. > Teflon changed their manufacturing process so it's made with polytetrafluoroethylene instead. So yes, pans made with teflon before 2014 absolutely due contain a toxic chemical. Incorrect. Just because something is used as a chemical precursor in a manufacturing process, does not mean that it is present in the final manufactured product. Teflon is an solid, non-reactive material. PFOA is a liquid acid. They are very, very different things. Even if manufactured Teflon contained any residual PFOA (it doesn't), it would be washed away the first time you rinsed the pan.
    - tedivm 2y ago
      > Most manufacturers assumed that PFOA burns off during the process of manufacture, but traces of PFOA were found in some Teflon-coated cookware. > A 1999 study found that 98% of people in the United States had PFOA in their blood. This was due to environmental exposure to the chemical. As a result, the US EPA put up a program to eliminate the use of PFOA by 2015. https://www.webmd.com/food-recipes/is-teflon-coating-safe https://www.webmd.com/food-recipes/is-teflon-coating-safe They just assumed it burned off, but never tested it. It wasn't until 2021 that they had to actually test and report for extra chemicals left in, well after it was banned. What happens when you actually test it? > In this study, we identified and measured perfluoroalkyl carboxylates (PFCAs), particularly PFOA, and fluorotelomer alcohols (FTOHs; 6:2 FTOH and 8:2 FTOH), released from nonstick cookware into the gas phase under normal cooking temperatures (179 to 233 degrees C surface temperature). PFOA was released into the gas phase at 7-337 ng (11-503 pg/cm2) per pan from four brands of nonstick frying pans. https://pubmed.ncbi.nlm.nih.gov/17593716/ https://pubmed.ncbi.nlm.nih.gov/17593716/ So yes, it absolutely contained residual PFOA, and no it didn't wash off.
      - timr 2y ago
        Hilariously, the webmd link you cited repeats what I said above: > The use of PFOA in the manufacturing of Teflon-coated cookware has been completely stopped. But, even when PFOA is used, it poses little or no harm to your health. Teflon on its own is safe and can’t harm you when you ingest it. ...not that I think webmd is worth citing. But OK, one paper you dug up found an incredibly tiny amount (500 picograms per square centimeter, at the highest), which they said declined over time for half the pans tested (I'm guessing the ones with the highest initial readings). Meanwhile, other groups didn't see the same thing: https://pubmed.ncbi.nlm.nih.gov/16096677/ https://pubmed.ncbi.nlm.nih.gov/16096677/ > Commercial grade cookware was obtained, then extracted with water and ethanol/water mixtures at 100 and 125 degrees C, and the resulting extracts were analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS). Detection and quantification limits as low as 100 pg cm(-2) were demonstrated. None of the fluoropolymer treated cookware samples analyzed showed detectable levels of PFOA when extracted under simulated cooking conditions. Anyway, I'm not going to get excited over a single paper, showing incredibly minute amounts of something which, as you say, is now ubiquitous in the environment (hello, cross-contamination risk!). The paper may or may not have been methodologically valid. You do you.
- socksy 2y ago
  > You can see this hyperbole in the sibling comment, where the quote "man-made compounds from household products didn’t belong in the human body" is asserted as some kind of fact. Even if you're predisposed to believe this (extremely general) statement is true, this isn't a claim that you can really defend with an evidence-based argument. Is there actually evidence here that these chemicals are harmless, or is this an absence of evidence of harm? Because the latter is a whole lot less persuasive than the former.

PFAS are everywhere, but my understanding was that not every PFAS substance is unsafe for humans. (Maybe it's just wishful thinking?)

by m_a_g 2y ago

PFAS are everywhere, but my understanding was that not every PFAS substance is unsafe for humans. (Maybe it's just wishful thinking?)

piskov 2y ago

It’s also in the article “The real issue is this stuff accumulates,” the professor said. “No chemical is totally innocuous, and it seems inconceivable that anything that accumulates would not eventually become toxic.” > man-made compounds from household products didn’t belong in the human body

hcurtiss 2y ago
These strike me as ideological, not scientific, positions.

timr 2y ago

You are correct. With regard to toxicity, PFAS is a term so broad that it is meaningless. It covers everything from Teflon (which is perhaps the most chemically inert substance ever created) fluorine-containing acids like PFOA, which are water soluble and bioavailable, and tend to accumulate in the environment. Because of this, you'll see all sorts of silly claims on every thread related to this topic, claiming that (for example) fry pans are toxic. This is silly, and driven by a poor understanding of chemistry, as well as some unfortunate hack scientists who continue to promote the idea that "alkyl-fluorine-containing = toxic", which isn't supported by evidence. You can see this hyperbole in the sibling comment, where the quote "man-made compounds from household products didn’t belong in the human body" is asserted as some kind of fact. Even if you're predisposed to believe this (extremely general) statement is true, this isn't a claim that you can really defend with an evidence-based argument.

tedivm 2y ago
Are you really claiming that perfluorooctanoic acid (PFOA) is safe? I'm not going to quote the whole "toxicology" section of wikipedia on that chemical but strongly recommend you read it: https://en.wikipedia.org/wiki/Perfluorooctanoic_acid#Toxicology https://en.wikipedia.org/wiki/Perfluorooctanoic_acid#Toxicol... PFOA was explicitly banned in the US in 2014, after being phased out the year before, due to it's toxicity. Teflon changed their manufacturing process so it's made with polytetrafluoroethylene instead. So yes, pans made with teflon before 2014 absolutely due contain a toxic chemical.
- idunnoman1222 2y ago
  Manufactured with a toxic chemical
- timr 2y ago
  No. I literally said the opposite. > Teflon changed their manufacturing process so it's made with polytetrafluoroethylene instead. So yes, pans made with teflon before 2014 absolutely due contain a toxic chemical. Incorrect. Just because something is used as a chemical precursor in a manufacturing process, does not mean that it is present in the final manufactured product. Teflon is an solid, non-reactive material. PFOA is a liquid acid. They are very, very different things. Even if manufactured Teflon contained any residual PFOA (it doesn't), it would be washed away the first time you rinsed the pan.
  - tedivm 2y ago
    > Most manufacturers assumed that PFOA burns off during the process of manufacture, but traces of PFOA were found in some Teflon-coated cookware. > A 1999 study found that 98% of people in the United States had PFOA in their blood. This was due to environmental exposure to the chemical. As a result, the US EPA put up a program to eliminate the use of PFOA by 2015. https://www.webmd.com/food-recipes/is-teflon-coating-safe https://www.webmd.com/food-recipes/is-teflon-coating-safe They just assumed it burned off, but never tested it. It wasn't until 2021 that they had to actually test and report for extra chemicals left in, well after it was banned. What happens when you actually test it? > In this study, we identified and measured perfluoroalkyl carboxylates (PFCAs), particularly PFOA, and fluorotelomer alcohols (FTOHs; 6:2 FTOH and 8:2 FTOH), released from nonstick cookware into the gas phase under normal cooking temperatures (179 to 233 degrees C surface temperature). PFOA was released into the gas phase at 7-337 ng (11-503 pg/cm2) per pan from four brands of nonstick frying pans. https://pubmed.ncbi.nlm.nih.gov/17593716/ https://pubmed.ncbi.nlm.nih.gov/17593716/ So yes, it absolutely contained residual PFOA, and no it didn't wash off.
    - timr 2y ago
      Hilariously, the webmd link you cited repeats what I said above: > The use of PFOA in the manufacturing of Teflon-coated cookware has been completely stopped. But, even when PFOA is used, it poses little or no harm to your health. Teflon on its own is safe and can’t harm you when you ingest it. ...not that I think webmd is worth citing. But OK, one paper you dug up found an incredibly tiny amount (500 picograms per square centimeter, at the highest), which they said declined over time for half the pans tested (I'm guessing the ones with the highest initial readings). Meanwhile, other groups didn't see the same thing: https://pubmed.ncbi.nlm.nih.gov/16096677/ https://pubmed.ncbi.nlm.nih.gov/16096677/ > Commercial grade cookware was obtained, then extracted with water and ethanol/water mixtures at 100 and 125 degrees C, and the resulting extracts were analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS). Detection and quantification limits as low as 100 pg cm(-2) were demonstrated. None of the fluoropolymer treated cookware samples analyzed showed detectable levels of PFOA when extracted under simulated cooking conditions. Anyway, I'm not going to get excited over a single paper, showing incredibly minute amounts of something which, as you say, is now ubiquitous in the environment (hello, cross-contamination risk!). The paper may or may not have been methodologically valid. You do you.
socksy 2y ago
> You can see this hyperbole in the sibling comment, where the quote "man-made compounds from household products didn’t belong in the human body" is asserted as some kind of fact. Even if you're predisposed to believe this (extremely general) statement is true, this isn't a claim that you can really defend with an evidence-based argument. Is there actually evidence here that these chemicals are harmless, or is this an absence of evidence of harm? Because the latter is a whole lot less persuasive than the former.