Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: Raftrommelmans on 14/07/2021 09:20:02
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I'll start off with a TLDR since this is is bound to turn into a longish post.
The main question, from a scientific point of view is: What really is known about PFAS's (Perfluoroalkyl chemicals) effects on the environment and on humans?
The second question comes after the post below, which details why I'm asking.
In June this year (2021) a pollution situation was uncovered in Belgium when samples taken at a very large construction site (the so called "Oosterweelverbinding") showed that PFAS / PFOS content of soil samples massively crossed the norm values. The situation transformed fairly rapidly into full blown scandal when documents emerged showing that the company responsible for the pollution (3M) had know about it for at least 20 years, probably a lot more and that the government contractor for the construction wharf had also known about it since at least 2017.That they had informed our government and... nothing. News and info was buried, they didn't act on any of it.
Deals were made between the contractor and 3M to make it illegal for them to sue 3M on the grounds of pollution on the construction site. They were paid of for a measly 75.000 euro's where the current tally for cleaning up the mess stands at around 60 million.
While trying not to stumble into the trap of strange and elaborate conspiracies... I find myself in the situation where I don't find any of the government's, the government's agencies for the environment, the contractor and the polluter 3M's explanations credible. There is very little actual information coming our way.
News about the situation rarely contains actual measurements, it's always interpretations by (government appointed) "experts" and they quite often blatantly use outdated norm-values when explaining what the samples actually mean. The general director of the 3M factory actually gave an interview on national TV, stating that 3M has been doing research on PFAS for over 20 years and that they haven't found any proof that the chemicals are harmful. Our government seems to do its best to push that concept of "it's all fine" as well. I can't shake the feeling that the director of the polluting company might not be the most neutral individual in this scenario.
This construction project is worth well over 5 billion Euro's, I have a hard time believing that something where that much government money is involved will get a neutral and fair analysis by that same government.
So my second question is if some international scientific attention to the situation and it's many dubious coincidences could be arranged through this vast network of scientists and indeed, our naked scientists themselves. Maybe get the subject of PFAS and other forever chemicals on the podcast or even as a newsworthy item on the BBC world service.
Thank you for reading!
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An aside...
It's good to see that the Antwerp Ring road is finally being completed.
When I lived north of Antwerp (Ekeren), it was a long way around if you wanted to travel west...
https://en.m.wikipedia.org/wiki/File:Ring_Antwerpen_-_Oosterweelverbinding.PNG
When we arrived, were greeted by another pollution scandal - it was discovered that there were Dioxins and PCBs (Poly-Chlorinated Biphenyls) in eggs, poultry, dairy, beef and many other foods.... Supermarket shelves were empty and Belgian chocolates were banned across Europe, for a while.
Now, back to the perfluorocarbons...
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paraphrased question: how dangerous are PFAS/PFOS?
Short answer: "it's complicated!"
what we do know for sure: carbon-fluorine bonds are very, very strong, and don't appear to be metabolized in humans or readily degraded in the environment (half lives for breakdown estimated to be centuries to millennia). This means that every spill leads to accumulation in people, wildlife and the environment.
what we don't know for sure: is it actually bad? all compounds are toxic, the question is: are people exposed to toxic levels of the compounds, and if so, what happened to them?
Unfortunately the jury is still out on that. They are not wildly toxic or carcinogenic—we would have noticed that by now. But there are several studies that show that people exposed to high levels of these compounds appear to have increased risks for several different bad outcomes.
This document is clearly designed to elicit concern about PFAS/PFOS, but appears (to my quick perusal) to be factually accurate and well-referenced: https://chemtrust.org/wp-content/uploads/PFAS_Brief_CHEMTrust_2019.pdf
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My optometrist recommended some new eye-drops that turned out to be perfluorocarbons.
- They have a few extra groups so that one end is water-soluble, and the other is fat soluble.
- The idea is to preserve the liquid film on your eyes
- However, that hydrophilic/hydrophobic combination is a recipe to be incorporated into the cellular membrane, which is a lipid layer surrounded by water. Could that affect the behaviour of the cell membrane?
- There have been complaints from firefighters exposed to perfluorocarbons; they are used to reduce the surface tension of water, so it can spread out farther, and smother a fire better. Presumably these would have a hydrophilic group, too?
For myself, I decided that I did not need teflon eyeballs at the moment, and I am staying with more conventional eyedrops for now...
See: https://en.wikipedia.org/wiki/Per-_and_polyfluoroalkyl_substances
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...yeah, I am fairly conservative when it comes to my eyes.
Depending on what groups are used for the hydrophilic end, one could imagine the possibility of some interference with or incorporation into the cell membranes (as I understand it, this is essentially what benzalkonium salts do to act as biocides.)
But that isn't a given. The fact that it is fluorinated actually probably makes it less likely to be incorporated. Highly fluorinated compounds are often poorly soluble in both water and hydrocarbon/organic phases, leading to the term "fluorous phase".
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The US Environmental Protection Agency (EPA) has proposed rules limiting the maximum concentration of PFAS/PFOS and similar chemicals in US drinking water.
- The proposal is out for a 60-day public review period
See press release: https://www.epa.gov/newsreleases/epa-takes-action-address-pfas-drinking-water