Post by Baron von Lotsov on May 7, 2023 19:39:48 GMT
First of all a definition:
"PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e. with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS." - OECD
Why are they important:
Fluorosurfactants are surfactants containing fluorocarbon chains such as those in PFASs. They can reduce the surface tension of water below what is attainable by using hydrocarbon surfactants.[14] This ability is due to the hydrophobic nature of fluorocarbons, so fluorosurfactants tend to concentrate at the liquid-air interface.[15] Fluorocarbons are lipophobic, as well as hydrophobic, allowing them to repel both oil and water. This lipophobicity results from the lack of attractive London dispersion forces in fluorocarbons compared to hydrocarbons, a consequence of fluorine's large electronegativity and small bond length, which reduce the polarizability of the surfactants' fluorinated molecular surface. Fluorosurfactants are more stable and fit for harsher conditions than hydrocarbon surfactants because of the stability of the carbon–fluorine bond. Perfluorinated surfactants persist in the environment for this same reason.[8]
So they were used in various cleaning substances, polishes and tough surfaces, as what you might appreciate with a surface coating like a protective paint against the environment and wear and tear.
The problem is these bonds are so strong they do not break down in nature anything like as readily as your other types. They are part of the group of chemicals which are man-made, so nature never really got a chance to combat them. I mean bacteria and enzymes can break down pretty strong chemical bonds, even plastic (hydrocarbons) but these things persist and they are now in our global weather system, both atmosphere and water.
They were introduced to the world by American corporations such as Dupont and 3M in the 1940s. I know you have heard that name somewhere before, but one has to say fair play to them, for they were a very good and useful invention at the time and despite carrying out studies on the worker in the factory who had much higher tan average quantities in their blood stream, they were found to not be suffering any effects. They did the correct and responsible monitoring as you would do yourself. It took a long time to understand why these things were bad.
Remember in 1940 the world had yet to even discover DNA, so any finer understanding of exactly how DNA works was way beyond them. It took a German-Swiss team of researchers to suss it. The problem is the peroxisome proliferator-activated receptor.
In the field of molecular biology, the peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that function as transcription factors regulating the expression of genes.[1] PPARs play essential roles in the regulation of cellular differentiation, development, and metabolism (carbohydrate, lipid, protein),[2] and tumorigenesis[3] of higher organisms.[4][5]
You can see this stuff is right in the midst of the microbiological machine the creates the building blocks for all life in the planet. Perhaps it will teach people not to mess with things they don't understand, but you know what they say about a little bit of knowledge is a dangerous thing. well that was 1940s America: innocent, excited, progressive, inventive and heading to greater prosperity. What could possibly go wrong?
I'll hand you over to the experts in Wikipedia for more reading on this very complicated part of the body.