| > What are the benefits these chemicals have provided They have a lot of properties that can be useful in materials - hydrophobicity, lipophobicity, chemical resistance, low friction, etc. They are certainly used in some niches (like medical devices, protective clothing, advanced manufacturing) that people would agree are Important, but a significant percentage of production goes into, and a significant amount of contamination comes out of, stuff like stain-proofing couches and making food packaging grease resistant. I’m under the impression that a lot of environmental contamination likely also comes from their use in firefighting foams - a useful application to be sure, but there are some things it’s not a great idea to spray straight into the environment. > Are they chemically bonded to something that reduces bio-interactivity? A huge part of the story of PFAS is that they are quite resistant to (permanent) chemical bonding, which has often lead to them being thought of as “inert” in a sense that is conflated with safety. But this sense of inertness is a bit of a red herring when it comes to biology (plenty of things interact with receptors without covalently bonding) and meanwhile makes them highly persistent both within organisms and in the environment. “PFAS” as a literal chemical category feels pretty broad. The ones best established to be harmful are fluorosurfactants like the whole list explicitly targeted here. But broadness is also kind of the point because there are tons of chemicals in use that are likely to have similar accumulative properties that have never really been studied for health effects, and which can’t really be assumed to be harmless if the others aren’t. |