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Comment by londons_explore | Hacker News Reader

What are the chances that this grinding just makes so much surface area for the pfas to stick to that it falls below the detection threshold of the measurement technique (which measures in a solution)?

If so, is it really eliminating the chemical?

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Presumably you perform chemical analysis rather than looking for globs of the stuff.

Yes, but you are only doing chemical analysis of the liquids, not the solids.

They take samples of the dirt and dissolve it in a solution. Paper below if you are curious.

https://pubs.rsc.org/en/content/articlelanding/2023/VA/D3VA0...

Analytical techniques are extremely sensitive and quite capable of determining their quantitative floor. A quick literate search shows PFAS LoQs of somewhere between 0.2-2.0 ng/L.

I don't know why you're getting downvoted just for asking a question, but my guess is that this process is actually damaging the chemical bonds or somehow breaking off any protective oxides so that all of the PFAs end up reacting with the other minerals in the soil so that they change their composition to something that is less dangerous, sort of how sodium and chloride, both potentially dangerous or deadly elements on their own, can combine into table salt which is an essential substance for life.

I would like to see a deeper analysis of what is found in the soils after the PFAs are broken up to make sure they haven't just changed one dangerous chemical for another one though. If they are being converted into a harmless salt, then great.

> I would like to see a deeper analysis of what is found in the soils after the PFAs are broken up to make sure they haven't just changed one dangerous chemical for another one though. If they are being converted into a harmless salt, then great.

I'd like that as well; it was weird that no single mention of the sub-products was made.

I wonder why they weren't able to perform a quick powder X-Ray Diffractometry analysis to verify that the formation of fluorine minerals was occurring.

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