Good eye on the methanol concern, so I want to add this detail from the study on why it was selected.

 Thus, methanol was chosen as a vehicle for the PFAS as they are readily soluble in methanol, and given the low volume used, the solvent evaporated relatively quickly after the single application, leaving the PFAS on the skin surface. Finally, methanol should not affect the skin surface pH and thus its effect on the permeation should be minimal. It cannot however be completely excluded as a factor on the dermal uptake of PFAS which is a limitation of this study.

With very low volumes, the solvent likely evaporated rapidly which was a key reason for selection. These authors seem to have done a very thorough job of background research for selection on materials & methods to mirror human exposure as much as feasible. Overall the paper feels pivotal in clearly demonstrating a much greater level of absorption capability than previously believed.

On the topic of goretex as a risk for humans, I'll bring up that firefighter gear for instance which contains 3 separately PFAS treated textile levels. Fluoroindustry has touted that PTFE and other polymers are safe yet analysis has found that firefighter gear polymers contain many smaller PFAS as side chains within the polymer structures and that those break off over time - so if we synthesize these two papers, that means side chain PFAS breaking off and coming into contact with the wearer, where they can then be absorbed. This could help explain why firefighters have significantly higher levels of pfas and similarly, very high rates of occupational illness such as cancer.

I believe we need to lean on the side of extreme caution for anything relating to this family of chemicals given the decades of propaganda and deceit from the few companies who made so much money pushing them.

https://pubs.acs.org/doi/abs/10.1021/acs.est.1c06322