They can be found in the blood of every person.

When they were trying to do a study and compare people without them in the blood, they went as far as remote indigenous populations, faraway Eskimos, basically anyone they could think of that had absolutely 0 contact with modern civilization. Nope. PFAS. It's worse if you're in the first world (probably significantly worse if you're in the US), but it's everywhere. Anywhere there is water, there is PFAS.

I'm sure the North Sentinelese have it.

Good luck checking. Those guys are awful about hospitality

Unless you show up with a lady and some coconuts.