I'm going to be the controversial one here and point out that despite saying they're "harmful", they've been everywhere for all these decades that a lot of other measures of quality of life have been increasing?
Most industrialized nations have average PFOA blood serum levels ranging from 2 to 8 parts per billion;[57] the highest consumer sub-population identified was in Korea—with about 60 parts per billion.[52] In Peru,[58] Vietnam,[59] and Afghanistan[60] blood serum levels have been recorded to be below one part per billion.
> despite saying they're "harmful", they've been everywhere for all these decades that a lot of other measures of quality of life have been increasing?
Might be unrelated (or not), but cancer rates have been exploding the last decades. Example via Google-Fu:
> Cancer cases in under-50s worldwide up nearly 80% in three decades, study finds
>cancer rates have been exploding the last decades
For reasons that are really quite well-understood. PFASs are not known to be significantly carcinogenic, particularly not at the miniscule levels most people are exposed to. We willingly fill ourselves with things that are definitely very carcinogenic - processed meat, alcohol, tobacco smoke, diesel fumes, etc etc ad nauseum.
Exposure to some of these carcinogens has been static or declining in some western countries, which has led to static or declining age-adjusted cancer incidence rates. They have vastly increased in the middle-income countries that are home to most of the world's population. The life of the average Chinese or Indian person has been transformed beyond all recognition in recent decades (for better and for worse) by urbanisation and industrialisation.
There isn't some unseen and unrecognised carcinogen that is sweeping the world and wreaking havoc; the global poor are just getting rich enough to develop the kind of lifestyle-related cancers that we're accustomed to in the west, while also getting rich enough to be diagnosed rather than just getting sick and dying.
Look at the source cited by that article - the growth in cancer rates is completely dominated by rapidly-growing economies in the global south.
And just as importantly, is it controlled for changes in diagnostic criteria, improvements in testing and pre-screening? In the past decades, we got better at classifying and discriminating between cancers and other illnesses and causes of death.
From https://en.wikipedia.org/wiki/Perfluorooctanoic_acid#Global_... there is this interesting quote:
Most industrialized nations have average PFOA blood serum levels ranging from 2 to 8 parts per billion;[57] the highest consumer sub-population identified was in Korea—with about 60 parts per billion.[52] In Peru,[58] Vietnam,[59] and Afghanistan[60] blood serum levels have been recorded to be below one part per billion.