PS: especially as Colorado and Ohio are among the worst, through my lens they seem the states that are most about protecting the land.
Note that more dots on the map does not mean more PFAS. It means more data.
Also so far as military bases go it seems to be all of them.
I live in upstate NY and I've never heard of anyone testing for PFAS. In our schools they do bi-yearly drinking water tests for lead and a handful of other things, but not PFAS.
It also just might be where chemical plants or recycling centers are located. My brother used to work at a chemical recycling plant in New Jersey, there's a LOT of those kinds of plants in New Jersey. Surely the goal is 0 spills or accidental dumping but there's no way that's 100% fool proof so surely where this stuff has been created/treated/recycled there's going to be higher concentrations.
As of last year, maximum limits for public water went into effect. I believe testing has gone on for longer than that.
EDIT: linked fixed
https://www.health.ny.gov/environmental/water/drinking/docs/...
Historical reasons, for one - for example, the Silicon Valley has the most Superfund sites in the US (https://www.theatlantic.com/technology/archive/2019/09/silic...) as a legacy of the chip production that was concentrated there. For PFAS contamination specifically, part of the answer is the distribution and size of airports and military bases, where PFAS are / have been used in firefighting activities and the runoff water was not filtered.
Another reason is lax supervision, enforcement and willful ignorance on part of politics - many local politicians don't want to disturb the major employers in town for fear of driving them away and the federal government isn't much better, the Trxmp administration was notorious for de-regulating (https://www.nytimes.com/interactive/2020/climate/trump-envir...).
Or alternatively, https://xkcd.com/1138/
Its also not clear how to gauge these dots. One dot may cover an enormous area or a small area. One might wonder if some instances are double counted. On the big picture level, it's reasonable down to the level of "where the people at"
If you turn off drinking water, the distribution looks more even. It just seems to be bias in the water testing/reporting.
An unholy coalition politicians, gov't administration, scientists and corporate interest tried to cover up historical PFOS pollution around the 3M production site in Zwijndrecht (BE). They were caught red handed by a vigilant citizen journal when some politicians wanted to expedite some car-centric public construction works smack in the middle of the polluted area.
The ministers for environment and public works ordered their administrations to turn a blind eye, not to sample the wider area to assess the extent of the PFOS pollution, and under no circumstance communicate to the public about the pollution.
A renowned toxicologist was commissioned write down safety norms for the public works in the context of pre-existing PFOS pollution. He took a European reference norm that was already outdated at the time given new toxicological insights, messed up the arithmetic, and, lo and behold, came up with a threshold that was _just_ right for the works to start.
A special parliamentary commission was established to investigate, and so we had 3M testify in parliament on how they believe it is a harmless chemical etc.
At some point in 2010s 3M switched the production process over to use PFAS which they are dumping in the Scheldt river in absurd amounts to this day.
We got some reassuring corporate sop that they promise to reduce PFAS levels in wastewater discharges to 54 kg/year by 2024 (5.375 kg/year in 2021). For reference, Chemours (NL) had a permit for dumping just 2 kg/year in 2020, which sounds about right given our current understanding of the human toxicological effects of PFAS.
The original "Scotchguard" was PFOS and it was reformulated in the early 2000s to PFAS which is believed to be less dangerous.
PFOS and PFAS are "fluorosurfactants" which are surfactants in the sense of "surface acting agents" but are very different from the usual soaps, detergents and disinfectants that help things mix. Applied to solid surfaces it does the opposite. It's pretty amazing that you can apply it to a rug, pour coffee on it, and it wipes right off without sticking.
This should be PFBS, according to Wikipedia. PFAS is the whole family of chemicals, PFBS is a particular member with a much shorter half-life than PFOS. “PFAS” getting a non-abbreviation moniker would sure help to disambiguate things.
Also from WP, Scotchgard now uses “a proprietary fluorinated urethane,” which means we know next to nothing about it.
[1] https://disasterarea.home.blog/2019/07/12/apple-headquarters...
[2] https://twitter.com/richgel999/status/1436934781955190788
Xerox even has a bunch of patents about how to suck up and treat ground water.