How do we know that the source of contamination was the military?
I looked up an article published in the New York Times, which cited a Nature Geoscience magazine. I guess it combined a whole bunch of studies of 45,000 water samples from around the world. They found that 31% of groundwater not near sources of contamination had harmful levels of PFAS in it—the levels were based on the U.S. Environmental Protection Agency levels—as did 16% of surface water. It seems like it's fairly ubiquitous even around places where you don't have obvious sources of contamination.
If you find it in a place, how do you know it was the military that caused it, or do we not know that or assume that?