Often soil is washed with solvents to remove the Dense Non Aqueous Polar Liquids (DNAPL). These are chloro/fluoro - carbon liquids that settle down to the botto

Often soil is washed with solvents to remove the Dense Non Aqueous Polar Liquids (DNAPL). These are chloro/fluoro - carbon liquids that settle down to the bottom of the water table and flow downhill over many years - deep in the ground, and finally emerge as a DNAPL 'spring' on a river bank. Many of the super fund sites are these. Here is the rabbit hole for them https://www.google.com/search?q=DNAPL+super+fund&rlz=1C1CHBF_enCA924CA924&oq=DNAPL+super+fund&aqs=chrome..69i57.10034j0j15&sourceid=chrome&ie=UTF-8 https://www.google.com/search?q=DNAPL+super+fund&rlz=1C1CHBF...