See EEA Briefing de. 2019 Emerging chemical Risk in Europe – Per- and polyfluorinated alkyl substances (PFAS). PFAS are a group of more than 4700 man-chemicals (such as perfluorooctanoic acid and Perfluorooctane Sulfonic Acid); their persistency and high mobility in air and water of PFAS increase the risk of health and ecological impacts. Perfluorooctane Sulfonic Acid and their derivatives are included as a priority hazardous substance under the WFD. The EEA states that the total number of sites potentially emitting PFAS is estimated to be “in the order of 100 000 in Europe”. PFAS water pollution has found in countries across Europe (Austria, France, Denmark, Sweden and the Netherlands).