Background

Per- and Polyfluoroalkyl Substances (PFAS) are ubiquitous contaminants in the water environment. These compounds are detected in surface water, groundwater, drinking water and wastewater. Broadly speaking, PFAS can be divided into three groups: 1) Conventional PFAS, such as perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) representing long-chain perfluoroalkyl acids (PFAAs). PFAAs are perceived as end products of PFAS degradation. Due to their persistent, bioaccumulative, and potentially toxic nature, U.S. EPA recommended a health advisory level of 70 ppt for PFOA and PFOS. Several states in the U.S. have established maximum contaminant levels (MCLs) for different kinds of PFAAs and at even lower concentrations, like 10 or 20 ppt; 2) PFAS alternatives. These alternatives are supposed to replace PFOA and