Sources, occurrence and toxic effects of emerging per- and polyfluoroalkyl substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) cause potential threats to biota and are persistent and never-ending substances in the environment. Regulations and ban on legacy PFAS by various global organizations and national level regulatory agencies had shifted the fluorochemical production to emerging PFAS and fluorinated alternatives. Emerging PFAS are mobile and more persistent in aquatic systems, posing potential greater threats to human and environmental health. Emerging PFAS have been found in aquatic animals, rivers, food products, aqueous film-forming foams, sediments, and a variety of other ecological media. This review summarizes the physicochemical properties, sources, occurrence in biota and the environment, and toxicity of the emerging PFAS. Fluorinated and non-fluorinated alternatives for several industrial applications and consumer goods as the replacement of historical PFAS are also discussed in the review. Fluorochemical production plants and wastewater treatment plants are the main sources of emerging PFAS to various environmental matrices. Information and research are scarcely available on the sources, existence, transport, fate, and toxic effects of emerging PFAS to date.