Legacy and emerging per- and poly-fluoroalkyl substances in polar regions

Per-and poly-fluorinated alkyl substances (PFASs) have been investigated in various environmental compartments in the Arctic and Antarctica. Available data indicated that PFASs are ubiquitous and constitute one group of 'forever chemicals' in the pristine polar environment. Long-range environmental transport with oceanic currents and atmosphere are major pathways in which PFAS reach polar regions. Novel PFASs have been identified in the Arctic and Antarctic, such as hexafluoropropylene oxide dimer acid and fluorotelomer sul-fonates (6:2 and 8:2 FTS), although these alternatives have just been produced as replacements of perfluorooctane sul-fonate (PFOS) and perfluorooctanoic acid (PFOA) for a few years. Spatial distribution of PFASs showed declining trends from the continental sources to the polar oceans, suggesting ongoing discharge and transport processes. Elevated con-centrations of PFAS often occur in the coastal areas of the Arctic and Antarctica, highlighting glacier melting and sea ice retreat act as secondary sources of PFASs.