Assessment of per- and polyfluoroalkyl substances in Sydney drinking water

Per- and polyfluoroalkyl substances (PFAS) have emerged as major persistent organic contaminants in global drinking water supplies. While PFAS contamination has been widely reported, their occurrence in Australian drinking water remains understudied. To address this gap, 32 tap water and 12 bottled water samples were collected across Sydney, Australia. The samples were preconcentrated using StrataX-AW solid-phase extraction (SPE) cartridges and analysed for 50 PFAS compounds using liquid chromatography-tandem mass spectrometry (LC-MS/MS), obtaining ultra-trace detection limits (0.031-5.1 ppt), low relative standard deviation (9-12 %), and high recovery (92-99 %). Of the 50 PFAS monitored, 31 were detected, including the first-reported detection of a short-chained fluorotelomer carboxylic acid (3:3 FTCA) in any drinking water and a fluorophosphoric acid diester (6:2 diPAP) in tap water. Compared to previous studies, 21 PFAS were detected in Sydney tap water that had not been previously reported in Australia. PFAS profiles differed between the catchment source and drinking tap water, persisting or appearing in altered proportions at the tap. Notably, maximum PFOS concentrations in some North Richmond catchment samples (6 ppt) were at or above U.S. EPA (4 ppt) but below endorsed 2025 Australian drinking water guidelines (8 ppt). These findings expand current knowledge of PFAS occurrence in drinking water and underscore the need for further assessment of their sources, distribution and environmental persistence.