Nationwide Occurrence and Exposure Assessment of PFAS in Australian Tap Drinking Water Using a Citizen Science
Wejdan Alghamdi1, Ivanhoe K H Leung2, Bradley O Clarke3
1Australian Laboratory for Emerging Contaminants, School of Chemistry, University of Melbourne, Victoria 3010, Australia; Department of Chemistry, College of Science, University of Bisha, Bisha 61922 P.O. Box 551, Saudi Arabia.
Abstract:
Per- and polyfluoroalkyl substances (PFAS) are widely detected in water sources, making contaminated potable water a direct and ongoing exposure pathway for the general population. In Australia, nationally comparable drinking water data remain limited. This study presents the first nationwide citizen science project of PFAS in tap drinking water using a broad targeted panel with an ultra-trace LC-MS/MS. A total of 117 Australian tap water samples were collected across eight states and territories and classified as urban, suburban, or rural. 75 PFAS were targeted, of which 65 were detected at least once, with 32 analytes occurring in ≥ 50% of samples. Total targeted PFAS (∑75 PFAS) ranged from 0.21 to 29 ng/L, with a median of 1.4 ng/L (IQR 0.85 - 2.7 ng/L). No statistically significant differences in ∑75 PFAS concentrations were observed among states and territories or among area types. Principal component analysis showed no clear geographic fingerprint in PFAS composition indicating the variability was driven mainly by a small number of elevated samples rather than consistent regional differences. Fluorotelomer sulfonic acids and perfluoroalkyl carboxylic acids contributed 48% and 36% of cumulative PFAS mass, respectively, with short-chain and fluorotelomer PFAS contributing substantially to the overall profiles. The six PFAS included in the U.S. EPA regulatory framework represented a median of only 11% of ∑75 PFAS, demonstrating that the broader panel captured substantial contributions beyond routinely regulated compounds. Priority PFAS remained below Australian drinking water guidelines and relevant international benchmarks, and the maximum hazard index remained < 1. Hazard ratios remained ≤ 0.44 for PFOS, whereas PFOA exceeded unity under the maximum scenario for all age groups and the high (P95) scenario for children aged 2 - 4 years. These findings demonstrate the value of broad analytical coverage beyond routinely monitored legacy PFAS in drinking water.
