Little is known about the background concentrations of per- and polyfluoroalkyl substances (PFAS) in Australian urban waterways and whether their presence and concentrations are associated with particular catchment land-uses.
A survey was conducted of 33 per- and polyfluoroalkyl substances (PFAS) in streams and wetlands (n = 65) in Greater Melbourne, Australia, to determine background concentrations and major catchment land-uses contributing to PFAS pollution. Sites consisted of streams and constructed urban wetlands with independent catchments that were classified by their dominant catchment land-use – either residential, industrial, municipal wastewater treatment plants or rural. Melbourne was considered a suitable city to establish background concentrations as there is no manufacturing of PFAS and few point sources of PFAS pollution.
Samples were extracted using solid phase extraction (SPE) and analysed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) at the National Measurement Institute (NMI), Australia.
While diffuse PFAS pollution was detected across the urban waterways, statistically significant differences between land-use types were observed depending on the PFAS congener. For example, the major perfluorosulfonic acids (PFSAs), PFOS and PFHxS were found at significantly higher concentrations in sites with industrial catchments compared to all other land-use types. Conversely, the perfluorocarboxylic acids (PFCAs) that were widely detected (>75 % detection, e.g., PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, and PFDA) were not detected at significantly different concentrations in industrial and residential areas.
Findings suggest that different types of PFAS-containing products were used in the various catchment land-uses and that congeners may have been transported in air and water to varying degrees. Results will be discussed based on occurrence patterns across the different land-use types for total PFAS and individual PFAS compounds.