Assessment of legacy and emerging PFAS in the Oder River: Occurrence, distribution, and sources.

The purpose of the study was to evaluate the occurrence and distribution of emerging contaminants, poly- and perfluoroalkyl substances (PFAS), in the Polish Oder River, aiming to uncover new insights into their environmental impact. The research aimed to identify potential sources of PFAS, assess water quality levels, and verify compliance with European Union environmental quality standards. The concentrations of 25 PFAS (20 legacy and 5 emerging) in 20 samples from intakes upstream and downstream of urban areas were analyzed using novel, developed in these studies, environmental analytical procedures involving solid phase extraction and liquid chromatography-tandem mass spectrometry. The presence of 14 PFAS was confirmed, and the concentration of ΣPFAS ranged from 7.6 to 68.0 ng/L. The main components were short-chain analogs. PFBA was the most abundant, accounting for about one-third of all PFAS detected. An exception was observed in the waters of the Gliwice Canal, where ADONA represented half of the detected ΣPFAS. Alternative PFOS replacements were found in all samples. In 11 of 20 water samples, environmental quality standards for PFOS exceeded the limit of 0.65 ng/L. In 5 of 9 cases, the ability of urban areas to increase PFAS levels in the river was determined. 9.5%-54.4% share of alternative PFAS in relation to the sum of the targeted PFAS showing their increasing use as substitutes for phased-out PFOS. Hierarchical cluster analysis was used to identify potential sources of PFAS. Analysis revealed that PFAS in the Oder River most likely originated from domestic and agricultural wastewater, as well as chemical industry discharges. However, the occurrence of PFAS in the Oder River is low and comparable to other recent European studies. These findings provide valuable insights for environmental management to mitigate the risks associated with PFAS pollution in Polish rivers. Moreover, the developed analytical procedure provides a valuable tool that can be successfully applied by other researchers to monitor PFAS in rivers around the world.