Enhancing the ability to detect and monitor PFAS

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101036756. Enhancing the ability to detect and monitor PFAS. Water Resilience Workshop EUROPEAN COMMISSION DIRECTORATE-GENERAL FOR RESEARCH AND INNOVATION Directorate B –Healthy Planet B.4 –Oceans, Seas and Waters Brussels, November 21, 2025 Hans Peter H. Arp Norwegian Geotechnical Institute (NGI) Norwegian University of Science and Technology (NTNU) Contact: [email protected] PFAS contaminated sites in Europe 22,934 known contamination sites 21,426 presumptive contamination sites 231 known PFAS users 20 PFAS manufacturing facilities Source: Forever Pollution Project foreverpollution.eu Cordner et al. Environ. Sci. Technol.2024, 58, 15, 6616-6627 The Flow •Advancing Detection Advancing Monitoring Advancing Public-Private Partnerships •Advancing Detection Types of PFAS Analysis Principle Limitations Target PFAS analysis High sensitive methods for selected PFAS (LOD pg/L –ng/L) Only small fraction of PFAS analysed Total oxidizable precursor (TOP) Assay Oxidize precursors of target PFAS to target PFAS Not good for volatiles, ultra-short PFAS and polymers (but methods improving, e.g dTOP and PhotoTOP) Extractable organofluorine (EOF) Extractable organoflourine in a solvent or solid phase, quantify “F-” after destruction Same as TOP, does not differentiate PFAS and non-PFAS organoflourine and fluoridized metals, high LOD Adsorbable organofluorine (AOF) Adsorbable organfluorine on a solid phase (e.g. activated carbon), follwed by «F-» quantification Same as EOF, generally higher LOD Non-target PFAS and 19NMR Good for structural elucidation of nontarget PFAS Not quantitative (though semi-quantititive methods emerging). Expensive Smith et al. ES&T 2024 https://pubs.acs.org/doi/10.1021/acs.est.3c10617 Extractable eTOP vs Direct dTOP protocols, e. g. for soil Lange et al., 2024 TrEAC 44, e00242 Discrimination of •non-oxidizable PFAS •non-extractable PFAS •volatiles •ultrashort-chain PFAAs (TFA, PFPrA) Lower matrix effects (eTOP) vs more PFAS (dTOP) TOP assay of a technical product Liquid product with a side-chain fluorinated acrylate-based polymer for textile coating Analysis of native sample accounts for only 0.02 % of the TOP assay result. eTOP assay analysis of the dried product accounts for only 1.44 % of dTOP assay result. dTOP is needed for polymer digestion! ΣF(PFAS) = 1.18 % Supplier information: 1.2 % 0 10 20 30 Native TOP dTOP µmol/kg TFA PFPrA PFBA PFPeA PFHxA PFHpA Data from Lange et al. 2025, Mitt. Umweltchem. Ökotox. 31/2, 33-37 F F F F F F F F F F F F F Crosslinker to textile Nonfluorinated side chain Polyfluorinated side chain Polyacrylate chain O OO OO OO O F F F F F F F F F F F F F eTOP dTOPNative What is special about TFA in TOP assay? TFA matters! Wild boar liver Corn leaves Conc. in µg/kg d.m. Surface runoff before TOPA after TOPA a) 6:2 FTSA, b) 4:2 FTSA, c) Fluopicolide, d) Tritosulfuron, e) Tembotrione, f) Flufenacet, g) Fluopyram, h) Flurtamone, i) Fluoxetine, j) Sitagliptin, k) Bisphenol AF, l) 4-Chloro-3nitrobenzotrifluoride, m) 4-chlorobenzotrifluoride And many, many more… and: They are PFASs!!! Precursors galore (millions)! Rupp et al. 2023, Sci. Total Environ. 871, 162028. Janda 2019, Polare Perfluoralkylcarbonsäuren, Ph.D. thesis (wine-growing area) Chemical-free TOP alternative with good perspective Because TFA needs to be included and any discrimination by sample pre-treatment (i.e. extraction) should be avoided, a persulfate-free direct TOP assay is needed! Online sensors of PFAS: the limits of selectivity and sensitivity Colorimetric PFAS Detection Colorimetric sensors use catalysts like Cu-CN to detect PFOS via visible color changes caused by catalytic site blockage. Paper-Based Analytical Devices Low-cost paper devices with methylene green dye detect PFAS by changes in spot diameter on wax-patterned paper. Fluorescent Sensors Fluorescent sensors like perylene diimide derivatives show quenching when PFOS binds, enabling very sensitive detection. Surface-Enhanced Raman Spectroscopy SERS uses plasmonic nanostructures to detect PFOS at ultra-low levels, showcasing advanced optical sensing technology. Limitations of sensor technology •Target PFAS thresholds are at the ng/L (e.g. for PFOS) •To date no sensor has been this sensitive, particularly in complex matrices •Higher the concentration, the more potential for sensor technology. Albert and Süstenfuss, Environ. Sci. Technol. Lett. 2024, 11, 10, 1090-1095 Advancing Public-Private Partnerships Private-public collaborations accross supply chains EEA 2025 https://www.eea.europa.eu/en/analysis/pu blications/pfas-polymers-in-focus Product testing for supply chain components/products 0 10 20 30 Native TOP dTOP µmol/kg TFA PFPrA PFBA PFPeA PFHxA PFHpA Data from Lange et al. 2025, Mitt. Umweltchem. Ökotox. 31/2, 33-37 F F F F F F F F F F F F F Crosslinker to textile Nonfluorinated side chain Polyfluorinated side chain Polyacrylate chain O OO OO OO O F F F F F F F F F F F F F eTOP dTOPNative 1) Make a network of water shed representatives 2) Water companies monitor for PFAS substances 3) Upstream investigation to find sources 4) Network works together with emitting sources to collaborate on (financial) solutions Regional/national authorities coordinate and co-create at the watershed level where: •Strong leadership •Clear policy •Citizen participation •Socioeconomics •Environmental sociologists Detection and Monitoring of PFAS Needs Watershed Managment Thinking Closing the mass balance for treatment technology development Xiao et al. Environ. Sci. Technol. Lett.2021, 8, 4, 364-365 Radjenovic et al. Environ. Sci. Technol.2020, 54, 23, 14815-14829 Xu et al. Environ.Sci.Technol.2025,59,21567−21578 Thermodestruction Electrolysis Biodegradation Example: Electrolysis Scale: 10 L Soft drinking water κ≈ 600 µS/cm I = 1.5 A Initial PFAS conc.: 100 µg/L each Heico Schell et al. In prep Example: Sludge biodegradation Li et al Water Research Volume 189,1 February 2021, 116583 Public-priviate collaboration to to lower the energy needed for PFAS mineralization from thermal methods Abou-Khalil ES&T (2024), 58-11162-11174 https://doi.org/10.1021/acs.est.3c09795