Graphical summary, based on the “there’s always a bigger fish”, for the analysis of PFASs in suspended particulate matter samples using 4 complementary approaches: while the common target analysis (smallest shark) underestimates the PFAS pollution, other parameters may reflect it better.
Source: BAM, Inorganic Trace Analysis Division
Per- and polyfluoroalkyl substances (PFASs) are a group of several thousand individual compounds. PFAS include all compounds that have at least one perfluorinated methyl (-CF3) or methylene group (-CF2-). Because of their persistence, bioaccumulation in food chains, toxicity and their ubiquitous appearance worldwide, PFASs are emerging pollutants. The analysis of PFASs is a major challenge because of diverse physical and chemical properties within the substance class and the very high number of compounds. Since it is still uncertain for many applications which PFASs are used, how they enter the environment and which transformation or degradation products are formed, analytical approaches that only aim to analyze individual substances reach their limits.
However, the most used approach for PFAS analysis is still target analysis. Furthermore, non-target screening (NTS), based on high-resolution mass spectrometry, can be used to identify previously unknown PFAS. However, the method is limited by qualitative/semi-quantitative data. In contrast, PFAS sum parameter methods aim at comprehensive capture the PFAS pollution situation. Two main approaches can be distinguished here: the (direct) total oxidizable precursor assay ((d)TOPA), which is based on mass spectrometry, and organofluorine sum parameters, which are based on fluorine-sensitive detection systems such as high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR -CS-GFMAS).
In our study, a total of 200 suspended particulate matter (SPM) samples were analyzed in time series (2005-2020) of German rivers using 4 complementary methods for PFAS analysis - (non-)target HRMS, dTOPA and extractable organically bound fluorine (EOF). Overall, the PFAS target analysis drastically underestimated the PFAS burden in SPM of German rivers and does not appear to be suitable as a stand-alone method for PFAS monitoring and risk assessment. Using organofluorine mass balance approaches, a higher proportion of PFAS was identifiable in the earliest samples analyzed. Over time, the PFAS pattern in SPM of German rivers became more complex, resulting in an increase in the unidentified EOF. The results of this study highlight the need to integrate sum parameters such as EOF and dTOPA into risk assessment strategies to comprehensively map the PFAS exposure situation.
Quantification and characterization of PFASs in suspended particulate matter (SPM) of German rivers using EOF, dTOPA, (non-)target HRMS
Fabian Simon, Lennart Gehrenkemper, S. Becher, G. Dierckes, Nicole Langhammer, Antje Cossmer, Marcus von der Au, B. Göckener, A. Fliedner, H. Rüdel, J. Koschorreck, Björn Meermann
Published in Science of the total environment, volume 885, article number 163753, pages 1-12, 2023.
BAM Department Analytical Chemistry; Reference Materials
BAM Division Inorganic Trace Analysis