Pharmaceuticals Account for a Significant Proportion of the Extractable Organic Fluorine in Municipal Wastewater Treatment Plant Sludge
By Kyra M. Spaan, Fredric Seilitz, Merle M. Plassmann, Cynthia A. de Wit, and Jonathan P. Benski
Environ. Sci. Technol. Lett.
April 17, 2023
DOI: 10.1021/acs.estlett.3c00108
Fluorine mass balance studies have shown that monomeric per- and polyfluoroalkyl substances (PFAS) with perfluoroalkyl chain lengths of ∼5–14 carbon atoms (i.e., “conventional” PFAS) account for a fraction (∼2%) of the extractable organic fluorine (EOF) in municipal wastewater treatment plant (WWTP) sludge. The identity of the remaining EOF has thus far been unclear but may be partly attributable to fluorine-containing pharmaceuticals and pesticides used throughout society. To test this hypothesis, we applied high resolution mass spectrometry-based suspect screening to samples of municipal WWTP sludge which had been previously subjected to a fluorine mass balance. Sixteen pharmaceutical substances (including transformation products [TPs]), one pesticide, and thirteen conventional PFAS were confirmed at confidence levels 1–4 and (semi)quantified, revealing concentrations ranging from 0.07 to 155 ng/g dw. Notably, eight pharmaceutical substances did not meet the OECD definition of PFAS. When converted to fluorine equivalents, the newly detected organofluorine substances increased the percentage of known EOF from ∼2% to ∼27%, of which ∼22% was attributed to pharmaceutical and pesticide substances, with the greatest contributions from ticagrelor TP (4.0%), ezetimibe (3.9%), and bicalutamide (3.5%). These data highlight the importance of considering both unconventional and non-PFAS organofluorine substances in addition to conventional PFAS when closing the organofluorine mass balance in WWTP sludge.
Topics: