Pharmaceuticals Account for a Significant Proportion of the Extractable Organic Fluorine in Municipal Wastewater Treatment Plant Sludge

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.