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Environ. Sci. Technol. 2020, 54, 7378−7387
链接:https://pubs.acs.org/doi/abs/10.1021/acs.est.0c01644
Abstract:
Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are two
environmentally persistent per- and polyfluoroalkyl substances (PFAS)
that have been detected globally in human tissues and fluids. As part of
a project investigating the indirect sources of PFOA/PFOS in the
environment and engineered systems, this study is concerned with the
mechanisms leading to their in vivo generation in terrestrial
invertebrates. We demonstrate here the formation of PFOA and PFOS in
earthworms (Lumbricus terrestris) from a group of four
zwitterionic/cationic polyfluoroalkyl amides and sulfonamides. In
bioaccumulation tests, the zwitterionic PFAS compounds were metabolized
within 10 days to PFOA/PFOS at yields of 3.4–20.8 mol % by day 21 and
several infrequently reported PFAS species for which chemical structures
were determined using high-resolution mass spectrometry. Cationic PFAS,
on the other hand, were found to be much less metabolizable in terms of
the number (n = 2) and yields (0.9–5.1 mol %) of metabolites.
Peak-shaped bioaccumulation profiles were frequently observed for the
studied PFAS. Residual zwitterionic/cationic PFAS in earthworms were
detected at the end of the elimination phase, indicating that not all
zwitterionic/cationic PFAS molecules in vivo are available for enzymatic
degradation. Finally, the relative importance of different exposure
routes (i.e., waterborne and dietary exposure) was investigated.
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