Levels, Isomer Profiles, and Estimated Riverine Mass Discharges of Perfluoroalkyl Acids and Fluorinated Alternatives at the Mouths of Chinese Rivers

An
extensive sampling campaign was undertaken to study the levels,
isomer profiles and riverine mass discharges of perfluoroalkyl acids
(PFAAs) and fluorinated alternatives in 19 Chinese rivers. The levels
and homologue profiles of Σ10PFAAs varied considerably
among the 19 rivers (mean 106; median 16.3, range 8.9–1240
ng/L), indicating the influence of specific point sources. Highly
branched isomer profiles of perfluorooctanoic acid (18–25%
br-PFOA) in rivers with elevated concentrations (96–352 ng/L)
indicate that releases during production of PFOA by electrochemical
fluorination and/or its use in fluoropolymer manufacture were the
dominant sources to these rivers. The fluorinated alternatives 6:2
fluorotelomer sulfonate (detection frequency 21%, < 0.1–3.1
ng/L) and chlorinated polyfluoroalkyl ether sulfonate F-53B (51%,
< 0.56–78.5 ng/L) were also found in some rivers. The total
Chinese riverine mass discharges of PFOA (mean 80.9; range 16.8–168
t/y) (including monitoring data from this and other studies) were
in good agreement with theoretical PFOA emission estimates (17.3–203
t/y) whereas riverine mass discharges of PFOS (mean 3.6; range 1.9–5.6
t/y) could only account for a minor fraction of theoretically estimated
PFOS releases (70 t/y). This study provides empirical evidence that
emissions from Chinese point sources likely dominate the global emissions
of several legacy PFASs (notably PFOA) and fluorinated alternatives
(e.g., F-53B).