Spatial and Temporal Trends of Perfluoroalkyl Substances in Global Ocean and Coastal Waters

Per- and polyfluoroalkyl
substances (PFAS) have been widely detected
in global surface waters since the early 2000s. Here, we have compiled
and analyzed the published data for perfluorocarboxylates (PFCAs)
and perfluorosulfonates (PFSAs) in surface waters of coastal seas,
the Great Lakes, and open oceans to examine temporal and geospatial
trends. Mass discharges from major rivers were also estimated. A large
number of measurements of individual PFAS have been made in these
surface waters (29 500 values), with seven C4–C10 PFSAs
and nine C4–C12 PFCAs accounting for 83% of all data. However,
most results (85% for PFSAs; 80% for PFCAs) were for the coastal seas
of Western Europe, China, Korea, and Japan, while results were limited
for coastal North America and lacking for South America and Africa.
Highest median concentrations of PFCAs and PFSAs were reported in
the Bohai and Yellow Seas region of China as well as in the North
and Baltic seas in Europe. Significant declines in median PFSAs and
C7–C12 PFCAs were also observed for the period 2012–2018
in these same regions, and for 2004–2017 in the Great Lakes.
Mass discharge estimates indicated continued substantial riverine
emissions of long chain (C7–C12) PFCAs in the period 2015–2019
for the coastal seas of China and reductions in emissions for Western
European rivers compared to earlier time periods.