Poly- and perfluoroalkyl substances (PFASs) are aliphatic organofluorine molecules with highly fluorinated carbon chain “tails,” and a hydrophilic “head” group of carboxylates, sulfonate, or phosphonates/phosphinates. Many are terminal degradation products of more complex industrial chemical precursors. Riverine and direct inputs of municipal and industrial wastewaters, as well as atmospheric deposition, represent the major sources to coastal seas. Open oceans serve as a terminal sink for PFAS which are effectively undegradable under ambient environmental conditions. This study builds on an ongoing review of PFAS in surface waters for the Stockholm Convention Global Monitoring Report http://chm.pops.int/Implementation/GlobalMonitoringPlan/Overview/tabid/83/Default.aspx). Our goal is to provide an updated overview of spatial trends, and where possible, temporal trends of PFASs in coastal marine environments and the open oceans globally. While a broad range of PFAS are currently measured in estuarine and marine waters ranging from ultrashort chains such as trifluoroacetic acid, short chains such as perfluorobutanoic acid, to long chain (C9-C18) perfluorocarboxylates, the majority of long-term monitoring has been for perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorooctanoic acid (PFOA), which have been globally regulated under the Stockholm Convention. Thus our broader objective is to assess the effectiveness of national and global bans on PFOS, PFHxS, and PFOA which have been implemented over the past 10 to 15 years. We found that the spatial coverage of PFAS measurements in coastal marine environments was dominated by information from the North Sea and Baltic Sea in Europe and the coastal seas of China, as well as the adjacent major river estuaries. For open oceans the majority of measurements were from the North Atlantic, the Southern Ocean near Antarctica, and the Arctic Ocean. The results showed that ice and snow melt inputs of PFAS are likely to be important during spring melt events and need to be considered in timing of monitoring programs in polar areas. The presence of PFOS and PFOA in remote sectors of the Southern Ocean, the Arctic Ocean and the mid-North Atlantic, including deep waters (>1000 m), illustrated the long range ocean transport of PFASs and their value as tracers of ocean circulation. We compared their concentrations reported for pre-2015 samples with those reported from 2016-2024. Temporal trend information has improved over the past 10 years due to repeat sampling of some locations, especially for the Eastern North Atlantic and the Bohai and Yellow Seas. The first evidence is emerging of declining PFOS and PFOA concentrations particularly in the North Atlantic. A major knowledge gap remains for the spatial and temporal trends of short chain (C4-C7) and ultra-short chain (C2-C3) PFAS which are recognized to have a wide range of precursors and multiple sources.

暂无