10/21/2026
Ever wonder what happens when PFAS in groundwater meets the ocean? New USGS research has uncovered the role tidal pumping plays in its movement! 🌊
The study looks at PFAS transport in groundwater from sources to seeps into surface waters, focusing on two fuel tanker-truck roll-over accidents where aqueous film-forming foam (AFFF) was applied as a fire precaution, creating a plume of PFAS toward nearby coastal waters over decades. They found that the PFAS from the AFFF traveled with groundwater and discharged within the coastal area between high and low tides (known as the intertidal zone) at detectable concentrations. A novel finding of the study was the widespread influence of 'tidal pumping' on discharge of groundwater and PFAS at the intertidal seeps, which is movement of the seawater in and out of the coastal sediments across the tidal cycle. In higher salinities, some PFAS chemicals are known to 'stick' to sediment grains, and therefore PFAS intertidal processes deserve further research to understand how the intertidal zone influences PFAS loading of coastal waters.
Led by USGS research hydrologist Martin Briggs, the journal article "PFAS from a Discrete-Event Terrestrial Source Migrates with Groundwater to Intertidal Seepages," published in the May-June 2026 issue of "Groundwater" has been named Editor's Choice! 🥳According to the journal, studies selected as "Editor's Choice" are reflective of the "best content published in the journal.”
🎊Congratulations to Marty and the other USGS Water Science Center and Water Mission Area staff who contributed to this study! 🎊
Read the full study here: https://ow.ly/56PI50ZW0ig
📸1: USGS scientists Eric White and Patrick Scordato collect electromagnetic imaging data at high tide to map areas of terrestrial groundwater discharge and the depth of ocean water infiltration into the sediments. They are at Hen Cove in Bourne, MA, in September 2022. Credit: USGS/Martin Briggs
📸2: USGS scientist Zach O'Neal installs piezometers in areas of terrestrial groundwater discharge to track groundwater-surface water exchange through a full lunar tidal cycle to coincide with PFAS chemical sampling. Zach is at Hen Cove in Bourne, MA, in September 2022. Credit: USGS/Martin Briggs
