STEEP Project 1 researchers, led by Dr. Elsie Sunderland, and USGS collaborated to collect extensive PFAS data from a Cape Cod Superfund site impacted by historic AFFF contamination with the goal of better understanding how geochemical and hydrological factors affect PFAS transport and transformation and lead to susceptibility of drinking water supplies to PFAS contamination. The downgradient plume of PFAS contamination in groundwater at this site passes through large gradients in dissolved oxygen, nutrients, and redox transformations as it passes through groundwater/surface water exchange points, flows into a groundwater fed kettle lake, and re-enters downwelling groundwater. Researchers found that the composition of PFAS precursors fluctuates significantly at these interfaces from approximately 16% in the oxic lake water to slightly less than 7% in downwelling groundwater, likely indicating degradation of precursors in these regions. The terminal PFAA measured in these areas also appears to fluctuate by a factor of 2-3 seasonally, while remaining stable in the groundwater plume and downgradient ecosystems.
