Figure 3.

Relationship between PFAS concentrations and proxy for degree of soil saturation. The proxy for soil saturation is the water-level altitude of a proximate exclusively groundwater-fed kettle lake (Ashumet Pond, Figure 1c). The altitude of the water level of the kettle lake is from USGS Water Data for the Nation station number 413758070320501.³⁷ The difference in average daily altitude of the lake level from measurements collected every 30 minutes on the same day as the groundwater sample is shown in the figure (0 = lowest recorded altitude). (a–d) Relationship between PFAS concentrations and the soil saturation proxy on the same day (n = 12). Lines represent the best fit ordinary least squares linear relationship (solid = p-value < 0.05; dashed = p-value > 0.05). Data for precursors are shown in Figure S10.