Spectral induced polarization (SIP) measurements across a PFAS-contaminated source zone.

Area of Science:

• Geophysics
• Environmental Science
• Soil Science

Background:

• Aqueous film-forming foam (AFFF) is a significant environmental contaminant at former fire training sites.
• Poly- and per-fluoroalkyl substances (PFAS) in AFFF pose risks to soil and water resources.
• Effective in situ screening technologies are needed to assess AFFF contamination levels.

Purpose of the Study:

• To evaluate the efficacy of field-scale Spectral Induced Polarization (SIP) for detecting AFFF and PFAS in soils.
• To establish correlations between SIP measurements and PFAS concentrations in soil samples.
• To assess the potential of SIP as a screening tool for AFFF-contaminated sites.

Main Methods:

• Acquisition of field-scale SIP data along a transect over an AFFF source zone.
• Collection and analysis of soil samples to determine PFAS concentrations and soil texture.
• Laboratory SIP measurements on soil columns to correlate geophysical response with PFAS levels.

Main Results:

• SIP measurements demonstrated sensitivity to AFFF constituents sorbed to soil pore surfaces.
• Laboratory SIP data showed a linear correlation between specific polarizability/phase and total soil-PFAS concentration.
• Field SIP phase measurements were highest above areas with maximum measured PFAS concentrations.

Conclusions:

• SIP is a promising geophysical technique for characterizing AFFF source zones in situ.
• The study supports the use of SIP for assessing soil contamination by PFAS.
• Further research is needed to establish robust correlations between field SIP data and PFAS concentrations.