Geophysical Signatures of Soil AFFF Contamination from Spectral Induced Polarization and Low Field Nuclear Magnetic Resonance Methods
Citation:
Falzone, S., C. Schaefer, E. Siegenthaler, K. Keating, D. Werkema, AND L. Slater. Geophysical Signatures of Soil AFFF Contamination from Spectral Induced Polarization and Low Field Nuclear Magnetic Resonance Methods. JOURNAL OF CONTAMINANT HYDROLOGY. Elsevier Science Ltd, New York, NY, 260:104268, (2024). https://doi.org/10.1016/j.jconhyd.2023.104268
Impact/Purpose:
Understanding the spatial distribution of PFAS within the near subsurface can guide sampling to known, or likely, locations of PFAS. However, few field methods are successful in the non-invasive detection of PFAS impacted soil. This paper shows the potential utility of non-invasive geophysical characterization of source zones impacted by PFAS compounds. Using laboratory and initial field scale experiments, this research suggests that using spectral induced polarization (SIP) PFAS impacted soil can be identified relative to local non-impacted soil. This potential detection capability could then guide additional field investigations with targeted sampling locations. These initial innovative findings are promising in showing the potential utility of the geophysical response to PFAS source zones. Future investigations will continue to test SIP to locate anomalous zones impacted with PFAS.
Description:
Few field methods are available for characterizing source zones impacted with aqueous film forming foam (AFFF). Non-invasive geophysical characterization of AFFF source zone contamination in situ could assist with the delineation and characterization of these sites, allowing for more informed sampling regimes aimed at quantifying subsurface poly- and perfluoroalkyl substances (PFAS) contamination. We present initial results from the investigation of the sensitivity of two existing surface and borehole-deployable geophysical technologies, spectral induced polarization (SIP), and low field nuclear magnetic resonance (NMR), to soils impacted with AFFF. To investigate the sensitivity of these methods to AFFF-impacted soil, bench-scale column experiments were conducted on samples consisting of natural and synthetic soils and groundwater. While our findings do not show strong evidence of NMR sensitivity to soil PFAS contamination, we do find evidence that SIP has sufficient sensitivity to detect sorption of AFFF constituents (including PFAS) to soils. This finding is based on evidence that AFFF constituents associated with the pore surface produce a measurable polarization response in both freshly impacted synthetic soils and in soils historically impacted with AFFF. Our findings encourage further exploration of the SIP method as a technology for characterizing contaminant concentrations across AFFF source zones.
URLs/Downloads:
DOI: Geophysical Signatures of Soil AFFF Contamination from Spectral Induced Polarization and Low Field Nuclear Magnetic Resonance Methods