29-9 Geophysical Delineation of a Subsurface Trapping Layer for Per- and Polyfluoroalkyl Substances (PFAS) in the Little Miami River Aquifer, Loveland, Ohio

Session: Undergraduate Research, Part II (Posters)

Presenting Author:

Authors:

Abstract:

Per- and polyfluoroalkyl substances (PFAS) or “forever chemicals” are persistent contaminants that pose long-term risks to groundwater systems due to their stability and limited natural degradation. Detection of PFAS and related compounds in regional groundwater and surface water in Loveland, Ohio have raised concerns about PFAS transport pathways and subsurface accumulation potential. Identifying sediment layers that can naturally retain or slow PFAS movement is essential for predicting contaminant behavior and guiding future monitoring and treatment strategies. This study applies non-invasive geophysical methods to evaluate the subsurface materials along a point bar where O’Bannon Creek meets the Little Miami River near Loveland (centered around 39.2706, −84.2587) to locate potential PFAS sorption hotspots and identify the fine-grained layers most capable of trapping these “forever chemicals.”

To evaluate subsurface stratigraphy, we conducted electromagnetic induction (EMI) and electrical resistivity tomography (ERT) surveys, using a Geophex GEM-2 multi-frequency broadband electromagnetic instrument and an IRIS Syscal Kid 24switch, respectively. These data indicate a presence of laterally extensive zone at approximately 2.5 m depth. This zone shows higher electrical conductivity and lower resistivity compared to surrounding materials. These signatures are consistent with finer-grained sediments, such as clays and silts. The variations in geophysical responses suggest that the subsurface composition is heterogeneous in places, but overall, the results point to the presence of a layer fine-grained material.

The geophysical patterns observed this study correspond to sediment types that have been shown to have higher sorption capacity for PFAS and related compounds. Although we didn’t collect PFAS samples during this study, the identified zone may represent an area where PFAS could accumulate or experience delayed migration. This work demonstrates that EMI and ERT can serve as useful preliminary tools for highlighting subsurface features that warrant further investigation. The results offer a starting point for locating possible PFAS sorption hotspots and can help guide future sampling, monitoring, and characterization efforts in regions where PFAS transport remains a growing concern.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.