Relationship between self‐potential (SP) signals and redox conditions in contaminated groundwater

In situ measurements of redox potential are rather difficult to perform and provide only sparse information on its spatial distribution. To delineate redox fronts in a contaminant plume, the self‐potential (SP) method can be a helpful complement to geochemical measurements. Here, we apply the SP method to the Entressen municipal waste landfill (south‐eastern France) over a 20 km 2 area. The results show a large negative SP‐anomaly of ∼−400 mV with respect to a reference station taken outside the contaminant plume. Once removed the electrokinetic component associated with groundwater flow, the residual self‐potential signals are linearly correlated with in situ measurements of redox potential. We propose a quantitative relationship between self‐potential and redox potential, which would be used to invert self‐potential measurements in terms of in situ redox potential values in contaminant plumes.