Geophysical Investigation of Organic Contaminant Plume using ERT and IP — a Case Study from Hungary

The presentation highlights the geoelectrical IP investigation of contamination hotspots at an abandoned pharmaceutical waste disposal site. The aim of the study was to identify potential fracture zones in the host tuff formation with increased porosity and to clarify the distribution of non-aqueous phase liquid contaminants. The dense infrastructure of the area significantly complicated the investigations. Prior to conducting the measurements, model studies were performed to determine the measurement parameters (survey arrangement, IP time window length etc.). Following the processing and interpretation of the data, the distribution of specific resistivity and chargeability along the profile was mainly influenced by the effects of biogenic degradation associated with contamination and, in some places, by surface structures, even overriding the geological structure. The effects of the built structures were relatively well distinguishable due to the high signal-to-noise ratio of the measured data and the positioning of the anomalies. The location of the anomalous zones could be directiy correlated with the high contamination zones revealed by the boreholes.