Delineation of LNAPLs Contaminant Plume at a Former Perfumery Plant Using Electrical Resistivity Tomography

Abstract:

Non-aqueous phase liquids (NAPLs) is a common material in industrial production; however, contamination of the soil by NAPLs is well known as they may reach to the subsurface and groundwater, creating toxicity for ecosystem. Adequate delineation of contaminant plume distribution is critical for effective remediation of contaminated sites. Electrical resistivity tomography (ERT) measurements on soil contaminated with NAPLs show great potential. A total of six profiles were conducted on a former perfumery plant contaminated with benzene and ethylbenzene in this study. The electrical resistivity of ERT profiles was consistent with the borehole sampling results. Comparison results between resistivity and contaminant concentration suggest that the threshold resistivity value for the contaminated area is 18 Ω·m, which can be an indication of the contaminated area. In addition, four sites were excavated to verify the results of ERT profiles, with an aromatic hydrocarbon odor, the ground truth of C1 was consistent with the high-resistivity layer of L1. According to the investigation results, the contaminated sources in the plant could be divided into four types and a potential sewage pipe was speculated. In conclusion, ERT is successful in delineating the LNAPLs plume, helping to design sampling strategies, saving cost and time.