Over the past five years, TEPA has obtained many good results in soil and groundwater pollution investigations by employing geophysical prospecting techniques. Therefore, many private sectors have actively taken initiatives to conduct contamination investigations and remediation work. Otherwise, TEPA can suspend the operation of a plant or debar the transfer of the land's ownership.

Taiwan Environmental Protection Administration (TEPA) has the power to require polluters to remediate contaminated sites. With the enhancement of environmental awareness, Taiwan holds an increasingly positive attitude for facing soil and groundwater pollution problems. Based on the distinctive property differences of the contaminated soil and the clean silt, the completion of the remediation was confirmed by the differences between pre-remediation and post-remediation in GPR, ERT and FDEM results. The principal remediation scheme was soil replacement by replacing the contaminated soil with clean silt. The existence of the UST and the sludge within were confirmed by ERT and the UST shape was mapped by FDEM. Thus, the first attempt to use GPR in the pre-remediation investigation did not achieve the desired results and other methods were deployed. However, due to the highly conductive nature of the heavy-metal laden sludge, the GPR signals were attenuated severely. In general, the GPR survey was effective at locating shallowly buried objects. The main goals were to verify the position and the integrity of the underground storage tanks (UST), and to determine the effectiveness of remediation to ensure no contaminants remained at the site. This study employed the combination of three methods, namely the Frequency Domain Electromagnetic (FDEM), Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) to evaluate a heavy-metal contaminated site for both pre- and post-remediation investigations.

Geomodel of underground water