## 2 Materials and Methods
After the PlumeStop(tm) injection, some surveys were conducted in the pilot test area using direct push (Geoprobe) penetrometers [43]. These investigations were aimed at visually checking the sediment color after injection and collecting soil samples for various analyses and tests. Seven penetrometric surveys were performed to investigate the subsurface to a depth of 10 m.  
The sediments subjected to treatment with PlumeStopTM underwent slight color variation, due to the covering of soil particles with activated carbon. During the monitoring activity, a passive groundwater sampling system was installed in some piezometers intercepting the intermediate aquifer. Snap Samplers(@(Q.E.D. Environmental Systems, Inc., Dexter, MI, USA) minimize the impact of the sampling process on groundwater chemistry [44]. Groundwater samples were collected using this method after PlumeStopTM injection. Among the monitoring activities, time-lapse geophysical investigations played a specific role. The use of repeated geophysical measurements to highlight changes in the system is state of the art for several hydrological applications but is used relatively scarcely at contaminated sites, particularly during remediation activities [40; 45; 46; 47]. An ERT profile during pilot testing was acquired to verify the correct product spread in the first application area. The pilot test was conducted in a limited area, with the purpose of optimizing procedures and operational modes of interventions to scale up the process. Analytical monitoring at the sampling points constituting the piezometric network was done to check the effectiveness of the intervention adopted. The results of full-scale intervention provide information on the long-term trend of the groundwater treatment onsite. The multisource and multitemporal data were organized, georeferenced, and stored in a geodatabase, also useful for visualization and data processing. The hydrogeophysical 3D model was reconstructed by means of RockWorks 17 software (RockWare Inc., Golden, CO, USA) [48]. This software enables the acquisition, analysis, visualization, and integration of information from georeferenced data. The data integration and analysis phase involved interpolating and processing the geological, geophysical, and hydrochemical parameters [49; 50]. The parameters included the characteristics of stratigraphic horizons, groundwater levels, geophysical information, and the chemical analysis of the sampled water. Data belonging to different scientific spheres were elaborated with the inverse distance weighted geostatistical method [50; 51; 52] to obtain an integrated multidisciplinary model. The interpolation of punctual data, performed using the appropriate algorithm, generated 3-dimensional models, which illustrate the spatial distribution of the parameters obtained from all investigations. The combination of these highly complementary data types--geology, hydrogeology, geophysics, geochemistry--enables the production of value-added photorealistic outcrop models, adding new information that can be used to capture the geological uniqueness, contamination dynamics, and performance of the adopted remediation intervention.