Multi-Sensor Approach Combined with Pedological Investigations to Understand Site-Specific Variability of Soil Properties and Potentially Toxic Elements (PTEs) Content of an Industrial Contaminated Area

A combination of indirect soil investigation by proximal soil sensors (PSS), based ongeophysical (ARP, EMI), physical (Cone Index -CI- by ultrasound penetrometry) and spectrometric(?-rays) techniques, as well as pedological surveys, was applied in the field to assess the spatialvariability of soil pollution and physical degradation in an automobile-battery recycling plant insouthern Italy. Five homogeneous zones (HZs) were identified by the PSS and characterized by soilprofiles. CI measurements and field analysis showed clear features of physical (i.e., soil compaction,massive structure) degradation. XRF in situ (on profiles) analysis using portable equipment (pXRF)showed Pb, Cd and As concentrations exceeding the contamination thresholds provided by theItalian regulation for industrial land use up to 20 or 100 cm of depth. Hence, a validation procedure,based on pXRF field survey, was applied to the PSS approach used for the HZs identification. Highconsistency was found between the HZs and the PTEs in the most contaminated areas. Significantnegative Pearson correlation coefficients were found between ?-rays dose rate and Pb, Cu, Zn, As andNi; positive ones were found between ?-rays and autochthonous lithogenic elements (V, Ti, Mn, K, Sr,Nb, Zr, Rb, Th), confirming that higher radionuclide activity correlated with lower pollution levels.