USE OF PROXIMAL SENSORS AND PEDO-GEOCHEMICAL SURVEY IN A OUTDOOR SHOOTING RANGE FOR THE ASSESSMENT OF SPATIAL VARIABILITY AND FATE OF CONTAMINANTS IN SOILS

Sources of anthropogenic environmental pollution are widespread, not only as a result of industrial activities, but also due to recreational facilities. Outdoor shooting ranges, involving millions of people everywhere in the world, can produce several negative effects on environment and public health.The area of a dismissed outdoor shooting range in Campania region (Southern Italy) has been declared unsuitable for agricultural and forest-pastoral production by the Italian Ministry of Agricultural, Food and Forestry Resources, due to an extensive long term (approximately 10 years of activity) soil contamination associated with Pb, Sb, PAHs, dioxins, PCBs and C> 12 hydrocarbons.In the framework of a site characterization plan aiming at its reclamation, the shooting range area was surveyed by means of i) proximal sensors (such as EMI - Electromagnetic Induction - and Gamma Ray - dose rate, K, eU, eTh - spectroscopy) for indirect, cost effective and rapid measurements at field scale, to identify homogeneous zones in terms of soil degradation; ii) ultrasonic penetrometry to evaluate both soil compaction rate and depth of occurring hard layers, iii) direct investigations by means of hand drillings to preliminary characterize the soil down to the presence of a hardened, impenetrable layer; iv) direct XRF measurements on the soils sampled at different depths, to assess the total content of some potentially toxic metals (PTE); v) chemical analyses of PAHs compounds on topsoil samples collected on the basis of the regular grid across the study area.Apparent electrical conductivity (ECa) map, consistently with the Gamma Ray dose rate map, evidenced three key zones, wide bands North-South oriented. Cone index data, obtained by ultrasonic penetrometer measurements, indicated the presence of a very dense, hard and impenetrable to hand hauger layer, recognised as travertine rock, from 25 to more than 55 cm of depth, and dipping northward. Sandy soils, frequently enriched of coarse fragments, were identified to a variable depth from 25 to 80 cm of depth. Elemental analyses, carried out with the portable XRF analyzer on soil sampled until the travertine layer, showed a high contamination by Pb (greater than 1000 mg/kg) and Sb (greater than 30 mg/kg) in the first 15 cm of depth, at approximately 90 m from the shooting platforms. Concentrations of 13 PAHs compounds determined on 32 topsoil samples showed the highest values close to the firing lanes where a huge amount of shooting target and fragments were present. Data were analyzed by means of GIS and multivariate analysis was completed jointly considering compositional and non-compositional variables to explore hidden potential relationships among involved parameters.