Geochemical sources of vanadium in soils: Evidences in a southern Italy area

Identifying differences of vanadium concentrations in soils is essential to individuate pollution sources and potential risks to humans and the environment. Marked differences in the geochemical composition of the rocks, which form the parent materials of soils, and variations in the intensity of soil-forming processes can result in wide ranges of concentrations of vanadium in soils, even in those unaffected by contamination. Conversely, the anthropogenic input can give rise to contamination in urban soil. The main aim of this study was to analyse the concentrations of vanadium in a southern Italy area, in both rural and urban soils, in order to determine different geochemical sources. In the study area, 149 topsoil samples were collected (0.10 m) and analysed for vanadium and other elements by ICP-MS. Statistical and geostatistical methods were used to identify the main factors influencing the different sources of vanadium in urban and peri-urban soils and to map the concentrations of vanadium. The concentrations of V were higher in the rural soils where were related to the ophiolite-bearing units outcroppings, which influenced importantly the distribution of vanadium, rather than in the urban soil, where were lowly affected by anthropogenic pollution due, predominantly, to circulating vehicle fuels. In urban area the mean concentration of vanadium amounted below the critical threshold value imposed by Italian Decree 152/2006.