Geochemical baseline values determination and spatial distribution of trace elements in topsoils: An application in Sicily region (Italy)
Daniela Varrica, Federica Lo Medico, Marino Vetuschi Zuccolini, Marianna Miola, Maria Grazia Alaimo
Abstract
This study proposed an approach to determine the geochemical baseline values in topsoils. The chosen study area is Sicily (Italy), a region characterized by significant lithological heterogeneity. Eighty-three topsoil samples were collected at several sites away from potential anthropogenic pollution sources. The concentrations of potentially toxic elements (As, Cd, Cr, Cu, Mo, Pb, Sb, V, and Zn) were quantified via inductively coupled plasma (ICP-MS). The elements showed median concentrations in the range 68.8–0.23 μg g −1 and the trend of abundance was: Zn > V > Cr > Cu > Pb > As>Mo > Sb > Cd. Regional geochemical baseline values for trace elements were determined using statistical methods (Me±2MAD; P95 and UTL95–95). The use of UTL95–95 was found to be the most suitable, obtaining appropriate geochemical baseline values for the entire region, regardless of lithology. The spatial distribution of the elements was determined by stochastic simulations on a convex-concave boundary with a resolution of 5 km, obtaining detailed geochemical maps that predict the distribution of concentrations of each element even in unsampled areas. The results of this study provide a methodology for a more correct assessment of the environmental contamination status of soils. • Statistical approach was used to define the geochemical baseline in the Sicily region. • The geochemical baseline was determined using UTL95-95 values by ProUCL 5.1 software. • Regional baseline value for each trace elements are suitable for the Sicily region. • Geochemical maps using geostatistical method provided values in unsampled areas. • Baseline values provide a statistical way to assess contamination in topsoils.