POTENTIALLY TOXIC ELEMENTS ALONG SOIL PROFILES IN AN URBAN PARK, AN AGRICULTURAL FARM, AND THE SAN VITALE PINEWOOD (RAVENNA, ITALY)

Abstract

Potentially toxic elements (PTEs) abundances in top soil and along the soil profiles from affected by different anthropogenic inputs were investigated.. The study area is located within the Ravenna Municipality, a complex territorial system highly affected by industrial (a large petrolchemical complex) agricultural activities. Three zones with distinct environmental features were identified: the San Vitale Pinewood affected by atmospheric deposition pollutans from the industrial complex (PW1, PW4, PW6 and PW8 soil profiles); a public garden within the Ravenna city center, mainly affected by traffic pollution (GP1 soil profile); the Luigi Perdisa farm located immediately northwards Ravenna was selected due to the use of fertilizers as well as atmospheric deposition (PER2 soil profile). The total concentration of PTEs (Ba, Cr, Cu, Cr, Ni, Pb, Zn) was determined by X ray fluorescence spectrometry (XRF), and the pseudo-total concentration with aqua regia digestion (AR) and ICP-OES quantification in order to evaluate the extractability of the elements. Results showed a significant increase of some PTEs (Cu, Pb, Zn) in the top soil compared to the pedological substrate. In the Ravenna urban park (GP1 station), Pb and Zn concentrations exceeded the threshold values established by current Italian laws for soils from public, residential and private areas (D. Lgs 152/2006). The correlation between top soil and the subsoil highlighted that some PTEs, such as Cu, Pb and Zn, are anthropogenic and they are mainly associated to the deposition of airborne pollutants, whereas other elements (Cr and Ni) are lithologenic.