Map of the natural background 1:250,000 of the Emilia-Romagna plain — Cr, Cu, Ni, Pb, V, Zn

Represents the distribution of area in the subsoil (90-140 cm depth) of the content of 6 metals (Cr, Cu, Ni, Pb, V, Zn) in agricultural soils. This depth is considered representative of the natural background content (‘pedo-geochemical content’ according to ISO/DIS 19258, 2005). The cartographic units are represented by groups of polygons belonging to the same concentration classes. The factors that regulate the natural content of metals in soils are: origin of the sediment in which the soil was formed, weaving, and evolutionary degree. For chromium as well as nickel the dominant factor is the origin of the sediments that originate the soil. The map has an original approach in that it uses the genetic-environmental interpretation for the assessment and geographical extension of the geochemical data, associating with groups of soils with geochemical affinity the same natural background values. Point data are obtained using the XRF (X-ray Fluorescence Spectrometry) analytical method in order to determine the total content to perform a thorough and correct geochemical analysis.