GEMAS: Cobalt, Cr, Cu and Ni distribution in agricultural and grazing land soil of Europe

In the framework of the GEMAS project, 2211 samples of agricultural soil (Ap, 0-20 cm, regularly ploughed fields), and 2118 samples from land under permanent grass cover (Gr, 0-10 cm, grazing land soil) were collected across almost the whole European continent, at a density of 1 sample site/2500 km(2), in accordance with a common sampling protocol.Among many other elements, the concentrations of Co, Cr, Cu and Ni in European soil were determined by ICP-MS after a hot aqua extraction, and WD-XRFS analytical methods, and their spatial distribution patterns generated by means of a GIS software.The presence of mafic and ultramafic rocks, ophiolite complexes and mineralisation, is widespread across the European continent, and seems to explain most of the variability of the elements studied in this paper. A large belt, north of the last glaciation maximum limit, is generally dominated by lower concentrations compared with central European and Mediterranean areas and to some areas in Northern Europe where higher Co, Cr, Cu and Ni values also occur.The application of the guideline value set for Cu and Ni by the EU Directive 86/278/EEC to the Ap soil samples of the GEMAS data set highlighted that at the continental scale the use of a unique reference interval is a tool of limited effectiveness; the lithological variation, occurring across a whole continent, generates changes in the geochemistry of soil, which cannot be accommodated by using a single reference interval even if it is very wide. The GEMS data set should form the sound basis to set at the European scale the geochemical background reference intervals, at least, for regions sharing common lithological settings and a common geological history. (C) 2015 Elsevier B.V. All rights reserved.