GEOCHEMICAL BASELINE MAPPING OF EUROPEAN SOILS: A FOREGS project as an input to IUGS/IAGC Global Geochemical Baselines

R. Salminen1, M.J. Batista2, M. Bidovec3, A. Demetriades4, B. De Vivo5, W. De Vos6, M. Duris7, A. Gilucis8, V. Gregorauskiene9, J. Halamic10, P. Heitzmann11, A. Lima5, G. Jordan12, G. Klaver13, P. Klein14, J. Lis15, J. Locutura16, K. Marsina17, A. Mazreku18, J. Mrnkova17, P.J. O'Connor19, S.Å. Olsson20, R.T. Ottesen21, V. Petersell22, S. Pirc3, J.A. Plant23, S. Reeder23, C. Reimann21, I. Salpeteur24, H. Sandström1, U. Siewers25, D. Smith26, A. Steenfelt27, T. Tarvainen1

1Geological Survey of Finland; 2Geological Survey of Portugal; 3Geological Survey of Slovenia; 4Institute of Geology and Mineral Exploration, Greece; 5University of Napoli "Federico II", Italy; 6Geological Survey of Belgium; 7Czech Geological Survey; 8State Geological Survey of Latvia; 9Geological Survey of Lithuania; 10Croatian Geological Survey; 11Swiss National Hydrological and Geological Survey; 12Hungarian Geological Institute; 13TNO-NITG, The Netherlands; 14Geological Survey of Austria; 15Polish Geological Institute; 16Instituto Geologico y Minero de Espána; 17Geological Survey of Slovak Republic; 18Centre of Civil Geology, Albania; 19Geological Survey of Ireland; 20Geological Survey of Sweden; 21Geological Survey of Norway; 22Geological Survey of Estonia; 23British Geological Survey; 24Geological Survey of France; 25Bundesanstalt fûr Geowissenschaften und Rohstoffe, Germany; 26United States Geological Survey; 27Geological Survey of Denmark and Greenland

The Chernobyl accident in 1986 made geochemists aware that no reliable geochemical baseline data were readily available across Europe to evaluate the ongoing contamination of the surface environment by radioactive and toxic elements. For the next ten years preparations were made to realise a widely-spaced multi-sampling media geochemical survey over western European countries in a standardised manner, at first through a pilot project of the WEGS (Western European Geological Surveys), later by its successor FOREGS (Forum of European Geological Surveys). In the same period IGCP project 259 on “International Geochemical Mapping” was carried out under the auspices of UNESCO, its objective being to elaborate the specifications of the geochemical baseline mapping of the global land surface, in recognition of the global dimensions of environmental degradation. Twenty-six FOREGS countries decided in 1996 to go ahead with the regional geochemical mapping of Europe, according to the specifications of the IGCP 259 project. A sampling and sample preparation methodology was worked out, for soils, humus, stream water, stream sediment and floodplain sediment. The resulting “FOREGS Geochemical Mapping Field Manual”, published in 1998, is available at http://www.gsf.fi/foregs/geochem/index.htm. Sampling itself began in 1997 and was completed in 2001, except for some later additions. Part 1 of the FOREGS “Geochemical Atlas of Europe”, comprising 354 geochemical maps, background information and methodology, was published in June 2005. The electronic version is available from: http://www.gsf.fi/publ/foregsatlas/. The atlas contains geochemical baseline data across Europe for more than 50 chemical elements, including all bioessential and most toxic elements. Part 2 of the atlas is expected to be published by June 2006, and will include the interpretation, additional maps, diagrams and tables. The widely spaced FOREGS soil sampling does not represent all the soil types of Europe. In accordance with the field manual, soil samples were taken from residual and sedentary soils, which generally reflect the underlying bedrock. They were collected from small, second order drainage basins. Two different depth related residual soil samples were collected, a topsoil sample from 0-25 cm (excluding material from the organic layer), and a subsoil sample from a 25 cm thick section within a depth range of 50 to 200 cm (the C-soil horizon). In addition, a surface floodplain sediment or alluvial soil sample (0-25 cm) was collected from a larger catchment basin. The main purpose of the FOREGS geochemical survey is not to document different soil types, but to display large patterns of geochemical signatures on the scale of the continent, and to investigate the different factors influencing these patterns, notably bedrock geology, climate and human influences. Detailed pedogenetic processes fall outside the scope of this investigation. The results show an overwhelming influence of bedrock geology on the geochemistry of soils, but comparison of topsoil with subsoil points to substantial man-induced contamination for certain elements. The FOREGS geochemical baseline survey is considered to be the pilot project of the IUGS/IAGC “Global Geochemical Baselines” programme, because many operational problems were solved with the participation of 26 different national teams. The experience gained will be used for the efficient planning of the global project, and also to promote the methodology for developing low cost environmental baseline data in third world countries.