EuroGeoSurveys geochemical mapping of agricultural and grazing land soil of Europe (GEMAS). Field manual.

REACH (Registration, Evaluation and Authorisation of Chemicals), the new European Chemicals Regulation was adopted in December 2006. It came into force on the 1st June 2007. REACH, as well as the pending EU Soil Protection Directive, require additional knowledge about "soil quality" at the European scale. The GEMAS (geochemical mapping of agricultural soils and grazing land of Europe) project aims at providing harmonized geochemical data of arable land and land under permanent grass cover at the continental, European scale. Geological Surveys in 34 European countries, covering an area of 5.6 million km2, have agreed to sample their territory at a sample density of 1 site each, arable land (0-20 cm) and land under permanent grass cover (0-10 cm), per 2500 km2. Sampling will take place during 2008, following a jointly agreed field protocol which is presented in this report. All samples will be prepared in just one laboratory, a strict quality control procedure has been established and all samples will always be jointly analyzed in just one laboratory for any one chemical element/parameter

The EuroGeoSurveys geochemical mapping of agricultural and grazing land soils project (GEMAS) - Evaluation of quality control results of aqua regia extraction analysis.

Rigorous quality control (QC) is one of the keystones to the success of any regional geochemical mapping programme. For the EuroGeoSurveys (EGS) GEMAS (Geochemical mapping of agricultural and grazing land soils) project 2211 samples (including field duplicates) of agricultural soil (Ap, Ap-horizon, 0-20 cm) and 2118 samples (including field duplicates) from land under permanent grass cover ("grazing land" - Gr, topsoil 0-10 cm) were collected from a large part of Europe, centrally prepared (air dried, sieved to <2 mm, homogenised and split into sub-samples) and randomised prior to being sent out to contract laboratories. QC consisted of (1) collection of a field duplicate at a rate of 1 in 20 field samples, (2) preparation of two large project standards ("Ap" and "Gr") for insertion between the routine project samples, (3) preparation of an analytical replicate from each field duplicate and (4) randomisation of all samples prior to analysis. Here QC-results covering analysis of 53 chemical elements (Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, Ge, Hf, Hg, In, K, La, Li, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Pd, Pt, Rb, Re, S, Sb, Sc, Se, Sn, Sr, Ta, Te, Th, Ti, Tl, U, V, W, Y, Zn, Zr), following an aqua regia extraction on a 15 g aliquot per sample of both sample materials, are reported. Practical detection limits and precision, as well as the analytical results for the two project standards Ap and Gr are provided for all 53 elements. All analyses were carried out within twenty days at ACME laboratories in Vancouver, Canada. No serious quality problems, other than a few occasional outliers for a number of elements (B, Ca, and Sn) were detected, and the analytical results were accepted after investigating the reasons for these outliers

U-Th signatures of agricultural soil at the European continental scale (GEMAS): Distribution, weathering patterns and processes controlling their concentrations

Agricultural soil (Ap-horizon, 0–20 cm) samples were collected in Europe (33 countries, 5.6 million km2) as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil-mapping project. The GEMAS survey area includes diverse groups of soil parent materials with varying geological history, a wide range of climate zones, and landscapes. The soil data have been used to provide a general view of U and Th mobility at the continental scale, using aqua regia and MMI® extractions. The U-Th distribution pattern is closely related to the compositional variation of the geological bedrock on which the soil is developed and human impact on the environment has not concealed these genuine geochemical features. Results from both extraction methods (aqua regia and MMI®) used in this study support this general picture. Ternary plots of several soil parameters have been used to evaluate chemical weathering trends. In the aqua regia extraction, some relative Th enrichment-U loss is related to the influence of alkaline and schist bedrocks, due to weathering processes. Whereas U enrichment-Th loss characterizes soils developed on alkaline and mafic bedrock end-members on one hand and calcareous rock, with a concomitant Sc depletion (used as proxy for mafic lithologies), on the other hand. This reflects weathering processes sensu latu, and their role in U retention in related soils. Contrary to that, the large U enrichment relative to Th in the MMI® extraction and the absence of end-member parent material influence explaining the enrichment indicates that lithology is not the cause of such enrichment. Comparison of U and Th to the soil geological parent material evidenced i) higher capability of U to be weathered in soils and higher resistance of Th to weathering processes and its enrichment in soils; and, ii) the MMI® extraction results show a greater affinity of U than Th for the bearing phases like clays and organic matter. The comparison of geological units with U anomalies in agricultural soil at the country scale (France) enables better understanding of U sources in the surficial environment and can be a useful tool in risk assessments

GEMAS: Cadmium distribution and its sources in agricultural and grazing land soil of Europe â\u80\u94 Original data versus clr-transformed data

Over 4000 agricultural and grazing land soil samples were collected for the â\u80\u9cGeochemical Mapping of Agricultural and Grazing Land Soil of Europeâ\u80\u9d (GEMAS) project carried out by the EuroGeoSurveys Geochemistry Expert Group. The samples were collected in 33 European countries, covering 5.6 million km2at a density of 1 sample site per 2500 km2. All samples were analysed by ICP-MS following an aqua regia extraction. The European median Cd concentration is 0.182 mg/kg in agricultural soil and 0.197 mg/kg in grazing land soil (including eastern Ukraine). The Cd map demonstrates the existence of two different geochemical background regimes in northern and southern Europe, separated by the southern limit of the Quaternary glaciation. Cadmium shows two times higher background concentrations in the older and more weathered southern European soil than in northern European soil. The spatial distribution patterns of Cd in the collected soil samples are mainly governed by geology (parent material and mineralisation), as well as weathering, soil formation and climate since the last glaciation period. Locally, in several areas, the natural anomaly pattern is overprinted by anthropogenic emissions from former mining, ore processing and related metal industries. Some Cd anomalies can be attributed to urbanisation and the use of fertilisers. A comparison of the raw data Cd concentration map with its clr-transformed counterpart and selected single element ratio maps demonstrates that substantial additional information about sources and processes governing the distribution of Cd in agricultural soil at the European scale can be obtained. Results of a PCA, carried out following the classical approach (standardised) versus a PCA based on the statistically acceptable approach, using clr-transformed data, are quite comparable