Geochemical baseline

Covelli, S. Fontolan, G. 1997. Application of a normalization procedure in determining regional geochemical baselines. Environmental Geology, 30, 34-45. 

Demetriades, A. 2008. Overbank sediment sampling in Greece a contribution to the evaluation of methods for the Global Geochemical Baselines mapping project. Geochemistry Exploration, Environment, Analysis, 8, 229-240. 

Zhu, L.X., Ma, S.M., Wang, Z.F. 2006. Soil eco-geochemical baseline in alluvial plains of eastern China. Geology in China, 33(6) 1400-1405 (in Chinese with an English abstract). 

The need for environmental geochemical baseline data in Europe.8... 

Data on geochemical baselines are urgently needed in Europe, because environmental authorities are defining limits for levels of contaminants in soils used for different purposes in most European countries. As geochemists know, the natural concentrations of elements are different in the various constituents of overburden, and vary markedly between geologically disparate areas. State authorities, however, are not aware of these significant natural variations, which should be taken into account in defining action limits. There are already examples of action limits that are lower than natural concentrations. 

The need for geochemical baseline data in Europe has been stated very clearly by Plant et al. (1996) in an inventory of existing geochemical data in... 

The report by Plant et al. (1996) also gives reasons why Geological Surveys or equivalent governmental institutions are particularly well suited to provide the data needed to establish systematic environmental geochemical baseline databases for Europe. 

In Europe, the results of the Global Terrestrial Network (GTN, also called the Global Reference Network) sampling, as recommended by IGCP 259 and 360 projects (Darnley et al. 1995), will be used as reference material to normalise baseline datasets of Europe. The final product will then be geochemical baseline datasets of Europe. 

Figure 1.2 Sampling density (sampling sites per km2) for different scales of geochemical studies according to the new classification scheme after the continent-wide geochemical baseline surveys were started.

Salminen, R., and Gregorauskiene, V. (2000). Considerations regarding the definition of a geochemical baseline of heavy metals in the overburden in areas differing in basic geology. Appl. Geochem. 15, 647-653. 

Figure 5.1 Example of a Geochemical Baseline Survey of the Environment (G-BASE) sample number defined by four key fields to give a unique sample identity.

Figure 5.3 Example of a Geochemical Baseline Survey of the Environment (G-BASE) random number list used for issuing site numbers with 8% of the numbers reserved for duplicates, replicates (sub-samples), standards and blanks. The blank column is used to record details of the date and sampbng pair assigned to each number.

Figure 5.8 Examples of duplicate-replicate plots from soil analyses from the Geochemical Baseline Survey of the Environment (G-BASE) project generated by an MS Excel macro (for the relationship of control samples, see Fig. 5.4). Note that the cited detection limits for Cu, U and I are 1.3, 0.5 and 0.5 mg/kg, respectively.

Lima, A., Albanese, S., and Cicchella, D. (2005). Geochemical baselines for the radioelements K, U, and Th in the Campania region, Italy A comparison of stream-sediment geochemistry and gamma-ray surveys. Appl. Geochem. 20, 611—625. 

Statistical methods based on histograms, cumulative frequency probability curves (see above), univariate and multivariate data analysis (Miesh, 1981 Sinclair, 1974, 1976, 1991 Stanley, 1987) are widely used to separate geochemical baseline (natural and/or anthropogenic) values from anomalies. 

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