GcBÜK400 — Nickel in the upper floor

Nickel is an essential trace element for some animals, plants and microorganisms; this has not been proven for humans. The ni concentration in the upper continental crust (total content) is 19 mg/kg, but can vary greatly in the different rock types. The mean Ni levels (median) of the Saxon main rock types vary from 1 to 1 900 mg/kg, the regional Clarke of the Ore Mountains/Vogtland is 23 mg/kg. For uncontaminated soils, Ni levels of 5 to 50 mg/kg are considered normal. Additional geogenic Ni enrichments in soils can be found mainly in the area of the Ni weathering deposits (main ore mineral garnerite) via serpentinites in the Granulite Mountains and its slate mantle, which, however, occupy only small areas. In the gear deposits, the mineralisations of the quartz arsenide association (“Bi-Co-Ni-Ag-U” formation) have little environmental geochemical relevance. An influence of the Ni-mineralisation of Sohland/Spree is also not recognisable in this scale. Anthropogenic ni entries are mainly carried out by ferrous metallurgy or by ni-processing industries (alloys, apparatus construction, paints, plastics) and by the combustion of fossil fuels. Other notable Ni entries are possible mainly with wastewater in aquatic ecosystems (e.g. sewage sludge). The regional distribution of increased Ni levels in Saxon soils is mainly determined by the geogenic specialisation of substrates. Due to the increased Ni levels of serpentinites (1 900 mg/kg), tertiary basaltes (120 mg/kg), amphibolites and gabbros (110 mg/kg) and devonian diabase (80 mg/kg), the spread of these substrates, partly to area-like, partly point-shaped anomalous ni contents in the upper soil. By involving metabasites in the phyllite and mica flaws, as well as due to the weakly increased Ni levels in these rocks (30 to 40 mg/kg), the Vogtland and the West Ore Mountains appear clearly in the map image as areas of increased Ni levels. Analogous to the Cr, the substrates of the acidic magmatites and metamorphites, the sandstones of the Elbtalk grains and the periglaciary deck sediments present the lowest levels of Ni in the soils. In the case of the floodplains, there are clear links with the geological construction of water catchment areas with regard to the Ni levels. Whereas in the floodplains of the White Elster, the Muldensystem and the Elbe (Ore Mountains, Vogtland) there are medium and sometimes slightly increased grades, the floodplains, among others, of the Black Elster and Spree (Lasatian catchment area) are relatively ni-arm. This is certainly also due to the lower density and lower density of industrial sites in the Lau-sitz. The problem is the conversion of Ni-total content into Ni-king water content (KW). Practical experience in soil studies shows that the KW content is about 10 to 30 % lower compared to total levels depending on the binding form in the substrates. The test values set out in the Federal Soil Protection and Contaminant Ordinance (BBodSchV) for the soil-human impact pathway (KW content) are only partly exceeded in Saxony via the diabass and the small-scale serpentines. However, hazards can be largely excluded here, as the Ni is siliconically bound and a release is not to be feared. The ni-transfer soil plant on grassland areas is insignificant; the action value of 1 900 mg/kg is not reached.