Background values - HGW: Cadmium, 90th percentile (surface)
Description
Soils were created in millennia by the interaction of diverse natural processes. For centuries, however, they have increasingly been shaped by human activities such as land use and material inputs. For most inorganic substances, the starting substrate of soil formation determines the natural (geogenic) basic content of a soil. In addition, there is an anthropogenic component, whereby the ratio of geogenous and anthropogenic proportion varies greatly in element-specific terms. Background values characterize the typical background contents of a substance or group of substances in the soil. In accordance with the procedure of the Federal-State Working Group on Soil Protection (LABO), the 50. percentile (median) and the 90th percentile (median). The percentile is used. The median represents the median background content, which is 90. Percentile is the upper limit of the typical background content. For the purposes of determining background levels, the anthropogenic fraction shall not come from an identifiable individual source or source of pollution. Rather, they must be diffuse, i.e. they must be the result of general large-scale (ubiquitous) distributions of substances over longer periods of time. Specifically polluted soils must therefore be removed from the data before background values are calculated. The substrate is the most important differentiation criterion for natural contents of inorganic substances. The next deeper level of division are horizon groups such as topsoil, subsoil and subsoil. If there is still a sufficient number of cases, the group of topsoil horizons is further subdivided into use classes. The State Office for Geology and Mining Rhineland-Palatinate has been dealing with physical and chemical investigations of soils for many years within the framework of the land survey as well as through cooperation with other state authorities. The information bases could be significantly improved with data collected during the project Bodenbelastungskataster Rheinland-Pfalz. Since this project, comprehensive soil investigations have been successively continued with the Rhineland-Palatinate Soil Status Report. This long-term project of the Ministry of the Environment, Forests and Consumer Protection is carried out on behalf of the State Office for the Environment, Water Management and Trade Inspectorate. In the meantime, about 18 percent of the country's area with at least one investigated site per km2 has been recorded. The data basis for the spatial distribution of the substrate groups comes from the soil specialist information system (FISBO) of the LGB. This system manages data from boch heterogeneous soil mapping (scale 1:25,000 to 1:200,000). Although this leads to recognizably different resolutions and differentiation problems, these data are suitable for nationwide surveys in small-scale applications above the scale of 1:50,000, despite their inhomogeneity. Further information on this topic can be found in the loose-leaf collection background values of the soils of Rhineland-Palatinate.:As a 90.P background value, this is 90. Percentile of a Data Collective. It is the value at which 90% of the cases observed so far have lower levels. The calculation is made after the data group of outliers has been cleaned up. The 90. The percentile often serves as the upper limit of the background range to delineate unusually high levels. The total content is determined from the aqua regia extract (according to DIN ISO 11466 (1997)). The concentration is given in mg/kg. The salary classes take into account, among other things, the pension values of the BBodSchV (1999). These are 0.4 mg/kg for sand, 1.0 mg/kg for clay, silt and very silty sand and 1.5 mg/kg for clay. According to LABO (2003) a sample count of >=20 is required for the calculation of background values. However, the map also shows groups with a sample count >= 10. This information is then only informal and not representative.
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https://www.geoportal.rlp.de/mapbender/php/wms.php?inspire=1&layer_id=26251&withChilds=1&REQUEST=GetCapabilities&SERVICE=WMS |
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- sgd_geochemie