Manganese background values in groundwater of Lower Saxony 1: 500.000 (WMS Service)

In order to fulfil the tasks of the EC Water Framework Directive (EC-WRRL) and the Groundwater Ordinance (GrwV), background values for dissolved manganese in groundwater were determined for the hydrogeological sub-areas of Lower Saxony (Elbracht et al., 2016). The background values of dissolved manganese include the levels that occur under natural conditions due to the contact of the groundwater with the surrounding rock matrix of the aquifer. The map shows the color-differentiated manganese background values of the hydrogeological subdivisions of Lower Saxony.The classification is based on the valid de minimis thresholds (JFS) of the State Working Group on Water (LAWA), the limit values of the Drinking Water Ordinance (TrinkwV) and the guidelines of the World Health Organisation (WHO). By selecting a subspace you get further information (e.g. number of samples, combined subspaces, etc.). Background values are not current measurements of groundwater quality and cannot be used as such! Information about the data: The groundwater analyses used come from the database of the Lower Saxony Soil Information System (NIBIS). Background values are defined as the 90th percentile of the normal population of the geogenic concentration of the analysed parameter.The most recent analysis of a groundwater monitoring site was used to determine the background values, but no measurements dated before 2000. If the number of samples (n < 10) is too small, lithologically similar subspaces have been combined to form a common background value where possible.The calculation of the background values followed the procedure for statistical analysis of the data using the probability network of the State Geological Services (Wagner et al., 2011). Sources: ELBRACHT, J., MEYER, R. &AMP; REUTTER, E. (2016): Hydrogeological spaces and subspaces in Lower Saxony.— Georeports 3, LBEG, Hannover. DOI: 10.48476/geober_3_2016 WAGNER, B., WALTER, T., HIMMELSBACH, T., CLOS, P., BEER, A., BUDZIAK, D., DREHER, T., FRITSCHE, H., HÜBSCHMANN, M., MARCZINEK, S., PETERS, A., POESER, H., SCHUSTER, H., STEINEL, A., WAGNER, F. &AMP; WIRSING, G. (2011): Hydrogeochemical background values of groundwater in Germany as a web map service. — Groundwater 16(3): 155-162; Springer, Berlin/Heidelberg.