Hydrogeological overview map of Lower Saxony 1: 500 000 — Groundwater quality: Potassium content

The Hydrogeological Overview Map of Lower Saxony 1: 500 000 — Groundwater quality: Potassium content shows the evaluation of a representative selection of potassium concentrations from the laboratory database of the LBEG. The data collected over a period from 1967 to 2000 have been averaged twice. For groundwater measuring points with multiple analyses, mean values of the available test results were formed. In addition, the values of all sampling points in a radius of 2 000 m were subjected to further averaging. Increased concentrations clearly attributable to point-shaped anthropogenic inputs (e.g. potash extraction plants) are not reflected in this overview map. Potassium levels are shown at depth levels without reference to the local hydrogeological situation. The rod diagrams in the example shown on the right reflect results for the depths up to 20 meters, over 20 to 50 meters, over 50 to 100 meters and over 100 to 200 meters. A comparison of values is therefore not permissible without taking into account the respective hydrogeological situation (e.g. hydrogeological floor construction) as well as the use of the data for detailed examinations. During the extraction and processing of the potassium compounds, significant quantities of potassium are released locally. For example, surface and groundwater near the potash salt deposits in mining often contains increased anthropogenic concentrations. An area-based entry is made by the use of potash fertiliser. Fertilised soils of agricultural land often show increased potassium levels in groundwater.