Hydrogeological overview map of Lower Saxony 1: 500 000 — Groundwater quality: pH value (WMS service)

The Hydrogeological Overview Map of Lower Saxony 1: 500 000 — Groundwater quality: pH-value shows the evaluation of a representative selection of pH values 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. pH values, which are clearly due to point-shaped anthropogenic entries (e.g. old landfills), are not reproduced in this overview map. The pH values are shown at depth levels without reference to the local hydrogeological situation. 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. The pH values shown on the overview map range between 3.3 and 8.8 (median value = 6.7). Very low pH values of 3.5-5,5 are found mainly in groundwater in areas with bogs (e.g. Vehnemoor southwest of Oldenburg, Lichtemoor northeast of Nienburg or Wietingsmoor west of Sulingen). In calcareous rocks where silicates and alumosilicates primarily determine the groundwater quality, pH values are reached between 5 and 6 (e.g. Lüneburg Heath and Solling). The solution of carbonates leads to an increase in pH values to 7.5-8.