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

The Hydrogeological Overview Map of Lower Saxony 1: 500 000 — Groundwater quality: Nitrate content shows the evaluation of a representative selection of nitrate concentrations from the laboratory database of the LBEG. The data collected over a period from 1980 to 2005 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. The rod diagrams represent the analysis data available in the laboratory database of the LBEG depending on the depth and concentration. At the depth level above 100 m, there are generally no nitrate values in the laboratory database. A representation is therefore not possible in this field. The classification of the classes is carried out taking into account the limit values of the Drinking Water Ordinance (TVO) of 50 mg/l. The nitrate contents are presented 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) nor the use of the values in the overview map in scale 1: 500,000 averages shown for detailed examinations. Predominantly geogenic nitrate values in both looser and solid rock areas in oxygen-containing groundwater rarely exceed 1-10 mg/l (e.g. Gorleben fir fir about 1 mg/l, Solling approx. 7-8 mg/l, west resin approx. 10 mg/l). These are often composed of a geogenic basic content and a diffuse anthropogenic input from the atmosphere. In deeper areas of the loose rock aquifer, the groundwater is predominantly nitrate-free, due to the long dwelling times of this groundwater and the favourable conditions for nitrate mining (org. Substance, Fe (II), sulphides) is due in the quaternary rocks. Especially through agricultural nitrogen fertilisation, nitrate concentrations of up to 350 mg/l can be achieved. In areas with high nitrate concentrations, there are usually also high potassium content.