Zmiany składu chemicznego wód podziemnych na obszarach sandrowych na przykładzie rejonu Borów Tucholskich

The article presents the results of investigations conducted within NCN grant no. 2015/17/B/ST10/03233. The aim of the research is to access changes in the chemical composition of groundwater occurring in a glacial-outwash aquifer, on the basis of the natural hydrogeochemical background. The research includes the area of the Brda and Wda outwash plains belonging to the Tucholskie Forest mesoregion. The study compares the natural hydrogeochemical background identified 30 years ago with the current chemical composition of groundwater from the glacial outwash aquifer. Local changes were observed, expressed as an increase of the concentration of nitrate compounds, TDS and to a certain extent also chlorides and sulphates. In the remaining area, the chemical composition of the groundwater similar to the natural composition.