Ogólna ocena stanu wód podziemnych na terenie Gdańska i Sopotu – podsumowanie

Abstract

Groundwater assessment in the Gdañsk and Sopot aera – a summary.A b s t r a c t. This paper synthetically describes results of research conducted in Gdańsk in 2009–2014. The chemical composition of groundwater varies between aquifers. Intermoraine, Miocene and Oligocene aquifers conduct freshwater with a mineralisation of below 600 mg/dm3. These waters preserve natural chemical composition and are characterized by first- and second-class quality. The groundwater of the Cretaceous formation are low-mineralised and represent mainly the HCO3–Na type and, to a smaller extent, to the HCO3–Ca type. High concentrations of fluoride ion are also a specific feature of these waters, reaching even 2 mg/dm3 in some places. The groundwater composition of the Pleistocene-Holocene aquifer is often altered due to the impact of anthropogenic factors. The performed study has enabled identification of zones of past groundwater pollution. The work was focused on determining the type, extent, concentration and the rate of transport of contaminants. Two zones of polluted water have been identified with different specific substances. Based on the study, activities aimed at reducing the risks and improving an appropriate water management have been undertaken, particularly with regard to the endangered groundwater intakes.