Zmienność chemizmu wód podziemnych na obszarze Łodzi

This papers presents a picture of chemical variability of groundwaters in a region of high anthropogenic pollution, around the city of Łódź. The research as conducted in three groups of wells, all representing aquifres of potable waters within the Łódź hydrogeological basin. Two groups of wells chosen within the city area and one outside it, in a rural area. Research showed that the Łódź hydrogeological basin were presents the inversion type, regarding mineralization and chemical composition of water. Within Cainozoic rocks, inversion is caused by anthropopression, but in deeper aquifers geogenic processes play a domiant role. The same pattern of conditions varies also horizontally in each aquifer. Ca, Mg, Na and CI ions are of greater importance in the group of indicators ofhydrochemical variability of groundwaters. These elements have connection with pollution processes of groundwaters, visible in changes of hardness and salinity. Hydrochemical changes are also indicated by NO2 and NH4