Mjerenje tvrdoće vode u odabranim krškim pojavama Žumberačke gore

In the paper are published the results of deteremination of total, Calcium and Magnesium water hardness from four caves, one karst spring and one sinking creek in the area of Žumberacka Gora Mt. in NW Croatia. Water hardness is a measure of carbonate rocks dissolution and corrosion. Besides, it can give a hint of undergorund water courses since the stream that flows from dolomite has higher Magnesium content and one that flows from limestone has higher Calcium ions content. Geological, geomorphological and hydrological characteristics of all features from which water samples were taken are also described.