Chemistry of cave water in Smocza Jama, city of Kraków, Poland

Abstract

Chemizm wód podziemnych w Smoczej Jamie, Kraków, Polska The chemical composition of the water in Smocza Jama cave (city of Kraków, Kraków–Wieluń Upland) was studied. The cave is 276 m long and it was developed in the Upper Jurassic limestone. Nineteen water samples were collected between March 1995 and January 1998. The pool water and drip water were sampled. The former water samples represent Ca - Na - HCO3 - SO4 - Cl, while the latter ones SO4 - Ca - Na type. In pool water the concentrations of Cl are higher than in drip water, while in drip water the SO4 predominates. The chemical composition of the studied samples of both the pool and drip waters differs considerably from the composition typical of the limestone cave water. The studied water differs also in its chemical composition from the ground- water of the Kraków–Wieluń Upland. High concentrations of NO3, SO4, Cl, Na, K, and P suggest that the water in Smocza Jama is considerably affected by pollution. The chemical composition of the studied pool water can be the effect of mixing of, at least, two components. The water can: (i) filtrate from the Vistula river, (ii) percolate down from the surface of Wawel Hill, (iii) migrate from the nearby area, where the city centre is located, and (iv) ascend as artesian water from deeper confined aquifer. The former three of the four mentioned water sources may be strongly degraded due to long lasting human occupation of both Wawel Hill and the city centre, as well as pollution of the Vistula river. The high amount of SOS ions reaching 1439 mg/L in drip water results probably from leaching of litter and rubble poured over the cave in the 19th century.