Chemistry measurements of dripping water in Postojna Cave
Barbara Vokal, Bogomil Obelić, Dominique Genty, Ivan Kobal - (28/1,1999)
Environmental factors influencing speleothem formation such as air and water temperature as well as water properties at the surface and in the cave (pH, electrical conductivity, Ca2+, HCO3- and Mg2+ ion concentrations and drip rates) were measured during an entire year in order to follow seasonal variations. The influence of the thickness of cave roof on the water properties was also taken into consideration, and the difference between various cave water types (pool, stalactite drip waters and fast-drip waters) was followed. Monthly water samples were collected at three locations in the cave and also from the river Pivka and spring of Mo╦ilnik. Rainwater samples were also collected and analyzed. From the results it was found that the temperature of cave waters is more or less constant during the year. Mean values of pH for all karst waters are 7.8 ▒ 0.2. There is a good correlation between the chemical parameters (Ca2+ and HCO3- ion concentrations and electric conductivity) and the different types of cave waters. The ratio Mg/Ca concentrations and the saturation index were determined, too.