| Summary: | The decrease in pH of natural waters, or in other words acidification of waters, and consequent acidification of soil is a direct consequence of intensive oxidation of sulphides in mines and mining wastes. Mining water can be extremely acidic and leaches or dissolves the rock ore minerals more intensively than common surface or underground water. Such water may transfer various elements in a dissolved form. In addition to common alkaline elements and metals of alkaline earth, water mobilises heavy metals, as well as elements like Al and As. Smolník deposit is one of localities, where the unfavourable influence of acidic water on the surface water can be observed. The analysis of water in the deserted mine and in the broader area surrounding this mine was made after the ecological accident in the Smolník brook in 1995. In addition to a dominant content of sulphates, this water has a high content of Fe and Al and other metals, such as Mg, Zn, Cu and Mn. The quality of brook water has improved decrease in the content of dissolved substances (tab.2). However, brook water is still very acidic, pH is lower than 6, what is a limiting value for surface water. The above-mentioned changes occurred due to adjustment of regime of mining water that took place after 1996. This adjustment caused a decrease in the quantity of leaking mining water into the brook. A new drainage discharging into the brook on the place of former shaft Charitas was built, but still brings contaminated waters. The total quantity of dissolved substances (sulphates, Fe, Al, Cu, Zn) decreased in the brook water in comparison with that in 1995. Water flowing out of mine through a new drainage is not only very acidic, but also contains a lot of sulphates and Fe, Al, Mg elements. Whether this favourable progress will continue or not, it will be shown by further monitoring of this territory.
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