The genesis of acid mine drainage (AMD) is conditioned by existence of indigenous chemolithotrophic iron and sulfur oxidizing bacteria, especially of genus Acidithiobacillus. The result of the oxidizing weathering of metal sulfides is a sequential formation of ochreous precipitates in drainage systems and in the surroundings of AMD seepage on the surface. The long-term monitoring of AMD waters collected at the shaft Pech that receives the majority of waters draining the flooded Smolník mine area point out the enduring contamination risk of particular components in the environment of Smolník mine area. Elemental analysis, X-ray diffraction, Mossbauer spectroscopy and scanning electron microscopy of the ochreous precipitates formed from Smolník AMD stream revealed schwertmannite as the dominant solid phase in the precipitates. The chemical analysis of AMD effluents and the elemental composition of related sediments indicated considerable scavenging potential of the ochreous precipitates towards metal cations and oxyanions of arsenic and sulfate

The natural bentonite and bentonite/iron oxide composite were used as sorbents of Cu(II). Theirsorption properties were examined under the different conditions such as pH of the solution, initialmetal ion concentration. The bentonite removed 71 % Cu(II) while composite 90 %. Their maximumadsorption capacities were 34.1 and 44.4 mg Cu(II) g-1, respectively. The chemical regeneration ofcomposite sorbent by organic acids (oxalic, citric) led to partial Cu(II) dissolution. The hydrochloricacid caused its structural destruction. For the bacterial regeneration, the sorbents were inoculated withheterotrophic indigenous bacteria. After 10 days the bacteria released approximately 80 % of loadedCu(II), leaving the sorbents stable. Longer treatment and higher concentration of metal cations causedthe reverse sorption of Cu(II) by bacteria. The regenerated sorbent was successfully repeatedly used forthe Cu(II) adsorption.