The mining activities from Calimani Mountain for sulphur ore between 1965 and 1997 generate a large amount of waste rocks and tailings, which get deposited in four dumps (Pinu, Puturosu, Dumitrelu and Ilva) at the surface. The degraded soils, the waste dumps are often very unstable and become sources of pollution. The direct effects was the loss of forest or grazing land, and the overall loss of production from more than 200 ha during the mining  exploitation. The indirect effects included air and water pollution of rivers. The aim of this paper is to evaluate the diversity of soil microbiota from targeted areas, namely Pinu, Puturosu, Dumitrelu and Ilva waste sterile deposits. At the microscopic scale, high concentration of sulphur may have negative effects on bacteria, which are the key-players of the nutrient cycles (nitrogen, carbon, sulphur) in soils of the investigated dumps. For an easy identification of different groups of micro organisms, different specifics media cultures were used. The inseminated dishes were incubated and analyzed respecting the protocol for each micro organism groups. Collecting, isolation and identifying activity of some groups of micro organisms allowed demonstrating their presence in the sterile depositions. For example, the highest number of aerobe nitrogen-fixing bacteria Azotobacter chroococcum was counted on  Dumitrelu Dump at 0-6 cm depth (29 x 14 6 UFC/g soil), while the lower have been evidenced in Puturosu Dump (66 x 10 3 UFC/g soil) at the same depth. The presence in the mine tailings of micro organisms, which are involved in nutrient cycles, creating the premises for an ecological reconstruction for degraded soils resulted in mining activities (vegetation cover reconstruction, waste dump stabilization).

microbial community; mine tailings; Calimani Mountain

Presentation: oral