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Old closed uranium mines can be a significant source of environmental pollution and hazards to human health. The problem could become more severe in time due to erosion if the restoration measures are not properly maintained. There are many uranium mines in Bulgaria that, even closed in the 1990s, could be a pollution source for surface and groundwater in their region. Through hydraulic connections, they can contaminate the rivers passing nearby. The aim of the present work was to check the hypothesis of a possibl...

A serious challenge for the construction of Sofia Metro is the shallow groundwater and the high water abundance of the hydrogeological units that are crossed by the construction route. The dewatering of the excavations for the facilities that are supported on deep foundations and the tunnels is most often associated with large and long-lasting local depressions of the water table. The joint action of the drainage systems around the metro stations and tunnel sections built simultaneously or in overlapping time inte...

The Dobrudzha Coal Deposit is characterized by complex geological, tectonic and hydrogeological conditions. The formed aquifers and complexes, on the one hand, hinder the possible exploitation of the coal deposit, on the other hand they are important for drinking water supply in the area. The aim of the present study is to develop a 3D hydrodynamic model in the area of the deposit to elucidate the dynamics of the flow processes, the hydraulic connections between the different hydrogeological units and the possibil...

Significant parts of important aquifers in Bulgaria are affected by the long-term in-situ leaching of uranium, using acid in borehole systems with reinjection. This is the case with the Momino uranium deposit formed in the lower part of the Neogene-Quaternary sedimentary complex, filling the Thracian depression. In this complex is formed one of the main sources of water supply in this part of the country. In order to assess the actual status and to predict the future changes in the quality and composition of the g...

The studied area is located in the vicinity of Rashid branch, part of the Nile Delta. This region is part of one of the most important aquifers in the world. The review of published information indicates that the existing zone of interaction between groundwater and sea salt water is complicated by the variable lithological composition in vertical and horizontal directions and by the relationship with the River Nile waters. Object of study are the upper parts of the aquifer where favorable conditions for natural sa...