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in English Chromium, particularly its two most stable oxidation states - hexavalent and trivalent chromium - plays a very significant role in the environment. While trivalent chromium is an essential nutrient both for humans and plants, hexavalent chromium proved to be one of the most dangerous contaminants negatively affecting people and the environment on a wide- ranging scale. This thesis aims to provide a complex overview of chromium occurrence in various natural systems, its physical and chemical properties as well as its mobility in the environment. Furthermore, the thesis will describe two case studies (from Greece and India), which illustrate both the natural and anthropogenic sources of hexavalent chromium contamination. Due to its mutagenic and carcinogenic properties, a complex set of remediation methods was suggested for hexavalent chromium removal, including both in-situ and ex-situ ones. Given their proven record in successful elimination of hexavalent chromium contamination from groundwater, in-situ methods are being utilised far more frequently nowadays; these will be explained more comprehensively. The most notable categories of in- situ remediation methods include biological and chemical reduction, chemical precipitation and chemical sorption. Besides these, other promising...

This recherché summarizes findings about the quality of mineral water in spa Teplice. This study describes the consequences of lignite mining in the past and their influence on mineral springs. This study emphasises water outbreak in mines, which caused destruction of this mineral springs. Last part of this study is focused on today's situation of mineral springs in spa Teplice.

Groundwater is our priceless natural resource and it is our duty to protect it and to take care of its quality. That is the reason why several techniques of pollution removal have been developed; the Groundwater Circulation Well technique (GCW) is one of them. This system enables us to clean contaminated groundwater effectively and in-situ (it means that there is no need to extract groundwater to the surface). This thesis is aimed at collecting and presenting our actual knowledge of the most common GCW systems. In the first part of the thesis the basic kinds of the GCW are introduced and their principles are presented. The remediation mechanisms are further described with respect to the character of the particular contamination. The chemical and biological processes controlling the contaminant degradation are described. Several experiments that were carried out and monitored in order to study the efficiency of GCWs are presented. In the last part of the thesis the mathematical modelling of GCWs is introduced. The partial differential equations governing the processes of flow and mass transport in the well surrounding parts of aquifers are presented and the corresponding initial and boundary conditions are formulated. The obtained numerical results and conclusions of their comparison with measured data are...

Adsorption of radionuclides in granite pores and micropores ABSTRACT This graduation thesis deals with laboratory determination of adsorption isotherms parameters. Granite from the central moldanubian pluton, site Panské Dubenky, Czech Republic, was chosen to the experiment. The place is one of the candidate sites to build a deep nuclear waste disposal. A batch experiment was performed in two modes, differing in the way of addition of radioactive nuclide 90 Sr. From this experiment, distribution coefficients for a linear isotherm or parameters for Langmuir isotherm were obtained. Beside this, a through-diffusion experiment was performed. The objective of this experiment was to identify whether some of the radionuclides used (137 Cs, 90 Sr, 125 I) is able to penetrate through the pores of a granite slice barrier between two solutions of different concentrations. During the period of the experiment no radionuclide was detected reliably.

The subject of the thesis is to characterize the vertical stratification of quality and to determine the source of contamination of groundwater in the north part of the Třeboň basin. In the thesis the quality of groundwater in peat bogs, in the sediments of the basin as well as in the underlying crystalline complex is described. The quality of groundwater was monitored in boreholes which are distributed in the whole area of the basin. The quality of groundwater in the collecting line Horusice - Dolní Bukovsko is also described in the thesis as it is the main source of drinking water in the area. The quality of groundwater is compared with the regulation 252/2004 Sb., which specifies drinking water hygienic requirements. For demonstrating groundwater flow and contamination propagation in parts of the basin a hydraulic model of groundwater flow was made. A part of the thesis is an evaluation of significant sources of contamination in the north part of the Třeboň basin and of the tendency of development of contamination propagation. Measures to protect and to increase the quality of groundwater are subsequently proposed. The quality of groundwater in the north part of the Třeboň basin is varying. There is groundwater meeting the drinking water criterion in the regulation 252/2004 Sb. but there is also...