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The Content of Mercury and Lead in Sediments from Vltava River and Lipno Reservoir.
MAŘÍKOVÁ, Helena
The aim of this thesis was to define and evaluate the load of sediments by exposure of mercury and lead on the upper flow of the Vltava river and in the Lipno lake. To evaluate possible influence of the glass factory in Lenora for pollution of this area by toxic metals mentioned above. The literature survey refers about problems of mercury and lead content in fresh water and reservoirs sediments, the structure of toxic heavy metals and risks of their release in the enviroment, then in chemical composition of water reservoirs. It also engages in glass manufacturing problems in the glass factory in Lenora, especially the raw materials, which where obviously used for its manufacture. Experimental part describes profile of sampling points, working methods, used chemicals and results of individual analyses. Sediments of the Lipno reservoir and the upper flow of the Vltava river aren{\crq}t seriously loaded with mercury or lead, but in the sediments below Lenora was shown multiple increase of lead and mercury content in comparison with the background. Forest soils has higher mercury content in all localities in comparison with the sediments. On the contrary, the content of EDTA-extractable lead in soils is lower. Detected isotopic ratio of lead 206/207 and 208/206 in sediments of the Vltava river below the glass factory in Lenora have different signature in comparison with the signature of sediments from the Vltava river above the glass factory. On the contrary the signature of lead in all sediments of the Lipno reservoir showed values relevant to natural background of this locality. The structure which corresponds to the lead from the glass factory was also surprisingly detected in humic horizont of the forest soils in Lenora{\crq}s surroundings. The thesis was extended with fish samples from Lipno reservoir and their liver{\crq}s load by lead and mercury content. There were determined isotop ratio (signature) of lead in the fish, the izotop ratio of lead not corresponds to the lead signature from the glass factory in Lenora.
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New methods for sediment description – how to their "metabolism"
Jan, Jiří ; Borovec, Jakub
Volume of reservoir sediments is usually small comparing to volume of water, but there are i) important place of nutrient recycling of water ecosystems and, ii) there are a dynamic part of the ecosystem. Large number of tightly coupled processes in the sediments is dependent on seasonal development and changes of physical, chemical and biological conditions (temperature, DO concentration, microbial activity, current conditions, amount and quality of settling material). Modern methods for nutrient balance in sediments, rates of release/uptake of nutrients and pore-water profiles were shown.
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Evaluation of sediment importance for phosphorus internal load
Borovec, Jakub ; Hejzlar, Josef
Eutrophication still belongs to the serious problems waiting for solution. Phosphorus is the nutrient most often limiting the primary producers. It is well known, the improvement of water quality can be, after successful decrease of external P load, retarded by P-release from sediments. It is also necessary to realize, that the decrease of external P-load to the demanding level cannot be due to technical, political or economical reasons always possible. Measures increasing P-retention in sediments are often employed in such conditions. Many cases are known when the level of the water quality improvement remained far behind the expectations. Technical problems, still unknown mechanisms or insufficient screening followed by inadequate solution might be the reasons for the failures. The aim of this paper is to show simple decision-support system for exclusion of improper solutions and increase of the effectiveness of activities made before the rehabilitation measures realization.
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Složení sedimentů, Al-Si gelů a precipitátů vázaných na výskyt elementálního Al, Si, Fe z monitorovacích vrtů u jímacího území Podluží
Ďurďová, Libuše
Occurrence of increased sulphate concentration in groundwater of the Quaternary sediments in the floodplane of the Morava river watershed is related to many specific features in hydrogeology, hydrochemistry, microbiology, geochemistry, exploitation of water resources, climatic conditions, and technical equipment of boreholes. One of the concsequences is genesis of 2-4 m thick layer of sediments at the bottom of moitoring boreholes Vis with mineral precipitates, sludge, Al and Si gelatines, precipitates of elemental forms of Al, Si and Fe. There were found also colloids of FeS2 composition and minerals goethite, magnetite, lepidocrocite, pyrite, greygite under extreme oxido-redox conditions.
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Excavation and treatment of sediments
Pokorný, J.
Methods aimed at reduction of internal nutrient loading in eutrophic water bodies are explained. Development of blue greens results both from external and internal loading. Eutrophic sediment in which anaerobic processes také place releases phospohorus which results in uncontrolled development of water blooms. Examples of hypertrophic lakes in which restoration was realised with success are given. Principles of sediment treatment aimed at immobilisation of phosphorus are explained. Aeration, P precipitation, nitrate application are described. Techniques for removal of eutrophic sediment both by classical and suction dreges are described. Relevant scientific literature is given.
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