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Arsenic Contamination of Waters in the World
Grecká, Marie ; Bendl, Jiří (advisor) ; Drahota, Petr (referee)
Summary: In this bachelor thesis there are summarized reasons of occurrence of too high As concentration in groundwater abroad and possibilities of the water treatment. There are mentioned mainly the Asian countries, where there were proved the cases of serious diseases of inhabitants in connection with long-term consumption of the water from the shallow groundwater in the area of big river deltas. Arsenic is released to the groundwater from the iron oxides by natural process in reductive environment (due to the oxidation of organic matter). In the arid climate areas in Asia or South America, there are also localities of high As groundwater. The groundwater in these arid areas is more saline and the reason of high As concentration there is the oxidation of sulphide minerals. Then there are given the other examples of arsenic release by the oxidation of pyrite in the gold (or tin) mining areas etc. Another source of arsenic in water is a geothermal system. A suitable method for the arsenic removal from water is a coprecipitation of iron and As (V).
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Speciation of arsenic in fluvial systems
Jaxylykova, Anastassiya ; Drahota, Petr (advisor) ; Peřestá, Magdaléna (referee)
4 Summary This bachelor work is devoted to the distribution of the increased concentrations of arsenic in fluvial systems near the villages of Mokrsko and Smolotely in the Central Bohemian region of the Czech Republic. Arsenic in these areas is found in sulfidic minerals associated with gold- bearing mineralizations in the bedrock. Due to the toxicity of arsenic, natural weathering of the mineralized rocks represents a danger for the population of these sites. The theoretical part of the work is devoted to general concepts of the occurrence and concentrations of arsenic in different environments. In the practical part, a small separate study is presented, which studies the concentration of arsenic in fluvial sediments and stream water of the study sites. The results show that the highest arsenic concentrations in the fluvial sediments are almost the same (500- 550 mg/kg). The highest dissolved arsenic concentration was found at Mokrsko (360 g/l), while the highest aqueous arsenic at Smolotely was 160 g/l. Keywords: Arsenic, fluvial sediments, stream water, arsenic contamination
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Arsenic Contamination of Waters in the World
Grecká, Marie ; Bendl, Jiří (advisor) ; Drahota, Petr (referee)
Summary: In this bachelor thesis there are summarized reasons of occurrence of too high As concentration in groundwater abroad and possibilities of the water treatment. There are mentioned mainly the Asian countries, where there were proved the cases of serious diseases of inhabitants in connection with long-term consumption of the water from the shallow groundwater in the area of big river deltas. Arsenic is released to the groundwater from the iron oxides by natural process in reductive environment (due to the oxidation of organic matter). In the arid climate areas in Asia or South America, there are also localities of high As groundwater. The groundwater in these arid areas is more saline and the reason of high As concentration there is the oxidation of sulphide minerals. Then there are given the other examples of arsenic release by the oxidation of pyrite in the gold (or tin) mining areas etc. Another source of arsenic in water is a geothermal system. A suitable method for the arsenic removal from water is a coprecipitation of iron and As (V).
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