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Mercury dynamics in soil systems: A comprehensive study on natural and anthropogenic sources using elemental and isotopic analysis
Domingues Vieira, Alda Maria ; Vaňková, Maria (advisor) ; Navrátil, Tomáš (referee) ; Doušová, Barbora (referee)
Human activities (in)directly affects the biogeochemical cycle of mercury (Hg) in the environment. However, many aspects of Hg behaviour remain poorly understood. In this thesis, three different case studies addressed two main themes: i) the influence of climate change on Hg re-emissions from fire-affected soils and ii) the fate and behaviour of Hg in soils contaminated by non-ferrous ore mining and smelting. The first study investigated total Hg concentrations in uncontaminated soil profiles and Hg pools in organic horizons to estimate the fire-induced Hg emissions from the soil during a wildfire in Portugal. Fire-undisturbed soil profiles displayed higher Hg concentrations (156 μg kg-1) in the organic horizons, decreasing with depth in the mineral horizons. The Hg pool in these organic horizons was estimated at 10.6 g ha- 1. We calculated the wildfire released up to 133 g of Hg from the forest floor within the 12.5 ha burned area, emphasising its dual role in Hg (im)mobilisation in a region increasingly affected by extreme fire-prone weather events. In the second study, Hg stable isotope ratios and solid phase speciation data were determined in soil profiles contaminated by historical Hg-Fe mining and smelting in Czechia (Jedová Hora). The total Hg soil concentration reached up to 17.8 mg kg-1....
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Coal burning as a source of mercury soil contamination
Paclíková, Karolína ; Vaňková, Maria (advisor) ; Mihaljevič, Martin (referee)
Mercury (Hg) is a global pollutant, released into the environment from both, anthropogenic and natural sources. The most significant Hg emission source is burning of fossil fuels, especially coal combustion (60%). Although Hg occurs in low concentration in coal, a large volume of coal combusted makes coaal-fired power plants ano of the largest source of Hg emission into the atmosphere and consequently to the environment. This bachelor thesis summarized the knowledge about the geochemistry of Hg in coal and soil. At the same time provides information on the distribution of Hg in soils in the Frýdlant district, area that has been affected by emissions from coal-fired power plants. The total Hg concentration in soils, coal and wastes (fly ash and bottom ash) from power plant Turów was determined by AMA-254. The concentration in the coal ranged between 217-973 µg.kg-1 Hg, the average concentration in fly ash was 94 µg.kg-1 Hg and the lowest concentration of Hg was in the bottom ash, 1-2 µg.kg-1 Hg. The average Hg concentration in soil organic horizons was 334 µg.kg-1 with the highest value 510 µg.kg-1 Hg. The obstained data were not consistent with previous study, where concentration of Hg in forest floor in Frýdlant district reached up to 1 148 µg.kg-1 . The Hg concentration in studied forest soils...
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Study of behaviour of selected elements in soil profiles on the Alsar deposit, North Macedonia.
Fizková, Karolína ; Mihaljevič, Martin (advisor) ; Vaňková, Maria (referee)
This thesis is dealing with the behaviour and mobility of hazardous elements Tl, Hg and As occurring in anthropogenic soils on the heaps of the former Alshar deposit in North Macedonia. As, Sb and Au mining had been taking here since the 15th century, peaking during the 19th and first half of the 20th century. Local soils were thus created by periodic layering of tailings of varying age and origin. Nowadays, the area is known mainly for its large number of unique mineral phases, as well as for its extensive possibilities for soil contamination research. The contents of the elements in the samples were exceptionally high and without optimisation of measurement and appropriate dilution would exceed the upper limit of detection of the analytical methods. Arsenic and Tl occur on average in the tens to hundreds of mg/kg, while Hg occurs in the hundreds of mg/kg. The behaviour of the hazardous elements was assessed in relation to soil characteristics, including granulometry, pH, cation exchange capacity, total carbon and sulphur content, or content of Fe, Mn and Al oxides. Correlation with concentrations of other elements was also taken into account. In addition, an isotopic ratio of ε 205 Tl was determined for Tl in the selected samples. However, from the complete measurement results, it was very...
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