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Speciation and isotopic composition of lead in coal samples from selected profile of the Most Basin
Semíková, Hana ; Chrastný, Vladislav (referee) ; Strnad, Ladislav (advisor)
Coal is one of the major energy sources in the world and contains most of the elements from the periodic table. During combustion of coal these elements are released and redistributed. This may lead to environmental problems. Some of these elements are considered to be very dangerous for human and animal health and ecosystems. The knowledge of concentration and speciation of elements in coal is important for the prevention of the adverse environmental phenomena associated with the use of coal. One of the hazardous elements in coal is lead. The purpose of this work is to determine the concentration of lead and its isotopic composition simultaneously with determining the speciation of lead in coal. The ICP-MS method was used to determine the concentration and isotope ratios of lead. A total of 62 samples of subbituminous coal was analyzed. The method of selective extraction analysis BCR was used on 9 samples of subbitumnious coal to identify the speciation of lead in coal. Lead concentrations in coal were measured in the range of 0.25 to 78.84 mg·kg-1 . These concentrations correspond to the average concentrations of lead in most of the coals. Isotope ratio 206 Pb/207 Pb in coal samples ranged from 1.169 to 1.219. Isotopic 208 Pb/206 Pb ratio was measured in the interval 2.047 to 2.093. The isotopic...
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Total contents and speciation of arsenic and selenium in plants growing in soils with different physico-chemical properties
Tremlová, Jana ; Száková, Jiřina (advisor) ; Vymazal, Jan (referee)
This dissertation thesis deals with uptake, accumulation and transformation of arsenic and selenium in plants growing on soils with different chemico-physical soil properties. The contents of arsenic were investigated in 99 wild plant species, coming from 27 different families and 6 different vegetables growing in arsenic contaminated soils. The results suggest that there are species-specific mechanisms which protects certain plants from the excessive uptake of arsenic from the soil. On the other hand, there are plants using a strategy of accumulation, which theoretically may increase the risk of arsenic entry into the food chain, whether through grazing cattle and wildlife or through consumption of vegetables growing on arsenic contaminated soils. The most prevalent arsenic compounds are AsV and AsIII. Other arsenic compounds occure as minor species. An important finding was detection of arsenobetaine in Plantago lanceolata L. and Carex praecox Schreb ..
The contents of selenium were examined in 73 species of wild plants, coming from 29 different families. The results suggest that naturally low levels of selenium in the soil of selected locations along with a low capability of selenium uptake via collected plant species lead to the low content of selenium in plant biomass which may contribute to selenium deficient throughout the food chain. Foliar application of selenate on wild plant communities and on some types of vegetables in our case Brassica oleracea var. italica can have a positive impact on increasing the selenium content in the aboveground biomass of these plants and by extension, increase the selenium content in the human diet. Dominant selenium compounds in the aboveground biomass of the analyzed plants were SeVI and selenomethionine, with variable proportion of other commonly occurring organic selenium compounds, which is mainly affected by plant species.
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Toxic metals in foods
Klímová, Martina ; Orsák, Matyáš (advisor) ; Hniličková, Helena (referee)
Summary
Bachelor thesis Toxic metals in food is focused on toxic metals, their description, toxicity and monitoring their content in foods. Toxic metals significantly contaminate the environment nowadays. The metals pollute the environment through burning fossil fuels, agriculture and producing and processing of metals. They occur in various forms and appear in compounds, rocks and minerals. Their toxicity for human and animals is substantial. Their toxicity is related to the form of occurrence, solubility in water and in organic solvents and their mobility in body and water. Toxic metals bind on SH group of proteins and work as an enzyme poisons. The most toxic effect was found in cadmium, but also other metals have significant toxic effect. Lead, Cadmium and Arsenic have carcinogenic effects and cause malignant tumour. Mercury and above mentioned have mutagenic and teratogenic effects. Significant contamination of the environment and food can lead to poisoning, which is expressed by various symptoms.
Toxic metals are absorbed especially by inhalation and consumption of contaminated food. Agriculture crops are polluted from contaminated soil, water and using of fertilizers and pesticides. To meat and animal products, toxic metals come mainly from contaminated plants, which animals eat. Meat products can be polluted by incorrect technological procedure. In general are toxic metals cumulated by organisms in tissues, especially in kidneys and liver. Animals living in polluted area have a lot of these metals in their tissues. With its increasing age, cattle more accumulate toxic metals in its tissues, therefore maximum recommended age of slaughter is 3 years. Serious problem is high amount of mercury in fish, especially in the sea fish. The larger and more carnivorous the fish is, the more they cumulate mercury and the other metals. Especially in the contaminated sea, mainly polluted sea from oil, fish have more metals in tissues. Across the European Union, there were currently set strict limits on the contents of metals in food. Some limits were updated and added by the last findings last year. Keeping these limits is regularly checked.
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Methods for Elemental Speciation of Arsenic Compounds.
Navrátilová, Jana ; Jarošová, Alžběta (referee) ; Golian,, Jozef (referee) ; Šimko, Peter (advisor)
Speciační analýza arsenu v různých matricích s využitím HPLC/ICPMS byla předmětem této práce. Toxicita arsenu závisí na oxidačním stavu a formě, ve které je přítomen. Znalost zastoupení specií arsenu je nutná k hodnocení toxicity a biodostupnosti. Obecně, anorganické specie jsou více toxické než organické. V práci byla studována degradace arsenocukrů v mořských řasách za simulovaných přirodních podmínek. Původní arsenocukry byly transformovány na arseničnan a kyselinu dimethylarseničnou. Arsen vstupuje do rostlin z půdy a vody a následně může vstoupit do potravního řetězce. S ohledem na tuto skutečnost byla speciační analýza provedena u vybraných vzorcích rýže, zakoupených v české obchodní síti. Stanovený celkový obsah arsenu se pohyboval v rozmezí 36.06 µg/kg - 218.11 µg/kg a hlavními speciemi byla kyselina dimethylarseničná a anorganický arsen (54-78%). Mořské ryby a tuky obsahují významnou část arsenu ve formě zvané arsenolipidy. Část práce byla zaměřena na analýzu arsenolipidů u máslové ryby (Lepidocybium flavobrunnrum) s celkovým obsahem arsenu 1.8 mg/kg a 22% celkového arsenu bylo vyextrahováno pomocí hexanu, což potvrzuje lipofilni charakter těchto sloučenin. Hlavní specií stanovenou ve vodném extraktu byl arsenobetain, představující 89%.
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Monitoring of arsenic forms in foodstuffs
Harkabusová, Veronika ; Hrstka, Miroslav (referee) ; Vitoulová, Eva (advisor)
The diploma thesis is dealing with monitoring of arsenic in foodstuffs. The aim of this thesis is the determination of arsenic in samples of fish and rice and the study of forms, in which arsenic occurs, using speciation analysis. Arsenic is known as a toxic element, but its measure of toxicity depends on the chemical form it occurs in. Arsenic is present in the environment naturally or it gets in the environment by human activities. Complete characterization of arsenic compounds is necessary to understand intake, accumulation, transport, detoxification and activation of this element in the natural environment and living systems. The field of arsenic speciation analysis has grown rapidly in recent years, because determination of the total element content is not sufficient in the case of arsenic. Speciation method was done using separation by high performance liquid chromatography and detection by atomic fluorescence spectrometry with hydride generation. Extractable arsenic was present in the form of nontoxic arsenobetaine in all analysed samples of fish. In samples of rice there was confirmed the presence of toxic inorganic species of arsenic, esspecially As (III), but their concentration was at low level.
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Speciation and fractionation analysis of metals in agricultural soils
Lepař, Petr ; Mládková, Zuzana (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with the procedures and analytical techniques associated with speciation analysis and fractionation of metals in agricultural soils. The first part defines the basic concepts related to speciation, fractionation, soils and elements contained within it. The following chapters describe procedures of samples withdrawal and its adjustment including a description of some methods used for the purpose of extraction, fractionation and speciation analysis. The last chapter is devoted to listing of some separation techniques and instrumental methods used for the purposes of speciation and fractionation.
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Dynamic karyotype evolution and unique sex determination systems in Leptidea wood white butterflies
VOLENÍKOVÁ, Anna
Chromosomal rearrangements such as fusions and fissions play an important role in promoting and maintaining speciation. To study these phenomena, genome architecture of three cryptic species of Leptidea wood white butterflies was investigated by means of standard and molecular cytogenetics. High variability in chromosome number and localization of cytogenetic markers was revealed, suggesting dynamic karyotype evolution in these species. Moreover, unique sex-determination system with 3-4 W chromosomes and 3-4 Z was found, possibly playing a role in the speciation process as well.
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Indirect speciation of mercury in soils and sediments with cold vapor atomic absorption spectrometry.
ŠPAČKOVÁ, Jitka
In the diploma thesis have been tested four extraction techniques for isolation of organic forms of mercury from sediments (liquid liquid extraction, microwave extraction in liquid liquid extraction, solid phase extraction and extraction with use of ionic exchange) followed by determination of mercury by atomic absorption spectrometer AMA?254. It has been achieved great results during liquid liquid extraction likewise ionic exchange extraction. Reached percents of orgHg were in accord with certified reference material for sediments CRM-580 and corresponded to 86,44 ? 16,63 %, resp. 87,01 ? 29,22 %. Thanks to a simple procedure, extraction speed and ease of determination of organic forms of mercury contain was first of all (in the first instance) verified a method with use of ionic exchange, whose principle and procedure is very elementary. This technique was applied to a number of real sediment samples collected from water tanks Jordan and Skalka. It was approved that this method has been presenting a suitable alternative to chromatographic methods or methods of electro?migration.
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