|
|
Trace elements and Pb isotopes in selected bone samples
Bartoš, Jan ; Mihaljevič, Martin (advisor) ; Strnad, Ladislav (referee)
The aim of this work is briefly summarize the current theoretical knowledge about trace elements and their inputs into calcified body tissues in a form of search. Here are described mechanisms of their inputs and depositing into human body and principles, which allows maintenance of their optimal levels. In this paper are also described the properties of bones and teeth and simply explained concepts such as an essential and toxic trace elements. The next part of this work is mainly about trace elements, which have the biggest potential to be used in an archeological research, particularly in paleodietary research. These elements are mainly Sr, Ba and Zn. Lead and its isotopes are discussed more here in relation to the effect of Pb to Romans in the past and to the identifying sources of pollution by this element. In the same chapter are also described principles of post-mortem alteration processes, to which are bones after burial exposed and which they have to face during analyzing and interpretations of data related to the amount of trace elements in origin bones.
|
|
|
Tree rings as a Pb pollution archive
Šimeček, Martin ; Mihaljevič, Martin (advisor) ; Strnad, Ladislav (referee)
The Bachelor's thesis is written as a research talking about storing Pb in tree rings. The first part speaks about the basic characteristic of the pollutant, his natural and anthropogenic deposits. Following chapters are comparing the tree rings with the peat bogs, which are often used as a natural archive of the contamination by the metallic elements. Than I continue with the description of the transport of Pb into wood and subsequent radial distribution in tree rings. One of the chapters concludes the results of certain researches of tree rings. The main time sections of environmental pollution in the 20th century are shown by the results of researches on the concentrations and isotope ratios of Pb. These studies informe us also about sources causing this pollution. The thesis includes also a chapter about bark pockets, which can be used as another alternative to observe the movement of Pb in the environment. The last part describes the method ICP-MS usually used to determine Pb in natural materials.
|
|
|
Determination of Pt metals in environmental samples
Kotková, Kristýna ; Mihaljevič, Martin (advisor) ; Strnad, Ladislav (referee)
Platinum group elements are increasingly used in various industries, and that generates their occurrence in many parts of the environment, including biota. The interest of scientists is currently focused on studying the behavior of Pt metals in the ecosystem because of the potential health risks of Pt metal compounds. There are used various techniques for this purpose, including analytical methods. This bachelor thesis deals with properties of PGE, their appearance and behavior in the environment. The aim of the bachelor thesis is to review the analytical methods used to determine the Pt metals in environmental samples. Key words: platinum group elements, determination, ICP-MS
|
|
|
Variation of Pb-isotopic composition in coal basins
Čurda, Michal ; Strnad, Ladislav (advisor) ; Mihaljevič, Martin (referee)
This Bachelor Thesis is devided into three main parts. The first part has a character of a research and describes the presence of lead in coal, in deposits of ore, in peat bogs, or in lake and flood sediments. The second part briefly describes the analythic methods used to determine lead in natural material. The third - practical part is focused on measurement of samples taken from the sokolov brown coal basin. It describes the laboratory method of the preparation of the samples for the analysis of contents and isotope composition of lead using ICP - QMS.
|
|
|
Lead isotopic ratio determination in soils
Kotrč, Vlastislav ; Mihaljevič, Martin (advisor) ; Strnad, Ladislav (referee)
This barchelor thesis deals with the issue of lead in the environment, with its main focus being on describing the right analytical method for determining the isotopic composition of lead in soil. First part this thesis summarizes the most important characteristics and properties of lead. Next part is concerned with the methodology of collection and preparation of soil samples for the analysis itself. The thesis then contains detailed description of the analytical method, which is being currently the most used for determining the isotopic composition of soil - mass spectrometry with inductively coupled plasma. Since this is not a research thesis, in the fifth part, results of studies from the Příbram region are presented, alongside other possible uses of this method. Key words: lead isotopic composition, soils
|
|
| |
|
|
Biogeochemical cycle of rare earth elements in the Lesní potok catchment
Dubroková, Jitka ; Mihaljevič, Martin (advisor) ; Strnad, Ladislav (referee) ; Chrastný, Vladislav (referee)
110 Summary The study of biogeochemical cycle of rare earth elements (REE) carried out in the Lesní potok catchment and its vicinity (located in the Nature State Reserve, Voděradské bučiny, 30 km SE of Prague) was focused on the monitoring of REE concentrations and distribution patterns in natural environment, their relationship with other analysed elements and compounds such as Al, Ca, Fe, K, Mg, Mn, Na, P, S, Si, F- , Cl- , NO3 - SO4 2- , HCO3 - and organic carbon, and its response to physicochemical conditions in various investigated ecosystem compartments. The samples of soil, stream sediment, stream and ground water, rainwater and throughfall in beech and spruce forest, samples of tree assimilatory organs, bark and stem wood of Norway spruce (Picea abies) and European beech (Fagus sylvatica) and lichens (Hypogymnia physodes) were collected in the catchment and its vicinity. Liquid samples were acidified with dilute nitric acid to prevent losses by adsorption, and filtered using a 0.45 µm membrane filter. Stream water samples sampled in months characterized by low and high discharge were processed by ion exchange chromatography and membrane dialyses. Solid samples were dried to constant weight (and sieved and homogenized in case of soil stream sediment samples) and decomposed in the microwave oven with...
|
|
|
Distribution of trace elements in tectites with using LA ICP-MS
Svatá, Adéla ; Strnad, Ladislav (advisor) ; Houzar, Stanislav (referee)
The following example deals with methods of determining major and trace elements in a particular special kind of natural glasses - tektites. Measurements were performed on seventeen samples. Two of them belonged to a group of Libyan desert glass and the remaining fifteen were originally from the Australasian tektite field. For these purposes, optical microscopy was used in the preparatory phase of study of the samples. The studied samples were prepared in the form of cross-sections. Microscopy was employed to ensure the correctness of the procedure for selecting appropriate samples and precise areas of cross-sections that are suitable for analysis. The main elements were determined by electron microanalysis. The values obtained in these measurements confirmed existing knowledge about the composition of tektites. The chemistry of Libyan desert glass corresponded to 98 weight percent of SiO2. In the Australian-Asian samples, this value was equal to 73 wt.%. The other major oxides include Al2O3, FeO, MgO, etc. The contents of these elements in the Libyan desert glass were determined in the range of 0.154 to 0.727 percent by weight. The Australasian tektites contained 0.598 to 0.875 wt.% of these elements. The most important data were obtained by inductively coupled plasma mass spectrometric (ICP-MS)...
|
|
|
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...
|
|
| |
guest ::
RSS feed.