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Deposition and mobility of Pb in floodplain of Morava River in Strážnice area
Gemeinerová, Veronika ; Grygar, Tomáš Matys (advisor) ; Hruška, Jakub (referee)
This work was focused on geochemical methods and analyses which were used for lithologic and facial description of floodplain sedimentary records and also for determination of depth dependence of Pb concentration and evaluation of possible mobility of Pb in six profiles, which were taken across the floodplain in two locations in the southern part of Morava River in study area called Strážnické Pomoraví. The aim was to confirm the stability of concentration of Pb in upper parts of all six profiles. Performing these analyses, a possible migration of Pb in lower parts of some profiles has unexpectedly been revealed. For better facial description of the profiles in floodplain fines, proxy methods such as cation exchange capacity (CEC), elementary analysis using energy dispersive X-ray fluorescence spectrometry (EDXRF) and also determination of content of magnetic particles using magnetic susceptibility in depth profiles were used. The results of these proxy methods were confirmed by conventionally used geochemical methods - BCR sequential extraction, elementary analysis with determination of Pb isotope ratios using ICP MS, and granulometric analysis.
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Evaluation of proposed revitalization of the river Ploučnice close to Mimoň in terms of remobilization of historical contamination
Slabá, Eva ; Matys Grygar, Tomáš ; Elznicová, J.
The aim of the study was to estimate the uranium contamination in the alluvial sediments of original river beds of the Ploučnice river between 72-73 river kilometer on a left bank, near Mimoň town, and evaluate if the contamination should be included into preparation of revitalization projects. The study of contamination was started by mapping the gamma activity of the surface of the floodplain. Based on the resulting map the sediment samples were taken by hand earth drill from the former floodplain and channels abandoned in the 1980s by regulations. The samples were analysed by laboratory X-ray fluorescence (XRF). This step was followed by subsequent mapping by handheld XRF to specify the contamination pattern in the floodplain in more details. The evolution of watershed as well as the exact terrain model were processed by GIS program. Two major contaminated areas have been found, and further sampling was conducted. This enabled us to reconstruct the historical development of contamination at exceptional time scale resolution and describe precisely the evolution from the 19th century to the time of the regulation of that river reach. It has also been shown, that any revitalization in the near future would be probably thwarted due to extremely fast river changes which would cause an immediate re-introduction of the historical contamination into the fluvial system.
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Nanokrystalické částice oxidů železa, karbidů železa a alfa-Fe připravené z ferihydritu
Schneeweiss, Oldřich ; Grygar, Tomáš ; David, Bohumil ; Pizúrová, Naděžda ; Žák, Tomáš ; Zbořil, R. ; Mašláň, M.
Preparation of nanocrystalline iron oxides (hematite alpha-Fe2O3, magnetite Fe3O4), Haag carbide (Fe5C2), and alpha-Fe by thermal treatment of ferrihydrite in various atmospheres is reported. The phase composition and size of nanoparticles was controlled using the annealing temperature and atmosphere (vacuum, hydrogen, or ethylene).
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Naples yellow containing Sn in 18th - 19th century: Technological peculiarity or a forgotten pigment ?
Grygar, Tomáš ; Hradil, David ; Hradilová, Janka ; Bezdička, Petr ; Fogaš, I. ; Machovič, V.
Several Pb-containing yellow pigments were used in traditional European painting. Recipes for their production were probably adapted by those for yellow glass and enamel, having been known from antiquity. The popularity of one of them, Naples yellow, PB2Sb2O7, is strictly limited to the period from 17th to 19th century and its actual composition chanced within this period.
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