National Repository of Grey Literature 130 records found  1 - 10nextend  jump to record: Search took 0.02 seconds. 
Evaluation of ecotoxicity of selected chemicals with using algal test.
Kosárová, Hedvika ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor thesis deals with the ecotoxicity of 2 - [(2,6-dichlorophenyl)aniline] benzene acetic acid (diclofenac), ?-methyl-4-(2-methylpropyl) benzene acetic acid (ibuprofen) and mixture of cadmium and diclofenac and studies the above using algal toxicity test in accordance with ISO 8692. The theoretical part describes the issue of pharmaceuticals in the environment, and characteristics of standards algae tests and alternative tests. Freshwater green algae Desmodesmus subspicatus were used as testing organisms in all the implemented algal toxicity tests. By the means of these tests, the IrC50 values for the standard substance potassium dichromate, the drugs diclofenac and ibuprofen and cadmium were determined. The toxicity of cadmium in mixture with diclofenac was also evaluated.
The study of vertical mobility of heavy metals and their transfer to mushrooms
Jurnečka, Roman ; Doležalová Weissmannová, Helena (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of contamination of forest soils and edible mushrooms with lead, cadmium, copper and zinc in the Jeseníky Mountains, specifically in the Domašov and Vápenná forests. Sampling took place at 12 localities, divided into spruce and beech stands. Atomic absorption spectrometry AAS ContrAA 800D was chosen to determine the content of selected heavy metals. Based on the measured values of the concentrations of the studied metals and other soil properties, dependences were created to determine the vertical mobility of selected metals in the soil profile. Vertical mobility depends on the physico-chemical properties of the soil (pH, C and S content). The dependence of the content of selected heavy metals in the soil on the pH value of the soil was found. In the case of lead, the sorption capacity of the soil organic component was confirmed. The risk and above-limit content of Pb, Cd and Cu was found on the yellow-boletus mushroom. Cadmium shows the highest bioavailability. Lead was evaluated as the element with the lowest mobility.
Thick-film sensors for heavy metals detection
Gajdoš, Libor ; Majzlíková, Petra (referee) ; Prášek, Jan (advisor)
This project describes the possibilities of heavy metals detections in solutions using differential pulse voltammetry with tree-electrode electrochemical thick-film sensors. In the theoretical part, the thick-film technology is described as well as thick-film pastes’ types and compositions, followed by introduction to electrochemistry and electro-analytical methods of measurement. This project also describes the three measured heavy metals – cadmium, lead and copper. In the practical part, heavy metals’ ions detection in solutions using carbon working electrode and determination of the detection limit and sensitivity are described and discussed. Finally the evaluation of obtained results and results comparison to hygienic limits are included.
Study of CdTe sensor properties
Vašíček, Martin ; Holcman, Vladimír (referee) ; Grmela, Lubomír (advisor)
This Bachelor Thesis is focused on studies of CdTe detector characteristics. It is to describe the analysis of transport and noise characteristics of CdTe samples at different temperatures. Evaluation of our results proves that CdTe junction behaves like an antiseries connection of a pair of diodes. The courses of VA characteristics are noted for linear or slightly exponential growth. When temperature is growing , conductivity of the samples is growing too. Our measurements demonstrated difference in conductivity of samples tested at the same temperature. It is also obvious that within very low range of frequencies the factor of noise 1/f is dominating. From 10Hz frequency the effect of thermal noise prevails.
Heavy metal contamination of selected Brno city localities
Šebková, Michaela ; Sommer, Lumír (referee) ; Dočekalová, Hana (advisor)
The aim of this work is to study the soil and plant contamination by heavy metals (lead, cadmium and mercury) in five selected places of Brno city. The sampling place Opuštěná represents the heavily polluted locality with high traffic density situated in the city centre. Sampling places Vídeňská and Podstránská belong to medium polluted localities, that are situated close to frequented roads. Relatively clean localities are represented by Musorgského and Šrámkova places, which are situated in peripheral city district with smaller traffic density. Soil and plants were sampled at two time periods (November 2008 and January 2009). Average amounts of mercury, cadmium and lead in collected soil samples are lower then limits of the Directive number 13/1994 of the Code of Ministry of the Environment. The content of heavy metals in soils corresponds to the sampling place. The highest value of metals content was found in the soil sampled at Opuštěná site. The content of lead and mercury in leaves of common dandelion was higher than the content in roots. In the case of cadmium the situation was opposite, the highest content was measured in underground part of the plant. It was found, that the content of heavy metals in leafy and underground part showed only small difference between sampling places. Nevertheless, the locality Opuštěná is found again as the highest contaminated place. Values of pH of collected soil samples were ranged in neutral area between 7 and 7,5.
Use of pollution indices for evaluation of soil contamination
Čmelíková, Dorota ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This thesis focuses on heavy metal contamination of soil and the use of pollution indices for its evaluation. Two regions were selected for assessment and comparison. The chosen heavy metals were mercury, zinc, copper, lead and cadmium. These heavy metals were analysed in 15 samples from Kyjov nad 15 samples from Ostrava. Methods of analysis were AMA-254 and FAAS. The established concentrations were used to calculate pollution indices and for health risk assessment. Pollution in Kyjov was assessed as low to medium without any health risks. Ostrava region was assessed as moderately to highly polluted with a low health risk, especially for children.
Analysis of noise characteristics of radioactive emission detectors
Šik, Ondřej ; Pfeifer, Václav (referee) ; Andreev, Alexey (advisor)
The main goal of this Master’s thesis is to describe relationship between low frequency noise spectral characteristics of Cadmium-Telluride radiation detectors depending on applied voltage and detectors reaction to illumination of various wavelengths. Also, the reaction and influence of higher operating temperatures were investigated. The noise measurements shown that the dominant noise type at low frequencies is the 1/f noise. Several samples with different resistivity were tested. By comparing results, we are able to estimate the quality of detectors and their sensibility to illumination and higher operating temperatures. We have found that all the studied CdTe detectors are sensitive to one particular wavelength of 548nm. Resulting data were processed by EasyPlot program that provided graphical representation of spectral noise characteristics. All measured characteristics of tested samples are compared and it’s estimated the similarity between the samples.
Determination of hazardous elements in soils with different anthropogenic contamination using sequential extraction analysis
Židek, Michal ; Sommer, Lumír (referee) ; Doležalová Weissmannová, Helena (advisor)
This diploma thesis deals about determination of hazardous elements and their mobility in soils from Brno and Ostrava. For extraction of soil samples was used sequential extraction by Tessier and BCR sequential extraction. Extraction by nitric acid was also used. Mercury was determinated by the advanced mercury analyser AMA 254. Lead, copper and zinc were determinated by the flame atomic absorption spectrometry. Cadmium and vanadium were determinated by the electrotermic atomic absorption.
Analysis of substances potentially dangerous to humans found in lipsticks
Horáková, Kristýna ; Kučerová, Simona (referee) ; Diviš, Pavel (advisor)
The diploma thesis deals with the determination of the content of risk elements and parabens in lipsticks and the assessment of possible negative effects on human health associated with the use of lipsticks. Parabens were analyzed by high performance liquid chromatography with diode array detection (HPLC-DAD). Aluminum, cadmium and lead were analyzed on an inductively coupled plasma mass spectrometer (ICP-MS). The mercury content was determined using an atomic absorption spectrometer with an UV detector (AAS-UV). A total of 36 lipstick samples from 22 cosmetic brands were selected for analysis, with a savings price in the range of CZK 50–1500. Based on the measured metal concentrations, the hazard quotients (HQ) for individual metals as well as the total hazard index (HI) for the sum of all metals were calculated. Metal concentrations in lipsticks were further processed using Kruskall-Wallis Anova to divide samples according to price categories. The relationship between the content of individual metals and the purchase price has not been proven. Furthermore, a Kolmogór-Smirnov test was performed on these data to compare groups with vegan and not vegan composition. The content of aluminum, which was about 2.5 times lower in vegan cosmetics, proved to be statistically significant for this distribution. Parabens were detected in the minimum number of lipsticks examined, but in some cases information on the content of parabens was missing on the product packaging.
Sorption of metal ions mixture on natural lignite
Doskočil, Leoš ; Taraba, Boleslav (referee) ; Pekař, Miloslav (advisor)
Sorption of quaternary metal ions (Pb2+, Cu2+, Cd2+ and Zn2+) was carried out on lignite from the South Moravia. Following experiments were tested: kinetic sorption, dependence of sorption on pH, initial concentration, temperature, effect of electrolytes (KNO3 and NaCl) and desorption in deionized water. Sorption studies was carried out in quaternary mixtures and in the case of inicial concentration effect additional in a single-component solution. The batch sorption experiments was used. Sorption time was 24 hour, although concentration of ions was a near equilibrium after two hour. As the optimal pH was determined pH 5. The order of affinity by lignite was obtained Pb >> Cd > Zn > Cu for the sorption of metals in the single-component solution and the order was Pb > Cu > Zn > Cd for the sorption of mixture of metals. The maximum adsorptium capacities from single solutions were for Pb 97,82 mg/g, Cd 60,34 mg/g, Zn 49,88 mg/g and Cu 30,28 mg/g and in the case of ones from mixture solutions were for Pb 39,03 mg/g, Cu 25,94 mg/g, Zn 15,21 mg/g and Cd 5,18 mg/g. Experimental data have been analysed using Langmuir and Freundlich model. Thermodynamic values H°, S° and G° were calculated. Desorption test showed that desorption efficiency is 0–3 %. NaCl had the greatest influence on sorption from electrolytes. On the basis obtained results we can say that metals are binding to lignite in particular due to chemical interactions. Lignite is s suitable as a sorption material for metal ions especially in the field of low concentrations.

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