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Monitoring of mercury and methylmercury content in fish meat and evaluation of risks associated with the consumption of this meat
Křížová, Lucie ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
Mercury and its compounds are one of the most toxic global pollutants in the environment. It occurs in all segments of the environment, and it attains the food chain ang human body by people consuming fish. The theoretical part of this thesis examines the characteristics of mercury, its occurrence, the roots of its pollution, and the toxicity of various forms of mercury. Consequently, the thesis delineates analytical methodologies applied to determine the overall level of mercury and chemical forms of mercury. The practical part focuses on monitoring the level of mercury and methylmercury in 12 extracts of fish meat. The analyzer AMA 254 has been used to determine the level of mercury and methylmercury in these extracts. Based on the level that resulted from the measurements, the thesis concludes a risk that correlates with consuming this type of meat.
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Contamination of soil and sediment by hazardous metals
Pidima, Tomáš ; Komendová, Renata (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor thesis deals with soil and sediments from the environmental perspective. For selected heavy metals – cadmium, lead and mercury are given information about their occurrence, characteristics and potential sources of environmental contamination. It is also mentioned legislation dealing with the topic. The limit concentrations in soil and sediments, determination methodology and principles of the most commonly used instrumental analytical methods for these elements are described.
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Determination of heavy metals in soils and sediments in the region Revúce
Kováč, Lukáš ; Vávrová, Milada (referee) ; Doležalová Weissmannová, Helena (advisor)
This thesis aims to assess the extent of contamination of soil and sediment with risk metals in Jelšava. The main polluter of the environment in this area is the magnetize factory. Sampling of soils and sediments were made in three seasons. Sampling times were staggered to represent different seasons and to take into account the impact of the seasons on the obtained values of the concentrations in soil and sediment. Sampling sites were selected according according to the different distances from the factory and according to the different loading of roads. In each of the collected samples were determined concentrations of the elements copper, lead, zinc, nickel, manganese, mercury, cadmium and vanadium. Copper, lead, zinc, nickel and manganese were analyzed by atomic absorption spectrometry with atomization in a flame (F AAS), cadmium and vanadium were determined by atomic absorption spectrometry with electrothermal atomization (ET AAS). For the determination of mercury was used mercury analyzer (AMA).
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Use of DGT technique for mercury determination in food liquid flavorings
Habartová, Aneta ; Reichstädter, Marek (referee) ; Diviš, Pavel (advisor)
This bachelor thesis deals with varification of the use of the diffusive gradient in thin films technique (DGT) for food analysis. It focuses on testing a new type of sorption gel containing Purolite S924 as well, commercially available for mercury determination in food liquid flavorings. Theoretical part contents of characteristics and production of fish sauces are described analytical methods for mercury determination and DGT technique. Experimental part focused on optimization of preparation of sorption gel and validation DGT techniques for mercury determination in fish sauces. After validation DGT technique was successfully used for analysis real samples of fish sauces.
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Study of nitrogen post-discharge by mercury vapor titration
Teslíková, Ivana ; Brablec, Antonín (referee) ; Mazánková, Věra (advisor)
The aim of this master thesis is a study of nitrogen post-discharge by mercury vapours titration. The nitrogen post-discharge is investigated for many years theoretically as well as for a practical use. The object of this master thesis is a study of kinetic processes ongoing at titrations of mercury vapours during the nitrogen post-discharge at different pressures and applied powers. All experimental data were obtained from an optical emission spectroscopy of nitrogen post-discharge. DC discharge in flowing regime was chosen for measurements. The first part of experiments was carried out at the constant discharge current (100 mA), voltage (1300 V) and wall temperature (300 K). The total gas pressure was varied in range of 500-3000 Pa at nitrogen flow in range of 0.12-0.68 l/min. Nitrogen flow values were arranged to obtain constant nitrogen flow velocity for all gas pressures. The second set of experiments studied power dependencies. The current was varied in the range of 50-200 mA for constant voltage 1300 V. The total gas pressure in this case was 1000 Pa. Mercury vapours were introduced into the system by titration tube at different post-discharge time. The nitrogen pink afterglow effect was well visible at all experimental conditions. This effect corresponds to the maximum intensity of light emission, which expresses as considerable growth of characteristic pink radiation in the post-discharge time. Optical emission spectra of post-discharge were taken in the range of 320-780 nm. Besides three nitrogen spectral systems (first and second positive and first negative), the mercury line at 254 nm was recorded in the second order spectrum at 508 nm under these conditions if mercury was added. This spectral line is excited under post-discharge conditions by collisionally induced resonance energy transfer from nitrogen highly vibrationally excited ground state metastables and it opens an unique technique for their monitoring. The dependence of relative intensities on decay time for mercury spectral line and selected nitrogen spectral systems at different titration positions were measured. The relative intensities of nitrogen bands decrease with increasing of mercury line relative intensity for all total gas pressures. The pink afterglow phenomenon shifts to the later decay times with the increasing of total gas pressure. In the case of experiments at different power, it can be seen that with decreasing power mercury spectral line intensity decreases in post-discharge time. The first detailed tests of the unique detection for highly excited of nitrogen metastables were completed. However this master thesis is concentrated on the basic research which supports better indication of kinetic processes and reactions leading to transformation of excitation energy, this new knowledge should be applied in future also in technologies based on the long-lived metastable induced reactions.
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Production of organic acids by fibrous microscopic fungi and utilization of their biomass for removal of risk elements
Juglová, Zuzana ; Hudečková, Helena (referee) ; Urík,, Martin (advisor)
The aim of this bachelor thesis was to determine the most advantageous method for production of organic acids by microscopic flamentous fungus Aspergillus niger and to evaluate mercury bioaccumulation efficiency on collected fungal biomass. The theoretical part focuses primarily on utilization, metabolism and production on individual organic acids. This is followed by section focused on the toxicity of mercury and the principles of bioaccumulation of heavy metals in biomass. The experimental part focuses mainly on the optimization of cultivation, determination of content of produced organic acids, depending on the type of cultivation. Second point of practicle part is evaluating of mercury bioaccumulation depending on the initial concentration of mercury in solution. In overall comparison, the best type of cultivation is dynamic. Higher biomass yeild resulted in higher production of organic acids. The higher biomass synthesis is also beneficial for bioaccumulation of mercury.
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Speciace rtuti v rybích tkáních
Hrůzová, Marie
The diploma thesis is focused on the issue of contamination of freshwater fish species by chemical forms (species) of mercury. To monitor mercury speciation in fish tissues, four locations in the Czech Republic were selected - the Záskalská reservoir, Rybníkářství Pohořelice a.s., the Smrk pond, and the Lipolec pond. The Záskalská reservoir is located near the historic cinnabar mine, hence an increased risk of fish contamination was expected. No significant source of mercury contamination was identified in the other aquatic ecosystems. Four fish species - perch (Perca fluviatilis), roach (Rutilus rutilus), pike (Esox lucius), and European eel (Anguilla anguilla) were caught for analysis. Fish tissue samples (muscles, gills, liver, and skin) were analyzed for total mercury concentrations using atomic absorption spectrometry on an AMA 254 and for individual mercury species using High-performance liquid chromatography with atomic fluorescence detection (HPLC-CV-AFS). The highest total mercury contents were found in the muscles of fish from the contaminated Záskalská reservoir. The muscle tissues of pike, perch, and roach from the Záskalská reservoir exceeded the limit set by Regulation No. 1881/2006 EC. Only inorganic mercury species (Hg2+) and methylmercury species (MeHg+) were found in fish tissues. The highest amounts of methylmercury were found in muscle tissues (63-96 %), followed by skin (55-90 %), liver (31- 82 %), and gills (42-81 %). Statistically significant differences in mercury species content were compared between predatory and non-predatory fish, contaminated and non-contaminated locations, and the thesis also assessed the impact of age, species, and diet on the speciation of mercury in fish tissues.
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Využití vodních rostlin pro fytoremediaci rtuti
Abdrazakova, Kamila
The theoretical part of this bachelor thesis contains general information about mercury, its forms (primarily Hg2+, monomethylmercury, dimethylmercury and complex mercury compounds) emerging in nature and their bioavailability for living organisms. It is focused on the study of phytoremediation, its types and efficiency in the removal of environmental mercury pollution. The practical part is focused on monitoring the bioaccumulation of mercury in the leaves and roots of Elodea canadensis and Eichhornia crassipes in laboratory conditions. The content of mercury in the leaves of Elodea canadensis and in the roots and leaves of Eichhornia crassipes increased with the accumulation time and with increasing Hg concentration in the aquatic environment. The bioaccumulation factor increased with increasing mercury concentration in the aquatic environment for submerged plant parts, i.e. watercress leaves and water hyacinth root. For water hyacinth leaves that are not in direct contact with mercury in the aquatic environment, an increase in BAF with mercury concentration in the aquatic environment was not observed. The translocation of mercury from the root of Eichhornia crassipes to its leaves was low, with translocation index ranging up to 0.11. The best option for the phytoremediation of the aquatic environment from mercury is the root of Eichhornia crassipes, which is its hyperaccumulator.
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Feasibility study: Hg removal technology using electrochemical methods - large unit and its comparison with alternative technology
Zach, Boleslav ; Veselý, Václav ; Šyc, Michal ; Puchýř, R. ; Foltýn, M. ; Přemyslovský, P. ; Pařízek, V.
In the introductory chapters, an introduction to the technology for Hg capture from combustion processes using electrochemical methods (membrane electrolyzer)and the design of a unit with capacity applicable to a typical power plant unit was made. This technology has not fully demonstrated its effectiveness from laboratory tests in semi-operational trials. These findings have been taken into account in the design of the unit for a larger power plant, therefore the design considers the use of more units in parallel, which places demands on the built-up space. The number of units used and the size of the built-up area is then matched by the high cost of the investment. Although this is a technology that does not consume any chemicals or sorbents - only electricity - it is an investment and operationally expensive technology, as can be seen from the comparison with alternative technologies. A comparison of the investment costs and cumulative expenditure (investment, reinvestment, maintenance and operating costs) for the electrochemical technology with electrolyzer and the two alternative technologies shows that if the economic aspect alone is the decisive criterion for the choice of technology, the technology of dosing Na2S solution into the scrubber absorber solution for flue gas treatment clearly comes out best at current prices.
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Semi-operational verification of mercury removal from flue gas by electrochemical methods
Šyc, Michal ; Grolig, O. ; Přemyslovský, P. ; Pařízek, V.
This is the final report of the project Pilot-scale verification of mercury removal from flue gas by electrochemical methods TK04020330 summarizing the course of activities for the last year of the project and the results achieved during the project. The content of the report is a description of the commissioning and operation of the pilot unit designed and constructed during the project. The results of laboratory experiments, pilot-scale verification of the technology, and testing of mercury oxidation in flue gas. The conclusions drawn from the experimental results are included in the report.
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