|
|
The study of PET bottles in terms of the content of risk elements
Kryštofová, Petra ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of PET bottles in terms of the possible content of risk elements. The contents of antimony, copper and lead were determined in the PET packaging material and in the beverages contained in the bottles. A total of 15 samples of bottled still and infant water available in the Czech sales network were analyzed. The PET material was decomposed in an acidic medium under the action of microwave radiation under optimized conditions. Atomic absorption spectrometric methods with flame or graphite cuvette atomization were used to determine selected risk elements based on the predicted analyte concentrations. In the PET packaging material, 159.35 to 265.68 mgkg-1 of antimony were determined, the determined values of lead concentration were in the range of 10.96-20.23 mg·kg-1 and the copper concentration in the range of 0.11-7,52 mg·kg-1. In bottled water and in bottled infant water, antimony was identified only in samples labeled 6a, 8a, 9a and 15a, all lead concentrations were measured below LODPb, copper was determined only in samples 2a, 6a and 8a. In none of the samples did the concentrations given by the valid legislation be exceeded. The limits of these metals are not set in legislation in the packaging materials, only specific migration limits and they have not been exceeded. However, the high concentration of antimony in PET poses a potential risk of contamination of the contents of these packages.
|
|
|
Determination of the risk elements and other elements concentration in animal feed
Křehlíková, Jana ; Juglová, Zuzana (referee) ; Diviš, Pavel (advisor)
This thesis deals with the determination of selected microelements and macroelements and risk elements in dog and cat food. The theoretical part describes the nutrition of dogs and cats and focuses on the safety of the food in the context of contamination with risk elements. Another topic discussed is the chemical analysis of feeds, specifically the determination of nutritionally important substances, beneficial elements, and contaminants. The experimental part deals with the preparation and digestion of feed samples and the subsequent analysis of these samples using ICP-OES and AAS methods. The detected concentrations of the elements of interest in the feeds were compared with the feed standards issued by the Department of Veterinary Medicine and the decree issued by the Ministry of Agriculture. The analysed feeds were found to be deficient in some elements. The content of the risk elements in the feed met the legal limits and did not pose a health risk to the animal. Elements for which the legislation does not provide a maximum permissible limit were present in the feed-in in high concentrations that could already harm the animal's health.
|
|
|
Assessment the impact of the application of excavated sediments from the dam Luhačovice on the content of risk elements in arable soil
Kratěnová, Pavla ; Komendová, Renata (referee) ; Řezáčová, Veronika (advisor)
This diploma thesis focuses on an issue concerning an excavated sediment application on an arable soil and its impact on the soil quality based on a particular case of a deposition of the sediment from the dam Luhačovice on an adjacent agricultural area. The theoretical part of this thesis is focused on a soil and sediment characteristics and functions, contained risk elements, sampling methods, determination possibilities of particular risk elements and a description of conditions which emerged from a need for the deposition of sediment obtained during scavenging of the dam Luhačovice. In the experimental part was described the process of sampling, samples processing and determining of concentration values for chosen risk elements (Cd, Cu, Hg, Ni, Pb) using flame or electrothermal atomic absorption spectrometry methods. This part also contains an evaluation of obtained results and a validation of an approval for the sediment deposition.
|
|
|
Content of risk elements in food for dogs and cats
Hrabalová, Karolína ; Slavíková, Zuzana (referee) ; Diviš, Pavel (advisor)
This bachelor's thesis deals with the determination of risk elements, namely mercury, arsenic, cadmium and lead in dog and cat food. The concentration of mercury was determined using the AAS technique, and the concentration of arsenic, cadmium and lead was determined by the ICP-MS method after microwave decomposition of the samples using mineral acids. A total of 30 feed samples were analyzed. In most samples, the concentrations of monitored elements were lower than the maximum permissible values given by the EU Commission Regulation, two samples did not meet the requirements of the regulation. The concentration of risk elements in the feed, except for arsenic, did not depend on the type of meat used in the feed. Feeds containing fish meat showed demonstrably higher concentrations of arsenic than feeds with other meats. Due to the relatively low proportion of meat in feed and due to the overall lower concentrations of risk elements in meat, it can be assumed that the vegetable or other component of the feed, or the technology of feed production, is responsible for the increased concentration of risk elements in feed.
|
|
|
Sewage sludge – a secondary source of environmental contamination with heavy metals
Sysel, Petr ; Zlámalová Gargošová, Helena (referee) ; Komendová, Renata (advisor)
This work deals with the elementary trace analysis of sewage sludge as a potential source of risk elements when applied to agricultural land. A total of 24 samples were analyzed, divided into two sets with different collection dates. The total content of zinc, copper, chromium, lead, mercury and cadmium in sewage sludge, as well as amount of risk elements that are extracted from sludge to water in 24 hours, was determined. Atomic absorption spectrometry was chosen for the analysis. It was found that the risk elements are in sewage sludge in amounts and order Zn (254.68 – 3084.53 mg/kg) > Cu (6.18 – 961.89 mg/kg) > Cr (26.95 – 387 .91 mg/kg) > Pb (0.84 – 155.30 mg/kg) > Hg (0.50 – 4.12 mg/kg) > Cd (0.06 – 2.61 mg/kg). A lower amounts of analyzed metals in the aqueous extracts than their total amounts in sludges were observed. The concentration of mercury and cadmium in the aqueous extracts was below the detection limits. It was evaluated that the risk elements in sewage sludge are found in less water soluble compounds. The results also show that the concentration of risk elements in the sludge does not depend on the number of equivalent inhabitants for which the treatment plant is dimensioned.
|
|
|
Assessment of heavy metal content in agricultural soils of the Moravian-Silesian Region
Skurňová, Eliška Anna ; Doležalová Weissmannová, Helena (referee) ; Komendová, Renata (advisor)
The aim of this bachelor's thesis is evaluation of the concentration levels of selected heavy metals (arsenic, beryllium, cadmium, cobalt, chromium, copper, nickel, lead, vanadium, and zinc) in agriculture soils on 19 sampling points in Moravian-Silesian Region. The Central Institute for Supervising and Testing in Agriculture provided data for this thesis. The samples were collected as part of the Basal Soil Monitoring in sampling cycles 1995, 2001, 2007, 2013 and 2019. The contents of risk elements in soils were determined by the optic inductively coupled plasma atomic emission spectroscopy after the Aqua regia decomposition in the National Reference Laboratory ÚKZÚZ. Villages Oldřišov, Markvartovice a Nové Sedlice in Opava district were the least contaminated. The most contaminated locality was Město Albrechtice in Bruntál district, here, the legislative preventive value for copper and lead content, and the indicative value for cadmium and zinc, were exceeded. The preventive values for chromium and nickel content were exceeded in the part of the city Žilina in Nový Jičín district. The highest concentration of zinc was found in Marklovice in Karviná district, where the legislative indicative values were exceeded multiple times. It was not possible to determine from the provided sample data if the concentration of heavy metals is increasing in generally long-term perspective.
|
|
|
Research on the content of risk elements in the material of PET bottles
Kryštofová, Petra ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This thesis deals with the research of the content of risk elements in the material of rPET (recycled polyethylene terephthalate), supplied from various countries, and the study of different factors (type of liquid, temperature) on the migration of antimony from this material. The recycling process has the potential to increase the content of unwanted substances and promote the formation of degradation products of chemical additives and by-products of polymerization, thus contributing to higher migration of these substances into food or food simulants [1]. The supplied rPET samples were subjected to total decomposition in an environment of concentrated sulfuric and nitric acid under the influence of microwave radiation prior to analysis. Prepared samples were analyzed by atomic absorption spectroscopy (AAS) techniques. The contents of Sb and Zn were determined by flame atomic absorption spectrometry (FAAS), and the concentrations of Pb, Cu, Zn, Cd, Cr, and Ni were determined by electrothermal atomic absorption spectrometry (ETAAS). Additionally, the concentrations of Sb were determined by this method in migration experiments. This thesis builds upon the author's bachelor's thesis, which included pilot experiments.
|
|
|
Determination of the risk elements and other elements concentration in animal feed
Křehlíková, Jana ; Juglová, Zuzana (referee) ; Diviš, Pavel (advisor)
This thesis deals with the determination of selected microelements and macroelements and risk elements in dog and cat food. The theoretical part describes the nutrition of dogs and cats and focuses on the safety of the food in the context of contamination with risk elements. Another topic discussed is the chemical analysis of feeds, specifically the determination of nutritionally important substances, beneficial elements, and contaminants. The experimental part deals with the preparation and digestion of feed samples and the subsequent analysis of these samples using ICP-OES and AAS methods. The detected concentrations of the elements of interest in the feeds were compared with the feed standards issued by the Department of Veterinary Medicine and the decree issued by the Ministry of Agriculture. The analysed feeds were found to be deficient in some elements. The content of the risk elements in the feed met the legal limits and did not pose a health risk to the animal. Elements for which the legislation does not provide a maximum permissible limit were present in the feed-in in high concentrations that could already harm the animal's health.
|
|
|
Chemical composition of photovoltaic panels
Koudelová, Marta ; Šebek, Ondřej (advisor) ; Tejnecký, Václav (referee)
The bachelor's thesis is focused on the issue of photovoltaic cells and panels. The literature search was formed from selected available literature with the purpose to characterize different types of the crystalline silicon photovoltaic cells and thin-films photovoltaic cells and describe the application of photovoltaic cells in the world and in the Czech Republic. In the next part of this thesis is a summary of current knowledge about recycling of photovoltaic cells and other utilization of layers and their possible impact on the environment. The practical part of the thesis deals with selected samples of PV panels. A few samples of photovoltaic panels were taken for chemical analyses. Chemical analyses are performed of the five samples of the photovoltaic panels. The results of chemical analyses were compared with acquired data from the literature. The results of the multielementary analysis of selected samples was that the photovoltaic panels contain a risk elements (e. g. As, Cd, Sb, Mo). The PV panels also contain economics utilizable elements (Ag). Content of silicon is up to 78,18 % SiO2. Key words Photovoltaic panel, photovoltaic cell, chemical analysis, risk elements, recycling
|
|
|
The casuistry of fatal accidents in apparatus diving in the Czech Republic
Kleinová, Karolína ; Vondrášek, David (advisor) ; Bažant, Filip (referee)
Title: The casuistry of fatal accidents in apparatus diving in the Czech Republic Objectives: This paper's goal is to describe and explain some particular fatal accidents in apparatus diving in the Czech Republic in years 1997-2004. As well as to show possible reasons and contexts of the elements leading to divers'passings. Methods: In this work was used a case study method, qualitative analysis of a diving expert evidences and subsequent reading of surveyed information Results: An important discovery is frequent neglecting of safety policy and overrating self capability in connection with the level of competence and experience. The most frequent downfall in surveyed cases is drowning. Keywords: diving, fatal accidents, risk elements
|
guest ::
