|
|
Toxic metals in foods
Klímová, Martina ; Orsák, Matyáš (advisor) ; Hniličková, Helena (referee)
Summary
Bachelor thesis Toxic metals in food is focused on toxic metals, their description, toxicity and monitoring their content in foods. Toxic metals significantly contaminate the environment nowadays. The metals pollute the environment through burning fossil fuels, agriculture and producing and processing of metals. They occur in various forms and appear in compounds, rocks and minerals. Their toxicity for human and animals is substantial. Their toxicity is related to the form of occurrence, solubility in water and in organic solvents and their mobility in body and water. Toxic metals bind on SH group of proteins and work as an enzyme poisons. The most toxic effect was found in cadmium, but also other metals have significant toxic effect. Lead, Cadmium and Arsenic have carcinogenic effects and cause malignant tumour. Mercury and above mentioned have mutagenic and teratogenic effects. Significant contamination of the environment and food can lead to poisoning, which is expressed by various symptoms.
Toxic metals are absorbed especially by inhalation and consumption of contaminated food. Agriculture crops are polluted from contaminated soil, water and using of fertilizers and pesticides. To meat and animal products, toxic metals come mainly from contaminated plants, which animals eat. Meat products can be polluted by incorrect technological procedure. In general are toxic metals cumulated by organisms in tissues, especially in kidneys and liver. Animals living in polluted area have a lot of these metals in their tissues. With its increasing age, cattle more accumulate toxic metals in its tissues, therefore maximum recommended age of slaughter is 3 years. Serious problem is high amount of mercury in fish, especially in the sea fish. The larger and more carnivorous the fish is, the more they cumulate mercury and the other metals. Especially in the contaminated sea, mainly polluted sea from oil, fish have more metals in tissues. Across the European Union, there were currently set strict limits on the contents of metals in food. Some limits were updated and added by the last findings last year. Keeping these limits is regularly checked.
|
|
|
Problems of wells and water in the Křelovice village
PAVLÍKOVÁ, Kateřina
In my bachelor's thesis I wrote about problems of wells and water in the village Křelovice. I chose this village because I live there. I wanted to find new information about local water sources, their capacity and quality. My work is divided into two main parts - theoretical and practical. In the theoretical part I wrote about Křelovice and local water sources. I also wrote about indicators of drinking water quality acording to the legislative limits. I specified various indicators of water when we can find them in drinking water, how to eliminate them and how they affect the human body. I wrote a hygienic limit to each indicator of water quality which shouldn´t be exceeded. In the practical part I wrote about objectives of the work, hypothesis and research question. The goal of my work was: evaluate water quality from the local water source in Křelovice and find out the opinion of the population of the village of the quality of the local water source. I chose two research methods. As the first method I used a quantitative research. I prepared my own questionnaires for it. I gave these questionnaires to one hundred forty people who live in Křelovice. This number is a representative sample of 300 inhabitantes of the village older than 18 years. Then I analyzed the questionnaires and I made a color graph with a description to the each question. As the second method I chose secondary data analysis. The most information I recieved from the territorial workplace Pelhřimov of the Regional Station of Hygiene and the other from the mayor of Křelovice Ing. Jaromír Dolejš. I statistically processed the datas and compared them with hygienic limits that are determined by the legislation. Then I made graphs for the better visibility and orientation. After evaluating the quantitative research, I found out that the villagers are very satisfied with the quality of drinking water from the local sources. It is obvious that the municipality does everything for keeping the good quality of drinking water. Results of samplins of water corresponded with the public opinion. In last five years hasn't been exceeded hygienic limits which are set by the legislation. It means that the respondents are rightly satisfied with the quality of water. I think that my research showed not only a good quality of drinking water and the satisfaction of residents but also that the quality of water is regularly checked by statutory regulation. I think that the residents can be sure that the water is really high-quality so they needn´t be worry of using and drinking water from the public water sources. My research is also good for the municipal council headed by the mayor. I have clearly demonstrated that water quality is high and residents are very satisfied.
|
|
|
HYGIENIC QUALITY OF FISH FROM SIGNIFICANT FISHING WATERS BEROUNKA 1, LUŽNICE 6, OTAVA 4, OTAVA 7 (P)
BARTOŇ, Jiří
The main aim of this study was to evaluate hygienic quality of fish from significant fishing waters: Berounka 1, Lužnice 6, Otava 4, Otava 7 (P). Sampling was performed in 2010 by electrofishing and fishing rods. 173 individuals belonging to 13 different fish species were fished. The samples of fish muscle were analysed for the following substances: Hg, Pb, Cd, PCB, DDT and its metabolites (DDE and DDD), a-HCH, b-HCH, y-HCH, HCB. Samples of bream (Abramis brama) muscle were collected at all monitored sites (exception was Otava 7) and bream was used as reference species to compare the contamination among monitored rivers. The results were compared with valid hygienic limits. The values of contamination were in most cases very low and far below the limits. Only mercury was identified as a risk contaminant in all monitored rivers. Average concentrations of mercury in the muscle of bream were in the range of 0.261-0.284 mg/kg and were comparable in all rivers. The hygienic limit for mercury (0,5 mg/kg) was exceeded only in 4 cases - one individual sample of bream from Otava, two mixed samples of asp (Aspius aspius) from Berounka and Lužnice, one mixed sample of perch (Perca fluviatilis) drom Otava. The highest value of total mercury content (0.768 mg/kg) was found in asp from Lužnice 6. All concentrations of persistent organochlorinated pollutants in fish muscle were far below the valid hygienic limits. The only health risk was posed by increased content of mercury.
|
guest ::
