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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Exprese transgenu bphC u ječmene

Sedlářová, Kateřina January 2015 (has links)
Polychlorinated biphenyls are toxic organic compounds, characterized by a low degradability in the environment and accumulation in the food chain. This is the reason, why decontamination of soils polluted with such substances is very important issue for today's society. Decontamination of areas infected by PCBs is very complicated due to its physical and chemical characteristics. Appropriate decontamination method is phytoremediation, which is used for removing polychlorinated biphenyls by natural processes of plants. Using the transformation of plants can increase the efficiency of phytoremediation. The thesis has been investigated in expression of remediation gene bphC/His at T2 generation of spring barley (Hordeum vulgare L.), variety Golden Promise at the DNA, RNA and protein levels. Expression of the transgene was detected using PCR, real-time PCR and Western blot. To obtain dihaploid homozygous plants of spring barley, variety Golden Promise containing a phytoremediation gene bphC/His was used anther cultures technique. In the thesis were choosed plants from the T2 generation, showing the presence of the inserted gene to test the ability of transgenic plants to accumulate polychlorinated biphenyls.
2

Mechanismus mikrobiální biodegradace polychlorovaných bifenylů / Mechanism of microbial biodegradation of polychlorinated biphenyls

Šrédlová, Kamila January 2021 (has links)
Polychlorinated biphenyls (PCBs) are chlorinated organic compounds, which belong to persistent organic pollutants and exhibit various modes of toxic action, including mutagenicity, carcinogenicity, and endocrine disruption. PCBs were manufactured during the 20th century in many countries and extensively used due to their advantageous physicochemical properties. PCBs mostly served as insulating liquids in electrical equipment; however, they were also utilized in many open applications. Despite the worldwide ban on PCB manufacture imposed at the end of the 20th century, the contamination of the environment persists to this day as a result of their recalcitrance. Moreover, PCBs are still being inadvertently produced during many industrial activities. Because of their stability, the breakdown of PCBs in nature is extremely slow. This dissertation thesis focuses on the study of PCB biodegradation by ligninolytic fungi. This group of microorganisms belongs to the most promising, especially in regard to the degradation of organic pollutants. The biodegradation mechanism of PCBs was studied in vitro, including the identification of degradation intermediates. Laccase, an enzyme expressed by the oyster mushroom (strain Pleurotus ostreatus 3004), was able to degrade hydroxylated PCBs. In addition, chlorinated...
3

Sledování kontaminace Bezdrevského potoka polychlorovanými bifenyly

LET, Marek January 2018 (has links)
The aim of this study was to investigate a potential impact of the old polychlorinated biphenyls (PCBs) dump on their occurrence in Bezdrevsky stream basin. Wastes, containing PCBs, were illegally stored in the area of ex-agrochemical factory in Lhenice village. Six localities were chosen for sampling by the method of integrative passive samplers SPMD, which provides more valuable information about contamination than commonly used grab samples. Passive samplers were exponated for 18 days in June 2017. The samples extraction was performed at the Laboratory of environmental chemistry and biochemistry (Faculty of fisheries and protection of waters), followed by clean up and preparation of these extracts for analysis with gas chromatograph coupled to tandem mass spectrometer (GC-MS/MS). Obtained data on PCBs amount in the samples were recalculated to their concentration in water. Concentration of seven indicator PCBs congeners (PCB 28 + 31, PCB 52, PCB 101, PCB 118, PCB 138, PCB 153 a PCB 180) was determined. These congeners are typical for technical PCBs mixtures which were produced in Czechoslovakia in the past. From their relative abundance, the potential source and an age of the contamination were estimated. Their total sum indicated significant exceedance of the limit only for the first locality, in the reservoir draining the dump area. There was found the concentration of 100 ng.l-1 of the 7 indicator PCBs sum. Concentrations at other localities complied with required limits and varied between hundredths to tenths of ng.l-1. In comparison with older data acquired from this area, the concentration at the first locality did not change, whereas PCBs concentration at the second and third locality downstream is currently lower than in past. Our data were compared to the latest data of PCBs concentrations in selected localities in CZ, which were received from Czech hydrometeorological intitute. From measured values can be stated, that the basin of Bezdrevsky stream and its fish pond system are not endangered by the presence of PCBs. Only two localities situated near the source of PCBs are comparable with localities in CZ which are influenced by the long term industry presence.
4

Stanovení obsahu organických sloučenin v pevném uhlíkatém zbytku / Determination of content of organic compounds in biochar

Novotná, Martina January 2020 (has links)
Biochar is created during the pyrolysis of organic biomass. Once added into the soil, it can improve its features. Biochars made from sewage sludge have various compositions. It is because of the vast difference between entrance materials. Organic pollutants can be absorbed into its surface during the cooling proces sof pyrolysis. If released into the enviroment, these compounds can cause inhibition of plant growth, get into food chains and adversely affect living organisms. Organic pollutans are determined most often by GC/MS after organic solvent extraction.
5

Biodegradace polychlorovaných bifenylů v podzemní vodě pomocí biologických přístupů / Biodegradation of polychlorinated biphenyls in underground water using biological approaches.

Šrédlová, Kamila January 2015 (has links)
Polychlorinated biphenyls (PCBs) are a class of important organic pollutants which undergo very slow degradation and tend to persist for a long time in the environment. PCBs have various negative effects on living organisms, human health and the environment in general. A method for determining PCB levels in aqueous matrices was developed consisting of solid-phase extraction (SPE) and GC/MS determination. The average recoveries of PCB congeners from artificially spiked deionized water were around 85%. The PCB concentration of 3.3±0.1 μg·l-1 (a sum of selected congeners) was detected in contaminated groundwater originated from the area of a former asphalt concrete producing plant. The most abundant PCBs were trichlorinated congeners which together comprised about 80% of the total PCB content. The optimised SPE method was further applied together with accelerated solvent extraction (ASE) to assess the degradation potential of oyster mushroom (Pleurotus ostreatus) which shows high degradation efficiency of various organic pollutants including PCBs. P. ostreatus belongs to ligninolytic (white-rot) fungi, which is a very promising group of microorganisms frequently studied due to their bioremediation potential. P. ostreatus, strain KRYOS was able to remove 41±8% of the initial amount (50 μg) of the...
6

Analýza organických látek přítomných v biouhlu / Analysis of organic substances present in biochar

Bača, Ondřej January 2021 (has links)
This master's thesis deals with the analysis of organic substances, which are present in biochar. Biochar contains a number of organic compounds, that can be toxic and also carcinogenic to living organisms. In order for biochar to be used to improve soil quality or to be used for other applications, its safety must be declared by European or international certifications. Relevant European and international standards have been created for the determination of organic substances, that could be present in biochar. The theoretical part of the thesis was focused on selected organic substances, the process of pyrolysis and thermochemolysis, biochar characterisation and the used analytical methods. The experimental part of the thesis consisted of extraction with toluene and after that the determination of concentration of the 38 polycyclic aromatic hydrocarbons was performed. Qualitative analysis was performed by two-dimensional gas chromatography. Biochar samples were also subjected to thermochemolysis method and then they were analysed on GC-MS again. In both analytical methods, a large number of substances from groups such as PAHs, carboxylic acids, amines, substituted naphthalenes etc. was found, as well as smaller number of eg. polychlorinated biphenyls.
7

Distribuce organochlorových pesticidů do životního prostředí / Distribution of organochlorine pesticides into the environment

Plačková, Lucie January 2011 (has links)
The master’s thesis was focused on the determination of persistent organic pollutants, namely polychlorinated biphenyls were detected (PCB 28, 52, 101, 118, 138, 153 and 180) and organochlorine pesticides. A total of 31 were evaluated contamination of organochlorine compounds. The level of contamination by organic pollutants were detected in 20 samples, 9 samples were sediments from the river Jevišovka, which is located in the South Moravia and 11 samples represented arable soil samples and were collected in the vicinity of this river. In the theoretical part are characterized both groups of substances, their fate in the environment and negative effects on living organisms. The experimental part focuses on the sampling procedures and processing for analysis by gas chromatography. There is described a complex analytical process involving the three extraction methods (accelerated solvent extraction, microwave extraction and ultrasonic extraction), extract purification and self-determination by gas chromatography with electron capture detector (GC / ECD). In the samples of sediment were detected these PCB congeners (138, 153 and 180) and organochlorine pesticides (b-HCH, HCB, p,p’-DDE, p,p’-DDD, p,p’-DDT and o,p’-DDT).. In soil samples were detected PCB congener 28 and organochlorine pesticides (HCB, b-HCH, heptachlor, aldrin, dieldrin, p,p’-DDE, p,p’-DDD, p,p’-DDT and o,p’-DDT).
8

Biodegradace polychlorovaných bifenylů pomocí ligninolytických hub a jejich enzymů / Biodegradation of polychlorinated biphenyls by white - rot fungi and their enzymes

Linhartová, Lucie January 2010 (has links)
Polychlorinated biphenyls (PCB) represent relevant persistent organopollutants of the environment and the estimated amount of PCB released into the environment is 750000 metric tons. White-rot fungi have been studied for long time due to their degradative potential toward various aromatic pollutants and it is known that these fungi are able to decompose PCB in vivo. Biodegradation of PCB by the fungus Pleurotus ostreatus was studied in the frame of this work. A high degradative efficiency of P. ostreatus was observed in the first set of experiments, even in the presence of relative high amount of added PCB. Fungus was able to transform 780±50 µg out of the intial amount 1000 µg in 20 ml of a cultivation media within 42 days. A decrease in toxicity was recorded during the degradation that suggests the suitability of this organism for a practical use in decontamination. In vitro experiments with purified laccase induced with Cu2+ from this fungus did not prove any participation of the enzyme in the first step of PCB transformation. The enzyme did not show an ability to degrade PCB even after purification from cultivation media containing PCB. It was found that the first step of PCB transformation can be performed by an intracellular process with microsomal fraction. A degradation of 44-67% was observed for...
9

Persistentní organické polutanty v životním prostředí Jihomoravského kraje / Persistent Organic Pollutants in the Environment of the Southern Moravia Region

Lána, Radim January 2008 (has links)
Byla provedena studie bioakumulace POP v potravním řetězci a historických trendů hladin POP v sedimentech Brněnské přehrady. Současné úrovně kontaminantů byly stanoveny v jelci tloušti z řeky Svratky a rovněž byla posouzena hygienická kvalita ryb z rekreačního rybolovu. Současné úrovně POP v terestrickém ekosystému byly posouzeny pomocí analýz jehličí jako přirozeného indikátoru znečištění. Studium jedinců tří druhů dravých ptáků z ČR bylo zaměřeno na zhodnocení kontaminace těchto vrcholných predátorů POP. S pomocí analýz vybraných druhů ryb ze Záhlinických rybníků byl rovněž studován proces bioakumulace. Posouzení parametrů dvou moderních extrakčních technik a jejich využitelnosti pro izolaci POP z různých matric bylo námětem poslední části dizertace.
10

Bioremediace persistentních aromatických polutantů / Bioremediation of persistent aromatic pollutants

Stella, Tatiana January 2014 (has links)
The remediation of persistent chlorinated aromatic compounds has become a priority of great relevance due to the teratogenic, carcinogenic and endocrine-disrupting properties of these xenobiotics. The use of biological methodologies for the clean-up of contaminated sites, collectively referred to as "bioremediation", has been gaining an increasing interest in recent years because it represents an effective, cost-competitive and environmentally friendly alternative to the physico-chemical and thermal treatments. In this respect, "white rot" fungi, an ecological subgroup of filamentous fungi, display features that make them excellent candidates to design an effective remediation technology ("mycoremediation"). In spite of this, fungi have not been widely exploited for their metabolic capabilities and the mechanism by which they are able to degrade the aforementioned pollutants has not been fully elucidated yet. Within this frame, the present Ph.D thesis was aimed at: i) assessing the efficiency of different mycoremediation strategies for the clean-up of a polychlorinated biphenyl (PCBs)-contaminated soil; ii) understanding the fungal degradation pathways of polychlorinated biphenyls and their major metabolites, namely chlorobenzoic acids (CBAs) and hydroxylated polychlorinated biphenyls (OH-PCBs). i)...

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