National Repository of Grey Literature 132 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Effects of microplastics on earthworm gut microbiome, their immunity system and metabolome
Flohrová, Tereza ; Cajthaml, Tomáš (advisor) ; Lišková, Petra (referee)
Microplastics are widespread pollutants found in aquatic, atmospheric, and soil environments. They are released directly into the soil, for example, from mulch films and textiles. Microplastics accumulate in the soil and can have a negative impact on soil microfauna and macrofauna. Earthworms, acting as ecosystem engineers, and soil and gut bacteria play a significant role in biogeochemical cycles of biogenic elements. Disruption of earthworm function, their gut bacteria, or soil bacteria could have an impact on the entire ecosystem. In the context of this thesis, earthworms of the species Apporectodea sp. were exposed to microplastics from polypropylene black nonwoven textile at concentrations of 1 g/kg soil and 0.0265 g/kg soil for 14, 28, and 56 days. DNA was sequenced to identify bacteria from the earthworm gut, gut contents, and rearing soil. Additionally, untargeted analysis of metabolites from the earthworm body and extraction of immune cells from earthworms using three different methods were conducted. No significant changes caused by the presence of microplastics were found in the representation of bacteria from the gut, gut contents, and soil, but statistically significant changes in the metabolome were detected. A sufficient number of immune cells could not be isolated from the...
Microplastics in deep-sea fish
Fürychová, Barbora ; Cajthaml, Tomáš (advisor) ; Innemanová, Petra (referee)
Microplastics have become a significant problem in marine ecosystems, posing a serious threat to the biodiversity and stability of these environments. This bachelor's thesis focuses on investigating the presence of microplastics in the digestive tracts of deep-sea fish in the Indian Ocean. These fish represent interesting model organisms that can aid in understanding the distribution of microplastics in the marine water column. The introductory part of the paper summarizes the existing knowledge on microplastics, their occurrence, methods of analysis and the presence of microplastics in the aquatic environment. Particular attention is paid to deep- sea fishes, whose role in marine ecosystems is crucial. In the experimental part, detailed analyses of fish digestive tract samples were performed to detect and identify microplastics. The study confirmed the presence of microplastics in the digestive tracts of deep-sea fish, and various types of polymers were identified, including polystyrene, nylon, polyethylene terephthalate, polyvinyl chloride and polyester. This undergraduate thesis is the first study ever to demonstrate that microplastics are found in deep- sea fish in the western Indian Ocean. The conclusions of this thesis underscore the urgency of the situation regarding contamination of the...
Fate of micropollutants during vermicomposting
Grasserová, Alena ; Cajthaml, Tomáš (advisor) ; Macek, Tomáš (referee) ; Lhotský, Ondřej (referee)
Vermicomposting is recently becoming a rather popular environmentally friendly technique for stabilizing biowaste, including sewage sludge. There is an effort to utilize the sewage sludge as fertilizer on agricultural land. But apart from nutrients, the sludge also contains harmful pollutants, which subsequently after its deposition on fields can be taken up by plants and organisms contaminating the food chains. Micropollutants, the substances that can be found throughout the environment in trace concentrations, are one of the pollutants occurring in sludge. It is for example pharmaceuticals and personal care products, per- and polyfluoroalkyl substances, or pesticides. Their negative effects are known - they can be for instance endocrine disruption, antibiotic resistance, or the development of cancer. Although the deposition of sewage sludge on fields as a fertilizer is one of the main introduction routes of micropollutants to the environment, the content of micropollutants before deposition is not monitored nor regulated. This dissertation focuses on the fate of micropollutants during vermicomposting, especially in sewage sludge substrates. The vermicomposting method was applied to stabilize coffee spent grounds and sewage sludge obtained from distinct wastewater treatment plants mixed with...
Methods of sewage sludge treatment for agricultural applications with respect to micropollutants
Vítková, M. ; Komárek, M. ; Wickramasinghe, N. ; Pohořelý, Michael ; Moško, Jaroslav ; Hušek, Matěj ; Cajthaml, Tomáš ; Grasserová, Alena ; Čechmánková, J. ; Vácha, R. ; Zimová, M.
The aim of the methodology is to describe the possibilities of sewage sludge treatment by composting and pyrolysis for the application in agriculture, with particular respect to the so-called micropollutants, but also to conventional pollutants, and to assess the risks of treated sludge for the soil environment and the uptake of (micro)pollutants by cultivated crops. The methodology is based on the results from laboratory and field experiments of a three-year project and on a critical approach to sludge as a potentially hazardous waste on the one hand and a recyclable source of nutrients on the other.
Microplastics in solid matrices of the environment
Pospíchalová, Eliška ; Cajthaml, Tomáš (advisor) ; Innemanová, Petra (referee)
Microplastics, plastic particles of 5 mm-1 nm in size, are now widespread across different ecosystems. The increasing amount of microplastic contamination of aquatic and terrestrial environments requires the development of standardized methods for their separation and analysis. One of the main vectors of microplastic input to terrestrial ecosystems is through sewage sludge. The sludge is recycled for fertilization and reclamation due to its high organic matter content. Scientists have already been able to quantify and identify a range of microplastics in sewage sludge of different sizes, polymer types, shapes, etc. This thesis focuses on the optimization of existing methodologies to extract microplastics from solid environmental samples and their subsequent qualitative and quantitative analysis. The steps required for sample pre-treatment prior to analysis, namely reduction in organic matter content by the Fenton reaction process and density-based separation of microplastics by flotation in saturated NaI solution (1.8 g/cm3 ) using centrifugation, were optimized. Microplastics in size fractions of 20-40 μm and 150-300 μm were fabricated and introduced into flotation and total recovery experiments of the methodology to determine the recovery. Fluorescence microscopy was chosen for quantitative...
Low-energy recycling of poly(ethylen terephthalate) waste
Slabá, Jitka ; Beneš, Hynek (advisor) ; Cajthaml, Tomáš (referee)
This thesis deals with a new low-energy method of chemical recycling of poly(ethylene terephthalate) (PET) using natural oils as reagents and microwave irradiation to accelerate depolymerization. The results of experiments with PET waste and castor oil, when the reaction mixture was heated in microwave reactor, showed that a complete depolymerization of PET chain has occured. Optimal conditions for the depolymerization PET were established: wt. ratio of PET / castor oil = 1 / 9.7, when the molar ratio of ester bonds of PET / hydroxyl groups of castor oil = 1 / 2.7, catalyst : zinc acetate at wt 1% from the PET mass, reaction temperature ranging from 235 to 245řC and the reaction time 60 min. Decomposition experiments also showed, that microwave irradiation accelerated decomposition of PET. Depolymerization reactionin MW reactor was complete at 6x shorter reaction time than the decomposition in the classically heated reactor. The results of analysis showed that the resulting product,the recyclate, was composed of unreacted castor oil and polyol products, that contained partially or fully esterified structural unit of PET, which were ended by ester-linked units of castor oil.
Community vermicomposting within student dormitories
Lipan, Andrej ; Innemanová, Petra (advisor) ; Cajthaml, Tomáš (referee)
Through the Green Study Room pilot project, the thesis explores the integration of a circular bio-waste management model at the Otava College under the administration of Charles University. The thesis describes the circular economy as an essential method for the efficient management of bio-waste, which is supported in particular by legislation and strategic goals for sustainable development of states, cities and institutions. A questionnaire survey was conducted to assess the awareness and interest of students in establishing a community vermicomposting site. The reconstruction of the study room creates a space to prevent the generation of biodegradable waste on the dormitory premises. Vermicomposting was used as an eco-friendly approach that takes advantage of earthworm's natural ability to convert organic waste into nutrient-rich compost. The establishment of a community shared study room sets the stage for ongoing projects in the areas of centralized bio-waste management, student education, and social-psychological phenomena associated with the transition to a more sustainable society. It also creates an ideal space for seminars, workshops and activities of the university in the field of improving the living standards of students staying at Otava College. The incorporation of the community...
Analysis of organic pollutants and micropollutants in landfill leachates
Poslušná, Markéta ; Cajthaml, Tomáš (advisor) ; Innemanová, Petra (referee)
The stated aim of this thesis was the quantitative and qualitative analysis of relevant organic pollutants and micropollutants in Czech and Danish landfill leachate. Point sampling of liquid and solid samples (sediments) were taken from the landfill water sumps or from their vicinity. Sediments were collected only at Czech landfills. The Danish and Czech landfill leachate samples were compared with each other due to their different histories. Czech landfill leachate were found to contain higher concentrations of detected organic pollutants than in Denmark. The detected concentrations for the sum of 21 PFASs in the landfill leachate ranged from 956.5- 11 011.3 ng/l for the Czech landfill leachate samples. The measured concentrations of sum 14 PFAS ranged from 414.5 to 2 589.3 ng/l for the Danish landfill leachate samples. Concentrations in Czech landfill leachate for the sum of 24 PPCPs ranged from 131.3 to 27 471.4 ng/l. For the Danish samples, concentrations ranging from 122.6 to 12 351.5 ng/l (for the sum of 11 PPCPs) were measured. PCBs were analysed in both liquid and solid samples. In all liquid samples they were below the limit of quantification, therefore they were analysed in sediment from Czech landfills, where values from LOQ-20.9 mg/kg (sum of PCBs) were determined. This work represents...
Endocrine-disruptive effects of bisphenol A and other representatives of bisphenols
Kromková, Lucia ; Cajthaml, Tomáš (advisor) ; Vítků, Jana (referee)
Xenoestrogens are substances of anthropogenic origin that disrupt the human endocrine system. This work deals with bisphenol A, a substance found in plastics all around us, and its effect on the human reproductive system. As the toxicity of bisphenol A is gradually being proven, its production is regulated by legislation, and therefore bisphenol A is being replaced by other derivatives. This work focuses only on the 7 most widespread bisphenol derivatives - S, F, E, B, AP and AF. The endocrine-disrupting effect of bisphenols is discussed from carefully selected relevant studies with an emphasis on the last 5 years (2018-2023) and compiled into clear tables. It turns out that bisphenol AP has the least endocrine disruption per organism, while bisphenol AF and bisphenol S have the highest. In in vitro and in vivo studies, bisphenol A has different concentrations that influence disruptiveness, which indicates the interaction of bisphenol A with other factors in the organism. The greatest risk to humanity is the proven cocktail effect of bisphenol A and transgenerational transmission. Key words: endocrine disruptors, xenoestrogens, bisphenol A, in vitro, bisphenol derivatives, in vivo
Priority pharmaceutical micropollutants in the context of the Czech Republic and the Water Framework Directive draft
Stonawski, Eva ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee)
One of the major global environmental problems is the pollution by priority micropollutants. These are substances that can have a negative impact on the environment and human health even at relatively low concentrations. Their identification and subsequent regulation on an international level is essential for prevention of the negative effects of these substances. This thesis focused on the assessment of relevance of the proposal of Water Framework Directive in relation to pharmaceuticals and related substances in the context of the situation in the Czech Republic. The analysed input data comprised of results of data monitoring from the Vltava River Basin and information on the distribution of pharmaceuticals from the State Institute for Drug Control between years 2016 and 2022. The data was collected from two sampling points that are situated right before the confluence with the Elbe River. The average of the concentrations above the limit of quantification (LOQ) and without outliers was considered, thus creating a model considering the maximum contamination load. On the basis of this model and information about individual substances, the relevance of the draft WFD for the Czech Republic was assessed. The result of the monitoring showed that during the monitoring period, none of the NECs of the...

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