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Detection of PET microplastics in soils
Kameníková, Eliška ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
The use of plastics leads to their gradual degradation and consequently to the formation of microplastics, i.e. the millimeter sized particles, which have been shown to cause environmental problems. Currently, the microplastics detection studies are focused on aquatic environments, but the investigation of microplastics in soils is still limited by the lack of appropriate analytical methods. The aim of this thesis was to verify the possibility to detect the PET microplastics in different soil types based on the results obtained by using thermogravimetry. Thermogravimetry data were evaluated in two ways, using a blank soil sample and using a recalibrated universal soil standard. The results showed that the thermo-oxidative properties of PET microplastics were not influenced by soil type, but vice versa, PET has affected the thermo-oxidative behavior of soils and soil processes. Furthermore, it was confirmed that recalibrated equations of the universal soil model can be used to analyze microplastics in soils.
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Influence of biodegradation of polyhydroxyalkanoates on soil properties and composition
Denková, Pavla ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
Biodegradable plastics are presented as a promising replacement for synthetic polymers. In soil, they are expected to be fully degraded by micro-organisms within a short time and to be inherently harmless to the environment. However, this assumption needs to be verified, and it is important to pay attention to the impact on soil´s biota as well as the effect of the biodegradation process could have on soil properties, composition and structure. In this work was studied the effect of biodegradation of poly(R-3-hydroxybutyrate), (P3HB), belonging to the group of polyhydroxyalkanoates, on the structure and physicochemical properties of soil. P3HB particles were mixed in different concentrations with soil in which biodegradation experiments were carried out under different conditions - i.e. with and without growing plant, with and without nitrogen fertilization. After 90 days, were soil analyzed. Thermogravimetry was used to determine the amount of residual non-degraded micro-bioplastics and to determine the effect of biodegradation on the properties of soil organic matter. Differential scanning calorimetry provided information on the effect of biodegradation on the evaporation enthalpy of adsorbed water from the soil, while the amount of water in the soil was also determined. Furthermore, the effect on field water holding capacity was determined and sieve analysis of individual samples was performed to characterize the effect of biodegradation on soil particle size distribution. Biodegradation conditions were shown to affect not only the rate of biodegradation but also some soil parameters. As expected, biodegradation of P3HB was proved to be faster in a nutrient-rich environment. In contrast, lack of nitrogen in soil with growing plant caused a decrease in the evaporation enthalpy of water and a reduction in the amount of water in soil, which can lead to easier soil drying and cause stress conditions for plant growth. Increased soil particle aggregation was observed in all sample series with P3HB compared to soils without P3HB addition.
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Influence of microbioplastics on aquatic plants
Mácová, Sabina ; Maršálková, Eliška (referee) ; Kučerík, Jiří (advisor)
Plastic pollution is becoming a serious environmental problem, for this reason, in recent years efforts have been made to propose alternatives to conventional plastics. Biodegradable plastics appeared to be a possible alternative due to similar properties to synthetic plastics and because they are considered safe and degradable in the environment. However, under real conditions, biodegradation is a relatively time-consuming process that can lead only to biofragmentation into small particles, co-called microbioplastics. So far, very little is known about their impact on the environment. This work deals with the ecotoxicological influence of biodegradable poly(3-hydroxybutyrate) (P3HB) microparticles in two size fractions (particles
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Influence of biodegradation of polyhydroxyalkanoates on soil properties and composition
Denková, Pavla ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
Biodegradable plastics are presented as a promising replacement for synthetic polymers. In soil, they are expected to be fully degraded by micro-organisms within a short time and to be inherently harmless to the environment. However, this assumption needs to be verified, and it is important to pay attention to the impact on soil´s biota as well as the effect of the biodegradation process could have on soil properties, composition and structure. In this work was studied the effect of biodegradation of poly(R-3-hydroxybutyrate), (P3HB), belonging to the group of polyhydroxyalkanoates, on the structure and physicochemical properties of soil. P3HB particles were mixed in different concentrations with soil in which biodegradation experiments were carried out under different conditions - i.e. with and without growing plant, with and without nitrogen fertilization. After 90 days, were soil analyzed. Thermogravimetry was used to determine the amount of residual non-degraded micro-bioplastics and to determine the effect of biodegradation on the properties of soil organic matter. Differential scanning calorimetry provided information on the effect of biodegradation on the evaporation enthalpy of adsorbed water from the soil, while the amount of water in the soil was also determined. Furthermore, the effect on field water holding capacity was determined and sieve analysis of individual samples was performed to characterize the effect of biodegradation on soil particle size distribution. Biodegradation conditions were shown to affect not only the rate of biodegradation but also some soil parameters. As expected, biodegradation of P3HB was proved to be faster in a nutrient-rich environment. In contrast, lack of nitrogen in soil with growing plant caused a decrease in the evaporation enthalpy of water and a reduction in the amount of water in soil, which can lead to easier soil drying and cause stress conditions for plant growth. Increased soil particle aggregation was observed in all sample series with P3HB compared to soils without P3HB addition.
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Detection of PET microplastics in soils
Kameníková, Eliška ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
The use of plastics leads to their gradual degradation and consequently to the formation of microplastics, i.e. the millimeter sized particles, which have been shown to cause environmental problems. Currently, the microplastics detection studies are focused on aquatic environments, but the investigation of microplastics in soils is still limited by the lack of appropriate analytical methods. The aim of this thesis was to verify the possibility to detect the PET microplastics in different soil types based on the results obtained by using thermogravimetry. Thermogravimetry data were evaluated in two ways, using a blank soil sample and using a recalibrated universal soil standard. The results showed that the thermo-oxidative properties of PET microplastics were not influenced by soil type, but vice versa, PET has affected the thermo-oxidative behavior of soils and soil processes. Furthermore, it was confirmed that recalibrated equations of the universal soil model can be used to analyze microplastics in soils.
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