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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...

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...

The aim of this bachelor thesis is to summarize available approaches for quantification of occult deposition of sulphur and nitrogen from fog and rime. Atmospheric deposition is a complex of processes by which pollutants are transferred from the air to the earth's surface and therefore it contributes to the atmosphere's self-cleaning. At the same time it represents an input of these pollutants to other components of the environment. Atmospheric deposition consists of dry deposition, which occurs in the absence of precipitation, and wet deposition, which occurs during precipitation. Wet deposition further consists of a vertical component (rain, snow, hail) and an occult component (fog, rime, hoarfrost). The common approach to quantifying total deposition nowadays is simply combining dry plus vertical wet deposition. But when applying this approach and neglecting occult deposition we are likely to substantially underestimate the true total deposition (e.g. Hůnová et al., 2011). This means we don't know the actual amount of pollutants transferred to the environment. The importance of occult deposition rises with increasing altitude (Lange et al., 2003). Occult precipitation also often contains higher concentrations of ions and stays longer in contact with the vegetation than vertical precipitation. There are...