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The risk element contents in soil and vegetation cover at selected locations within Hradec Králové city
Bartošová, Tereza ; Száková, Jiřina (advisor) ; Hejtmánková, Alena (referee)
The county town named Hradec Králové is located in eastern Bohemia on the confluence of Elbe and Orlice rivers. It is situated in a flat area, with many green areas and the absence of heavy industry. The industrial activity is concentrated in small business - engineering, chemical, electrical and food processing industries. All these aspects of human activity may be associated with risk elements contamination of the environment. The town is characterised by the high traffic density; we can therefore also assume the presence of risk elements in the air and subsequently soil contamination in the proximity of these roads. The aim of the study was to analyze the level of contamination of soil and vegetation in the city caused by risk elements (As, Be, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn). According to sampling scheme, which involved 86 sampling points, there were taken samples of soils and aboveground parts selected plant species: dandelion (Taraxacum sect. Ruderalia) and doorweed (Polygonum aviculare) occurring at all the sampling points. These samples were analysed for the risk elements contents.
In most of cases the risk element levels did not exceed the maximum allowable limits for the content of elements in soil and plants given by Decree no. 13/1994 Coll. and Directive no. 2002/32/EC. In the case of soil, there were significantly higher values of potentially mobilizable contents measured for arsenic. But this was not reflected on the contents of this element in the vegetation when all results were below the detection limit of the analytical method. Rarely, the values exceeding the limits were observed in several soil samples in the case of lead and cadmium. While for lead no increased concentrations of this element in the vegetation was observed, the cadmium levels occurring in dandelion exceeded in several cases the limits for fodder crops. The ability of doorweed to accumulate the risk elements was lower compared to dandelion.
Linear regression analysis showed that there is no significant relationship between the element contents in the soil and vegetation and the distance from the road. It therefore appears that the contents of elements in the soil and vegetation are not affected by traffic. Due to the significant positive correlation of most elements (except Cd and Zn) in the soil can be estimated that the levels in the soil are given rather by the character of the subsoil. This speculation but would require more detailed geological and geochemical survey of the site.
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The contents of selected persistent organic pollutants in soils at selected locations within Hradec Králové city
Bartošová, Barbora ; Száková, Jiřina (advisor) ; Radim, Radim (referee)
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants entering the environment from both natural and anthropogenic sources. The main anthropogenic sources are processes for the production of electricity and thermal energy, waste incineration, road traffic and motor vehicles, aircraft, boats, steam and diesel-electric locomotives and some industrial technologies. Besides these main sources there are still a number of others, less important, e.g. working with hot tar, asphalt pavement wear and tire during vehicle operation, coking plants, plants for processing of oil and some metals plants. An indispensable source in the cities as domestic solid fuel burning furnaces.
Although Hradec Králové do not belong to the cities with extreme levels of contaminants in the air, according to the Czech Hydrometeorological Institute, the levels of benzo(a)pyrene in the case of annual average concentrations exceeding the maximum allowable concentrations occurred here in 2013. While air quality is monitored regularly, the PAHs contents in soils and vegetation are not so. In our simple single experiment, we decided to assess the level of contamination of soil PAHs in the land of Hradec Kralove. It was collected 86 soil samples, in which were determined contents of 16 PAHs. Further, mushroom fruit samples that were found in the individual sampling points were analyzed.
The results showed large variability of PAHs content in the city, but did not indicate significant levels of contamination. The sum of all the determined PAU does not exceed the permissible value of the contents of these elements in soils. However, in several cases exceeding the maximum allowable content in soils with different PAHs, especially fluoranthene, anthracene and chrysene. Linear correlation analysis showed that the levels of all monitored PAHs are close correlations, which indicates that the entire spectre of PAHs in this case always originates from the same source. The PAH contents in mushrooms were in most cases below the detection limit of the determination, only rarely the detectable contents of individual PAHs were found (Cylocybe gambosa, Agaricus arvensis). We can speculate about the limited ability of fungi to accumulate PAHs or their ability to degrade these substances.
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