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Obsah základních forem přístupného dusíku v lesních půdách
Vicher, Matouš
Flows of nitrate ions NO3- and amonnium ions NH4+ in biologically active layers of soil were measured, using ionexes, at forest stands in northern -- eastern regions of Czech republic, between May and September, 2010. Seasonal amounts, expressed in mg.(m2)-1, were analysed, focused on its relations with tree species compositon, impact of tree rhisosphere (location of ionexes close to the tree stems, or in a few meters distance), and forest altitudinal vegetation zones. NO3- showed significantly higher values, as compared to NH4+, and its values were more influenced by tree species composition. Norway spruce (Picea Abies [L.] Karst.), European birch (Betula pendula Roth.) and European beech (Fagus sylvatica L.) were recognised as a tree species with significantly low seasonal amounts of nitrogen ions NO3-. Sycamore maple (Acer pseudoplatanus L.) was recognised as a tree species with the significantly wide range of NH4+seasonal amounts values. Impacts of forest altitudinal vegetation zones, and tree rhisosphere, were recognised as insignificant, respectively inconclusive
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Indirect speciation of mercury in soils and sediments with cold vapor atomic absorption spectrometry.
ŠPAČKOVÁ, Jitka
In the diploma thesis have been tested four extraction techniques for isolation of organic forms of mercury from sediments (liquid liquid extraction, microwave extraction in liquid liquid extraction, solid phase extraction and extraction with use of ionic exchange) followed by determination of mercury by atomic absorption spectrometer AMA?254. It has been achieved great results during liquid liquid extraction likewise ionic exchange extraction. Reached percents of orgHg were in accord with certified reference material for sediments CRM-580 and corresponded to 86,44 ? 16,63 %, resp. 87,01 ? 29,22 %. Thanks to a simple procedure, extraction speed and ease of determination of organic forms of mercury contain was first of all (in the first instance) verified a method with use of ionic exchange, whose principle and procedure is very elementary. This technique was applied to a number of real sediment samples collected from water tanks Jordan and Skalka. It was approved that this method has been presenting a suitable alternative to chromatographic methods or methods of electro?migration.
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