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Radon in a lake – an estimation of ground water input.
Porcal, Petr
A balance study of radon activity in Lake Plešný and its tributaries was carried out in 2020 to refine the estimate of groundwater resources. The balance is based on quantification of sources, monitoring of the amount of water draining from the lake, and lead concentrations in the overlying sediments.
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Content of iron and quality of organic matter as a factor affecting stabilization of carbon and nutrients in fresh water ecosystems.
Osafo, Nana O. A. ; Jan, Jiří ; Porcal, Petr ; Borovec, Jakub
The effect of watershed geochemistry, in terms of soil pH, Fe concentration and organic matter quality, on the stability of organic carbon and nutrients level in freshwater sediments of shallow lakes was studied. Twelve fishponds were divided into two groups based on the typical soil pH: i) watershed with acidic soils (pH 5.1 – 6.3) rich in Fe called H_Fe and ii) watershed with neutral pH soils (pH 6.8 – 7.6) poor in Fe called L_Fe. The parameters of the water column, pore water and sediment chemical extractions were compared. A higher concentration of hydrated Fe oxides, together with the aromatic character of organic substances were shown to highly contribute to the overall stabilization of the sediment. Conversely, low Fe concentrations were accompanied by lower mineralization of sediments and a higher risk for the aquatic ecosystem in terms of nutrient release or the development of anoxic conditions.
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Freshwater macroinvertebrates and their use for assessment of environmental changes in running waters
Kolaříková, Kateřina ; Stuchlík, Evžen (advisor) ; Matěna, Josef (referee) ; Porcal, Petr (referee)
The dissertation thesis consists of five articles, bringing together results from investigations of macroinvertebrates in running waters. The use of freshwater macroinvertebrate organisms to assess environmental changes was based on the following facts: a) the presence/absence of taxa provide information about abiotic factors and/or about the pollution status of the site, b) they are indigenous and sedentary species, so that the environmental implications can be related to the site they live on, c) the organisms accumulate xenobiotic elements or compounds, thus reflecting the contaminant level in the environment. Localization of the sampling sites was related to the "hot-spots" of environmental problems. The particular investigations were carried out in the Elbe River catchment and in the Czech mountains on the selected headwater streams of the GEOMON network of the Czech Geological Survey. The Elbe was considered one of the most polluted rivers across Europe in the second half of the past century until the socio-economic transformation after 1989. The headwater streams in the Czech Republic were chosen with respect to the problem of acidification. The ability of bioaccumulation of xenobiotics in macroinvertebrate organisms was used to assess the long-term load of the Elbe ecosystem with trace...
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