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The role of winter chemical maintenance of roads on ecosystems
Zývalová, Jana ; Mihaljevič, Martin (advisor) ; Galušková, Ivana (referee)
The annual use of de-icing salts leads to a continuous increase of Cl- and Na+ concentration in the surroundings of treated roads. It particularly affects soil and water environment and vegetation. The Na+ are accumulated in soils, they are bound into the cation exchange complex (CEC). It leads to the displacement of other cations (Ca2+ , Mg2+ , K+ , NH4 + , etc.), which are washing out from soils. The excessive amount of Na+ disturbs the soil structure and leads to a soil particles dispersion. Thus, the mobilisation of heavy metals (Cd, Zn, Pb, etc.) can occur. Increase of pH and electrical conductivity (EC) has an effect on the overall chemistry of the soil. Cl- are more mobile than Na+ in the soil column and they are flushed into water, where they altogether contribute to an increase of total dissolved solids and they cause acute and chronic contamination. The vitality of aquatic communities is influenced by the long-term exposure to the stress conditions. Finally, a shift from alkali to halophytic communities can occur. A slowdown, even stoppage of water layers mixing can be observed in water reservoirs. Biogeochemistry of water sediments is changed due to the anoxia of the benthic waters. Vegetation in the surroundings of treated roads shows visible symptoms of damage. The coniferous trees are...
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