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• Elemental concentration in deposited dust on urban tree leaves depending applied washing method

  45-52

  Vanda Molnár

  Views:

  201

  In our study, the concentrations of elements were determined in leaves and deposited dust of Quercus robur and Celtis occidentalis which were washed with distilled water, rainwater and tap water. According to our results, each washing solutions had a significant effect on the elemental concentrations in the foliage dust. The highest concentrations of aluminum, chromium, copper, iron, manganese and zinc were detected in the foliage dust which was washed down with rainwater. The highest strontium and barium concentrations were found in the foliage dust which was washed down with tap water. We observed chromium and manganese accumulation in Q. robur leaves, while the concentrations of barium, copper and strontium were the highest in C. occidentalis leaves. Our results demonstrated the effect of rainwater on tree leaves which phenomenon occurs naturally. Rainwater may wash down the dry deposited foliage dust from the leaf surface, but it also delivers a certain concentration of elements through wet deposition.

• Spatial and temporal pattern of soil pH and Eh and their impact on solute iron content in a wetland (Transdanubia, Hungary)

  34-45

  Zoltán Szalai

  Views:

  42

  Land mosaics have direct and indirect influence on chemical reaction and redox condition of soils. The present paper deals with the relationship between some environmental factors (such as soil and vegetation patterns, micro-relief, water regime, temperature and incident solar radiation) and the pH, Eh of soils and solute iron in a headwater wetland in Transdanubia, Hungary. Measurements have been taken in four different patches and along their boundaries: sedge (Carex vulpina, Carex riparia, three patches and two species), horsetail (Equisetum arvense), common nettle (Urtica dioica). The spatial pattern of the studied parameters are influenced by the water regime, micro-topography, climatic conditions and by direct and indirect effects of vegetation. The indirect effect can be the shading, which has influence on soil temperature and on the incident solar radiation (PAR). Root respiration and excretion of organic acids appear as direct effects.. There have been measured individual pH and Eh characteristic in the studied patches. Soil Eh, pH and solute iron have shown seasonal dynamics. Higher redox potentials (increasingly oxidative conditions) and higher pH values were measured between late autumn and early spring. The increasing physiological activity of plants causes lower pH and Eh and it leads to higher spatial differences. Although temperature is an essential determining factor for Eh and pH, but our results suggest it rather has indirect effects through plants on wetlands.