Evaluation of concentrations of bivalent and univalent alkaline cations in water of the Nature Reserve Žitavský luh - Wetland

Abstract

We evaluated concentrations of bivalent and univalent alkaline cations in the water of the Nature Reserve (NR) Žitavský luh, wetland over the years 2003-2005. According to the results obtained, we can state that the amounts of alkaline cations in water of the wetland followed the ordering: Ca2+ > Mg2+ > Na+ > K+. The mean share of calcium on the total sum of alkaline cations for the whole monitored period was 52.03%, magnesium 21.02%, sodium 19.83% and potassium 7.13%. Over the whole monitoring period, the ratio of Ca2+/Mg 2+ was 2.48/1 and the ratio of Na+/K+ was 2.78/1. Over the whole monitoring period, there have not been discerned any trends in seasonal dynamics in concentrations of the alkaline cations or their dependence on the sampling site. We calculated characteristic values of concentration of calcium and also magnesium, and compared these with the limit values given by STN 75 7221 "Classification of the water surface quality". The result was classification of water in all the sampling sites as belonging to the 2nd class of water surface quality (clean water). As no sources of anthropogenic pollution with calcium and magnesium were present in the river basin of the Žitava River, we can conclude that their presence in the wetland water is of natural origin - resulting from the nature of the parent rock in the monitoring area, mostly consisting of calcium loess and from soil genealogy - controlled by presence of basic cations in the surrounding soils.