Changing of Cations Concentrations in Waters of Polluted Urban River

Water from urban river Okhta polluted with domestic and industrial wastewaters was investigated. Specific electric conductivity (k), molar concentrations of ions Na+, K+, Mg++ and Ca++, concentration of total nitrogen (TN) were measured in water samples. Increasing of k happened together with increasing of molar fraction of sodium-ion (RNa) among all studied cations (and correspondingly decreasing of molar fractions of other cations). Good correlations were found between RNa and TN (r = 0.67), k and TN (r = 0.84). The results support the idea of the leading role of wastewaters in changing of k and cations concentrations. Electric conductivity and RNa could be used to distinguish between polluted and not polluted waters in the Okhta