Salinization of River Waters and Suitability of Electric Conductivity Value for Saving Freshwater from Salts in Aral Sea Basin

Abstract

The dynamics of water salinization (WS) and its relationship with electric conductivity (EC, μS/cm), the suitability of EC for saving freshwater from salts as well as ionic composition in the main rivers of the Aral Sea Basin (ASB), Amudarya, Syrdarya and Chirchiq were analyzed. Preliminary results reveal that there are strong linear relationships between salinity and EC with r² values 0.84-0.99. Thus EC value can be recommended as suitable criterion for assessing freshwater pollution with salts. The water quality standard of 1000 mg/L in ASB corresponds to an EC value of 1330-1930 μS/cm depending on the ionic proportions in the specific river basin. Currently, in waterbodies of middle and lower reaches of Amudarya and Syrdarya Rivers, sulphates are the leading anions followed by chlorides in the Amudarya and bicarbonates in the Syrdarya River. The most abundant cations are sodium in case of Amudarya and calcium in case of Syrdarya.