Assessment of water quality and hydrogeochemical processes of Salda alkaline lake (Burdur, Turkey).

Abstract

Salda Lake is one of the rare alkaline lakes in the world. In this study, the major and trace element contents of the Salda Lake water were analysed in two periods. Lake water samples were taken at the surface, at 10 m and 20 m depths. The pH and EC values of the lake water varied from 9.08 to 9.34 and from 1690 to 2124 μS/cm, respectively. The dominant water type of the lake water was Mg-CO3-HCO3. The high Mg content in the lake water originated from the weathering of ultramafic rocks which were located in the lake basin. All of the Ca, Cl and SO4 contents were high in surface samples in the dry period. The CO3 and HCO3 contents of the lake water did not show a change with depth and were constant in the wet period. The Mg, Na and K contents of the lake water increased depending on the depth in both periods, while CO3 and HCO3 contents showed depth-dependent increases only in the dry period. Weathering processes and anthropogenic inputs are the largest dissolution mechanisms that control the chemical structure of the lake water. The Salda Lake water is generally classified as class I in terms of T, DO, oxygen saturation, NH4 and NO2 parameters according to the SWQR and USEPA regulations. But, the water is in classes II, III, IV and V with respect to pH, EC, NO3, biochemical oxygen demand (BOD), oxygen saturation, As and Cr in the different periods. The increase in the As and Cr concentrations is geogenic in origin and is related to the lithological units that interact with the bottom and surroundings of the lake.