Гидрохимические особенности озёр Большое и Малое Турали по результатам исследований в 2018 и 2021 годах

Abstract

In the summer months of 2018 and 2021, concentrations of major ions, dry residue, pH and temperature were determined in the water of the Maloe and Bolshoe Turali lakes; in various horizons (up to 20 cm) of bottom sediments, in addition to concentrations of methane and total hydrogen sulfide, Eh and pH values, humidity and density were determined. The mineralization of the waters of the Bolshoe and Maloe Turali lakes in 2018 was 275.8 and 19.1 g/dm3, respectively. According to the chemical composition, the class of waters in lakes is chloride, the sodium group, the second type. In 2021, the mineralization of lakes decreased, especially strongly in the lake Bolshoe Turali. It is shown that the significant salinization of its waters is not associated with precipitation, but is caused by artificial flooding of the feeding channel with water. Lake sediments are characterized by a neutral or slightly alkaline environment (pH from 7.01 to 7.88) and strong variability of redox conditions (Eh from -213.8 to 177.1 mV). The concentrations of CH4 in the sediments of the Maloe and Bolshoe Turali lakes varied in the range of 0.006–0.070 μg/g of wet sediment and 0.011–0.12 μg/g, respectively. The concentrations of ΣH2S varied from <0.005 to 0.241 mg/g in the lake of Maloe Turali and from <0.005 to 1.47 mg/g in the lake of Bolshoe Turali. The relationship between CH4 and ΣH2S is weakly manifested, which is due to their insignificant concentrations associated with Eh not low enough for intensive anaerobic processes in most sediment horizons.