Salt Lakes of Crimea 2. Modern Hydrochemical Features of the Lakes of the Perekop Group

The article presents data on the chemical composition of the waters of seven salt lakes of the Crimean Peninsula, belonging to the Perekop group: Staroe, Krasnoe, Kiyatskoe, Kirleutskoe, Aigul’skoe, Krugloe, and Yangul. A brief description of the physical–geographical and geological–hydrogeological features of the study area is presented. The method of thermodynamic modeling was used to calculate water saturation indices for calcium and magnesium carbonates, gypsum, and halite. To assess the time dynamics, a similar calculation was also performed for 1916, the year for which the most complete data are available in the literature. The studies showed a noticeable change in the hydrochemical characteristics of the brines of the Perekop lakes, expressed in a change in the hydrochemical type of brines. The main reason for this is the intense technogenic impact on the lakes from industrial enterprises (JSC Brom, JSC Crimean Soda Plant, AF JSC Titanium Investments). Calculation of brine saturation indices showed that the greatest oversaturation is observed for magnesium-containing carbonates. For all lakes, the saturation indices for calcium carbonates (calcite and aragonite) are positive or close to zero. Saturation or oversaturation for gypsum is observed for all lakes, with the exception of the southern part of Lake Krasnoe, and closeness to saturation for halite is observed only for lakes Staroe, Krasnoe, Krugloe, and Yangul.