Hydrochemical characteristics and anthropogenic components of the ionic effluent of the Samara river

The aim of this work was to provide a retrospective review of the main hydrochemical indicators of the water of the Samara River and to calculate the anthropogenic component of ion flow in the modern period, to provide a comparative assessment of the relevant indicators for the entire period of scientific observations. From the average-long-term data of the hydrochemical composition of the water of the Samara River, it can be seen that the ionic composition of the water of the Samara River had chloride and chloride-sulfate classes, calcium, calcium-magnesium and sodium groups. There is a trend towards increasing water mineralization in the Samara River. So, in 1929, the total mineralization of river water ranged from 965 to 1738 mg/dm3. During the period from 1929 to 2006, total mineralization increased by an average of 1,800 mg/dm3. The hardness increased by 12 mg-eq/dm3. The content of chlorine ions increased by an average of 300 mg/dm3. The fact of the growth of these indicators can be connected, first of all, with the inflow of mine waters from the mines of Central and Western Donbass. In the modern period, the saline composition of the water of the Samara River was characterized by an increased content of salts. The dry balance as of January 2022 was equal to 4228 mg/dm3. Such indicators can be considered record for the entire time of observations. There are several possible reasons for this phenomenon. One of them can be a change in the ratio of natural runoff and discharges of mine drainage water, with an increased share of the latter. Another factor may be the global aridization of the climate and, as a result, the reduction of the water content of the region and the reduction of the share of natural river flow. The anthropogenic component of the total removal of salts during the period from 1929 to the present has increased by 1 million 100 thousand tons, while the total amount of water-soluble salts does not grow uniformly. A sharp increase is noticeable since 1978, which coincides with the period of active commissioning of the mines of Western Donbass. Since then, the growth of the anthropogenic component has relatively stabilized. Relatively constant values of anthropogenic content – 53.5–64.4% are noted for calcium ions. Moreover, the anthropogenic component of magnesium ions at the time of our research (February 2022) was in negative dynamics. The largest percentage of the growth of the anthropogenic component of the Samara River ion flow is associated with sulfate and sodium ions. In general, anthropogenic influence on the formation of the salt composition of the Samara River water has been noted since the very beginning of observations – in the mid-thirties of the last century.