Hydrochemical Regime and Quality of Subsoil Water in Built-Up Territories in the Southern Rostov Oblast

Seasonal dynamics of the mineralization, ionic composition, and the concentrations of specific pollutants in subsoil water are studied in populated localities in the southern Rostov oblast. Four major water types are identified: hydrocarbonate–sulfate (sulfate–hydrocarbonate), sulfate, chloride–sulfate (sulfate–chloride), and mixed type of subsoil water. The quality of subsoil water was found to fail to meet the sanitarytoxicological standards in terms of many characteristics. The values of MAC are exceeded for calcium, magnesium, sodium, chloride and sulfate ions, oil products, cadmium, total iron, silicon, and nitrate and ammonium nitrogen. Relationships were found to exist between the concentrations in water of cadmium, potassium, and phosphorus ions; oil products; pH values; water mineralization and total hardness; and seasonal variations of subsoil water levels. The identified relationships were substantiated.