Group 1 water and slightly mineralized Acid source (0.6—0.9 g/l), bicarbonate-sulfate-chloride, bicarbonate-chloride, magnesium-sodium-calcium and magnesium—calcium; contains trace elements (mg/l): bromine (0.42—0.99), boron (0.05-0.40), fluorine (0.01—1.00), iodine (0.004—0.025); oxygen and hydrogen sulfide by gas composition;