Hydrochemical study of water supply of Ulaanbaatar city

We conducted this study to determine the seasonal dynamics of chlorine organic compound and physico-chemical characteristics of two sources of drinking water in Ulaanbaatar city. There are seven sources of wells suppluying drinking water. The first is “Uildver” source whuch is placed in the highly occupied industrial zone showing pH 6.11-6.94 and the conductivity (EC) 41.5-60.2 mS/m. The general hardness was 3.8-5.9 mg-eqv/l, general mineralization is classified as SO42 - - Ca2+ and Mg2+ which grades up to 274.96-470.8 mg/l. The second industrial source called “Mah kombinat” shows pH 6.14-6.85 and the conductivity (EC) is 54.5-62.4 mS/m. The general hardness is 4.9-6.0 mg-eqv/l and the general mineralization is classified as SO42-, Ca2+ and Mg2+ which grades up to 420.4-520.7 mg/l. In addition, in cations the main component is the Ca2+ ion in drinking water of these two sources and SO42- and HCO3- ions are abundant anions. The obtained results meet the requirements of Drinking water standard MNS 0900:2016, any changes of composition depending on the season have not been revealed. Moreover, the analysis of microelements by using ICP-MS facility in drinking water on the way to water supply to the user’s pipeline showed presence of several elemental components and severe radioactive elements, but they don’t exceed the national standards.