Tap water quality analysis in Ulaanbaatar City

There have been several issues concerning the water quality in Ulaanbaatar, Mongolia in the past few years. In 2019, some apartment residents filed complaints regarding tap water quality, and others suffered from health issues. In this study, we collected 28 samples from 6 districts of Ulaanbaatar to check if the water supply quality met the standards of the World Health Organization, the Environmental Protection Agency, and a Mongolian National Standard, MNS 0900:2018. We hypothesized that the water in Zaisan, an area where the underground well is used as a water resource rather than the central water system, will have poorer quality, show higher hardness levels, and lower pH and total alkalinity than the other regions in Ulaanbaatar. We carried out a comprehensive analysis of metal concentrations (lead, iron, copper, mercury, aluminum, manganese, and zinc), mineral concentrations (nitrite, nitrate, sulfate, free chlorine, and total chlorine), pH, alkalinity, and hardness using a water test kit and pH meter. Only three of the samples fully met all the requirements of the global standards. However, 21 samples had a lower pH level than the recommended range of 6.5–8.5. Supporting our hypothesis, the samples in Zaisan showed higher hardness (>120 ppm) and alkalinity levels (20–200 ppm) over the other districts in the city. Overall, the results show that it is important to ensure a safe and accessible water supply in Ulaanbaatar to prevent future water quality issues.