High levels of uranium in groundwater of Ulaanbaatar, Mongolia

► We analyzed water samples from wells across the city of Ulaanbaatar, Mongolia for total uranium along with arsenic, manganese, cobalt, zinc, selenium, cadmium and lead. ► We found that compared to other trace metals and metalloids, the levels of uranium were surprisingly elevated with the values for many samples exceeding the World Health Organization's guideline for drinking water. ► Local rocks and soils appear to be the natural source of the uranium. ► The health risk associated with drinking the groundwater with elevated levels of uranium in Ulaanbaatar should be a matter for some concern. ► The contamination of groundwater with uranium may be more prevalent in other parts of the world than is generally realized.