Determination of uranium concentrations and isotopic ratios in drinking water in Xilingol League of Inner Mongolia by ICP-MS

Objective: To ascertain the uranium concentrations and uranium isotopic ratios in drinking water in Xilingol League, the Inner Mongolia Autonomous Region. Methods: Drinking water samples were collected in Xilingol League, the Inner Mongolia Autonomous. Region inductively coupled plasma mass spectrometry (ICP-MS) was applied to determine the concentration of uranium and uranium isotope abundance. Results: The uranium concentrations in all samples were in the range of 2.73-18.9 μg/L, with an average of 8.20 μg/L. The ²³⁴U/²³⁸U isotope ratio varied from 7.513 × 10^-5 to 3.003 × 10^-4 and ²³⁵U/²³⁸U from 7.196 × 10^-3 to 7.391 × 10^-3. The relative standard deviation (RSD) was less than 0.5% for ²³⁴U/²³⁸U and 0.2% for ²³⁵U/²³⁸U. Conclusions: The uranium concentration in samples collected from Dongwuqi was high than 15 μg/L, whih is the limit given by World Health Organization (WHO). The uranium in drinking water originates from the natural environment. The ²³⁴U is enriched in drinking water. (authors)