Rapid sequential determination of ²²²Rn and ²²⁶Ra in drinking water by liquid scintillation counting

Since daily drinking water is one of the major source for the ingestion of radiotoxic ²²²Rn and ²²⁶Ra, the demand for a simple method to determine these two radionuclides has significantly increased. In the present study, a rapid, simple sequential analysis method for determining ²²²Rn and ²²⁶Ra in drinking water using a liquid scintillation counter was developed. The method employs solvent extraction and correction equations for the effect of native ²²²Rn for ²²⁶Ra analysis. Validation and examination of applicability for drinking water analysis were conducted using ²²²Rn-injected water and ²²⁶Ra standard source. Minimum required counting times for examining drinking water on Quantulus 1220 and Hidex 300SL were estimated via minimum detectable activity depending on the counting time. In addition, the correction method, including an equation for reducing analysis time by more than 10 days, was suggested based on the analytical results for different elapsed times between sampling and measurement.