Treatment for removing radium in soil and groundwater

The results of ²²⁶Ra activity concentration measurements in 50 soil and groundwater samples in Ninh Son region, Vietnam were evaluated in the present study. Average activity concentration in the soils was significantly higher than the worldwide average concentration in soils published by UNSCEAR, 2008. 90% of groundwater samples had concentrations of ²²⁶Ra that were higher than the USEPA drinking water standard. The results showed that there was a linear correlation between the ²²⁶Ra radioactivity in the soils and the concentration of ²²⁶Ra in the groundwater samples. The procedure for removal of ²²⁶Ra from soil and groundwater samples was built upon the chemistry behavior of radium. ²²⁶Ra in contaminated groundwater samples was removed by using MnO₂ fiber. The removal efficiency of ²²⁶Ra reached ∼ 91% for the groundwater samples and ∼ 70% for the soil samples. Chemical removal of ²²⁶Ra from soils was investigated using a three-step extraction procedure (Easily leachable and exchangeable, Acid-reducible, and Oxidisable-organic). A moderate mobility of ²²⁶Ra (22-52%) was noted and mainly found in acid-reducible fractions, which suggests that ²²⁶Ra is mainly bound to Fe/Mn oxides and hydroxides. A multiple regression indicates that the ²²⁶Ra removal efficiency appears to be significantly dependent on Fe/Mn and organic matter content.