Treatment for removing radium in soil and groundwater

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