Determination of uranium and thorium: a comparison study of radio-analytical techniques for soil monitoring purposes in Singapore
摘要
This paper provides a comparison of 3 techniques that are potentially useful for routine analysis of soil samples from selected monitoring sites in Singapore. The soil samples were measured for naturally occurring actinides (mainly 232Th and 238U). This study also highlights the adopted workflow for gamma measurements ensured equilibrium has been established from 226Ra to 214Pb suggesting that the 222Rn has been wellcontained during the sample packing for gamma measurements. Among the three techniques evaluated in this paper, laser ablation ICP-MS demonstrated significant benefits in sample turnover (< 5 min per analysis) while providing information of the Uranium (isotopic information of 235U and 238U) and Thorium levels (232Th). On the other hand, the complete dissolution of soil samples and analyzed by the ICPMS/MS provides both precision and accuracy which correlates to values obtained by Gamma measurements. This study provides a general overview of both time requirement, sample size and precision of the data obtained which are important factors for consideration in a monitoring program.