Thorium and uranium rapid quantification in soil with portable X‐ray fluorescence

Abstract

This study aims to evaluate the thorium (Th) and uranium (U) quantification in soil employing a commercial routine in a portable X‐ray fluorescence (pXRF) spectrometer. Certified reference materials (CRMs), as well as a soil sample set, were measured by pXRF and gamma‐ray spectrometry. The pXRF results showed that the thorium average detection and quantification limits (in mg kg−1) were 3.3 ± 0.5 and 11.0 ± 1.7, respectively. The uranium values were 3.0 ± 0.4 and 9.9 ± 1.3. Quantitative pXRF results for Th were in accordance with the reference reported for most CRMs analyzed, and the same accordance was obtained in the comparison with gamma‐ray spectrometry results for the soil sample set. However, U results were overestimated by pXRF when compared both with the CRM‐reported values and the gamma‐ray spectrometry results. In conclusion, the tested pXRF commercial routine may be a viable technique to identify variations in natural Th levels in soil but needs to be used with caution to identify and quantify U.