Investigating the effect of Pb on As determination in soil materials using x‐ray fluorescence spectrometry at high levels of Pb contamination

Abstract X‐ray fluorescence spectrometry (XRF) is a method of quantifying elements in soil and other media widely used by researchers in many fields. Inaccuracy in XRF can result from spectral interference between Pb and As, two of the most toxic and highly prevalent soil contaminants. In this study, one of two XRF analyzers detected As in Pb‐spiked clays (100–2000 mg kg −1 Pb) which contained no As. The level overestimation of As ranged from 19.3 to 136 mg kg −1 (and increased in magnitude as Pb concentration increased). False As readings generally did not appear for the other XRF analyzer, suggesting instrument dependence. The potential for inaccuracies in quantification of As by XRF in soils with high levels of Pb contamination should be considered by operators. Confirmation of measured As in soils with high Pb contamination with inductively coupled plasma–optical emission spectrometry is prudent.