Moisture, organic matter, and large particle correction for accurate Pb portable X‐ray fluorescence assessment in urban soils

Abstract

The need for accurate quantification of lead concentrations in urban centers around the world is turning attention towards rapid methods for contamination assessment. Portable X‐ray Fluorescence (pXRF) has been recognized as a more accessible alternative to traditional digestion methods. This study was conducted to produce measurement corrections for in‐situ pXRF measurements conducted on field soils under varying conditions of moisture, organic matter (OM) content, and particle size heterogeneity. Urban forest soils were analyzed for Pb under increasing soil moisture, OM, and coarse fraction contents with two different pXRF and the results were compared to reverse aqua regia digestions. While both instruments showed a strong correlation despite using different calibration methods, correction of pXRF data to digestion values improved accuracy but potentially underestimated Pb concentrations. We propose an empirical correction equation derived from the regression of variance between theoretical and observed concentrations to correct for moisture effects. OM and particle size heterogeneity did not produce a significant effect on Pb measurement and did not warrant correction. Our study confirms other work showing that pXRF provides an accurate and precise alternative to traditional digestion methods for Pb screening, provided that moisture is corrected.

Quantitative Determination Of Cd Using Energy Dispersion XRF Based On Gaussian Mixture Clustering-Multilevel Model Recalibration

“…When the considered being analyzed show high concentrations during XRF detection, there are low detection errors occur because of the substantial spectral peak intensity and the relatively minor impact of soil matrix effects. 20 However, for elements with low concentrations, the influences of both soil matrix phenomena and soil background values become significant, leading to issues such as low concentration-high detection error and high concentrationlow detection error phenomena. Moreover, under similar error conditions, there is a certain degree of similarity among soil environments.…”

The Application of Portable X-ray Fluorescence (pXRF) for Elemental Analysis of Sediment Samples in the Laboratory and Its Influencing Factors

“…pXRF has been used in mineral resource exploration [13,14] and environmental evaluation [15,16], and many other fields. It can analyze sample types including rock [17,18], soil [19][20][21], plants [22,23], bone [24], alloys [25], artworks [26,27], etc. Stream sediment is the most commonly used sample medium in mineral resource exploration.…”