Portable X-ray Fluorescence (pXRF) as a Tool for Environmental Characterisation and Management of Mining Wastes: Benefits and Limits

Abstract

Portable X-ray fluorescence (pXRF) is one of the main geochemical techniques employed in multi-elemental analysis screening for contaminated sites management. As the confidence of pXRF analyses are matrix-specific, efforts are made to provide studies of pXRF quality on different geochemical datasets, focusing on less investigated elements such as mercury (Hg) and antimony (Sb), to help both new and experienced users. The analysis of environmental solid samples from two decommissioned mining sites in NE Italy, characterised by Pb-Zn and (Hg-rich) Cu-Sb ore deposits, were prepared with two different protocols and compared with traditional destructive analyses. Sample composition was found strictly dependent to the occurrence of false positives and overestimation at low concentrations. In contrast, milling the sample did not produce major variations in the overall quality. Lead (Pb), Sb, and Zn reached the definitive data quality in at least one of the two datasets. Consequently, as far as a thorough QA/QC protocol is followed, pXRF can rapidly produce chemical data that is as accurate as that produced by destructive standard laboratory techniques, thus allowing to identify potential sources of contamination that could be reprocessed for the extraction of valuable elements and mitigating the dispersion of contaminants and ecological or health risks.

Using portable X‐ray fluorescence elemental analysis to explore porous skeletal lesions: Interplay of sex, age at death, and cause of death

“…Nevertheless, despite its utility, pXRF is not without limitations. Barago et al (2022) have noted that pXRF may have higher limits of detection (LOD) compared with other techniques, and the absence or occurrence of very low concentrations could be misinterpreted as higher background levels. This concern is particularly relevant for elements lighter than Mg (Byrnes & Bush, 2016).…”

“…This concern is particularly relevant for elements lighter than Mg (Byrnes & Bush, 2016). Elements such as Mn, Zn, and Pb are reliably detected by pXRF, with minimal analytical issues related to concentration effects (Barago et al, 2022). The LOD provided for the Thermo Scientific Niton XL3t900 (Table S4) support this observation.…”

2023 atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…The benefits and limits of portable XRF spectrometry for the characterisation and management of mining wastes was demonstrated by Barago et al 71 who studied samples from two decommissioned mining sites and classified the results obtained according to the data quality criteria established by the US-EPA. Air-dried samples were prepared either by sieving to <2 mm or by milling to a fine powder.…”

On the Possibility of Universal Chemometric Calibration in X-ray Fluorescence Spectrometry: Case Study with Ore and Steel Samples

“…In spite of the fact that accuracy and selectivity of EDXRF are not that high compared to WDXRF, EDXRF is a more popular variety as it provides for simple, inexpensive, and fast measurements and can be miniaturized for in-field applications. Due to these features, EDXRF has found numerous applications in various fields of applied science: geochemistry [1], material science [2], pharmacology [3], archeology [4], environmental studies [5], etc. [6].…”