Use of portable XRF: Effect of thickness and antecedent moisture of soils on measured concentration of trace elements

Padilla, Joshua; Hormes, J.; Selim, H. M.

doi:10.1016/j.geoderma.2018.09.022

Cited by 37 publications

(28 citation statements)

References 11 publications

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“…Padilla et al . (2019) showed that the Compton pXRF calibration cannot account for moisture despite reports suggesting it can, whereas the best results were achieved from dried samples with 10 cm thickness. In‐situ analysis in cold environments may require additional consideration; Weindorf et al .…”

Section: Preparation Methods For Pxrf Soil Analysismentioning

confidence: 99%

pXRF method development for elemental analysis of archaeological soil

2020

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Portable X‐ray fluorescence (pXRF) is now widely used for detecting the elemental composition of a material. Elemental analysis can enhance archaeological interpretations, such as mapping, preservation analysis and identifying anthropogenic activities. However, validated and reproducible protocols for analysing archaeological soil are still required. The elemental concentrations detected with three sets of preparation methods were compared: in‐situ (no preparation), in‐field (analysing through plastic bags) and ex‐situ analysis (laboratory‐based preparation). Influential factors were also investigated: calibration parameter, moisture, homogeneity, sieve size and soil type. In‐field analysis attempted to improve reliability without offsite processing, but instead substantially reduced elemental concentrations and skewed the proportional distributions. Ex‐situ analysis significantly increased elemental concentrations and reduced variation. Proportional distribution was different between the three methods, but unchanged following homogenizing and sieving. These comparisons demonstrated that ex‐situ analysis maximizes detection and ensures consistent samples.

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Section: Preparation Methods For Pxrf Soil Analysismentioning

confidence: 99%

pXRF method development for elemental analysis of archaeological soil

2020

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“…The resulting dilution effect is counterbalanced by a reduced matrix absorption. Measurements performed at variable stages of sample drying (Figure 15) show that it is possible to estimate Pb, Zn, and Cu dry concentrations from measurements on samples with water contents of between 25% and 50% (Figure 16) by correcting linear biases [10,17,43,46]. This not really bias, as water is actually part of the sample in the field [47] but it is often interpreted as such when comparing with laboratory analyses.…”

Section: Effects Of Moisture In Fine-grained Samplesmentioning

confidence: 99%

“…Hence, the notion of infinite thickness. Overall, insufficient sample thickness can cause inaccurate measurements below 10 mm, depending on the element [46]. The results of analyses of ten samples of polluted soils with different preparations were compared for lead and zinc.…”

Section: Depth Of Analytical Investigationsmentioning

confidence: 99%

Possible Pitfalls in the Analysis of Minerals and Loose Materials by Portable XRF, and How to Overcome Them

Laperche

Lemière

2020

Minerals

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Portable X-ray fluorescence spectroscopy is now widely used in almost any field of geoscience. Handheld XRF analysers are easy to use, and results are available in almost real time anywhere. However, the results do not always match laboratory analyses, and this may deter users. Rather than analytical issues, the bias often results from sample preparation differences. Instrument setup and analysis conditions need to be fully understood to avoid reporting erroneous results. The technique’s limitations must be kept in mind. We describe a number of issues and potential pitfalls observed from our experience and described in the literature. This includes the analytical mode and parameters; protective films; sample geometry and density, especially for light elements; analytical interferences between elements; physical effects of the matrix and sample condition, and more. Nevertheless, portable X-ray fluorescence spectroscopy (pXRF) results gathered with sufficient care by experienced users are both precise and reliable, if not fully accurate, and they can constitute robust data sets. Rather than being a substitute for laboratory analyses, pXRF measurements are a valuable complement to those. pXRF improves the quality and relevance of laboratory data sets.

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“…Studies have shown that for every 1% increase in soil water content, there is a 1.15% -1.75% decrease in reported elemental concentration for Mn through to As, while elements lighter than Mn are even more greatly attenuated (Parsons et al, 2013;Imanishi et al, 2010). This means that sample water content must be measured and corrected for, as light element values determined in situ will likely not be directly comparable to results of a traditional laboratory analysis (Padilla et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Portable X-Ray Fluorescence (pXRF) Analysis of Heavy Metal Contamination in Graveyards with Contrasting Soil Types

Madden

Pringle

Jeffery

et al. 2021

Preprint

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Human remains have been interred in burial grounds since historic times. Although the re-use of graveyards differs from one country, region or time-period to another, over time graveyard soil may become contaminated or enriched with heavy metal elements. This paper aims to present heavy metal element soil analysis from two UK church graveyard study sites with contrasting necrosols, but similar burial densities and known burial ages dating back to the 16th Century and some possibly older than 1,000 years. Portable X-Ray Fluorescence (pXRF) element analyses were undertaken, both in-situ on surface locations and laboratory-based on surface and near-surface soil pellets. Results show elevated levels of Pb, Mn, Cr, Cu, Zn and Ca in both necrosols when compared to background values. Element concentration anomalies remained consistently higher than background samples down to 2 m bgl, where sampled, but reduced away from church buildings which may reflect burial densities. Element concentration anomalies were higher in the clay-rich necrosol than in sandy necrosol. Field-based rapid measurements gave similar relative concentration values to laboratory-based soil pellet measurements, although laboratory-based analyses were more precise. Study results implications suggest that long-used necrosols are likely to be more contaminated with heavy-metal elements than similar soil outside graveyards with implications for burial grounds management, adjacent populations and where burial grounds have been deconsecrated and turned to residential dwellings.

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Use of portable XRF: Effect of thickness and antecedent moisture of soils on measured concentration of trace elements

Cited by 37 publications

References 11 publications

pXRF method development for elemental analysis of archaeological soil

pXRF method development for elemental analysis of archaeological soil

Possible Pitfalls in the Analysis of Minerals and Loose Materials by Portable XRF, and How to Overcome Them

Portable X-Ray Fluorescence (pXRF) Analysis of Heavy Metal Contamination in Graveyards with Contrasting Soil Types

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