Laboratory-based characterization of plutonium in soil particles using micro-XRF and 3D confocal XRF

McIntosh, Kathryn; Cordes, Nikolaus L.; Patterson, Brian M.; Havrilla, George J.

doi:10.1039/c5ja00068h

Cited by 23 publications

(12 citation statements)

References 11 publications

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“…This re-absorption of X-rays limits the 3D measurements to minute samples, extending to at most a few mm in any direction. In that context, McIntosh et al (2015) used 3D micro X-ray fluorescence spectroscopy to determine non-destructively the elemental composition of minute aggregates of a plutonium-contaminated soil, within which they could identify distinct 30 μm-size Pu particles with a limit of detection <15 ng.…”

Section: The (Bio)chemical Picturementioning

confidence: 99%

Emergent Properties of Microbial Activity in Heterogeneous Soil Microenvironments: Different Research Approaches Are Slowly Converging, Yet Major Challenges Remain

et al. 2018

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Over the last 60 years, soil microbiologists have accumulated a wealth of experimental data showing that the bulk, macroscopic parameters (e.g., granulometry, pH, soil organic matter, and biomass contents) commonly used to characterize soils provide insufficient information to describe quantitatively the activity of soil microorganisms and some of its outcomes, like the emission of greenhouse gasses. Clearly, new, more appropriate macroscopic parameters are needed, which reflect better the spatial heterogeneity of soils at the microscale (i.e., the pore scale) that is commensurate with the habitat of many microorganisms. For a long time, spectroscopic and microscopic tools were lacking to quantify processes at that scale, but major technological advances over the last 15 years have made suitable equipment available to researchers. In this context, the objective of the present article is to review progress achieved to date in the significant research program that has ensued. This program can be rationalized as a sequence of steps, namely the quantification and modeling of the physical-, (bio)chemical-, and microbiological properties of soils, the integration of these different perspectives into a unified theory, its upscaling to the macroscopic scale, and, eventually, the development of new approaches to measure macroscopic soil characteristics. At this stage, significant progress has been achieved on the physical front, and to a lesser extent on the (bio)chemical one as well, both in terms of experiments and modeling. With regard to the microbial aspects, although a lot of work has been devoted to the modeling of bacterial and fungal activity in soils at the pore scale, the appropriateness of model assumptions cannot be readily assessed because of the scarcity of relevant experimental data. For significant progress to be made, it is crucial to make sure that research on the microbial components of soil systems does not keep lagging behind the work on the physical and (bio)chemical characteristics. Concerning the subsequent steps in the program, very little integration of the various disciplinary perspectives has occurred so far, and, as a result, researchers have not yet been able to tackle the scaling up to the macroscopic level. Many challenges, some of them daunting, remain on the path ahead. Fortunately, a number of these challenges may be resolved by brand new measuring equipment that will become commercially available in the very near future.

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Section: The (Bio)chemical Picturementioning

confidence: 99%

Emergent Properties of Microbial Activity in Heterogeneous Soil Microenvironments: Different Research Approaches Are Slowly Converging, Yet Major Challenges Remain

et al. 2018

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“…Measurement of Pu fall-out particles in soil matrices is of interest to those working in nuclear safeguarding, forensics and remediation activities. In a powerful demonstration 75 of advances in analytical capabilities, the elemental composition of two Pu-contaminated soil samples was characterised using both high resolution µXRFS and 3D confocal XRFS. The LOD was <15 pg for samples with a nominal 30 µm grain size.…”

Section: X-ray Spectrometrymentioning

confidence: 99%

Atomic spectrometry update – a review of advances in environmental analysis

Butler

Cairns

Cook

et al. 2017

J. Anal. At. Spectrom.

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This is the 29th annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This Update refers to papers published approximately between September 2012 and July 2013 and continues the series ofAtomic Spectrometry Updates (ASUs) Developments in geochemical analysis included the production and (re)certification of new geological RMs for bulk, isotopic and microspatial analysis. Optimisation of LA-ICP-MS techniques for the interrogation of geochemical samples continues to be reported and a number of useful instrumental review articles (AMS, ICP-MS and SIMS) have been published.Feedback on this review is most welcome and the review coordinator can be contacted using the email address provided. Sampling techniquesThe development of personal workplace air samplers, used to monitor workers' exposure to airborne particles, continues to be a fertile area of research. cartridge assembly which could then be loaded directly into an XRF system for analysis. Initial wind tunnel tests using test aerosols of known particle size indicated that this sampler could collect representative particle size distributions.Generation of test particle atmospheres in a laboratory environment is difficult and it is most informative to see publications describing the development and validation of aerosol test chambers. A system 21 for source characterisation and controlled human exposure to NPs generated during gas-metal arc welding had an airtight 22 m 3 climate-controlled stainless steel chamber at its core. A variety of online measurements, e.g. using TEOM or SMPS, and offline measurements, e.g. using electron microscopy and PIXE techniques, could be made via sampling ports/samplers. Test particles were generated in a separate chamber and subsequently piped into the main chamber. Stable concentrations of atmospheric particles could be maintained for up to 6 h and concentrations could be varied from <5 µg m by EDXRF spectrometry (Cr, Cu, Fe, Ni, Pb and Zn), there were no significant differences in values between the two measurement approaches (paired t-test, p > 0.2, 95 % CI). In summary, the authors concluded that this method was suitable for the high throughput analysis of lightly loaded air filter samples. 11The bioaccessible metal fraction in urban aerosol particles may be a more informative metric than the total metal composition in assessng the potential health effects of exposure to inhaled particles. . Using this optimised method, the airborne levels of Ag in Buenos Aires was determined to be 2-4.5 ng m , respectively. Emission spectroscopyInvestigation into the use of LIBS for the analysis of aerosol samples is a focus of a number of research groups. Elemental emission intensities were normalised to carbon (measured at 247.856 nm) which could be used as an internal standard because the carbon emission from the underlying nylon filter was much larger and relatively more stable than the signal from the deposited carbonaceous particles. This approach was useful for minimising shot-to-...

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“…The use of the confocal setup, in conjunction with a sample stage that moves in 3 dimensions, allows for 3D elemental profiling of the sample (see Figure 8). This can be very powerful because when you use this technique in tandem with X-ray CT imaging, it's possible to reconstruct a 3D image of the sample to show the morphology and the 3D elemental composition 1,17,18 , whether it be at a laboratory setup or performed at a synchrotron.…”

Section: X-ray Fluorescence Spectroscopymentioning

confidence: 99%

“…Since the 1970's, X-ray tomography has been used to image and study the 3D structure of many materials and systems, ranging from plutonium in soil 1 to patient diagnosis 2,3 . The reason this technique is widely used is because of the nondestructive nature of the process, providing morphological detail from the micro-to nano-level without loss or damage to the system 4 .…”

Section: Introductionmentioning

confidence: 99%

Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

Shear

2017

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Laboratory-based characterization of plutonium in soil particles using micro-XRF and 3D confocal XRF

Abstract: Multiple laboratory-based techniques including confocal XRF, which provides 3D elemental maps, have been used to nondestructively detect and characterize Pu in contaminated soil particles.

Cited by 23 publications

References 11 publications

Emergent Properties of Microbial Activity in Heterogeneous Soil Microenvironments: Different Research Approaches Are Slowly Converging, Yet Major Challenges Remain

Emergent Properties of Microbial Activity in Heterogeneous Soil Microenvironments: Different Research Approaches Are Slowly Converging, Yet Major Challenges Remain

Atomic spectrometry update – a review of advances in environmental analysis

Review of X-ray Tomography and X-ray Fluorescence Spectroscopy

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