Speciation of Radionuclides in the Environment

Gunten, H. R. von; Beneš, P.

doi:10.1524/ract.1995.69.1.1

Cited by 74 publications

(37 citation statements)

References 173 publications

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“…A plethora of reviews have been published on speciation methods for radionuclides and/or metals in surface waters and sediments [21,22,23,24,25]. The intention of this review is to summarize the methods that have been used to specifically determine the speciation of U.…”

Section: Speciation Methodsmentioning

confidence: 99%

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Markich

2002

The Scientific World JOURNAL

200

142

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The speciation of uranium (U) in relation to its bioavailability is reviewed for surface waters (fresh-and seawater) and their sediments. A summary of available analytical and modeling techniques for determining U speciation is also presented. U(VI) is the major form of U in oxic surface waters, while U(IV) is the major form in anoxic waters. The bioavailability of U (i.e., its ability to bind to or traverse the cell surface of an organism) is dependent on its speciation, or physicochemical form. U occurs in surface waters in a variety of physicochemical forms, including the free metal ion (U 4+ or UO 2 2+ ) and complexes with inorganic ligands (e.g., uranyl carbonate or uranyl phosphate), and humic substances (HS) (e.g., uranyl fulvate) in dissolved, colloidal, and/or particulate forms. Although the relationship between U speciation and bioavailability is complex, there is reasonable evidence to indicate that UO 2 2+ and UO 2 OH + are the major forms of U(VI) available to organisms, rather than U in strong complexes (e.g., uranyl fulvate) or adsorbed to colloidal and/or particulate matter. U(VI) complexes with inorganic ligands (e.g., carbonate or phosphate) and HS apparently reduce the bioavailability of U by reducing the activity of UO 2 2+ and UO 2 OH + . The majority of studies have used the results from thermodynamic speciation modeling to support these conclusions. Time-resolved laser-induced fluorescence spectroscopy is the only analytical technique able to directly determine specific U species, but is limited in use to freshwaters of low pH and ionic strength. Nearly all of the available information relating the speciation of U to its bioavailability has been derived using simple, chemically defined experimental freshwaters, rather than natural waters. No data are available for estuarine or seawater. Furthermore, there are no available data on the relationship between U speciation and bioavailability in sediments. An understanding of this relationship has been hindered due to the lack of direct quantitative U speciation techniques for particulate phases. More robust analytical techniques for determining the speciation of U in natural surface waters are needed before the relationship between U speciation and bioavailability can be clarified.

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Section: Speciation Methodsmentioning

confidence: 99%

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Markich

2002

The Scientific World JOURNAL

200

142

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“…These elements are of concern since they are released into the environment as a result of nuclear weapons production and testing and nuclear fuel cycle operations (15,16). Siderophores and other naturally occurring ligands may therefore affect actinide mobility in waste repositories and the environment and may also be used to treat radioactive waste prior to storage or to decontaminate soils and waters (15,24,42,56). Siderophores and siderophore analogues have also been investigated for possible medical use in the decorporation of actinides from the body (25,48,49), while simple hydroxamates may have uses in the reprocessing of nuclear fuel (31,32,51,52).…”

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confidence: 99%

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Renshaw¹,

Halliday

Robson

et al. 2003

Appl Environ Microbiol

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An assay to detect UO 2 2؉ complexation was developed based on the chrome azurol S (CAS) assay for siderophores (B. Schwyn and J. B. Neilands, Anal. Biochem. 160:47-56, 1987) and was used to investigate the ability of fungal metabolites to complex actinides. In this assay the discoloration of two dyed agars (one containing a CAS-Fe 3؉ dye and the other containing a CAS-UO 2 2؉ dye) caused by ligands was quantified. The assay was tested by using the siderophore desferrioxamine B (DFO), and the results showed that there was a regular, reproducible relationship between discoloration and the amount of siderophore added. The ratio of the discoloration on the CAS-UO 2 2؉ agar to the discoloration on the CAS-Fe 3؉ agar was independent of the amount of siderophore added. A total of 113 fungi and yeasts were isolated from three soil samples taken from the Peak District National Park. The fungi were screened for the production of UO 2 2؉ chelators by using the CAS-based assay and were also tested specifically for hydroxamate siderophore production by using the hydroxamate siderophore auxotroph Aureobacterium flavescens JG-9. This organism is highly sensitive to the presence of hydroxamate siderophores. However, the CAS-based assay was found to be less sensitive than the A. flavescens JG-9 assay. No significant difference between the results for each site for the two tests was found. Three isolates were selected for further study and were identified as two Pencillium species and a Mucor species. Our results show that the new assay can be effectively used to screen fungi for the production of UO 2 2؉ chelating ligands. We suggest that hydroxamate siderophores can be produced by mucoraceous fungi.

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“…Fission products are very important signatures of many nuclear activities [70,71] and an inventory of fission products in spent nuclear fuels is required to understand the environment around nuclear facilities [72][73][74][75][76]. The complete determination, both of the isotopic ratio and elemental concentration of the fission products is not possible using α, β or Ү-spectrometry, and mass spectrometry though hindered by some isobaric interferences appears as an alternative and the procedure becomes more attractive when separations are carried out to remove interferences chemical separation is needed [77,78].…”

Section: Applications In Nuclear Industrymentioning

confidence: 99%

Mass Spectrometry: A Boon to Nuclear Industry

Ramkumar¹

2014

J Anal Bioanal Tech

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What is Mass Spectrometry?Mass spectrometry is analytical instrument which has been used for more than a century with its initial work on mass charge ratio being carried out by W. Wien, J.J. Thomson, and other physicists [1]. Mass Spectroscopy is an analytical laboratory technique to separate the components of a sample by their mass. The sample is vaporized into a gas and then ionized. The ions are then accelerated through a potential difference and focused into a beam. The ion beam passes through a magnetic field which bends the charged stream. Lighter components or components with more ionic charge will deflect in the field more than heavier or less charged components. A detector counts the number of ions at different deflections and the data can be plotted as a 'spectrum' of different masses. Therefore it is clear that mass spectrometer performs a simple measurement that of mass. The earlier work in the measurement of mass had led to the discovery of isotopes and it was in the 1930s that these measurements were correlated to the chemical structures and therefore were used extensively for biological applications for the characterization of natural products. Further progress in the field of mass spectrometry including isotopic labeling methods, hyphenated techniques and softer ionization methods made it an ideal tool for the analysis of macromolecules [2]. With the various fields that employ mass spectrometry growing in number, nuclear industry is also an important area wherein applications of mass spectrometry exist. Chronological Development in Mass spectrometryThe earliest mass spectrometry was in 1897 with the discovery of electrons made by J.J.Thomson. Around 1919, the observation studies of isotopes using mass spectrometry were carried out by F.W. Aston created a mass spectrometer in which ions were dispersed by mass and focused by velocity. This design improved the mass spectrometer resolving power by an order of magnitude compared to that achieved by AbstractMass spectrometry is a versatile technique that is used for the determination of elements at the trace and ultratrace level along with the isotope ratios. The accuracy in the quantification of isotope ratios of radionuclides is essential for environmental monitoring, migration studies, dating, determination of burn-up of fuel, nuclear material accounting and radioactive waste control. Inductively coupled plasma mass spectrometry (ICP-MS) is advantageous due to its outstanding sensitivity, precision and good accuracy for isotope ratio measurements and enhanced figures of merit for the determination of isotope ratio measurements. These advantages can be enhanced by various other variations of ICP-MS like the use of a multiple ion collector device (MC-ICP-MS). The review gives an idea of the various applications in the nuclear field and touches upon some of the important elements used in nuclear industry.

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Speciation of Radionuclides in the Environment

Cited by 74 publications

References 173 publications

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Uranium Speciation and Bioavailability in Aquatic Systems: An Overview

Development and Application of an Assay for Uranyl Complexation by Fungal Metabolites, Including Siderophores

Mass Spectrometry: A Boon to Nuclear Industry

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