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Davies HS, Rosas-Moreno J, Cox F, Lythgoe P, Bewsher A, Livens FR, Robinson CH, Pittman JK. Multiple environmental factors influence 238U, 232Th and 226Ra bioaccumulation in arbuscular mycorrhizal-associated plants. Sci Total Environ 2018; 640-641:921-934. [PMID: 30021326 DOI: 10.1016/j.scitotenv.2018.05.370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/16/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Ecological consequences of low-dose radioactivity from natural sources or radioactive waste are important to understand but knowledge gaps still remain. In particular, the soil transfer and bioaccumulation of radionuclides into plant roots is poorly studied. Furthermore, better knowledge of arbuscular mycorrhizal (AM) fungi association may help understand the complexities of radionuclide bioaccumulation within the rhizosphere. Plant bioaccumulation of uranium, thorium and radium was demonstrated at two field sites, where plant tissue concentrations reached up to 46.93 μg g-1 238U, 0.67 μg g-1 232Th and 18.27 kBq kg-1 226Ra. High root retention of uranium was consistent in all plant species studied. In contrast, most plants showed greater bioaccumulation of thorium and radium into above-ground tissues. The influence of specific soil parameters on root radionuclide bioaccumulation was examined. Total organic carbon significantly explained the variation in root uranium concentration, while other soil factors including copper concentration, magnesium concentration and pH significantly correlated with root concentrations of uranium, radium and thorium, respectively. All four orders of Glomeromycota were associated with root samples from both sites and all plant species studied showed varying association with AM fungi, ranging from zero to >60% root colonisation by fungal arbuscules. Previous laboratory studies using single plant-fungal species association had found a positive role of AM fungi in root uranium transfer, but no significant correlation between the amount of fungal infection and root uranium content in the field samples was found here. However, there was a significant negative correlation between AM fungal infection and radium accumulation. This study is the first to examine the role of AM fungi in radionuclide soil-plant transfer at a community level within the natural environment. We conclude that biotic factors alongside various abiotic factors influence the soil-plant transfer of radionuclides and future mechanistic studies are needed to explain these interactions in more detail.
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Affiliation(s)
- Helena S Davies
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Jeanette Rosas-Moreno
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Filipa Cox
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Paul Lythgoe
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Alastair Bewsher
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Francis R Livens
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK; Centre for Radiochemistry Research, School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Clare H Robinson
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Jon K Pittman
- School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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Newsome L, Morris K, Trivedi D, Bewsher A, Lloyd JR. Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate. Environ Sci Technol 2015; 49:11070-11078. [PMID: 26292021 DOI: 10.1021/acs.est.5b02042] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Stimulating the microbial reduction of aqueous uranium(VI) to insoluble U(IV) via electron donor addition has been proposed as a strategy to remediate uranium-contaminated groundwater in situ. However, concerns have been raised regarding the longevity of microbially precipitated U(IV) in the subsurface, particularly given that it may become remobilized if the conditions change to become oxidizing. An alternative mechanism is to stimulate the precipitation of poorly soluble uranium phosphates via the addition of an organophosphate and promote the development of reducing conditions. Here, we selected a sediment sample from a U.K. nuclear site and stimulated the microbial community with glycerol phosphate under anaerobic conditions to assess whether uranium phosphate precipitation was a viable bioremediation strategy. Results showed that U(VI) was rapidly removed from solution and precipitated as a reduced crystalline U(IV) phosphate mineral similar to ningyoite. This mineral was considerably more recalcitrant to oxidative remobilization than the products of microbial U(VI) reduction. Bacteria closely related to Pelosinus species may have played a key role in uranium removal in these experiments. This work has implications for the stewardship of uranium-contaminated groundwater, with the formation of U(IV) phosphates potentially offering a more effective strategy for maintaining low concentrations of uranium in groundwater over long time periods.
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Affiliation(s)
- Laura Newsome
- Williamson Research Centre and Research Centre for Radwaste Disposal, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Williamson Building, Oxford Road, Manchester M13 9PL, U.K
| | - Katherine Morris
- Williamson Research Centre and Research Centre for Radwaste Disposal, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Williamson Building, Oxford Road, Manchester M13 9PL, U.K
| | - Divyesh Trivedi
- National Nuclear Laboratory , Chadwick House, Birchwood, Warrington WA3 6AE, U.K
| | - Alastair Bewsher
- Williamson Research Centre and Research Centre for Radwaste Disposal, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Williamson Building, Oxford Road, Manchester M13 9PL, U.K
| | - Jonathan R Lloyd
- Williamson Research Centre and Research Centre for Radwaste Disposal, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester , Williamson Building, Oxford Road, Manchester M13 9PL, U.K
- National Nuclear Laboratory , Chadwick House, Birchwood, Warrington WA3 6AE, U.K
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Zwinkels JC, Gignac DS, Nevins M, Powell I, Bewsher A. Design and testing of a two-monochromator reference spectrofluorimeter for high-accuracy total radiance factor measurements. Appl Opt 1997; 36:892-902. [PMID: 18250755 DOI: 10.1364/ao.36.000892] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A two-monochromator reference spectrofluorimeter has been developed at the National Research Council of Canada in accordance with International Commission on Illumination and American Society for Testing and Materials colorimetry standards to permit high-accuracy total spectral radiance factor measurements of fluorescent materials. This fully automated instrument employs a xenon-arc light source, all-reflective optics, two grating monochromators with order-sorting filters, a cooled photomultiplier tube analyzing detector, and a calibrated silicon photodiode monitor detector. The instrument operating range is 250-1050 nm with a selectable bandpass (optimized for a 5-nm resolution), and the measurement geometry is 45 degrees annular illumination and 0 degrees viewing (45/0). We describe the instrument's design, testing, and verification procedures. Systematic errors that have been determined and corrected for include instrument polarization, beam nonuniformity, wavelength shifts, stray light, and system drift. The wavelength accuracy and reproducibility are estimated to better than +/-0.1 and +/-0.03 nm, respectively. The photometric short-term repeatability and long-term reproducibility are estimated to be better than +/-0.15% and +/-0.5%, respectively. The overall photometric accuracy is better than 1% of the value over a wide range of reflectances, and the reproducibility of the color specification of a fluorescent material is better than 0.25 DeltaE(ab) units.
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Affiliation(s)
- J C Zwinkels
- Institute for National Measurement Standards, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
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Abstract
The design and fabrication of several single-element laser-beam projectors are described. These projectors take a Gaussian laser beam and expand it into a uniform intensity diverging shape, which can be either a single line, circle, cross, star, or a D. Each element consists of a single segmented surface designed so as to produce the required projected shape.
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Powell I, Bewsher A. Ultraviolet-visible spectrograph optics: ODIN project. Appl Opt 1995; 34:6446-6452. [PMID: 21060493 DOI: 10.1364/ao.34.006446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We describe one of the possible designs for the UV-visible spectrograph optics to be employed in the ODIN project. The spectrograph will be used in a future satellite mission for aeronomy observations and will image a column of atmosphere just above the Earth's surface onto a two-dimensional CCD array with the spatial and spectral content aligned orthogonal to one another.
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Bewsher A, Boland W. Design of a single-element laser-beam uniform cross projector. Appl Opt 1994; 33:7367-7370. [PMID: 20941296 DOI: 10.1364/ao.33.007367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A single optical element has been designed that takes a Gaussian laser beam and expands it into a uniform diverging cross. The design and fabrication of such an element are described.
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Bewsher A, Powell I. Optical transfer function measurment facility for aerial survey cameras. Appl Opt 1994; 33:6573-6577. [PMID: 20941194 DOI: 10.1364/ao.33.006573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The optical transfer function measurement facility developed at the National Research Council of Canada primarily for testing aerial survey cameras has been upgraded to perform the task in an appreciably more convenient manner. Modifications made to the facility, which is based on the line spread function technique, include the replacement of the cumbersome physical scanning mechanism and detector unit with a detector assembly comprising a relay lens and a linear photodiode array. While eliminating the need for physically scanning the line spread function, it did require a change of light source, a daylight filter, and a new computer software package. The new setup is described in this paper. Several aerial survey cameras have been evaluated with the system, and results are given for a fairly standard Zeiss camera.
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