Publications by category
Journal articles
Newsome L (In Press). Dissimilatory Fe(III) reduction controls on arsenic mobilisation: a combined biogeochemical and NanoSIMS imaging approach.
Frontiers in Microbiology Full text.
Newsome L, Solano Arguedas A, Coker VS, Boothman C, Lloyd JR (In Press). Manganese and cobalt redox cycling in laterites; biogeochemical and bioprocessing implications.
Chemical Geology Full text.
Newsome L (In Press). Natural attenuation of lead by microbial manganese oxides in a karst aquifer.
Science of the Total Environment Full text.
Newsome L, Falagan C (In Press). The microbiology of metal mine waste: bioremediation applications and implications for planetary health.
GeoHealth Full text.
Goulet RR, Newsome L, Vandenhove H, Keum D-K, Horyna J, Kamboj S, Brown J, Johansen MP, Twining J, Wood MD, et al (2022). Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling.
J Environ Radioact,
244-245Abstract:
Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling.
Predictions of radionuclide dose rates to freshwater organisms can be used to evaluate the radiological environmental impacts of releases from uranium mining and milling projects. These predictions help inform decisions on the implementation of mitigation measures. The objective of this study was to identify how dose rate modelling could be improved to reduce uncertainty in predictions to non-human biota. For this purpose, we modelled the activity concentrations of 210Pb, 210Po, 226Ra, 230Th, and 238U downstream of uranium mines and mills in northern Saskatchewan, Canada, together with associated weighted absorbed dose rates for a freshwater food chain using measured activity concentrations in water and sediments. Differences in predictions of radionuclide activity concentrations occurred mainly from the different default partition coefficient and concentration ratio values from one model to another and including all or only some 238U decay daughters in the dose rate assessments. Consequently, we recommend a standardized best-practice approach to calculate weighted absorbed dose rates to freshwater biota whether a facility is at the planning, operating or decommissioned stage. At the initial planning stage, the best-practice approach recommend using conservative site-specific baseline activity concentrations in water, sediments and organisms and predict conservative incremental activity concentrations in these media by selecting concentration ratios based on species similarity and similar water quality conditions to reduce the uncertainty in dose rate calculations. At the operating and decommissioned stages, the best-practice approach recommends relying on measured activity concentrations in water, sediment, fish tissue and whole-body of small organisms to further reduce uncertainty in dose rate estimates. This approach would allow for more realistic but still conservative dose assessments when evaluating impacts from uranium mining projects and making decision on adequate controls of releases.
Abstract.
Author URL.
Buchanan DM, Newsome L, Lloyd JR, Kazemian M, Kaulich B, Araki T, Bagshaw H, Waters J, van der Laan G, N’Diaye A, et al (2022). Investigating Nanoscale Electron Transfer Processes at the Cell-Mineral Interface in Cobalt-Doped Ferrihydrite Using Geobacter sulfurreducens: a Multi-Technique Approach. Frontiers in Earth Science, 10
Cleary A, Lloyd JR, Newsome L, Shaw S, Boothman C, Boshoff G, Atherton N, Morris K (2019). Bioremediation of strontium and technetium contaminated groundwater using glycerol phosphate.
Chemical Geology,
509, 213-222.
Abstract:
Bioremediation of strontium and technetium contaminated groundwater using glycerol phosphate
Groundwater at legacy nuclear facilities around the world is contaminated with radionuclides including strontium-90 and technetium-99, which are often present as co-contaminants. Here we investigated whether biostimulation of indigenous microbial communities by glycerol phosphate can co-treat 90 Sr through incorporation into phosphate biominerals, and 99 Tc through microbially-induced reduction of the sediment to form less mobile Tc(IV) phases via reaction with reduced species (e.g. Fe(II)). Results showed that 95% of Sr was removed from solution in sediment microcosms treated with glycerol phosphate, and sequential extraction showed that ~18% of the Sr in the resulting solid phase was associated with the pH 5 Na-acetate fraction and 75% was in the ion exchangeable fraction. This removal and partitioning to recalcitrant phases during glycerol phosphate treatment was greater than in the untreated controls, where only 60% of Sr was removed from solution, and of the solid-associated Sr, 95% was present in the exchangeable fraction. Fitting of Sr K-edge EXAFS spectra confirmed these findings, with shell by shell fitting suggesting ~30% of sediment-associated Sr was present in a coordination environment consistent with phosphate biominerals following glycerol phosphate treatment, whilst Sr was present only as outer-sphere complexes in the controls. In addition,16S rRNA sequencing of sediments stimulated with glycerol phosphate demonstrated the growth of potential phosphate-solubilising species such as Chryseobacterium and Serratia spp. Finally, glycerol phosphate treatment stimulated bioreduction via addition of electron donor in the form of glycerol to the system, in turn this stimulated the removal of 99 Tc from solution concomitant with microbial Fe(III) reduction to form poorly soluble hydrous Tc(IV)O 2 like phases. In sediments amended with an electron donor, the microbial community also reflected the onset of bioreduction with an increased relative abundance of Fe(III) and sulfate-reducing bacteria such as Geothrix, Geobacter and Desulfobulbus spp. Overall these results suggest application of glycerol phosphate offers a promising bioremediation strategy to co-treat both 90 Sr and 99 Tc contaminated groundwaters, and promotes the formation of Sr-phosphate and Tc(IV) bearing biominerals when reducing conditions are maintained. Combined with past work which shows the scavenging of uranium from solution following addition of glycerol phosphate, this extends the scope for glycerol phosphate as a treatment for radioactive contamination in groundwaters.
Abstract.
Newsome L, Morris K, Cleary A, Masters-Waage NK, Boothman C, Joshi N, Atherton N, Lloyd JR (2019). The impact of iron nanoparticles on technetium-contaminated groundwater and sediment microbial communities.
Journal of Hazardous Materials,
364, 134-142.
Abstract:
The impact of iron nanoparticles on technetium-contaminated groundwater and sediment microbial communities
Iron nanoparticles are a promising new technology to treat contaminated groundwater, particularly as they can be engineered to optimise their transport properties. Technetium is a common contaminant at nuclear sites and can be reductively scavenged from groundwater by iron(II). Here we investigated the potential for a range of optimised iron nanoparticles to remove technetium from contaminated groundwater, and groundwater/sediment systems. Nano zero-valent iron and Carbo-iron stimulated the development of anoxic conditions while generating Fe(II) which reduced soluble Tc(VII) to sparingly soluble Tc(IV). Similar results were observed for Fe(II)-bearing biomagnetite, albeit at a slower rate. Tc(VII) remained in solution in the presence of the Fe(III) mineral nano-goethite, until acetate was added to stimulate microbial Fe(III)-reduction after which Tc(VII) concentrations decreased concomitant with Fe(II) ingrowth. The addition of iron nanoparticles to sediment microcosms caused an increase in the relative abundance of Firmicutes, consistent with fermentative/anoxic metabolisms. Residual bacteria from the synthesis of the biomagnetite nanoparticles were out-competed by the sediment microbial community. Overall the results showed that iron nanoparticles were highly effective in removing Tc(VII) from groundwater in sediment systems, and generated sustained anoxic conditions via the stimulation of beneficial microbial processes including Fe(III)-reduction and sulfate reduction.
Abstract.
Newsome L, Lopez Adams R, Downie HF, Moore KL, Lloyd JR (2018). NanoSIMS imaging of extracellular electron transport processes during microbial iron(III) reduction. FEMS Microbiology Ecology, 94(8).
Newsome L, Cleary A, Morris K, Lloyd JR (2017). Long-Term Immobilization of Technetium via Bioremediation with Slow-Release Substrates. Environmental Science & Technology, 51(3), 1595-1604.
Newsome L, Morris K, Trivedi D, Bewsher A, Lloyd JR (2015). Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate.
Environmental Science and Technology,
49(18), 11070-11078.
Abstract:
Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate
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.
Abstract.
Newsome L, Morris K, Shaw S, Trivedi D, Lloyd JR (2015). The stability of microbially reduced U(IV); impact of residual electron donor and sediment ageing.
Chemical Geology,
409, 125-135.
Abstract:
The stability of microbially reduced U(IV); impact of residual electron donor and sediment ageing
The stimulation of microbial U(VI) reduction to precipitate insoluble U(IV) has been proposed as a means of remediating mobile uranium groundwater contamination. Crucial to the success of such a remediation strategy is determining the longevity of U(IV) biominerals in the subsurface, particularly if the groundwater becomes oxidising. Here we describe experiments to assess the susceptibility of microbially-reduced U(IV) to oxidative remobilisation both via aeration and by the addition of nitrate at environmentally-relevant conditions. Additional factors examined include the possibility of biogenic U(IV) becoming more crystalline (and potentially more recalcitrant) during a period of ageing, and the role played by residual electron donor in controlling the long-term fate of the uranium. Biogenic U(IV) was precipitated as a non-crystalline U(IV) or "monomeric" phase, with a small but increasing contribution to the EXAFS spectra from nanocrystalline uraninite occurring during 15. months of ageing. Despite this, no evidence was observed for an increase in recalcitrance to oxidative remobilisation. However, the presence of residual electron donor post-biostimulation was shown to exert a strong control on U(IV) reoxidation kinetics, highlighting the importance of maintaining the presence of electron donor in the subsurface, in order to protect biogenic U(IV) from oxidative remobilisation.
Abstract.
Newsome L, Morris K, Lloyd JR (2015). Uranium biominerals precipitated by an environmental isolate of Serratia under anaerobic conditions.
PLoS ONE,
10(7).
Abstract:
Uranium biominerals precipitated by an environmental isolate of Serratia under anaerobic conditions
Stimulating the microbially-mediated precipitation of uranium biominerals may be used to treat groundwater contamination at nuclear sites. The majority of studies to date have focussed on the reductive precipitation of uranium as U(IV) by U(VI)- and Fe(III)-reducing bacteria such as Geobacter and Shewanella species, although other mechanisms of uranium removal from solution can occur, including the precipitation of uranyl phosphates via bacterial phosphatase activity. Here we present the results of uranium biomineralisation experiments using an isolate of Serratia obtained from a sediment sample representative of the Sellafield nuclear site, UK. When supplied with glycerol phosphate, this Serratia strain was able to precipitate 1 mM of soluble U(VI) as uranyl phosphate minerals from the autunite group, under anaerobic and fermentative conditions. Under phosphate-limited anaerobic conditions and with glycerol as the electron donor, non-growing Serratia cells could precipitate 0.5 mM of uranium supplied as soluble U(VI), via reduction to nano-crystalline U(IV) uraninite. Some evidence for the reduction of solid phase uranyl(VI) phosphate was also observed. This study highlights the potential for Serratia and related species to play a role in the bioremediation of uranium contamination, via a range of different metabolic pathways, dependent on culturing or in situ conditions.
Abstract.
Newsome L, Morris K, Trivedi D, Atherton N, Lloyd JR (2014). Microbial reduction of uranium(VI) in sediments of different lithologies collected from Sellafield.
Applied Geochemistry,
51, 55-64.
Abstract:
Microbial reduction of uranium(VI) in sediments of different lithologies collected from Sellafield
The presence of uranium in groundwater at nuclear sites can be controlled by microbial processes. Here we describe the results from stimulating microbial reduction of U(VI) in sediment samples obtained from a nuclear-licensed site in the UK. A variety of different lithology sediments were selected to represent the heterogeneity of the subsurface at a site underlain by glacial outwash deposits and sandstone. The natural sediment microbial communities were stimulated via the addition of an acetate/lactate electron donor mix and were monitored for changes in geochemistry and molecular ecology. Most sediments facilitated the removal of 12. ppm U(VI) during the onset of Fe(III)-reducing conditions; this was reflected by an increase in the proportion of known Fe(III)- and U(VI)-reducing species. However U(VI) remained in solution in two sediments and Fe(III)-reducing conditions did not develop. Sequential extractions, addition of an Fe(III)-enrichment culture and most probable number enumerations revealed that a lack of bioavailable iron or low cell numbers of Fe(III)-reducing bacteria may be responsible. These results highlight the potential for stimulation of microbial U(VI)-reduction to be used as a bioremediation strategy at UK nuclear sites, and they emphasise the importance of both site-specific and borehole-specific investigations to be completed prior to implementation.
Abstract.
Newsome L, Morris K, Lloyd JR (2014). The biogeochemistry and bioremediation of uranium and other priority radionuclides.
Chemical Geology,
363, 164-184.
Abstract:
The biogeochemistry and bioremediation of uranium and other priority radionuclides
Microbial metabolism has the potential to alter the solubility of a broad range of priority radionuclides, including uranium, other actinides and fission products. of notable interest has been the biostimulation of anaerobic microbial communities to remove redox-sensitive radionuclides such as uranium U(VI) from contaminated groundwaters at nuclear sites. Particularly promising are bioreduction processes, whereby bacteria enzymatically reduce aqueous U(VI) to insoluble U(IV) coupled to oxidation of an organic electron donor; and uranium phosphate biomineralisation, in which bacterial phosphatase activity cleaves organophosphates, liberating inorganic phosphate that precipitates with aqueous U(VI) as uranyl phosphate minerals. Here we review the mechanisms of uranium bioreduction and phosphate biomineralisation and their suitability to facilitate long-term precipitation of uranium from groundwater, with particular focus on in situ trials at the US Department of Energy field sites. Redox interactions of other priority radionuclides (technetium, neptunium, plutonium, americium, iodine, strontium and caesium) are also reviewed. © 2013 the Authors.
Abstract.
Vives i Batlle J, Beaugelin-Seiller K, Beresford NA, Copplestone D, Horyna J, Hosseini A, Johansen M, Kamboj S, Keum D-K, Kurosawa N, et al (2011). The estimation of absorbed dose rates for non-human biota: an extended intercomparison.
Radiat Environ Biophys,
50(2), 231-251.
Abstract:
The estimation of absorbed dose rates for non-human biota: an extended intercomparison.
An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of ±20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.
Abstract.
Author URL.
Newsome L (2010). Selecting suitable materials to avoid radioiodine contamination.
J Radiol Prot,
30(4), 813-815.
Author URL.
Conferences
Buchanan DM, Lloyd J, Coker V, Kaulich B, Newsome L, van der Laan G (2021). Investigating nanoscale electron transfer processes at the cell mineral interface in Co doped ferrihydrite using Geobacter sulfurreducens and a multi-technique approach. Goldschmidt2021 abstracts.
Buchanan D, Lloyd JR, Kaulich B, Newsome L, Mulroy D, Van der Lann G, N'Diaye A, Coker V (2020). SXM Analysis of Nanoscale Electron Transfer Processes at the Cell-Mineral Interface in Co-bearing Fe/Mn Minerals. Goldschmidt Abstracts.
Newsome L, Solano Arguedas A, Lloyd JR (2020). The Role of Redox Buffering by Electron Donors in Mediating the Behaviour of Metals in Sediments Under Aerobic Conditions. Goldschmidt Abstracts.
Real A, Horemans N, Newsome L, Oudalova A, Stark K, Willrodt C, Yoshida S, Hinton T (2011). Frederica effects database update within the EMRAS-II programme: Contributing to evaluate the environmental impact of ionizing radiation.
Abstract:
Frederica effects database update within the EMRAS-II programme: Contributing to evaluate the environmental impact of ionizing radiation
Abstract.
Stocki TJ, Telleria DM, Bergman L, Proehl G, Amado V, Bonchuk I, Boyer P, Chyly P, Curti A, Heling R, et al (2011). Reference methodologies for radioactive controlled discharges an activity within the IAEA's program environmental modelling for radiation safety II (EMRAS II).
Abstract:
Reference methodologies for radioactive controlled discharges an activity within the IAEA's program environmental modelling for radiation safety II (EMRAS II)
Abstract.
Publications by year
In Press
Newsome L (In Press). Dissimilatory Fe(III) reduction controls on arsenic mobilisation: a combined biogeochemical and NanoSIMS imaging approach.
Frontiers in Microbiology Full text.
Newsome L, Solano Arguedas A, Coker VS, Boothman C, Lloyd JR (In Press). Manganese and cobalt redox cycling in laterites; biogeochemical and bioprocessing implications.
Chemical Geology Full text.
Newsome L (In Press). Natural attenuation of lead by microbial manganese oxides in a karst aquifer.
Science of the Total Environment Full text.
Newsome L, Falagan C (In Press). The microbiology of metal mine waste: bioremediation applications and implications for planetary health.
GeoHealth Full text.
2022
Goulet RR, Newsome L, Vandenhove H, Keum D-K, Horyna J, Kamboj S, Brown J, Johansen MP, Twining J, Wood MD, et al (2022). Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling.
J Environ Radioact,
244-245Abstract:
Best practices for predictions of radionuclide activity concentrations and total absorbed dose rates to freshwater organisms exposed to uranium mining/milling.
Predictions of radionuclide dose rates to freshwater organisms can be used to evaluate the radiological environmental impacts of releases from uranium mining and milling projects. These predictions help inform decisions on the implementation of mitigation measures. The objective of this study was to identify how dose rate modelling could be improved to reduce uncertainty in predictions to non-human biota. For this purpose, we modelled the activity concentrations of 210Pb, 210Po, 226Ra, 230Th, and 238U downstream of uranium mines and mills in northern Saskatchewan, Canada, together with associated weighted absorbed dose rates for a freshwater food chain using measured activity concentrations in water and sediments. Differences in predictions of radionuclide activity concentrations occurred mainly from the different default partition coefficient and concentration ratio values from one model to another and including all or only some 238U decay daughters in the dose rate assessments. Consequently, we recommend a standardized best-practice approach to calculate weighted absorbed dose rates to freshwater biota whether a facility is at the planning, operating or decommissioned stage. At the initial planning stage, the best-practice approach recommend using conservative site-specific baseline activity concentrations in water, sediments and organisms and predict conservative incremental activity concentrations in these media by selecting concentration ratios based on species similarity and similar water quality conditions to reduce the uncertainty in dose rate calculations. At the operating and decommissioned stages, the best-practice approach recommends relying on measured activity concentrations in water, sediment, fish tissue and whole-body of small organisms to further reduce uncertainty in dose rate estimates. This approach would allow for more realistic but still conservative dose assessments when evaluating impacts from uranium mining projects and making decision on adequate controls of releases.
Abstract.
Author URL.
Buchanan DM, Newsome L, Lloyd JR, Kazemian M, Kaulich B, Araki T, Bagshaw H, Waters J, van der Laan G, N’Diaye A, et al (2022). Investigating Nanoscale Electron Transfer Processes at the Cell-Mineral Interface in Cobalt-Doped Ferrihydrite Using Geobacter sulfurreducens: a Multi-Technique Approach. Frontiers in Earth Science, 10
2021
Buchanan DM, Lloyd J, Coker V, Kaulich B, Newsome L, van der Laan G (2021). Investigating nanoscale electron transfer processes at the cell mineral interface in Co doped ferrihydrite using Geobacter sulfurreducens and a multi-technique approach. Goldschmidt2021 abstracts.
2020
Buchanan D, Lloyd JR, Kaulich B, Newsome L, Mulroy D, Van der Lann G, N'Diaye A, Coker V (2020). SXM Analysis of Nanoscale Electron Transfer Processes at the Cell-Mineral Interface in Co-bearing Fe/Mn Minerals. Goldschmidt Abstracts.
Newsome L, Solano Arguedas A, Lloyd JR (2020). The Role of Redox Buffering by Electron Donors in Mediating the Behaviour of Metals in Sediments Under Aerobic Conditions. Goldschmidt Abstracts.
2019
Cleary A, Lloyd JR, Newsome L, Shaw S, Boothman C, Boshoff G, Atherton N, Morris K (2019). Bioremediation of strontium and technetium contaminated groundwater using glycerol phosphate.
Chemical Geology,
509, 213-222.
Abstract:
Bioremediation of strontium and technetium contaminated groundwater using glycerol phosphate
Groundwater at legacy nuclear facilities around the world is contaminated with radionuclides including strontium-90 and technetium-99, which are often present as co-contaminants. Here we investigated whether biostimulation of indigenous microbial communities by glycerol phosphate can co-treat 90 Sr through incorporation into phosphate biominerals, and 99 Tc through microbially-induced reduction of the sediment to form less mobile Tc(IV) phases via reaction with reduced species (e.g. Fe(II)). Results showed that 95% of Sr was removed from solution in sediment microcosms treated with glycerol phosphate, and sequential extraction showed that ~18% of the Sr in the resulting solid phase was associated with the pH 5 Na-acetate fraction and 75% was in the ion exchangeable fraction. This removal and partitioning to recalcitrant phases during glycerol phosphate treatment was greater than in the untreated controls, where only 60% of Sr was removed from solution, and of the solid-associated Sr, 95% was present in the exchangeable fraction. Fitting of Sr K-edge EXAFS spectra confirmed these findings, with shell by shell fitting suggesting ~30% of sediment-associated Sr was present in a coordination environment consistent with phosphate biominerals following glycerol phosphate treatment, whilst Sr was present only as outer-sphere complexes in the controls. In addition,16S rRNA sequencing of sediments stimulated with glycerol phosphate demonstrated the growth of potential phosphate-solubilising species such as Chryseobacterium and Serratia spp. Finally, glycerol phosphate treatment stimulated bioreduction via addition of electron donor in the form of glycerol to the system, in turn this stimulated the removal of 99 Tc from solution concomitant with microbial Fe(III) reduction to form poorly soluble hydrous Tc(IV)O 2 like phases. In sediments amended with an electron donor, the microbial community also reflected the onset of bioreduction with an increased relative abundance of Fe(III) and sulfate-reducing bacteria such as Geothrix, Geobacter and Desulfobulbus spp. Overall these results suggest application of glycerol phosphate offers a promising bioremediation strategy to co-treat both 90 Sr and 99 Tc contaminated groundwaters, and promotes the formation of Sr-phosphate and Tc(IV) bearing biominerals when reducing conditions are maintained. Combined with past work which shows the scavenging of uranium from solution following addition of glycerol phosphate, this extends the scope for glycerol phosphate as a treatment for radioactive contamination in groundwaters.
Abstract.
Newsome L, Morris K, Cleary A, Masters-Waage NK, Boothman C, Joshi N, Atherton N, Lloyd JR (2019). The impact of iron nanoparticles on technetium-contaminated groundwater and sediment microbial communities.
Journal of Hazardous Materials,
364, 134-142.
Abstract:
The impact of iron nanoparticles on technetium-contaminated groundwater and sediment microbial communities
Iron nanoparticles are a promising new technology to treat contaminated groundwater, particularly as they can be engineered to optimise their transport properties. Technetium is a common contaminant at nuclear sites and can be reductively scavenged from groundwater by iron(II). Here we investigated the potential for a range of optimised iron nanoparticles to remove technetium from contaminated groundwater, and groundwater/sediment systems. Nano zero-valent iron and Carbo-iron stimulated the development of anoxic conditions while generating Fe(II) which reduced soluble Tc(VII) to sparingly soluble Tc(IV). Similar results were observed for Fe(II)-bearing biomagnetite, albeit at a slower rate. Tc(VII) remained in solution in the presence of the Fe(III) mineral nano-goethite, until acetate was added to stimulate microbial Fe(III)-reduction after which Tc(VII) concentrations decreased concomitant with Fe(II) ingrowth. The addition of iron nanoparticles to sediment microcosms caused an increase in the relative abundance of Firmicutes, consistent with fermentative/anoxic metabolisms. Residual bacteria from the synthesis of the biomagnetite nanoparticles were out-competed by the sediment microbial community. Overall the results showed that iron nanoparticles were highly effective in removing Tc(VII) from groundwater in sediment systems, and generated sustained anoxic conditions via the stimulation of beneficial microbial processes including Fe(III)-reduction and sulfate reduction.
Abstract.
2018
Newsome L, Lopez Adams R, Downie HF, Moore KL, Lloyd JR (2018). NanoSIMS imaging of extracellular electron transport processes during microbial iron(III) reduction. FEMS Microbiology Ecology, 94(8).
2017
Newsome L, Cleary A, Morris K, Lloyd JR (2017). Long-Term Immobilization of Technetium via Bioremediation with Slow-Release Substrates. Environmental Science & Technology, 51(3), 1595-1604.
2015
Newsome L, Morris K, Trivedi D, Bewsher A, Lloyd JR (2015). Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate.
Environmental Science and Technology,
49(18), 11070-11078.
Abstract:
Biostimulation by Glycerol Phosphate to Precipitate Recalcitrant Uranium(IV) Phosphate
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.
Abstract.
Newsome L, Morris K, Shaw S, Trivedi D, Lloyd JR (2015). The stability of microbially reduced U(IV); impact of residual electron donor and sediment ageing.
Chemical Geology,
409, 125-135.
Abstract:
The stability of microbially reduced U(IV); impact of residual electron donor and sediment ageing
The stimulation of microbial U(VI) reduction to precipitate insoluble U(IV) has been proposed as a means of remediating mobile uranium groundwater contamination. Crucial to the success of such a remediation strategy is determining the longevity of U(IV) biominerals in the subsurface, particularly if the groundwater becomes oxidising. Here we describe experiments to assess the susceptibility of microbially-reduced U(IV) to oxidative remobilisation both via aeration and by the addition of nitrate at environmentally-relevant conditions. Additional factors examined include the possibility of biogenic U(IV) becoming more crystalline (and potentially more recalcitrant) during a period of ageing, and the role played by residual electron donor in controlling the long-term fate of the uranium. Biogenic U(IV) was precipitated as a non-crystalline U(IV) or "monomeric" phase, with a small but increasing contribution to the EXAFS spectra from nanocrystalline uraninite occurring during 15. months of ageing. Despite this, no evidence was observed for an increase in recalcitrance to oxidative remobilisation. However, the presence of residual electron donor post-biostimulation was shown to exert a strong control on U(IV) reoxidation kinetics, highlighting the importance of maintaining the presence of electron donor in the subsurface, in order to protect biogenic U(IV) from oxidative remobilisation.
Abstract.
Newsome L, Morris K, Lloyd JR (2015). Uranium biominerals precipitated by an environmental isolate of Serratia under anaerobic conditions.
PLoS ONE,
10(7).
Abstract:
Uranium biominerals precipitated by an environmental isolate of Serratia under anaerobic conditions
Stimulating the microbially-mediated precipitation of uranium biominerals may be used to treat groundwater contamination at nuclear sites. The majority of studies to date have focussed on the reductive precipitation of uranium as U(IV) by U(VI)- and Fe(III)-reducing bacteria such as Geobacter and Shewanella species, although other mechanisms of uranium removal from solution can occur, including the precipitation of uranyl phosphates via bacterial phosphatase activity. Here we present the results of uranium biomineralisation experiments using an isolate of Serratia obtained from a sediment sample representative of the Sellafield nuclear site, UK. When supplied with glycerol phosphate, this Serratia strain was able to precipitate 1 mM of soluble U(VI) as uranyl phosphate minerals from the autunite group, under anaerobic and fermentative conditions. Under phosphate-limited anaerobic conditions and with glycerol as the electron donor, non-growing Serratia cells could precipitate 0.5 mM of uranium supplied as soluble U(VI), via reduction to nano-crystalline U(IV) uraninite. Some evidence for the reduction of solid phase uranyl(VI) phosphate was also observed. This study highlights the potential for Serratia and related species to play a role in the bioremediation of uranium contamination, via a range of different metabolic pathways, dependent on culturing or in situ conditions.
Abstract.
2014
Newsome L, Morris K, Trivedi D, Atherton N, Lloyd JR (2014). Microbial reduction of uranium(VI) in sediments of different lithologies collected from Sellafield.
Applied Geochemistry,
51, 55-64.
Abstract:
Microbial reduction of uranium(VI) in sediments of different lithologies collected from Sellafield
The presence of uranium in groundwater at nuclear sites can be controlled by microbial processes. Here we describe the results from stimulating microbial reduction of U(VI) in sediment samples obtained from a nuclear-licensed site in the UK. A variety of different lithology sediments were selected to represent the heterogeneity of the subsurface at a site underlain by glacial outwash deposits and sandstone. The natural sediment microbial communities were stimulated via the addition of an acetate/lactate electron donor mix and were monitored for changes in geochemistry and molecular ecology. Most sediments facilitated the removal of 12. ppm U(VI) during the onset of Fe(III)-reducing conditions; this was reflected by an increase in the proportion of known Fe(III)- and U(VI)-reducing species. However U(VI) remained in solution in two sediments and Fe(III)-reducing conditions did not develop. Sequential extractions, addition of an Fe(III)-enrichment culture and most probable number enumerations revealed that a lack of bioavailable iron or low cell numbers of Fe(III)-reducing bacteria may be responsible. These results highlight the potential for stimulation of microbial U(VI)-reduction to be used as a bioremediation strategy at UK nuclear sites, and they emphasise the importance of both site-specific and borehole-specific investigations to be completed prior to implementation.
Abstract.
Newsome L, Morris K, Lloyd JR (2014). The biogeochemistry and bioremediation of uranium and other priority radionuclides.
Chemical Geology,
363, 164-184.
Abstract:
The biogeochemistry and bioremediation of uranium and other priority radionuclides
Microbial metabolism has the potential to alter the solubility of a broad range of priority radionuclides, including uranium, other actinides and fission products. of notable interest has been the biostimulation of anaerobic microbial communities to remove redox-sensitive radionuclides such as uranium U(VI) from contaminated groundwaters at nuclear sites. Particularly promising are bioreduction processes, whereby bacteria enzymatically reduce aqueous U(VI) to insoluble U(IV) coupled to oxidation of an organic electron donor; and uranium phosphate biomineralisation, in which bacterial phosphatase activity cleaves organophosphates, liberating inorganic phosphate that precipitates with aqueous U(VI) as uranyl phosphate minerals. Here we review the mechanisms of uranium bioreduction and phosphate biomineralisation and their suitability to facilitate long-term precipitation of uranium from groundwater, with particular focus on in situ trials at the US Department of Energy field sites. Redox interactions of other priority radionuclides (technetium, neptunium, plutonium, americium, iodine, strontium and caesium) are also reviewed. © 2013 the Authors.
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2011
Real A, Horemans N, Newsome L, Oudalova A, Stark K, Willrodt C, Yoshida S, Hinton T (2011). Frederica effects database update within the EMRAS-II programme: Contributing to evaluate the environmental impact of ionizing radiation.
Abstract:
Frederica effects database update within the EMRAS-II programme: Contributing to evaluate the environmental impact of ionizing radiation
Abstract.
Stocki TJ, Telleria DM, Bergman L, Proehl G, Amado V, Bonchuk I, Boyer P, Chyly P, Curti A, Heling R, et al (2011). Reference methodologies for radioactive controlled discharges an activity within the IAEA's program environmental modelling for radiation safety II (EMRAS II).
Abstract:
Reference methodologies for radioactive controlled discharges an activity within the IAEA's program environmental modelling for radiation safety II (EMRAS II)
Abstract.
Vives i Batlle J, Beaugelin-Seiller K, Beresford NA, Copplestone D, Horyna J, Hosseini A, Johansen M, Kamboj S, Keum D-K, Kurosawa N, et al (2011). The estimation of absorbed dose rates for non-human biota: an extended intercomparison.
Radiat Environ Biophys,
50(2), 231-251.
Abstract:
The estimation of absorbed dose rates for non-human biota: an extended intercomparison.
An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of ±20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.
Abstract.
Author URL.
2010
Newsome L (2010). Selecting suitable materials to avoid radioiodine contamination.
J Radiol Prot,
30(4), 813-815.
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