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
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
Newsome L (In Press). Natural attenuation of lead by microbial manganese oxides in a karst aquifer. Science of the Total Environment
Lear L, Hesse E, Newsome L, Gaze W, Buckling A, Vos M (In Press). The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen <i>Pseudomonas aeruginosa</i>.
Abstract:
The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa
AbstractMetal contamination poses both a direct threat to human health as well as an indirect threat through its potential to affect bacterial pathogens. Metals can not only co-select for antibiotic resistance, but also might affect pathogen virulence via increased siderophore production. Siderophores are extracellular compounds released to increase ferric iron uptake — a common limiting factor for pathogen growth within hosts – making them an important virulence factor. However, siderophores can also be positively selected for to detoxify non-ferrous metals, and consequently metal stress can potentially increase bacterial virulence. Anthropogenic methods to remediate environmental metal contamination commonly involve amendment with lime-containing materials, but whether this reduces in situ co-selection for antibiotic resistance and virulence remains unknown. Here, using microcosms containing metal-contaminated river water and sediment, we experimentally test whether metal remediation by liming reduces co-selection for these traits in the opportunistic pathogen Pseudomonas aeruginosa embedded within a natural microbial community. To test for the effects of environmental structure, which can impact siderophore production, microcosms were incubated under either static or shaking conditions. Evolved P. aeruginosa populations had greater fitness in the presence of toxic concentrations of copper than the ancestral strain, but this effect was reduced in the limed treatments. Evolved P. aeruginosa populations showed increased resistance to the clinically-relevant antibiotics apramycin, cefotaxime, and trimethoprim, regardless of lime addition or environmental structure. Although we found virulence to be significantly associated with siderophore production, neither virulence nor siderophore production significantly differed between the four treatments. We therefore demonstrate that although remediation via liming reduced the strength of selection for metal resistance mechanisms, it did not mitigate metal-imposed selection for antibiotic resistance or virulence in P. aeruginosa. Consequently, metal-contaminated environments may select for antibiotic resistance and virulence traits even when treated with lime.Graphical abstract
Abstract.
Newsome L, Falagan C (In Press). The microbiology of metal mine waste: bioremediation applications and implications for planetary health. GeoHealth
2023
Proto M, Newsome L, Jensen E, Courtney R (2023). Geochemical analyses of metal(loid) fractions do not predict plant uptake behavior: Are plant bioassays better tools to predict mine rehabilitation success?.
Sci Total Environ,
861Abstract:
Geochemical analyses of metal(loid) fractions do not predict plant uptake behavior: Are plant bioassays better tools to predict mine rehabilitation success?
Management of metal(loid) tailings at historic sites presents environmental hazards usually requiring rehabilitation to mitigate pollution risks. Strategies employed include capping or establishing vegetation directly, which requires tailings assessments to determine suitable rehabilitation approaches. Assessments are typically geochemical analyses, but plant based approaches may provide a more accurate measure of revegetation success although they are often limited to germination indices. This study uses the plant bioassay (Rhizotest™) with common geochemical assessment to predict plant uptake of metal(loid)s and the subsequent likely rehabilitation success. Pb/Zn tailings from five legacy sites within the UK and Ireland were characterized for pH, EC, water soluble and CaCl2-extractable content and aqua regia extractable content. Uptake of Sb, As, Cd, Cu, Ca, Mg, Mn, Zn, Pb was determined in shoots and roots of Lolium perenne. Total Zn, Pb, Sb, Cd and As in tailings ranged from 694 to 2683 mg kg-1, 1252 to 8072 mg kg-1, 14 to 148 mg kg-1, 1.3 to 44 mg kg-1 and 1.3 to 45 mg kg-1, respectively. The only correlation found between total and water soluble or CaCl2-extractable metal(loid) contents was for Cd, where r = 0.8 for total and CaCl2-extractable fractions. Limited uptake and translocation risk was identified for major contaminants Zn and Pb in most tailings samples but in some cases exceedance of phytotoxic threshold values occurred that was not reflected in geochemical analysis. Crucially, although total Cd and Sb content was relatively low (< 20 mg kg-1) in some tailings, elevated plant content for some samples highlights phytotoxic risk from minor elements. Results indicate that screening based on geochemical content is not sufficiently predictive of metal(loid) phytoavailability to reliably inform mine rehabilitation strategies. We therefore strongly recommend that geochemical analyses are supplemented with plant based bioassay to plan mine tailings revegetation and reduce risk of wider ecosystem metal(loid) transfer.
Abstract.
Author URL.
Lear L, Hesse E, Newsome L, Gaze W, Buckling A, Vos M (2023). The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen <i>Pseudomonas aeruginosa</i>.
Evolutionary Applications,
16(7), 1377-1389.
Abstract:
The effect of metal remediation on the virulence and antimicrobial resistance of the opportunistic pathogen Pseudomonas aeruginosa
AbstractAnthropogenic metal pollution can result in co‐selection for antibiotic resistance and potentially select for increased virulence in bacterial pathogens. Metal‐polluted environments can select for the increased production of siderophore molecules to detoxify non‐ferrous metals. However, these same molecules also aid the uptake of ferric iron, a limiting factor for within‐host pathogen growth, and are consequently a virulence factor. Anthropogenic methods to remediate environmental metal contamination commonly involve amendment with lime‐containing materials. However, whether this reduces in situ co‐selection for antibiotic resistance and siderophore‐mediated virulence remains unknown. Here, using microcosms containing non‐sterile metal‐contaminated river water and sediment, we test whether liming reduces co‐selection for these pathogenicity traits in the opportunistic pathogen Pseudomonas aeruginosa. To account for the effect of environmental structure, which is known to impact siderophore production, microcosms were incubated under either static or shaking conditions. Evolved P. aeruginosa populations had greater fitness in the presence of toxic concentrations of copper than the ancestral strain and showed increased resistance to the clinically relevant antibiotics apramycin, cefotaxime and trimethoprim, regardless of lime addition or environmental structure. Although we found virulence to be significantly associated with siderophore production, neither virulence nor siderophore production significantly differed between the four treatments. Furthermore, liming did not mitigate metal‐imposed selection for antibiotic resistance or virulence in P. aeruginosa. Consequently, metal‐contaminated environments may select for antibiotic resistance and virulence traits even when treated with lime.
Abstract.
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.
Fitch V, Parbhakar‐fox A, Crane R, Newsome L (2022). Evolution of Sulfidic Legacy Mine Tailings: a Review of the Wheal Maid Site, UK.
Minerals,
12(7).
Abstract:
Evolution of Sulfidic Legacy Mine Tailings: a Review of the Wheal Maid Site, UK
Historic tailings dams and their associated mine waste can pose a significant risk to human and environmental health. The Wheal Maid mine site, Cornwall, UK, serves as an example of the temporal evolution of a tailings storage facility after mining has ceased and the acid‐generating waste subjected to surficial processes. This paper discusses its designation as a contaminated land site and reviews our current understanding of the geochemistry, mineralogy, and microbiology of the Wheal Maid tailings, from both peer‐reviewed journal articles and unpublished literature. We also present new data on waste characterisation and detailed mineral chemistry and data from laboratory oxidation experiments. Particularly of interest at Wheal Maid is the presence of pyrite-bearing “Grey Tailings”, which, under typical environmental conditions at the Earth’s surface, would be expected to have undergone oxidation and subsequently formed acidic and metalliferous mine drainage (AMD). The results identified a number of mechanisms that could explain the lack of pyrite oxidation in the Grey Tailings, including a lack of nutrients inhibiting microbial Fe(II) ox-idation, passivation of pyrite mineral surfaces with tailings processing chemicals, and an abundance of euhedral pyrite grains. Such research areas need further scrutiny in order to inform the design of future tailings facilities and associated AMD management protocols.
Abstract.
Dybowska A, Schofield PF, Newsome L, Herrington RJ, Mosselmans JFW, Kaulich B, Kazemian M, Araki T, Skiggs TJ, Kruger J, et al (2022). Evolution of the Piaui Laterite, Brazil: Mineralogical, Geochemical and Geomicrobiological Mechanisms for Cobalt and Nickel Enrichment.
MINERALS,
12(10).
Author URL.
Courtney R, Proto M, Newsome L, Jensen E (2022). Geochemical Analyses of Heavy Metal Fractions Do Not Predict Plant Uptake Behaviour: Are Plant Bioassays Better Tools to Predict Mine Rehabilitation Success?.
Solano-Arguedas AF, Boothman C, Newsome L, Pattrick RAD, Arguedas-Quesada D, Robinson CH, Lloyd JR (2022). Geochemistry and microbiology of tropical serpentine soils in the Santa Elena Ophiolite, a landscape-biogeographical approach.
Geochem Trans,
23(1).
Abstract:
Geochemistry and microbiology of tropical serpentine soils in the Santa Elena Ophiolite, a landscape-biogeographical approach.
The Santa Elena Ophiolite is a well-studied ultramafic system in Costa Rica mainly comprised of peridotites. Here, tropical climatic conditions promote active laterite formation processes, but the biogeochemistry of the resulting serpentine soils is still poorly understood. The aim of this study was to characterize the soil geochemical composition and microbial community of contrasting landscapes in the area, as the foundation to start exploring the biogeochemistry of metals occurring there. The soils were confirmed as Ni-rich serpentine soils but differed depending on their geographical location within the ophiolite area, showing three serpentine soil types. Weathering processes resulted in mountain soils rich in trace metals such as cobalt, manganese and nickel. The lowlands showed geochemical variations despite sharing similar landscapes: the inner ophiolite lowland soils were more like the surrounding mountain soils rather than the north lowland soils at the border of the ophiolite area, and within the same riparian basin, concentrations of trace metals were higher downstream towards the mangrove area. Microbial community composition reflected the differences in geochemical composition of soils and revealed potential geomicrobiological inputs to local metal biogeochemistry: iron redox cycling bacteria were more abundant in the mountain soils, while more manganese-oxidizing bacteria were found in the lowlands, with the highest relative abundance in the mangrove areas. The fundamental ecological associations recorded in the serpentine soils of the Santa Elena Peninsula, and its potential as a serpentinization endemism hotspot, demonstrate that is a model site to study the biogeochemistry, geomicrobiology and ecology of tropical serpentine areas.
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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
Monaghan AA, Bateson L, Boyce AJ, Burnside NM, Chambers R, de Rezende JR, Dunnet E, Everett PA, Gilfillan SMV, Jibrin MS, et al (2022). Time Zero for Net Zero: a Coal Mine Baseline for Decarbonising Heat.
Earth Science, Systems and Society,
2Abstract:
Time Zero for Net Zero: a Coal Mine Baseline for Decarbonising Heat
Mine water geothermal energy could provide sustainable heating, cooling and storage to assist in the decarbonisation of heat and achieving Net Zero carbon emissions. However, mined environments are highly complex and we currently lack the understanding to confidently enable a widespread, cost-effective deployment of the technology. Extensive and repeated use of the mined subsurface as a thermal source/store and the optimisation of operational infrastructure encompasses a range of scientific and technical challenges that require broad partnerships to address. We present emerging results of a pioneering multidisciplinary collaboration formed around an at-scale mine water geothermal research infrastructure in Glasgow, United Kingdom. Focused on a mined, urban environment, a range of approaches have been applied to both characterise the environmental change before geothermal activities to generate “time zero” datasets, and to develop novel monitoring tools for cost-effective and environmentally-sound geothermal operations. Time zero soil chemistry, ground gas, surface water and groundwater characterisation, together with ground motion and seismic monitoring, document ongoing seasonal and temporal variability that can be considered typical of a post-industrial, urban environment underlain by abandoned, flooded coal mine workings. In addition, over 550 water, rock and gas samples collected during borehole drilling and testing underwent diverse geochemical, isotopic and microbiological analysis. Initial results indicate a connected subsurface with modern groundwater, and resolve distinctive chemical, organic carbon and stable isotope signatures from different horizons that offer promise as a basis for monitoring methods. Biogeochemical interactions of sulphur, carbon and iron, plus indications of microbially-mediated mineral oxidation/reduction reactions require further investigation for long term operation. Integration of the wide array of time zero observations and understanding of coupled subsurface processes has significant potential to inform development of efficient and resilient geothermal infrastructure and to inform the design of fit-for-purpose monitoring approaches in the quest towards meeting Net Zero targets.
Abstract.
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.
Abstract.
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.
Author URL.