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Author Lach, P.; Cathelineau, M.; Brouand, M.; Fiet, N. url  openurl
  Title In-situ Isotopic and Chemical Study of Pyrite from Chu-Sarysu (Kazakhstan) Roll-front Uranium Deposit Type Journal Article
  Year 2015 Publication Procedia Earth and Planetary Science Abbreviated Journal  
  Volume 13 Issue Pages 207-210  
  Keywords LA-ICP-MS, pyrite, roll-front, SIMS, sulfur isotopy, traces elements, uranium  
  Abstract Pyrite is common in roll-front type uranium deposit in Chu-sarysu basin, Kazakhstan. Combined in-situ microstructural, isotopic and chemical analysis of pyrite indicates variation in precipitation conditions and in fluid composition. Broad-scale δ34S heterogeneity indicates a complex multi-facet evolution. First generation authigenic framboïdal aggregates are biogenic as demonstrated by the lowest δ34S values of -48‰ to -28‰. The latest generation pyrites are probably hydrothermal with greater δ34S variation (-30‰ to +12‰). This hydrothermal pyrite commonly displays variable enrichment of several trace elements especially As, Co and Ni. Strong variation in δ34S values and variable trace element enrichment is interpreted in terms of continuous variations in fluid composition.  
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  ISSN 1878-5220 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) THL @ christoph.kuells @ lach_-situ_2015 Serial 182  
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Author Lapworth, D.J.; Brauns, B.; Chattopadhyay, S.; Gooddy, D.C.; Loveless, S.E.; MacDonald, A.M.; McKenzie, A.A.; Muddu, S.; Nara, S.N.V. url  openurl
  Title Elevated uranium in drinking water sources in basement aquifers of southern India Type Journal Article
  Year 2021 Publication Applied Geochemistry Abbreviated Journal  
  Volume 133 Issue Pages 105092  
  Keywords Anthropogenic, Drinking waters, Geogenic, India, Speciation, Uranium  
  Abstract Groundwater resources in the crystalline basement complex of India are crucial for supplying drinking water in both rural and urban settings. Groundwater depletion is recognised as a challenge across parts of India due to over-abstraction, but groundwater quality constraints are perhaps even more widespread and often overlooked at the local scale. Uranium contamination in basement aquifers has been reported in many parts of India, locally exceeding WHO drinking water guideline values of 30 μg/L and posing a potential health risk. In this study 130 water samples were collected across three crystalline basement catchments to assess hydrochemical, geological and anthropogenic controls on uranium mobility and occurrence in drinking water sources. Groundwaters with uranium concentrations exceeding 30 μg/L were found in all three study catchments (30% of samples overall), with concentrations up to 589 μg/L detected. There appears to be a geological control on the occurrence of uranium in groundwater with the granitic gneiss of the Halli and Bengaluru study areas having higher mean uranium concentrations (51 and 68 μg/L respectively) compared to the sheared gneiss of the Berambadi catchment (6.4 μg/L). Uranium – nitrate relationships indicate that fertiliser sources are not a major control on uranium occurrence in these case studies which include two catchments with a long legacy of intense agricultural land use. Geochemical modelling confirmed uranium speciation was dominated by uranyl carbonate species, particularly ternary complexes with calcium, consistent with uranium mobility being affected by redox controls and the presence of carbonates. Urban leakage in Bengaluru led to low pH and low bicarbonate groundwater hydrochemistry, reducing uranium mobility and altering uranium speciation. Since the majority of inhabitants in Karnataka depend on groundwater abstraction from basement aquifers for drinking water and domestic use, exposure to elevated uranium is a public health concern. Improved monitoring, understanding and treatment of high uranium drinking water sources in this region is essential to safeguard public health.  
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  ISSN 0883-2927 ISBN Medium  
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  Notes Approved no  
  Call Number (up) THL @ christoph.kuells @ lapworth_elevated_2021 Serial 147  
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Author Lartigue, J.E.; Charrasse, B.; Reile, B.; Descostes, M. url  openurl
  Title Aqueous inorganic uranium speciation in European stream waters from the FOREGS dataset using geochemical modelling and determination of a U bioavailability baseline Type Journal Article
  Year 2020 Publication Chemosphere Abbreviated Journal  
  Volume 251 Issue Pages 126302  
  Keywords Bioavailable fraction, Geochemical mapping / baseline, Modelling, Speciation, Stream water, Uranium  
  Abstract The concentration of the bioavailable uranium fraction (Ubio) at the European scale was deduced by geochemical modelling considering several definitions found in the literature and the FOREGS European stream waters geochemical atlas dataset to produce a Ubio baseline. A sensitivity analysis was performed using three thermodynamic databases. We also investigated the link between total dissolved uranium (Uaq) concentrations, speciation and global stream water chemistry on the one hand, and the lithology and ages of the surrounding rocks on the other. The more U-enriched the stream sediments or rock type contexts are, which tends to be the case with rocks containing silicates (4.1 mg/kg), the less U-concentrated the stream waters are (0.15 μg/L). Sedimentary rocks lead to slightly higher Uaq concentrations (0.34 μg/L) even if the concentration in sediment (Used) is relatively low (1.6 mg/kg). This trend is reversed for Ubio, with higher concentrations in a crystalline context. The mean estimated Ubio value ranges from 1.5.10−3 to 65.3 ng/L and can fluctuate by 3 orders of magnitude depending on the considered definition as opposed to by 2 orders of magnitude accountable to differences between thermodynamic databases. The classification of the water in relation to the two surrounding rock lithologies makes it possible to reduce the mean variability for the Ubio concentrations. Irrespective of the definition of Ubio considered, in 59% of cases the Ubio fraction represents less than 1% of Uaq. Several threshold values relating to Ubio were proposed, assuming knowledge only of the aqueous concentrations of the major elements and Uaq.  
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  ISSN 0045-6535 ISBN Medium  
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  Notes Approved no  
  Call Number (up) THL @ christoph.kuells @ lartigue_aqueous_2020 Serial 141  
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Author Lawrinenko, M.; Kurwadkar, S.; Wilkin, R.T. url  openurl
  Title Long-term performance evaluation of zero-valent iron amended permeable reactive barriers for groundwater remediation – A mechanistic approach Type Journal Article
  Year 2023 Publication Geoscience Frontiers Abbreviated Journal  
  Volume 14 Issue 2 Pages 101494  
  Keywords Geochemistry, Iron, Permeable reactive barrier, Plating reactions, Reduction potential, Surface passivation  
  Abstract Permeable reactive barriers (PRBs) are used for groundwater remediation at contaminated sites worldwide. This technology has been efficient at appropriate sites for treating organic and inorganic contaminants using zero-valent iron (ZVI) as a reductant and as a reactive material. Continued development of the technology over the years suggests that a robust understanding of PRB performance and the mechanisms involved is still lacking. Conflicting information in the scientific literature downplays the critical role of ZVI corrosion in the remediation of various organic and inorganic pollutants. Additionally, there is a lack of information on how different mechanisms act in tandem to affect ZVI-groundwater systems through time. In this review paper, we describe the underlying mechanisms of PRB performance and remove isolated misconceptions. We discuss the primary mechanisms of ZVI transformation and aging in PRBs and the role of iron corrosion products. We review numerous sites to reinforce our understanding of the interactions between groundwater contaminants and ZVI and the authigenic minerals that form within PRBs. Our findings show that ZVI corrosion products and mineral precipitates play critical roles in the long-term performance of PRBs by influencing the reactivity of ZVI. Pore occlusion by mineral precipitates occurs at the influent side of PRBs and is enhanced by dissolved oxygen and groundwater rich in dissolved solids and high alkalinity, which negatively impacts hydraulic conductivity, allowing contaminants to potentially bypass the treatment zone. Further development of site characterization tools and models is needed to support effective PRB designs for groundwater remediation.  
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  ISSN 1674-9871 ISBN Medium  
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  Notes Approved no  
  Call Number (up) THL @ christoph.kuells @ lawrinenko_long-term_2023 Serial 143  
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Author Leibundgut, C.; Maloszewski, P.; Külls, C. url  doi
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  Title Tracers in Hydrology Type Book Whole
  Year 2009 Publication Abbreviated Journal  
  Volume Issue 1. Ed. Pages  
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  Publisher John Wiley & Sons, Ltd Place of Publication Editor  
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  Notes Approved no  
  Call Number (up) THL @ christoph.kuells @ Leibundgut2009tracers Serial 37  
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