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Author (down) Botha, R.; Lindsay, R.; Newman, R.T.; Maleka, P.P.; Chimba, G.
Title Radon in groundwater baseline study prior to unconventional shale gas development and hydraulic fracturing in the Karoo Basin (South Africa) Type Journal Article
Year 2019 Publication Applied Radiation and Isotopes Abbreviated Journal
Volume 147 Issue Pages 7-13
Keywords
Abstract The prospect of unconventional shale gas development in the semi-arid Karoo Basin (South Africa) has created the prerequisite to temporally characterise the natural radioactivity in associated groundwater which is solely depended on for drinking and agriculture purposes. Radon (222Rn) was the primary natural radionuclide of interest in this study; however, supplementary radium (226Ra and 228Ra) in-water measurements were also conducted. A total of 53 aquifers spanning three provinces were studied during three separate measurement campaigns from 2014 to 2016. The Karoo Basin’s natural radon-in-water levels can be characterised by a minimum of 1 ± 1 Bq/L (consistent with zero or below LLD), a maximum of 183 ± 18 Bq/L and mean of 41 ± 5 Bq/L. The mean radon-in-water levels for shallow aquifers were systematically higher (55 ± 10 Bq/L) compared to deep (14 ± 3 Bq/L) or mixed aquifers (20 ± 6 Bq/L). Radon-in-water activity concentration fluctuations were predominantly observed from shallow aquifers compared to the generally steady levels of deep aquifers. A collective seasonal mean radon-in-water levels increase from the winter of 2014 (44 ± 8 Bq/L) to winter of 2016 (61 ± 16 Bq/L) was noticed which could be related to the extreme national drought experienced in 2015. Radium-in-water (228Ra and 226Ra) levels ranged from below detection level to a maximum of 0.008 Bq/L (226Ra) and 0.015 Bq/L (228Ra). The 228Ra/226Ra ratio was characterised by a minimum of 0.93, a maximum of 6.5 and a mean value of 3.3 ± 1.3. Developing and improving baseline naturally occurring radionuclide groundwater databases is vital to study potential radiological environmental impacts attributed to industrial processes such as hydraulic fracturing or mining.
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ISSN 0969-8043 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ botha_radon_2019 Serial 169
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Author (down) Borrego-Alonso, D.; Quintana-Arnés, B.; Lozano, J.C.
Title Natural radionuclides behaviour in drinking groundwaters from Castilla y León (Spain); radiological implications Type Journal Article
Year 2023 Publication Water Research Abbreviated Journal
Volume 245 Issue Pages 120616
Keywords Drinking water, Environmental monitoring, Natural radioactivity, Public health, Radiological characterisation
Abstract Since the coming into force of the European Council Directive 51/2013 EURATOM and its transposition into the Spanish legislation, the presence of radioactive substances in drinking waters must be kept under surveillance to ensure that the health protection requirements are met. Driven by this regulatory framework, in an attempt to know the starting point from which to design surveillance plans, the groundwaters intended for human consumption of Castilla y León (Spain) have been radiologically characterised by using both low-level γ-ray and α-particle spectrometry to determine the activity concentration of the natural radionuclides needed to account for the indicative dose estimation. This extensive research has comprised the radiological characterisation of more than 400 drinking water samples from one of the European Union’s largest regions. Furthermore, the gross α and gross β activities have been analysed. Results showed a high geographical variability that can be related to the hydrogeological formations where the groundwaters come from. The uranium isotopes, 234U and 238U, are the main radionuclides present in the analysed drinking waters reaching values up to 2000 mBq/L, in the southwestern and western of Castilla y León, where U-rich minerals are part of the host rock. High 210Pb and 226,228Ra occurrences are found in the low permeability igneous and metasedimentary hydrogeological formations of Salamanca province. From a public health protection point of view, 4.4% of the total drinking water samples from intakes exceeded the Indicative Dose parametric value of 0.1 mSv, which is a not negligible number of samples, being very likely related to granitic and metamorphosed host rock under specific local conditions. This fact highlights the need for research and consideration of special surveillance of the groundwaters from these areas.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0043-1354 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ borrego-alonso_natural_2023 Serial 157
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Author (down) Bonnetti, C.; Zhou, L.; Riegler, T.; Brugger, J.; Fairclough, M.
Title Large S isotope and trace element fractionations in pyrite of uranium roll front systems result from internally-driven biogeochemical cycle Type Journal Article
Year 2020 Publication Geochimica et Cosmochimica Acta Abbreviated Journal
Volume 282 Issue Pages 113-132
Keywords Activity cycle, Pyrite composition, Roll front uranium deposits, S isotope and trace element fractionation
Abstract Complex pyrite textures associated with large changes in isotopic and trace element compositions are routinely assumed to be indicative of multi-faceted processes involving multiple fluid and sulfur sources. We propose that the features of ore-stage pyrite from roll front deposits across the world, revealed in exquisite detail via high-resolution trace element mapping by LA-ICP-MS, reflect the dynamic internal evolution of the biogeochemical processes responsible for sulfate reduction, rather than externally driven changes in fluid or sulfur sources through time. Upon percolation of oxidizing fluids into the reduced host-sandstones, roll front systems become self-organized, with a systematic reset of their activity cycle after each translation stage of the redox interface down dip of the aquifer. Dominantly reducing conditions at the redox interface favor the formation of biogenic framboidal pyrite (δ34S from −30.5 to −12.5‰) by bacterial sulfate reduction and the genesis of the U mineralization. As the oxidation front advances, oxidation of reduced sulfur minerals induces an increased supply of sulfate and metals in solution to the bacterial sulfate reduction zone that has similarly advanced down the flow gradient. Hence, this stage is marked by increased rates of the bacterial sulfate reduction associated with the crystallization of variably As-Co-Ni-Mo-enriched concentric pyrite (up to 10,000′s of ppm total trace contents) with moderately negative δ34S values (from −13.7 to −7.5‰). A final stage of pyrite cement with low trace element contents and heavier δ34S signature (from −6.9 to +18.8‰) marks the end of the roll front activity cycle and the transition from an open to a predominantly closed system behavior (negligible advection of fresh sulfate). Blocky pyrite cement is formed using the remaining sulfate, which now becomes quickly heavy according to a Rayleigh isotope fractionation process. This ends the cycle by depleting the nutrient supplies for the sulfate-reducing bacteria and cementing pore spaces within the host sandstone, effectively restricting fluid infiltration. This internally-driven roll front activity cycle results in systematic, large S isotope and trace element fractionation. Ultimately, the long-time evolution of the basin and fluid sources control the metal endowment and evolution of the system; these events, however, are unlikely to be preserved by the roll front, as a direct result of its hydrodynamic nature.
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ISSN 0016-7037 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ bonnetti_large_2020 Serial 185
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Author (down) Belz, L.; Schüller, I.; Wehrmann, A.; Köster, J.; Wilkes, H.
Title The leaf wax biomarker record of a Namibian salt pan reveals enhanced summer rainfall during the Last Glacial-Interglacial Transition Type Journal Article
Year 2020 Publication Palaeogeography, Palaeoclimatology, Palaeoecology Abbreviated Journal
Volume 543 Issue Pages 109561
Keywords -Alkanes, -Alkanols, Late Quaternary, Organic geochemistry, Palaeohydrology, Southern Africa
Abstract Conventional continental geoarchives are rarely available in arid southern Africa. Therefore, palaeoclimate data in this area are still patchy and late Quaternary climate development is only poorly understood. In the western Kalahari, salt pans (playas, ephemeral lakes) are common and can feature quasi-continuous sedimentation. This study presents the first climate-related biomarker record using sediments from the Omongwa Pan, a Kalahari salt pan located in eastern Namibia. Our approach to reconstruct vegetation and hydrology focuses on biogeochemical bulk parameters and plant wax-derived lipid biomarkers (n-alkanes, n-alkanols, and fatty acids) and their compound-specific carbon and hydrogen isotopic compositions. The presented record reaches back to 27 ka. During the glacial, rather low δ2H values of n-alkanes and low sediment input exclude a strong influence of winter rainfall. n-Alkane and n-alkanol distributions and δ13C values of n-hentriacontane (n-C31) indicate a shift to a vegetation with a higher proportion of C4 plants at the end of the Last Glacial Maximum until the end of Heinrich Stadial I (ca. 18–14.8 ka), which we interpret to indicate an abrupt excursion to a short wetter period likely to be caused by a temporary southward shift of the Intertropical Convergence Zone. Shifts in δ2H values of n-C31 and plant wax parameters give evidence for changes to drier conditions during early Holocene. Comparison of this dataset with representative continental records from the region points to a major influence of summer rainfall at Omongwa Pan during the regarded time span and demonstrates the potential of southern African salt pans as archives for biomarker-based climate proxies.
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Series Editor Series Title Abbreviated Series Title
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ISSN 0031-0182 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ belz_leaf_2020 Serial 104
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Author (down) Baptista, V.S.G.; Coelho, V.H.R.; Bertrand, G.F.; Silva, G.B.L. da; Caicedo, N.O.L.; Montenegro, S.M.G.L.; Stefan, C.; Glass, J.; Heim, R.; Conrad, A.; Almeida, C. das N.
Title Rooftop water harvesting for managed aquifer recharge and flood mitigation in tropical cities: Towards a strategy of co-benefit evaluations in João Pessoa, northeast Brazil Type Journal Article
Year 2023 Publication Journal of Environmental Management Abbreviated Journal
Volume 342 Issue Pages 118034
Keywords Flood control, Groundwater, Injection well, Stormwater management, Urban drainage, Aquifer storage and recovery
Abstract Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.
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Series Editor Series Title Abbreviated Series Title
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ISSN 0301-4797 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Baptista2023118034 Serial 237
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Author (down) Asare, P.; Atun, F.; Pfeffer, K.
Title Nature-Based Solutions (NBS) in spatial planning for urban flood mitigation: The perspective of flood management experts in Accra Type Journal Article
Year 2023 Publication Land Use Policy Abbreviated Journal
Volume 133 Issue Pages 106865
Keywords Naure-Based Solutions, Urban expansion, Urban floods, Urban flood management, Spatial planning, NBS integration
Abstract The rapid rate of urban expansion with its associated physical development in recent years conflicts with the urban ecosystem and the services it provides. In most Sub-Saharan African cities, rapid urban expansion often does not conform to existing spatial plans. Physical developments are sometimes carried out in unauthorized areas, contributing to urban floods. The Sub-Saharan African regions’ flood management strategies mainly focus on engineering solutions but have not been fully functional in mitigating urban floods. There is a scarcity of knowledge on how urban flood-related NBS measures can be part of the spatial development in Sub-Saharan African cities for effective flood management. In order to address this gap, this study employed content and text analysis of policy documents and interviews to understand how current spatial and flood mitigation schemes in Accra, Ghana reflect possible NBS applicability and identify possible approaches to integrating NBS into existing planning schemes to prevent urban floods. The study found that Accra’s spatial plans and flood mitigation schemes reflect a possibility of NBS integration. Additionally, the study unveiled techniques for integrating NBS measures and possible implementation barriers and facilitation in the Ghanaian context, which can be linked to combating the challenges that the Ghanaian spatial planning and flood management authorities face. The research, therefore, contributes to knowledge of how NBS can be integrated into spatial planning systems and flood mitigation schemes in Sub-Saharan African regions.
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ISSN 0264-8377 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Asare2023106865 Serial 236
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Author (down) Arya, S.; Kumar, A.
Title Evaluation of stormwater management approaches and challenges in urban flood control Type Journal Article
Year 2023 Publication Urban Climate Abbreviated Journal
Volume 51 Issue Pages 101643
Keywords Flood risk, Green infrastructure (GI), Stormwater management, Stormwater modelling, Vulnerability assessment, Urban floods
Abstract Across the globe, the damage caused by urban floods has increased manifold. The unchecked development has encroached the natural drainage, and the conventional drainage systems are inadequate in handling the augmented hydrological response. To counter this, a variety of approaches with the ability to adjust within the constraints of complex environments by managing surface runoff are being widely investigated and applied worldwide. These can put the flood water to better use, and the ecological balance may get restored. This review discusses recent progress made in the area of Green Infrastructure (GI), modelling tools that help in stormwater management, vulnerability analysis and flood risk assessment. Different ways of handling the problem are summarized through an extensive literature survey. The gaps and barriers that impede the implementation of stormwater management solutions and strategies for further improvement have also been presented. A case study of Gurugram city, India depicting the challenges being faced by urban flooding and the possible solutions through an expert survey is also presented.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-0955 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ Arya2023101643 Serial 224
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Author (down) Ammar, F.H.; Deschamps, P.; Chkir, N.; Zouari, K.; Agoune, A.; Hamelin, B.
Title Uranium isotopes as tracers of groundwater evolution in the Complexe Terminal aquifer of southern Tunisia Type Journal Article
Year 2020 Publication Quaternary International Abbreviated Journal
Volume 547 Issue Pages 33-49
Keywords CT southern Tunisia, Holocene, Mixing, Radicarbon, Uranium isotopes, Water-rock interaction
Abstract The Complexe Terminal (CT) multi-layer aquifer is formed by Neogene/Paleogene sand deposits, Upper Senonian (Campanian-Maastrichtian limestones) and Turonian carbonates. The chemical composition and isotopes of carbon and uranium were investigated in groundwater sampled from the main hydrogeological units of the (CT) aquifer in southern Tunisia. We paid special attention to the variability of uranium contents and isotopes ratio (234U/238U) to provide a better understanding of the evolution of the groundwater system. Uranium concentrations range from 1.5 to 19.5 ppb, typical of oxic or mildly reducing conditions in groundwaters. The lowest concentrations are found southeast of the study area, where active recharge is supposed to take place. When looking at the isotope composition, it appears that all the samples, including those from carbonate levels, are in radioactive disequilibrium with significant 234U excess. A clear-cut distinction is observed between Turonian and Senonian carbonate aquifers on the one hand, with 234U/238U activity ratios between 1.1 and 1.8, and the sandy aquifer on the other hand, showing higher ratios from 1.8 to 3.2. The distribution of uranium in this complex aquifer system seems to be in agreement with the lithological variability and are ultimately a function of a number of physical and chemical factors including the uranium content of the hosting geological formation, water-rock interaction and mixing between waters having different isotopic signatures. Significant relationships also appear when comparing the uranium distribution with the major ions composition. It is noticeable that uranium is better correlated with sulfate, calcium and magnesium than with other major ions as chloride or bicarbonate. The 14C activities and δ13C values of DIC cover a wide range of values, from 1.1 pmc to 30.2 pmc and from −3.6‰ to −10.7‰, respectively. 14C model ages estimated by the Fontes and Garnier model are all younger than 22 Ka and indicate that the recharge of CT groundwater occurred mainly during the end of the last Glacial and throughout the Holocene.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1040-6182 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ ammar_uranium_2020 Serial 119
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Author (down) Alvarado, J.A.C.; Balsiger, B.; Röllin, S.; Jakob, A.; Burger, M.
Title Radioactive and chemical contamination of the water resources in the former uranium mining and milling sites of Mailuu Suu (Kyrgyzstan) Type Journal Article
Year 2014 Publication Journal of Environmental Radioactivity Abbreviated Journal
Volume 138 Issue Pages 1-10
Keywords Former uranium mines, Kyrgyzstan, Mailuu Suu, Uranium contamination, Water resources
Abstract An assessment of the radioactive and chemical contamination of the water resources at the former uranium mines and processing sites of Mailuu-Suu, in Kyrgyzstan, was carried out. A large number of water samples were collected from the drinking water distribution system (DWDS), rivers, shallow aquifers and drainage water from the mine tailings. Radionuclides and trace metal contents in water from the DWDS were low in general, but were extremely high for Fe, Al and Mn. These elements were associated with the particle fractions in the water and strongly correlated with high turbidity levels. Overall, these results suggest that water from the DWDS does not represent a serious radiological hazard to the Mailuu Suu population. However, due to the high turbidities and contents of some elements, this water is not good quality drinking water. Water from artesian and dug wells were characterized by elevated levels of U (up to 10 μg/L) and some trace elements (e.g. As, Se, Cr, V and F) and anions (e.g. Cl−, NO3−, SO42−). In two artesian wells, the WHO guideline value of 10 μg/L for As in water was exceeded. As the artesian wells are used as a source of drinking water by a large number of households, special care should be taken in order to stay within the WHO recommended guidelines. Drainage water from the mine tailings was as expected highly contaminated with many chemicals (e.g. As) and radioactive contaminants (e.g. U). The concentrations of U were more than 200 times the WHO guideline value of 30 μg/L for U in drinking water. A large variation in 234U/238U isotopic ratios in water was observed, with values near equilibrium at the mine tailings and far from equilibrium outside this area (reaching ratios of 2.3 in the artesian well). This result highlights the potential use of this ratio as an indicator of the origin of U contamination in Mailuu Suu.
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Series Editor Series Title Abbreviated Series Title
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ISSN 0265-931x ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ alvarado_radioactive_2014 Serial 123
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Author (down) Alexander, A.C.; Ndambuki, J.M.
Title Impact of mine closure on groundwater resource: Experience from Westrand Basin-South Africa Type Journal Article
Year 2023 Publication Physics and Chemistry of the Earth, Parts A/B/C Abbreviated Journal
Volume 131 Issue Pages 103432
Keywords Acid mine drainage, Groundwater quality, Mine closure, Spatio-temporal variation, Westrand Basin
Abstract The mining sector is at the edge of expanding to cater for natural resources that are much needed for technological development and manufacturing. Mushrooming of mines will consequently increase the number of mines closure. Moreover, mines closure have adverse impact on the environment at large and specifically on water resources. This study analyses historical groundwater quality parameters in mine intensive basin of Westrand Basin (WRB) to understand the status of groundwater quality in relation to mining activities and mine closure. Geographic information system (GIS) was used to map the spatio-temporal variation of groundwater quality in the basin and groundwater quality index (GQI) to evaluate its status. The coefficient of variation (CV) was applied to understand the stability of groundwater quality after the mine closure. Results indicated unstable and altered trend with increasing levels of acidity and salts concentration around the mines vicinity following the mine closure. The resultant maps indicated a significant deterioration of groundwater quality around the WRB with concentrations decreasing downstream. Obtained average GQI for the study period of 1996–2015 suggested a moderate groundwater quality at a range of GQI = 64–73. The CV indicated varying water quality at CV \textgreater 30% suggesting presence of source of contamination. Observed groundwater quality trends in Westrand basin suggested that mines closure present potential threat on groundwater quality and thus, a need for a robust mine closure plan and implementation.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1474-7065 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number THL @ christoph.kuells @ alexander_impact_2023 Serial 134
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