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Author Külls, C.; Haering, M.; Leistert, H.; Oster, H. openurl 
  Title (down) Hydrological, physical and chemical constraints for groundwater age dating with CFC and SF6 Type Conference Article
  Year Publication G-DAT 2008-Leipzig Abbreviated Journal  
  Volume Issue Pages 29  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Kuells2008hydrological Serial 57  
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Author Gasse, F. url  openurl
  Title (down) Hydrological changes in the African tropics since the Last Glacial Maximum Type Journal Article
  Year 2000 Publication Quaternary Science Reviews Abbreviated Journal  
  Volume 19 Issue 1 Pages 189-211  
  Keywords  
  Abstract Paleohydrological data from the African tropics and subtropics, including lake, groundwater and speleothem records, are reviewed to show how environments and climates from both hemispheres are inter-related. Although orbitally induced changes in the monsoon strength account for a large part of long-term climatic changes in tropical Africa, the Late Pleistocene–Holocene hydrological fluctuations rather appear to have been a series of abrupt events that reflect complex interactions between orbital forcing, atmosphere, ocean and land surface conditions. During the Last Glacial Maximum (23–18ka BP), most records indicate that generally dry conditions have prevailed in both hemispheres, associated with lower tropical land- and sea-surface temperatures. This agrees with simulations using coupled ocean–atmosphere models, which predict cooling and reduced summer precipitation in tropical Africa; the global hydrological cycle was weaker than today when the extent of large polar ice-sheets and sea-ice was a prominent forcing factor of the Earth’s climate. Glacial-interglacial climatic changes started early: a first wetting/warming phase at ca. 17–16ka BP took place during a period of rapid temperature increase in Antarctica. Next, two drastic arid-humid transitions in equatorial and northern Africa occurred around 15–14.5ka BP and 11.5–11ka BP. Both are thought to match the major Greenland warming events, in concert with the switching of the oceanic thermohaline circulation to modern mode. However, part of the climatic signal after 15 ka BP also seems related to the Antarctica climate. During the Holocene, Africa has also experienced rapid hydrological fluctuations of dramatic magnitude compared to the climatic changes at high latitudes. In particular, major dry spells occurred around 8.4–8ka and 4.2–4ka BP in the northern monsoon domain. Comparison with other parts of the world indicates that these events have a worldwide distribution but different regional expressions. In the absence of large polar ice sheets, changes in the continental hydrological cycles in the tropics may have a significant impact on the global climate system. Climate information gathered here allows to identify geographical and methodological gaps, and raise some scientific questions that remain to be solved to better understand how the tropics respond to changes in major climate-forcing factors, and how they influence climate globally.  
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  ISSN 0277-3791 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ gasse_hydrological_2000 Serial 96  
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Author Gimeno, M.J.; Tullborg, E.-L.; Nilsson, A.-C.; Auqué, L.F.; Nilsson, L. url  openurl
  Title (down) Hydrogeochemical characterisation of the groundwater in the crystalline basement of Forsmark, the selected area for the geological nuclear repositories in Sweden Type Journal Article
  Year 2023 Publication Journal of Hydrology Abbreviated Journal  
  Volume 624 Issue Pages 129818  
  Keywords Crystalline bedrock, Deep geological repository, Glacial meltwater intrusion, Groundwater mixing, Hydrogeochemical model, Nuclear waste disposal  
  Abstract Numerous groundwater analyses from the crystalline bedrock in the Forsmark area have been performed between 2002 and 2019, together with thorough geological, geophysical, and hydrogeological studies, within the site investigations carried out by the Swedish Nuclear Fuel and Waste Management Company. The groundwater samples have been taken from boreholes down to ≈ 1000 m and the analysis include major- and trace-elements, stable and radiogenic isotopes, gases and microbes. The chemical and isotopic composition of these groundwaters evidences the presence of non-marine brackish to saline groundwaters with very long residence times (many hundreds of thousands of years) and a series of complex mixing events resulting from the recharge of different waters over time: glacial meltwaters, probably from different glaciations of which the latest culminated some 20,000 years ago, and marine waters from the Baltic starting some 7000 years ago. Later, meteoric water and present Baltic Sea water have recharged in different parts of the upper 100 m. These mixing events have also triggered chemical and microbial reactions that have conditioned some of the important groundwater parameters and, together with the structural complexity of the area, they have promoted a heterogeneous distribution of groundwater compositions in the bedrock. Due to these evident differences in chemistry, residence time and origin of the groundwater, several groundwater types were defined in order to facilitate the visualisation and communication. The differentiation (linked to the paleohydrological history of the area) was based on Cl concentration, Cl/Mg ratio (marine component), and δ18O value (glacial component). The work presented in this paper increases the understanding of the groundwater evolution in fractured and compartmentalised aquifers where mixing processes are the most important mechanisms. The model proposed to characterise the present groundwater system of the Forsmark area will also help to predict the future hydrogeochemical behaviour of the groundwater system after the construction of the repositories for the nuclear wastes.  
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  Series Volume Series Issue Edition  
  ISSN 0022-1694 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ gimeno_hydrogeochemical_2023 Serial 137  
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Author Christofi, C.; Bruggeman, A.; Külls, C.; Constantinou, C. url  doi
openurl 
  Title (down) Hydrochemical evolution of groundwater in gabbro of the Troodos Fractured Aquifer. A comprehensive approach Type Journal Article
  Year 2020 Publication Applied Geochemistry Abbreviated Journal  
  Volume 114 Issue Pages 104524  
  Keywords geochemistry  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Pergamon Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number THL @ christoph.kuells @ Christofi2020hydrochemical Serial 13  
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Author Orloff, K.G.; Mistry, K.; Charp, P.; Metcalf, S.; Marino, R.; Shelly, T.; Melaro, E.; Donohoe, A.M.; Jones, R.L. url  openurl
  Title (down) Human exposure to uranium in groundwater Type Journal Article
  Year 2004 Publication Environmental Research Abbreviated Journal  
  Volume 94 Issue 3 Pages 319-326  
  Keywords Groundwater, Human exposure, Uranium, Urine  
  Abstract High concentrations of uranium (mean=620μg/L) were detected in water samples collected from private wells in a residential community. Based on isotopic analyses, the source of the uranium contamination appeared to be from naturally occurring geological deposits. In homes where well water concentrations of uranium exceeded the drinking water standard, the residents were advised to use an alternate water source for potable purposes. Several months after the residents had stopped drinking the water, urine samples were collected and tested for uranium. Elevated concentrations of uranium (mean=0.40μg/g creatinine) were detected in urine samples, and 85 percent of the urine uranium concentrations exceeded the 95th percentile concentration of a national reference population. Urine uranium concentrations were positively correlated with water uranium concentrations, but not with the participants’ ages or how long they had been drinking the water. Six months later, a second urine sample was collected and tested for uranium. Urine uranium concentrations decreased in most (63 percent) of the people. In those people with the highest initial urine uranium concentrations, the urine levels decreased an average of 78 percent. However, urine uranium concentrations remained elevated (mean=0.27μg/g), and 87 percent of the urine uranium concentrations exceeded the 95th percentile concentration of the reference population. The results of this investigation demonstrated that after long-term ingestion of uranium in drinking water, elevated concentrations of uranium in urine could be detected up to 10 months after exposure had stopped.  
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  ISSN 0013-9351 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ orloff_human_2004 Serial 136  
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Author Gaj, M.; Beyer, M.; Hamutoko, J.; Uugulu, S.; Wanke, H.; Koeniger, P.; Külls, C.; Lohe, C.; Himmelsbach, T. openurl 
  Title (down) How do soil types affect stable isotope ratios of 2H and 18O under evaporation: A Fingerprint of the Niipele subbasin of the Cuvelai-Etosha basin, Namibia Type Conference Article
  Year 2014 Publication EGU Geophysical Abstracts Abbreviated Journal  
  Volume Issue Pages 5890  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Gaj2014soil Serial 44  
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Author Kazemi, A.; Esmaeilbeigi, M.; Sahebi, Z.; Ansari, A. url  openurl
  Title (down) Health risk assessment of total chromium in the qanat as historical drinking water supplying system Type Journal Article
  Year 2022 Publication Science of The Total Environment Abbreviated Journal  
  Volume 807 Issue Pages 150795  
  Keywords Qanat, Total chromium, Hazard quotient, Non-carcinogenic risk, Risk assessment, Eastern Iran  
  Abstract This study investigated the health risk assessment of total chromium (CrT) in qanats of South Khorasan, Eastern Iran. For this, concentration of CrT in a total of 83 qanats were measured in summer 2020. Samples were initially tested in the field for temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), and total dissolved solids (TDS). In the lab, collected samples were filtered and fixed with nitric acid (HNO3) for the detection of CrT using inductively coupled plasma mass spectrometry (ICP-MS). Hazard quotient (HQ) and carcinogenic risk assessments were considered to evaluate the risks of CrT to inhabitants. Results showed that concentration of CrT ranged from 1.79 to 1017.05 μg L-1, and a total of 25 stations illuminated CrT concentrations above the WHO standards (50 μg L-1). HQ demonstrated HQ < 1 for 90.37% of studied samples with negligible hazard, whereas 9.63% of stations illuminated HQ ≥ 1 meaning the presence of non-carcinogenic risk for water consumers. Carcinogenic risk (CR) exhibited CR > 1.00E-04 in 81.93% of qanats while 18.07% of stations had 1.00E-06 < CR < 1.00E-04 meaning no acceptable and acceptable CR for the studied qanats, respectively. Zoning map displayed that qanats in the south of South Khorasan possessed the highest HQ, but north regions showed the lowest ones. Together, CrT in qanats of South Khorasan is above the WHO limit, which results in a high risk of carcinogenicity for residents, and in turn, more efforts should be made to provide hygienic groundwater for consumers.  
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  ISSN 0048-9697 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Kazemi2022150795 Serial 269  
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Author Külls, C.; Schwarz, O. openurl 
  Title (down) Grundwasseranreicherung in den Waldbeständen der Teninger Allmend bei Freiburg im Breisgau Type Book Chapter
  Year 2000 Publication Beiträge zur Physischen Geographie Abbreviated Journal  
  Volume Issue Pages 67 - 78  
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  Corporate Author Fachbereich Geowissenschaften der Johann Wolfgang Goethe-Universität Frankfurt am Main Thesis  
  Publisher Werner-F. Bär Place of Publication Frankfurt am Main Editor  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Serial 72  
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Author Tisherman, R.A.; Rossi, R.J.; Shonkoff, S.B.C.; DiGiulio, D.C. url  openurl
  Title (down) Groundwater uranium contamination from produced water disposal to unlined ponds in the San Joaquin Valley Type Journal Article
  Year 2023 Publication Science of The Total Environment Abbreviated Journal  
  Volume 904 Issue Pages 166937  
  Keywords Groundwater, Oil & gas, Produced water, San Joaquin Valley, Uranium  
  Abstract In the southern San Joaquin Valley (SJV) of California, an agriculturally productive region that relies on groundwater for irrigation and domestic water supply, the infiltration of produced water from oil reservoirs is known to impact groundwater due to percolation from unlined disposal ponds. However, previously documented impacts almost exclusively focus on salinity, while contaminant loadings commonly associated with produced water (e.g., radionuclides) are poorly constrained. For example, the infiltration of bicarbonate-rich produced waters can react with sediment-bound uranium (U), leading to U mobilization and subsequent transport to nearby groundwater. Specifically, produced water infiltration poses a particular concern for SJV groundwater, as valley-fill sediments are well documented to be enriched in geogenic, reduced U. Here, we analyzed monitoring well data from two SJV produced water pond facilities to characterize U mobilization and subsequent groundwater contamination. Groundwater wells installed within 2 km of the facilities contained produced water and elevated levels of uranium. There are \textgreater400 produced water disposal pond facilities in the southern SJV. If our observations occur at even a fraction of these facilities, there is the potential for widespread U contamination in the groundwaters of one of the most productive agricultural regions in the world.  
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  ISSN 0048-9697 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ tisherman_groundwater_2023 Serial 159  
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Author Ruiz, O.; Thomson, B.; Cerrato, J.M.; Rodriguez-Freire, L. url  openurl
  Title (down) Groundwater restoration following in-situ recovery (ISR) mining of uranium Type Journal Article
  Year 2019 Publication Applied Geochemistry Abbreviated Journal  
  Volume 109 Issue Pages 104418  
  Keywords Aquifer stabilization, Ground water restoration, In-situ leach mining, In-situ recovery, Uranium  
  Abstract From 1950 through the early 1980’s New Mexico accounted for roughly half of domestic uranium (U) production for the nuclear power industry and the nation’s weapon programs. Increased interest in nuclear energy has led to proposals for renewed development using both underground mining and uranium in situ recovery (ISR). When feasible, ISR greatly reduces waste generated by the mining and milling processes, however, the ability to restore ground water to acceptable quality after ISR ends is uncertain. This research investigated two methods of stabilizing an aquifer following ISR. Batch and column studies were performed to evaluate chemical and biological methods of stabilization. Columns packed with ore were first leached with an aerated NaHCO3 ground water solution to simulate ISR. Constituents present at elevated concentrations after leaching included molybdenum (Mo), selenium (Se), U, and vanadium (V). Chemical stabilization was studied by passing a phosphate (PO43-) amended solution through the ore to achieve passivation of mineral surfaces by P precipitates. Microbial stabilization was studied by passing a lactate solution through the ore to stimulate growth of anaerobic metal- and sulfate-reducing organisms to reduce U and other elements to less soluble phases. Analyses of the solids from the columns after completion of these experiments by X-ray photo electron spectroscopy (XPS) identified phosphate on samples near the column inlet of the chemically stabilized columns. Microbial populations were characterized by Illumina DNA sequencing and confirmed the presence of metal- and sulfate-reducing organisms. Neither chemical nor microbial stabilization method achieved contaminant immobilization, which is believed due to limited mixing of the stabilization solutions with the contaminated leach solutions. These results emphasize that ground water hydrodynamics, especially mixing, must be considered in aquifer restoration of soluble constituents.  
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  ISSN 0883-2927 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ ruiz_groundwater_2019 Serial 153  
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