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Author Külls, C.; Bittner, A.; Marx, V. openurl 
  Title (down) Strategic Assessment of Water Resources for the Erongo Uranium Province Type Miscellaneous
  Year 2013 Publication IMWA Conf. Abbreviated Journal  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Kuells2012strategic Serial 70  
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Author Mühr-Ebert, E.L.; Wagner, F.; Walther, C. url  openurl
  Title (down) Speciation of uranium: Compilation of a thermodynamic database and its experimental evaluation using different analytical techniques Type Journal Article
  Year 2019 Publication Applied Geochemistry Abbreviated Journal  
  Volume 100 Issue Pages 213-222  
  Keywords  
  Abstract Environmental hazards are caused by uranium mining legacies and enhanced radioactivity in utilized groundwater and surface water resources. Knowledge of uranium speciation in these waters is essential for predicting radionuclide migration and for installing effective water purification technology. The validity of the thermodynamic data for the environmental media affected by uranium mining legacies is of utmost importance. Therefore, a comprehensive and consistent database was established according to current knowledge. The uranium data included in the database is based on the NEA TDB (Guillaumont et al., 2003) and is modified or supplemented as necessary e.g. for calcium and magnesium uranyl carbonates. The specific ion interaction theory (Brönsted, 1922) is used to estimate activity constants, which is sufficient for the considered low ionic strengths. The success of this approach was evaluated by comparative experimental investigations and model calculations (PHREEQC (Parkhurst and Appelo, 1999)) for several model systems. The waters differ in pH (2.7–9.8), uranium concentration (10−9-10−4 mol/L) and ionic strength (0.002–0.2 mol/L). We used chemical extraction experiments, ESI-Orbitrap-MS and time-resolved laser-induced fluorescence spectroscopy (TRLFS) to measure the uranium speciation. The latter method is nonintrusive and therefore does not change the chemical composition of the investigated waters. This is very important, because any change of the system under study may also change the speciation.  
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  ISSN 0883-2927 ISBN Medium  
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  Call Number THL @ christoph.kuells @ muhr-ebert_speciation_2019 Serial 142  
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Author N, D.; Panda, B.; S, C.; V, P.M.; Singh, D.K.; L, R.A.; Sahoo, S.K. url  openurl
  Title (down) Spatio-temporal variations of Uranium in groundwater: Implication to the environment and human health Type Journal Article
  Year 2021 Publication Science of The Total Environment Abbreviated Journal  
  Volume 775 Issue Pages 145787  
  Keywords Groundwater, Health risk, Speciation, Stable isotopes, Statistics, Uranium  
  Abstract Groundwater overexploitation has resulted in huge scarcity and increase in the demand for water and food security in India. Groundwater in India has been observed to have experienced various water quality issues like arsenic, fluoride, and Uranium (U) contamination, leading to risk in human health. Markedly, the health risk of higher U in drinking water, as well as its chemical toxicity in groundwater have adverse effects on human. This study has reported occurrence of U as an emerging and widespread phenomenon in South Indian groundwater. Data on U in groundwater were generated from 284 samples along the Cretaceous Tertiary boundary within 4 seasons viz. pre-monsoon (PRM), southwest monsoon (SWM), northeast monsoon (NEM), and post-monsoon (POM). High U concentrations (74 μgL−1) showed to be above the World Health Organization’s provisional guideline value of 30 μgL−1. The geochemical, stable isotope and geophysical studies suggested that U in groundwater could vary with respect to season and was noted to be highest during NEM. The bicarbonate (HCO3) released by weathering process during monsoon could affect the saturation index (SI)Calcite and carbonate species of U. However, the primary source of U was found to be due to geogenic factors, like weathering, dissolution, and groundwater level fluctuation, and that, U mobilization could be enhanced due to anthropogenic activities. The findings further indicated that groundwater in the study area has reached the alarming stage of chemical toxicity. Hence, it is urgent and imperative that workable management strategies for sustainable drinking water source be developed and preventive measures be undertaken, relative to these water quality concerns to mitigate their disconcerting effect on human health.  
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  ISSN 0048-9697 ISBN Medium  
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  Call Number THL @ christoph.kuells @ n_spatio-temporal_2021 Serial 146  
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Author Heaton, T.H.E. url  openurl
  Title (down) Sources of the nitrate in phreatic groundwater in the western Kalahari Type Journal Article
  Year 1984 Publication Journal of Hydrology Abbreviated Journal  
  Volume 67 Issue 1 Pages 249-259  
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  Abstract Elevated levels of nitrate occur in phreatic groundwater in the western Kalahari, Namibia. Nitrate in water containing 0.4–3.1 meq NO−3l−1, of widespread occurrence, has δ15N values in the range +4.9 to +8.0‰, suggesting natural derivation from the soil. The sporadic occurrence of very high levels of nitrate (> 4 meq NO−3l−1), which has δ15N between +9.3 to +18.7‰, reflects pollution derived from animal waste. The importance of considering the possible isotopic effects of denitrification, and the significance of leaching in the nitrogen budget of the Kalahari soil, are also discussed.  
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  ISSN 0022-1694 ISBN Medium  
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  Notes Approved no  
  Call Number THL @ christoph.kuells @ Heaton1984249 Serial 278  
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Author Rajfur, M.; Kłos, A.; Wacławek, M. url  openurl
  Title (down) Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water Type Journal Article
  Year 2010 Publication Bioelectrochemistry Abbreviated Journal  
  Volume 80 Issue 1 Pages 81-86  
  Keywords Biomonitoring, Heavy metal ions, Algae sp., Sorption kinetics, Langmuir isotherm  
  Abstract Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions – Mn2+, Cu2+, Zn2+ and Cd2+ – were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30min, with 90-95% of metal ions sorbed in first 10min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations.  
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  ISSN 1567-5394 ISBN Medium  
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  Notes A Selection of Papers presented at the 4th International Workshop on Surface Modification for Chemical and Biochemical Sensing (SMCBS 2009) Approved no  
  Call Number THL @ christoph.kuells @ Rajfur201081 Serial 283  
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