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Author Silva, M.L. da; Bonotto, D.M.
Title Uranium isotopes in groundwater occurring at Amazonas State, Brazil Type Journal Article
Year 2015 Publication (up) Applied Radiation and Isotopes Abbreviated Journal
Volume 97 Issue Pages 24-33
Keywords Amazon area, Dissolved uranium, Groundwater, Tube wells, U/U activity ratio
Abstract This paper reports the behavior of the dissolved U-isotopes 238U and 234U in groundwater providing from 15 cities in Amazonas State, Brazil. The isotope dilution technique accompanied by alpha spectrometry were utilized for acquiring the U content and 234U/238U activity ratio (AR) data, 0.01–1.4µgL−1 and 1.0–3.5, respectively. These results suggest that the water is circulating in a reducing environment and leaching strata containing minerals with low uranium concentration. A tendency to increasing ARs values following the groundwater flow direction is identified in Manaus city. The AR also increases according to the SW–NE directions: Uarini→Tefé; Manacapuru→Manaus; Presidente Figueiredo→São Sebastião do Uatumã; and Boa Vista do Ramos→Parintins. Such trends are possibly related to several factors, among them the increasing acid character of the waters. The waters analyzed are used for human consumption and the highest dissolved U content is much lower than the maximum established by the World Health Organization. Therefore, in view of this radiological parameter they can be used for drinking purposes.
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ISSN 0969-8043 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ silva_uranium_2015 Serial 140
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Author 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 (up) 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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Notes Approved no
Call Number THL @ christoph.kuells @ botha_radon_2019 Serial 169
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Author Romeo, N.; Mabry, J.; Hillegonds, D.; Kainz, G.; Jaklitsch, M.; Matsumoto, T.
Title Developments of a field gas extraction device and krypton purification system for groundwater radio-krypton dating at the IAEA Type Journal Article
Year 2022 Publication (up) Applied Radiation and Isotopes Abbreviated Journal
Volume 189 Issue Pages 110450
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Abstract The long-lived radio-krypton isotope 81Kr (t1/2 = 2.29 × 105 yr) is an ideal tracer for old groundwater age dating in the range of 105–106 years which goes beyond the reach of radio-carbon (14C) age dating. Analytical breakthrough made over the last two decades in Atom Trap Trace Analysis (ATTA) has enabled the use of this isotope with extremely low abundance (81Kr/Kr = 6 × 10−13) to be used as a practical dating tool for very old groundwater. The International Atomic Energy Agency aims to provide this new isotope tool for better groundwater resource management of Member States and developed a field sampling device to collect dissolved gas samples from groundwater and a system to separate and purify trace amounts of krypton from the gas samples for the ATTA analysis. The design, setup and performances of our sampling and purification systems are described here. Our system can produce a high purity aliquot of about 5 μL of krypton from 5 L of air sample (recovery yield of >90%). The samples made by our system were confirmed to be acceptable for the ATTA analysis.
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ISSN 0969-8043 ISBN Medium
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Notes Approved no
Call Number THL @ christoph.kuells @ Romeo2022110450 Serial 214
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Author Külls, C.; Schwarz, O.
Title Grundwasseranreicherung in den Waldbeständen der Teninger Allmend bei Freiburg im Breisgau Type Book Chapter
Year 2000 Publication (up) 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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Call Number THL @ christoph.kuells @ Serial 72
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Author Külls, C.
Title Rekonstruktion hydrologischer Extreme in der Namibwüste Type Journal Article
Year 2011 Publication (up) Berichte der naturforschenden Gesellschaft zu Freiburg im Breisgau Abbreviated Journal
Volume Issue 101 Pages 69-81
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Notes Approved no
Call Number THL @ christoph.kuells @ Serial 71
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