Uranium-Series Disequilibria in the Groundwater of the Shihongtan Sandstone-Hosted Uranium Deposit, NW China

Peng, Xinjian; Min, Maozhong; Hai-ming, Qiao; Wang, Jinping; Fayek, Mostafa

doi:10.3390/min6010003

Cited by 8 publications

(6 citation statements)

References 37 publications

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“…As mentioned earlier, differential leaching of 234 U from the host matrix leads to variations in the activity ratio ( 234 U/ 238 U) in the aquifer 48 . The 234 U/ 238 U ratios are explained either by oxidising waters close to recharge zones, which have high 238 U contents and low 234 U/ 238 U activity ratios, or by reducing conditions, which have lower solubilities of 238 U and higher 234 U/ 238 U activity ratios.Our results argue for reducing conditions, and a-recoil processes preferentially inject 234 U into solution 38 .…”

Section: Resultsmentioning

confidence: 77%

Dating of groundwater using uranium isotopes disequilibrium in Siwa Oasis, Western Desert, Egypt

Imam

2023

Sci Rep

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Data on the recent migratory history of radionuclides as well as geochemical circumstances can be obtained from the disequilibrium of the uranium series, which is often brought on by groundwater flow and host rock. Groundwater from the Siwa Oasis is a vital source of water for many uses, and it is distributed widely throughout the Western Desert. Groundwater in Siwa Oasis was dated using measurements of uranium in the water. In water samples that exhibited disequilibrium behavior, the activity concentrations of radionuclides from the 238U, 235U and 232Th series were measured. Therefore we conclude that the measured waters are rich in the 234U and 230Th. The secular equilibrium between 234U and 230Th indicates that colloidal transport could be the mechanism for the mobility of 230Th in groundwater. Higher 230Th levels in the samples show that the aquifer is deep and may have a large amount of thorium-bearing minerals. The lake and groundwater estimated ages showed that the time of uranium migration happened between 60 and 130 ka ago. This aquifer is rich in mineral deposits, as evidenced by the extraordinarily high content of radionuclides. The 230Th/232Th activity ratio of the samples, indicating pure carbonate minerals, ranged from 12.58 to 20.86.

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Section: Resultsmentioning

confidence: 77%

Dating of groundwater using uranium isotopes disequilibrium in Siwa Oasis, Western Desert, Egypt

Imam

2023

Sci Rep

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“…40 The available O 2 would oxidize uraninite in the solids into U(VI), if present, which is more mobile. 41 Uranium was highly soluble in oxic ground- waters and predominant as U(VI). 42 In addition, HCO 3 − promotes U mobilization in groundwater, which is evidenced from the fact that U concentrations were positively correlated with HCO 3 − in the fans (R = 0.71; p < 0.05).…”

Section: ■ Resultsmentioning

confidence: 99%

“…In the presence of CO 2 , both calcite and silicate could be dissolved and, therefore, mobilize fixed U . The available O 2 would oxidize uraninite in the solids into U(VI), if present, which is more mobile . Uranium was highly soluble in oxic groundwaters and predominant as U(VI) .…”

Section: Discussionmentioning

confidence: 99%

High Radionuclides in Groundwater of an Inland Basin from Northwest China: Origin and Fate

Guo

Zhao

et al. 2018

ACS Earth Space Chem.

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Inland basins show various redox conditions in the groundwater system, which control the distribution and transportation of redox-sensitive radionuclides. However, the origin and fate of groundwater radionuclides in those basins are still unclear. High levels of naturally occurring uranium (U) and radon (Rn) have been observed in low total dissolved solid and oxic groundwater in the recharge area of the Hetao basin, a typical inland basin. Around 80% of investigated groundwater had U concentrations above the international drinking water standards (30 μg/L), and 97% exceeded the United States Environmental Protection Agency (U.S. EPA) guideline of 11.1 Bq/L Rn. Groundwater U was mobilized by oxic weathering and complexation with carbonate, while Rn-222 was mainly provided by α recoil of adsorbed Ra on the aquifer solids. Relatively high radium (Ra) activities were frequently found in reducing groundwater of the transition area and the flat plain, although combined Ra-226 and Ra-228 did not exceed the international drinking water standard. Radium isotopes showed that Ra was mainly mobilized via reductive dissolution of Fe/Mn oxides and α recoil of parent Th isotopes on aquifer sediments. As a result of saturation of barite in groundwater, co-precipitation would be a significant removal mechanism for groundwater Ra, which restrains Ra activities within the U.S. EPA guideline of 0.185 Bq/L. This study suggested that, in other analogue arid/semi-arid basins of northwestern China with high U backgrounds, where both SO 4 2− and Ba concentrations are low under reducing conditions, activities of groundwater Ra isotopes deserve evaluation for their potential health risks. As a result of severe health impacts of drinking water U, the drinking water standard for the U level is needed in China.

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“…Peng et al [34] show that the groundwater from an oxidizing aquifer with a high dissolved oxygen concentration (O 2 ), like in the case of the Jelovička and Dojkinčka rivers is enriched in U. The material from this and similar outcrops is regularly washed out by runoff after heavy rainfall or snowmelt, into the Jelovička River (a tributary of the Dojkinačka).…”

Section: Discussionmentioning

confidence: 99%

Natural Radioactivity of Intrusive-Metamorphic and Sedimentary Rocks of the Balkan Mountain Range (Serbia, Stara Planina)

Abdulqader

Vakanjac

Kovačević³

et al. 2017

Minerals

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Stara Planina (also known as the Balkan mountain range) is known for numerous occurrences and deposits of uranium and associated radionuclides. It is also famous for its geodiversity. The geologic framework is highly complex. The mountain is situated between the latitudes of 43 • and 44 • N and the longitudes from 22 • 16 to 23 • 00 E. Uranium exploration and radioactivity testing on Stara Planina began back in 1948. Uranium has also been mined in the zone of Kalna, within the Janja granite intrusive. The naturally radioactive geologic units of Stara Planina are presented in detail in this paper. The main sources of radioactivity on Stara Planina can be classified as: 1. Granitic endogenous-syngenetic-epigenetic deposits and occurrences; 2. Metamorphogenic-syngenetic; and 3. Sedimentary, including occurrences of uranium deposition and fluctuation caused by water in different types of sedimentary rocks formed in a continental setting, which could be classified under epigenetic types. The area of Stara Planina with increased radioactivity (higher than 200 cps), measured by airborne gamma spectrometry, is about 380 square kilometers. The highest values of measured radioactivity and uranium grade were obtained from a sample taken from the Mezdreja uranium mine tailing dump, where 226 Ra measures 2600 ± 100 Bq/kg and the uranium grade is from 76.54 to 77.65 ppm U. The highest uranium (and lead) concentration, among all samples, is measured in graphitic schist with high concentrations of organic (graphitic) material from the Inovska Series-99.47 ppm U and 107.69 ppm Pb. Thorium related radioactivity is the highest in granite samples from the Janja granite in the vicinity of the Mezdreja granite mine and the Gabrovnica granite mine tailing dump, and it is the same-250 ± 10 Bq/kg for 232 Th, while the thorium grade varies from 30.82 to 60.27 ppm Th. In gray siltstones with a small amount of organic material, the highest radioactivity is related to potassium-2080 ± 90 Bq/kg for 40 K.

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Uranium-Series Disequilibria in the Groundwater of the Shihongtan Sandstone-Hosted Uranium Deposit, NW China

Cited by 8 publications

References 37 publications

Dating of groundwater using uranium isotopes disequilibrium in Siwa Oasis, Western Desert, Egypt

Dating of groundwater using uranium isotopes disequilibrium in Siwa Oasis, Western Desert, Egypt

High Radionuclides in Groundwater of an Inland Basin from Northwest China: Origin and Fate

Natural Radioactivity of Intrusive-Metamorphic and Sedimentary Rocks of the Balkan Mountain Range (Serbia, Stara Planina)

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