scholarly journals Distribution of Uranium Isotopes in Sandy Deposits by Sequential Extraction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 467
Author(s):  
Alexander I. Malov ◽  
Sergey B. Zykov ◽  
Alexey S. Tyshov
Keyword(s):  
Sequential Extraction ◽  
Extraction Procedure ◽  
Sedimentary Basins ◽  
Retardation Factor ◽  
Uranium Isotopes ◽  
Complex Nature ◽  
Carbonate Minerals ◽  
Fresh Groundwater ◽  
Mineral Phases ◽  
Amorphous Minerals

The sequential extraction procedure is used to reconstruct the processes of redistribution of uranium isotopes in the mineral phases of the aquifer of the Vendian sandy-argillaceous deposits developed in the coastal territory of the European North of Russia. This aquifer has large resources of drinking and mineral groundwater which, however, are used in extremely limited quantities. This is due to the very complex nature of the hydrochemical conditions, and uranium-isotopic methods are used to clarify these conditions. The following mineral phases of core samples were characterized: adsorbed trace materials and carbonate minerals; ferrihydrate, amorphous minerals of Fe, Al and Si, and secondary U minerals; crystalline iron minerals; clay and some refractory minerals; and all remaining resistant minerals. The most resistant minerals, whose fraction ranges from 70.58 to 96.4%, have a minimum average uranium concentration of 0.47 ppm. This uranium is practically conserved in the rock, as a result of which the average ratio of its 234U:238U isotopes is close to equilibrium. In the remaining fractions, uranium is redistributed by groundwater along their flow lines from recharge areas in watersheds to areas of discharge into river valleys. Its maximum concentration (12.89 ppm) measurement is carried out by coprecipitation with iron hydroxides, then the uranium is adsorbed and precipitated with carbonates (9.14 ppm). The average 234U:238U is maximum in adsorbed trace materials and carbonate minerals (2.39 ± 0.36) and is close to that in fresh groundwater (2.8 ± 0.42). It is also increased in the amorphous minerals of Fe (1.53 ± 0.23). In general, there is a dependence of the 234U:238U activity ratio in rock on the degree of participation of groundwater in the deposition of hydrogenic uranium isotopes into the cracks and pores of these rocks. The results obtained contribute to the refinement of such a parameter as the retardation factor, which is necessary for understanding the processes of migration and concentration of uranium in sedimentary basins.

scholarly journals Study of the Mobilization of Uranium Isotopes in a Sandstone Aquifer Using Methods for the Extraction of Uranium with Different Strength Reagents in Combination with Groundwater Data

2019 ◽  
Author(s):  
Alexander I. Malov ◽  
Sergey B. Zykov
Keyword(s):  
Iron Oxides ◽  
Extraction Procedure ◽  
Retardation Factor ◽  
Uranium Isotopes ◽  
Iron Hydroxides ◽  
Carbonate Minerals ◽  
Amorphous Iron ◽  
Mineral Phases ◽  
Clay Deposits ◽  
Total Digestion

A partial extraction procedure was used to study the distribution of uranium in the mineral phases of rocks of an aquifer of sandy-clay deposits of the Vendian in the northwest of Russia. This work is a part of a research project to develop a method for combined radiocarbon and uranium-isotope dating of groundwater. Representative aliquots of each core sample were subjected to five "partial" extractions by treatment with: distilled water, low mineralized fresh natural groundwater, minopolycarboxylic acid chelating agent (0.05M EDTA), 0.5M HCl, 15M HNO3, and a total digestion, with U isotopes reported in this study for each procedure. The following mineral phases of core samples: adsorbed material, carbonate minerals, amorphous iron oxides, aluminosilicates partial digestion and a crystalline iron oxides, aluminosilicates total digestion and a clay/quartz resistate were characterized. Red-colored siltstones depleted in uranium in relatively readily soluble mineral phases. The concentration of adsorbed uranium was established in the amount of 15.8±2.1 - 30.5±3.9 μg/kg. Carbonate minerals contain even less of this element. In iron hydroxides and the most readily soluble aluminosilicates, its concentrations are in the range 168±24 - 212±28 μg/kg. The most insoluble fraction contains 1.65±0.21 - 4.32±0.45 mg/kg of uranium. In green-colored siltstones, the concentration of adsorbed uranium is much higher: 106±14 - 364±43 μg/kg. Carbonate minerals and amorphous iron oxides contain 1.91±0.21 - 2.34±0.26 mg/kg of uranium. In aluminosilicates and a clay/quartz resistate, uranium concentrations are 5.6±0.5 - 16.8±1.4 mg/kg. Elevated values of 234U:238U activity ratio prevail in the adsorbed material and iron hydroxides. In aluminosilicates and clay/quartz resistate, the values decrease. This indicates the replacement of primary sedimentogenic uranium by secondary hydrogenic uranium adsorbed on the surface of minerals and coprecipitated with iron hydroxides. The results obtained made it possible to carry out preliminary quantitative estimates of the retardation factor and recoil loss factor of uranium in the groundwater of siltstones of the studied Vendian aquifer.

scholarly journals Study of the Mobilization of Uranium Isotopes in a Sandstone Aquifer in Combination with Groundwater Data

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 112
Author(s):  
Alexander I. Malov ◽  
Sergey B. Zykov
Keyword(s):  
Iron Oxides ◽  
Extraction Procedure ◽  
Chelating Agent ◽  
Retardation Factor ◽  
Uranium Isotopes ◽  
Iron Hydroxides ◽  
Carbonate Minerals ◽  
Amorphous Iron ◽  
Mineral Phases ◽  
Clay Deposits

This work is part of a research project that aims to develop a method for combined radiocarbon and uranium-isotope dating of groundwater. The specific objective of this study was to investigate the mobility of uranium isotopes in the various mineral phases of rocks of an aquifer of sandy-clay deposits of the Vendian in the northwest of Russia, for which a partial extraction procedure was used. Representative aliquots of each core sample were treated with various reagents: distilled water, low mineralized fresh natural groundwater, minopolycarboxylic acid chelating agent (0.05 M EDTA), 0.5M HCl, 15 M HNO3, as well as total digestion, and the U isotope data for each procedure are reported in this study. The following mineral phases of core samples were characterized: sorbed material, carbonate minerals, amorphous iron oxides, partially soluble aluminosilicates and crystalline iron oxides, totally digestible aluminosilicates and a clay/quartz resistate. Red-colored siltstones and sandstones were depleted in uranium in relatively readily soluble mineral phases. The concentration of sorbed uranium was established in the range 15.8 ± 2.1–30.5 ± 3.9 μg/kg and carbonate minerals contained even less uranium. For iron hydroxides and the most readily soluble aluminosilicates, uranium concentrations were in the range 168 ± 24–212 ± 28 μg/kg. The most insoluble fraction contained uranium in the range 1.65 ± 0.21–4.32 ± 0.45 mg/kg. In green-colored siltstones, the concentration of sorbed uranium was much higher in the range 106 ± 14–364 ± 43 μg/kg. Carbonate minerals and amorphous iron oxides contained uranium in the range 1.91 ± 0.21–2.34 ± 0.26 mg/kg. In aluminosilicates and a clay/quartz resistate, uranium concentrations were in the range 5.6 ± 0.5–16.8 ± 1.4 mg/kg. Elevated values of 234U:238U activity ratio prevailed in the sorbed material and iron hydroxides. In aluminosilicates and clay/quartz resistate, the values decreased. This indicates the replacement of primary sedimentogenic uranium by secondary hydrogenic uranium sorbed on the surface of minerals and coprecipitation with iron hydroxides. The results obtained made it possible to carry out preliminary quantitative estimates of the retardation factor and recoil loss factor of uranium in the groundwater of siltstones and sandstones of the studied Vendian aquifer.

Uranium isotopic distribution in the mineral phases of granitic fracture fillings by a sequential extraction procedure

1996 ◽  
Vol 47 (9-10) ◽  
pp. 927-931 ◽  
Author(s):  
M.T. Crespo ◽  
L. Pérez Del Villar ◽  
A. Jiménez ◽  
M. Pelayo ◽  
A. Quejido ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure ◽  
Isotopic Distribution ◽  
Mineral Phases

scholarly journals Sequential extraction procedure to obtain the composition of terrigenous detritus in marine sediments

MethodsX ◽  
2020 ◽  
Vol 7 ◽  
pp. 100888
Author(s):  
Margit H. Simon ◽  
Daniel P. Babin ◽  
Steven L. Goldstein ◽  
Merry Yue Cai ◽  
Tanzhuo Liu ◽  
...  
Keyword(s):  
Sequential Extraction ◽  
Marine Sediments ◽  
Extraction Procedure ◽  
Sequential Extraction Procedure

Environmental Availability of Potentially Toxic Elements in an Agricultural Mediterranean Site

2019 ◽  
Vol 25 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Dimitrios Alexakis ◽  
Dimitra Gamvroula ◽  
Eleni Theofili
Keyword(s):  
Sequential Extraction ◽  
Toxic Elements ◽  
Soil Depth ◽  
Extraction Procedure ◽  
Potential Ecological Risk ◽  
Potentially Toxic Elements ◽  
Geochemical Partitioning ◽  
Exchangeable Fraction ◽  
High Bioavailability

ABSTRACT Total contents of 36 potentially toxic elements are summarized for agricultural topsoil (n = 12; soil depth = 0–20 cm), subsoil (n = 12; soil depth = 20–40 cm), and representative rock samples collected from a Mediterranean site (Megara Plain, Greece). The five-stage sequential extraction procedure for the geochemical partitioning of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), and nickel (Ni), proposed by Tessier, was applied to topsoil and subsoil collected from the study area. Soil Cd was highly associated with exchangeable fraction, illustrating high bioavailability of this element. The order of mobility of the elements was as follows: Cd > Cu > Co > Zn > Ni > Cr > Mn. Results from sequential extraction experiments illustrated that the bioavailability of Cu, Co, and Zn is moderate, while Ni, Cr, and Mn presented low bioavailability, indicating that these elements could pose a limited threat to the quality of crops. Cadmium is the chief contamination controlling factor posing moderate potential ecological risk. The contamination sources of the examined elements are discussed.

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