Geochemical model of the environmental impact of low-level radioactive sludge repositories in the course of their decommissioning

Boguslavskii, A. E.; Gaskova, Olga; Shemelina, O. V.

doi:10.1134/s1066362216030164

Cited by 7 publications

(4 citation statements)

References 1 publication

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“…Filter-type tailing pond: technogenic solutions from the sludge storage are partially disposed of through the dam and enter the surface runoff, and, partially, water is disposed of through the bottom and walls to enter the first aquifer. After mixing with groundwater that comes from local watersheds, polluted water migrates northward followed by discharge into the same valley [26]. The thickness of the aquifer is non-persistent, varying from 1 to 5 m; water-bearing rocks dominate the sandy loam and sand of quartz-feldspar composition.…”

Section: Geological Hydrogeological and Hydrogeochemical Characterist...mentioning

confidence: 99%

Biogeochemical In Situ Barriers in the Aquifers near Uranium Sludge Storages

Boguslavsky,

Shvartseva,

Popova

et al. 2023

Water

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The long-term operation of uranium sludge storages causes serious problems: it contaminates the neighboring aquifers with dangerous substances (uranium, nitrate, ammonium, and sulfate). To purify the aquifers can be costly and time-consuming; therefore, it is important to use the potential of in situ conditions, e.g., the aboriginal microflora and its ability to biologically remediate water reservoirs. In this work, we study the geological, geochemical, and microbiological characteristics of groundwater contaminated by uranium sludge storages resulting from the production cycles of four Russian chemical plants. All of the sites under consideration were extremely contaminated with nitrate (up to 15 g/L); in each case, we used denitrifying bacteria as a dominant group of microorganisms for purification. Our laboratory studies showed that microbial stimulation of water samples by milk whey promotes O2 and nitrate removal; this, in turn, started the cycle of anaerobic processes of authigenic precipitation caused by the reduction of iron and sulfate in the system. Thus, a mineral geochemical barrier preventing uranium immobilization formed. As a result, the uranium of the liquid phase decreased about 92–98% after 3–6 months (decomposition time depends on the nitrate concentration in the groundwater probe). The resulting amorphous biogenic phases contain sulfur, iron, phosphorus, and uranium.

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Section: Geological Hydrogeological and Hydrogeochemical Characterist...mentioning

confidence: 99%

Biogeochemical In Situ Barriers in the Aquifers near Uranium Sludge Storages

Boguslavsky,

Shvartseva,

Popova

et al. 2023

Water

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“…After passage of organic-mineral deposits, the water comes into contact with the groundwater of the area (background). The latter are nearly neutral (pH [7][8] and have a low TDS value and a hydrocarbonate-calcium composition. ORP and pH of contaminated and natural waters are close, therefore, when mixing solutions there are no barriers associated with oxidation-reduction and acid-base transitions.…”

Section: Water-rock Interactionmentioning

confidence: 99%

“…With the preservation of sludge storage facilities that were designed dozens of years ago, the reliability of natural barriers is of particular importance [4][5][6]. Determination of reliability and sufficiency of the existing safety barriers in the future requires creation of a migration model for leading pollutants based on geological, hydrogeological and geochemical features of the site [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Assessment of geochemical barriers at preservation of low-level radioactive waste storages

2019

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The work considers geochemical aspects of the natural and man-made system for storing radioactive waste (RW) from one of the Siberian enterprises of the fuel and nuclear cycle. Careful geochemical testing of key sites of the system allows us to identify geochemical barriers that prevent the spread of uranium outside the sludge storage. In addition, experiments were conducted on the leaching of the sludge material in the laboratory using modern methods for determining the composition of solutions and solid phases, as well as experiments on uranium sorption on the main types of subsoil. Experimental and thermodynamic modeling of uranium deposition processes confirms that the system studied satisfactorily copes with the absorption of uranium taken out of the sludge storage due to dilution and sorption on rocks and bottom sediments. Particularly favorable are bottom sediments rich in organic matter, which bind uranium to organic-mineral complexes.

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“…Knowledge about the spatial distribution of in situ nitrate-and sulfate contaminated aquifers is crucial to predict the groundwater quality. The fate of trace oxyanions is dependent on the ability of main pollutants to change the redox state in groundwater systems and to change the sorption capacity of the underlying sediments (Boguslavskii et al, 2016). Groundwater was sampled from location not far from the sludge repositories from a depth of 8 meters within the Middle Quaternary sediments of the Krasnodubrovskaya suite, consisting of interbedded sands, sandy loams, and loams.…”

Section: Study Objectmentioning

confidence: 99%