Geochemical influence of waste trench no. 22T at Chernobyl Pilot Site at the aquifer: Long-term trends, governing processes, and implications for radionuclide migration

Bugai, D.; Tkachenko, E. Yu.; Meir, Nathalie Van; Simonucci, Caroline; Martin-Garin, A.; Roux, Clarisse; Salle, Corinne Le Gal La; Kubko, Yu.I.

doi:10.1016/j.apgeochem.2011.09.021

Cited by 16 publications

(9 citation statements)

References 20 publications

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“…There has been a major international study of trenches containing contaminated materials from the Chernobyl accident, which has resulted in a series of papers. ,, The Chernobyl trenches were located above the usual water table and underlain by sands with relatively high hydraulic conductivity . Therefore, water might not accumulate in the trenches and the collection of in-trench samples may not be possible there.…”

Section: Resultsmentioning

confidence: 99%

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Payne

Harrison

Hughes

et al. 2013

Environ. Sci. Technol.

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Radioactive waste containing a few grams of plutonium (Pu) was disposed between 1960 and 1968 in trenches at the Little Forest Burial Ground (LFBG), near Sydney, Australia. A water sampling point installed in a former trench has enabled the radionuclide content of trench water and the response of the water level to rainfall to be studied. The trench water contains readily measurable Pu activity (∼12 Bq/L of 239+240Pu in 0.45 μm-filtered water), and there is an associated contamination of Pu in surface soils. The highest 239+240Pu soil activity was 829 Bq/kg in a shallow sample (0–1 cm depth) near the trench sampling point. Away from the trenches, the elevated concentrations of Pu in surface soils extend for tens of meters down-slope. The broader contamination may be partly attributable to dispersion events in the first decade after disposal, after which a layer of soil was added above the trenched area. Since this time, further Pu contamination has occurred near the trench-sampler within this added layer. The water level in the trench-sampler responds quickly to rainfall and intermittently reaches the surface, hence the Pu dispersion is attributed to saturation and overflow of the trenches during extreme rainfall events, referred to as the ‘bathtub’ effect.

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Section: Resultsmentioning

confidence: 99%

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Payne

Harrison

Hughes

et al. 2013

Environ. Sci. Technol.

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“…A gradual decrease in 1998–2008 of mean 90 Sr plume concentrations was observed also at an experimental site near trench no.22 at “Red Forest” waste dump site equipped with detailed multilevel monitoring well network 69 . Attenuation of 90 Sr migration was explained by evolution of geochemical composition of groundwater (decrease of concentrations of Ca and other leached ions accompanied by an increase of pH) caused by humification of the organic matter (buried vegetation remnants) inside the waste trench, and of nutrient element uptake by roots of the pine forest growing on top of the trench 15 . Additional data on groundwater contamination at waste dump sites, showing similar trends, are presented in Supplemental information, Sect.…”

Section: Resultsmentioning

confidence: 99%

Natural attenuation processes control groundwater contamination in the Chernobyl exclusion zone: evidence from 35 years of radiological monitoring

Bugai

Kireev²,

Hoque

et al. 2022

Sci Rep

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The Chernobyl Exclusion Zone (CEZ) contains the vast majority of radionuclides released by the accident in nuclear fuel particle form. We present and analyze groundwater measurements collected from the monitoring network in CEZ covering key aquifers over 35 years since the accident. These new data, together with a comprehensive analysis of historical data shows that 90Sr remains mobile in the subsurface environment, while groundwater concentrations of 137Cs, Pu isotopes and 241Am are relatively low, and are not of radiological concern. During the last two decades, 90Sr and 137Cs levels have declined or remained stable over time in the majority of monitoring locations. This is due to natural attenuation driven by gradual exhaustion of the fuel particle source, geochemical evolution of groundwater downstream from waste dumps and radionuclide retention in surface soil due to absorption and bio-cycling. Decommissioning of the cooling pond and construction of the ‘New safe confinement’ over Unit 4 (damaged reactor) also favored better protection of groundwater close to the Chernobyl plant site. Data from confined and unconfined aquifers, as well as rivers, evidence low radiological risks from groundwater contamination both outside the CEZ and to onsite “self-settlers”. Though several groundwater contamination “hot spots” remain in the vicinity of Unit 4, “Red Forest” waste trenches and surface water bodies with contaminated bottom sediments, the findings of this study support a monitored natural attenuation approach to groundwater management in the CEZ.

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“…Strontium is a widely distributed alkaline earth metal whose mobility is controlled by incorporation into minerals and adsorption onto organic and inorganic compounds. The isotope 90 Sr is a toxic radiochemical with a half-life of 28.8 years − that is only produced by nuclear fuel irradiation . Due to its high mobility, it quickly enters groundwater resources through infiltration of contaminated water , or the leaching of wastes, ,, where nuclear facilities such as reactors or waste management areas are present .…”

Section: Introductionmentioning

confidence: 99%

“…The isotope 90 Sr is a toxic radiochemical with a half-life of 28.8 years − that is only produced by nuclear fuel irradiation . Due to its high mobility, it quickly enters groundwater resources through infiltration of contaminated water , or the leaching of wastes, ,, where nuclear facilities such as reactors or waste management areas are present . Despite stricter environmental and security regulations, the expected increase in the world’s total nuclear electricity production by 2050 could result in more sites being contaminated with 90 Sr. At such sites, many groundwater-fed wetlands are present, thus becoming a pathway of 90 Sr to surface water.…”

Section: Introductionmentioning

confidence: 99%

Biogeochemical Controls on Strontium Fate at the Sediment–Water Interface of Two Groundwater-Fed Wetlands with Contrasting Hydrologic Regimes

Boyer

Hatat-Fraile

2018

Environ. Sci. Technol.

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Radioactive strontium (Sr) is a common groundwater contaminant at many nuclear sites. Its natural retention in groundwater-fed wetlands is an attractive remediation strategy. However, at present, the biogeochemical mechanisms controlling Sr transport at the sediment-water interface are poorly understood. In this field study, Sr fate was investigated in two wetlands with contrasting vegetation and hydrologic regimes. The marsh was an open-water wetland with constant water table and no emergent vegetation. The swamp was vegetated with fluctuating water levels and a thick mat of submerged cattail litter in the water column. High-resolution porewater Sr concentrations and solid-phase sediment Sr species revealed distinct profiles between the two wetlands. The marsh exhibited a strongly reduced environment and sharp concentration peaks at the sediment-water interface. In contrast, the smaller concentration gradients of the swamp resulted in a reduced flux of Sr to the surface water. The organic fraction of the sediment dominated Sr retention compared to the inorganic iron and manganese oxides. However, the marsh had a significant fraction of recalcitrant Sr presumably due to its incorporation into sulfur and/or carbonate minerals. These results suggest that vegetated wetlands with fluctuating hydrologic regimes could act as efficient sinks for Sr pollution.

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Geochemical influence of waste trench no. 22T at Chernobyl Pilot Site at the aquifer: Long-term trends, governing processes, and implications for radionuclide migration

Cited by 16 publications

References 20 publications

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Trench ‘Bathtubbing’ and Surface Plutonium Contamination at a Legacy Radioactive Waste Site

Natural attenuation processes control groundwater contamination in the Chernobyl exclusion zone: evidence from 35 years of radiological monitoring

Biogeochemical Controls on Strontium Fate at the Sediment–Water Interface of Two Groundwater-Fed Wetlands with Contrasting Hydrologic Regimes

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