Speciation, Mobility and Fate of Actinides in the Groundwater at the Hanford Site

Buesseler, Ken O.; Dai, Minhan; Repeta, Daniel J.; Wacker, J. F.; Kelley, James M.

doi:10.2172/820366

Cited by 2 publications

(1 citation statement)

References 64 publications

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“…The contamination of groundwater with actinides due to accidents and unsafe storage of radioactive waste poses a long-term uncontrolled migration risk and the potential for the entry of such pollutants into water supply systems [1][2][3]. Low-level radioactive waste repositories with open-type storage are considered to be a significant part of the groundwater contamination problem [4][5][6]. Such storage facilities were used in the uranium enrichment process and nuclear fuel reprocessing plants in Russia and other countries during the mid-20th century.…”

Section: Introductionmentioning

confidence: 99%

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

Myasnikov,

Artemiev,

Lavrinovich

et al. 2023

Hydrology

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The complex contamination of groundwater near radioactive waste repositories by nitrates and actinides is a common problem for many nuclear fuel cycle facilities. One of the effective methods to remove nitrates and reduce actinide migration activity is bioremediation through the activation of native microbial communities by soluble electron donors and carbon sources. This work evaluated the effectiveness of using simple and complex electron donors to remove nitrate in the microbial community in an aquifer near the B2 storage of the Siberian Chemical Combine (Seversk, Siberia). The addition of sugar and milk whey led to the maximum efficiency of nitrate-ion removal and a decrease in the redox potential of the system, creating optimal conditions for the immobilization of actinide. Special attention was paid to the behavior of uranium, plutonium, neptunium, and americium under conditions simulating groundwater when sugar, acetate, and milk whey were added and when microbial metabolic products were formed. Neither microbial metabolites nor organic solutions were found to have a significant effect on the leaching of neptunium. At the same time, for plutonium, a decrease in yield was observed when rocks were treated with organic solutions were compared to groundwater treatment without them. Plutonium leaching is significantly affected by rock composition. In rocks with a low clay fraction content, its yield can reach 40%. At the same time, microbial metabolites can increase americium (Am) desorption from rocks with a low clay fraction content. Additionally, particle size analysis was performed using a step-by-step filtration approach, aiming to evaluate the risks that are associated with colloidal phase formation. It was shown that microbiological stimulation resulted in particle enlargement, substantially diminishing the presence of actinides in the form of dissolved or sub-50 nm nanoparticles. This outcome significantly reduced the potential for colloidal and pseudocolloidal transfer, thereby lowering associated risks.

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Section: Introductionmentioning

confidence: 99%

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

Myasnikov,

Artemiev,

Lavrinovich

et al. 2023

Hydrology

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Transuranic Contamination in Sediment and Groundwater at the U.S. DOE Hanford Site

Cantrell¹

2009

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SummaryThis document presents a review of transuranic radionuclide contamination in sediments and groundwater at the U.S. Department of Energy (DOE) Hanford Site. The review focuses primarily on plutonium-239/240 and americium-241; however, other transuranic nuclides are discussed as well, including neptunium-237, plutonium-238, and plutonium-241. The scope of the review includes liquid process wastes intentionally disposed to constructed waste disposal facilities such as trenches, cribs, and burial grounds, as well as unplanned releases to the ground surface. The review does not include liquid wastes disposed to tanks or solid wastes disposed to burial grounds.It is estimated that more than 11,800 Ci of plutonium-239; 28,700 Ci of americium-241; and 55 Ci of neptunium-237 have been disposed as liquid waste to the near surface environment at the Hanford Site. Despite the very large quantities of transuranic contaminants disposed to the vadose zone at the site, only minuscule amounts have entered the groundwater. Currently, no wells onsite exceed the DOE-derived concentration guide for plutonium-239/240 (30 pCi/L) or any other transuranic contaminant in filtered samples. The DOE-derived concentration guide was exceeded by a small fraction in unfiltered samples from one well ( The primary reason that disposal of these large quantities of transuranic radionuclides directly to the vadose zone at the Hanford Site has not resulted in widespread groundwater contamination is that under the typical oxidizing and neutral to slightly alkaline pH conditions of the Hanford vadose zone, transuranic radionuclides (plutonium and americium in particular) have a very low solubility and high affinity for surface adsorption to mineral surfaces common within the Hanford vadose zone. In addition, the vadose zone is typically very thick (hundreds of feet), and the net infiltration rate is very low due to the desert climate.In some cases in which transuranic radionuclides have been co-disposed with acidic liquid waste, transport through the vadose zone for considerable distances has occurred. For example, at the 216-Z-9 Trench, plutonium-239 and americium-241 have moved to depths in excess of 36 m (118 ft) below ground surface. Acidic conditions and the presence of possible complexants could increase the solubility of these contaminants and reduce adsorption to mineral surfaces. Subsequent neutralization of the acidity by naturally occurring calcite in the vadose zone (particularly in the Cold Creek unit) appears to have effectively stopped further migration. iv Characterization studies for most of the sites reviewed in the document are generally limited. The most prevalent characterization methods used centered around geophysical logging. Characterization of a number of sites included laboratory analysis of borehole sediment samples specifically for radionuclides and other contaminants, as well as for geologic and hydrologic properties. In some instances, more detailed research-level studies were conducted.The 216-Z-9 Trench is a case...

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Speciation, Mobility and Fate of Actinides in the Groundwater at the Hanford Site

Cited by 2 publications

References 64 publications

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

Transuranic Contamination in Sediment and Groundwater at the U.S. DOE Hanford Site

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