Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant. Part 2: Sorption and fixation behaviors and their relationship to sediment properties

Tachi, Yukio; Sato, Toyoyuki; Takeda, Chizuko; Ishidera, Takamitsu; Fujiwara, Kenso; Iijima, Kazuki

doi:10.1016/j.scitotenv.2020.138097

Cited by 8 publications

(3 citation statements)

References 56 publications

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“…The relatively wider uncertainty ranges in the tracer depletion and penetration profile in the stub section are due to the larger uncertainties of K d values for Cs + in the fracture fillings (Figure 4a). This may be explained by the complex sorption mechanisms of Cs, such as specific sorption at frayed edge sites (FES), and the significant dependence of these mechanisms on mineralogical heterogeneities at the fracture surface and the crushing effect (e.g., Bradbury & Baeyens, 2000;Kyllönen et al, 2014;Muuri et al, 2016;Tachi et al, 2011Tachi et al, , 2020Trinchero et al, 2017;Voutilainen et al, 2017). 4).…”

Section: Optimization Of K D : Results For Strong-sorbing Tracersmentioning

confidence: 99%

A Scaling Approach for Retention Properties of Crystalline Rock: Case Study of the In‐Situ Long‐Term Sorption and Diffusion Experiment (LTDE‐SD) at the Äspö Hard Rock Laboratory in Sweden

Tachi

Ito

Gylling

2021

Water Resources Research

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Crystalline rocks such as granites have been investigated as potential host rocks for the geological disposal of radioactive waste in many countries (e.g., EUR, 2005; NEA, 2012; NASEM, 2015). Radionuclide (RN) transport in fractured crystalline rocks can be conceptualized using a dual-porosity model where RNs are transported by advective water flow through a fracture and are retarded by diffusion and sorption into the surrounding rock matrix (Neretnieks, 1980). RNs can then diffuse from the fracture surfaces into the pore network of the fracture fillings and rock matrix and sorb onto pore walls. RN sorption on fracture surfaces and diffusion into the adjacent rock matrix are a key process influencing the safety of the geological disposal. To develop a realistic model and reliable parameters for long-term safety assessments, it is necessary to understand and quantify RN diffusion and sorption processes in the heterogeneous rock matrix and fracture systems.The different types and scales of heterogeneities that must also be considered for RN transport in fractured crystalline rocks include (a) heterogeneous distribution of minerals and pores in the rock matrix, (b) heterogeneity in mineral and pore distribution near fracture surfaces (e.g., fracture fillings and altered zones near fracture surfaces), and (c) heterogeneous flow distribution in the complex channel structures along fracture openings. As discussed in detail in Tachi et al. (2018), the first heterogeneity (a) in a rock matrix affects sorption and diffusion at a relatively smaller scale. The domain pore spaces between mineral grains and intragranular secondary pores form water-filled, heterogeneous networks with varying diffusion-related geometric factors, such as tortuosity and constrictivity, and accessible reactive surfaces related to sorption (e.

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Section: Optimization Of K D : Results For Strong-sorbing Tracersmentioning

confidence: 99%

A Scaling Approach for Retention Properties of Crystalline Rock: Case Study of the In‐Situ Long‐Term Sorption and Diffusion Experiment (LTDE‐SD) at the Äspö Hard Rock Laboratory in Sweden

Tachi

Ito

Gylling

2021

Water Resources Research

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“…Depending on their different physicochemical properties, such as chemical composition, expandability, cation exchange capacity (CEC), and layer charge, they are able to bind Cs to varying degrees (Cornell 1993;Mukai et al 2016;Park et al 2021). Moreover, in the case of clay minerals, the sorption of Cs is highly controlled by the specific sorption at frayed edge sites (FES) and the exchangeable sorption at regular exchange sites (RES) (Sawhney 1972;Cornell 1993;Zachara et al 2002;Tachi et al 2020b). The mineralogical composition of lake sediments can be additionally used to trace the origin of particles contaminated with 137 Cs (Hagiwara et al 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, it is known that the presence of OM might even inhibit the sorption of Cs + on clay minerals by blocking access to FESs (Rigol et al 2002;Fan et al 2014;Suga et al 2014). Therefore, the accumulation of 137 Cs can be more closely related to a combination of factors determining its immobilization, such as the grain size of sediment particles, their mineral composition, and OM content (Kim et al 2007;Fujii et al 2018;Tachi et al 2020b). In addition, the composition of OM can be used as an indicator of anthropogenic impacts or environmental changes (Meyers and Ishiwatari 1993;Contreras et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Factors controlling 137Cs distribution in bottom sediments of Koronowo Reservoir (Poland)

et al. 2022

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Purpose The main aim of this study was to investigate factors influencing the long-term distribution of 137Cs activity concentrations in the bottom sediments of the dam lake, Koronowo Reservoir, 32 years after the Chernobyl nuclear power plant accident. For this purpose, selected properties of the collected sediment samples, such as grain size, mineralogical composition, and organic matter (OM) content, were investigated. Materials and methods The samples of lake sediments were collected with a Kayak-type gravity corer. The spatial and vertical distributions of 137Cs and 40K activity concentrations in the bottom sediments were investigated based on gamma spectrometry measurements. The particle size distribution of surface lake sediments was determined using a laser particle size analyzer. SEM and XRD were used for the mineralogical analysis of the collected sediment samples. Additionally, the content of organic matter was examined in all samples using an elemental analyzer. Results The 137Cs content was significantly elevated in the case of fine-grained (< 63 µm) surface lake sediments (classified as silts, which are deposited in the profundal zone of Koronowo Lake) and ranged from 12.5 ± 4.1 to 29.2 ± 4.0 Bq kg−1. It was found that the increased concentration of 137Cs activity is more closely related to the content of the silt fraction (2–63 µm) than to the clay fraction (< 2 µm) in the collected surface lake sediments. The content of clay minerals also showed a significant positive correlation with 137Cs activity concentration in the surface lake sediments of Koronowo Lake. A similar relationship was noticed for the OM content, but it may be suspected that it is the result of radiocesium-bearing particle accumulation in OM-rich sediments. Conclusion The most important factor influencing the spatial distribution of 137Cs activity concentrations in the surface lake sediments of Koronowo Lake, apart from the bottom morphology and grain size of sediments, is the content of clay minerals. Moreover, the increased detrital inflow to the lake after the construction of the dam could have probably affected the vertical distribution of 137Cs activity concentrations in the bottom sediments, as evidenced by, e.g., the measurements of 40K activity concentration.

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Spatial and vertical distribution of 137Cs activity concentrations in lake sediments of Turawa Lake (Poland)

Sekudewicz

Gąsiorowski

2022

Environ Sci Pollut Res

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Key factors controlling radiocesium sorption and fixation in river sediments around the Fukushima Daiichi Nuclear Power Plant. Part 2: Sorption and fixation behaviors and their relationship to sediment properties

Cited by 8 publications

References 56 publications

A Scaling Approach for Retention Properties of Crystalline Rock: Case Study of the In‐Situ Long‐Term Sorption and Diffusion Experiment (LTDE‐SD) at the Äspö Hard Rock Laboratory in Sweden

A Scaling Approach for Retention Properties of Crystalline Rock: Case Study of the In‐Situ Long‐Term Sorption and Diffusion Experiment (LTDE‐SD) at the Äspö Hard Rock Laboratory in Sweden

Factors controlling 137Cs distribution in bottom sediments of Koronowo Reservoir (Poland)

Spatial and vertical distribution of 137Cs activity concentrations in lake sediments of Turawa Lake (Poland)

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