Sorption and desorption experiments using stable cesium: considerations for radiocesium retention by fresh plant residues in Fukushima forest soils

Manaka, Takuya; Ohashi, Shinta; Ogo, Sumika; Otsuka, Yuichiro; Furusawa, Hitomi

doi:10.1007/s10967-021-07749-1

Cited by 10 publications

(4 citation statements)

References 57 publications

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“…During this long residence time, the remaining leachable fraction of 137 Cs in the outer bark 40 might have been washed away by stemflow. Furthermore, previous studies have suggested that the outer bark has higher sorption capacity for soluble metal ions, including 137 Cs 37 , 42 . Thus, even small input of outer bark to the forest floor might lead large spatial heterogeneity of 137 Cs activity concentrations and bioavailability there.…”

Section: Discussionmentioning

confidence: 99%

“…Leaching experiments were conducted in the following settings, modified from the work of Manaka et al . (2019, 2021) 25 , 37 ; all samples were oven dried at 70–75 °C and then crushed roughly to a diameter of < 1 cm by using scissors or a cutting mill (U-140, Horai Co. Ltd., Higashi Osaka City, Osaka, Japan; or WT-150, Irie Shokai, Chiyoda City, Tokyo, Japan). Each sample and the leaching solutions [ultrapure water or ammonium acetate (1 mol kg −1 , pH 7.0)] was placed in a polypropylene centrifuge tube at a weight ratio of 1:20, and mixed for 2 h by a reciprocating shaker at room temperature.…”

Section: Methodsmentioning

confidence: 99%

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Radiocesium mobility in different parts of the two major tree species in Fukushima

Manaka

Araki

Ohashi

et al. 2023

Sci Rep

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Radiocesium (137Cs) released in the Fukushima Dai-ichi Nuclear Power Plant accident is still cycling in the forest ecosystem. We examined the mobility of 137Cs in the external parts—leaves/needles, branches, and bark—of the two major tree species in Fukushima, Japanese cedar (Cryptomeria japonica) and konara oak (Quercus serrata). This variable mobility will likely lead to spatial heterogeneity of 137Cs and difficulty in predicting its dynamics for decades. We conducted leaching experiments on these samples by using ultrapure water and ammonium acetate. In Japanese cedar, the 137Cs percentage leached from current-year needles was 26–45% (ultrapure water) and 27–60% (ammonium acetate)—similar to those from old needles and branches. In konara oak, the 137Cs percentage leached from leaves was 47–72% (ultrapure water) and 70–100% (ammonium acetate)—comparable to those from current-year and old branches. Relatively poor 137Cs mobility was observed in the outer bark of Japanese cedar and in organic layer samples from both species. Comparison of the results from corresponding parts revealed greater 137Cs mobility in konara oak than in Japanese cedar. We suggest that more active cycling of 137Cs occurs in konara oak.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Radiocesium mobility in different parts of the two major tree species in Fukushima

Manaka

Araki

Ohashi

et al. 2023

Sci Rep

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“…The identification of adsorption sites on clay minerals and zeolites has been studied in the fields of material science and environmental chemistry. − Understanding the adsorption mechanisms on zeolites is directly related to their performance as catalysts. The migration behavior of radioactive nuclides is dependent on the species of natural clay minerals.…”

Section: Introductionmentioning

confidence: 99%

New Approach To Understanding the Experimental ¹³³Cs NMR Chemical Shift of Clay Minerals via Machine Learning and DFT-GIPAW Calculations

et al. 2023

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Structural determination of adsorbed atoms on layered structures such as clay minerals is a complex subject. Radioactive cesium (Cs) is an important element for environmental conservation, so it is vital to understand its adsorption structure on clay. The nuclear magnetic resonance (NMR) parameters of 133 Cs, which can be determined from solid-state NMR experiments, are sensitive to the local neighboring structures of adsorbed Cs. However, determining the Cs positions from NMR data alone is difficult. This paper describes an approach for identifying the expected atomic positions on clay minerals by combining machine learning (ML) with experimentally observed chemical shifts. A linear ridge regression model for ML is constructed from the smooth overlap of atomic position descriptor and gauge-including projector augmented wave (GIPAW) ab initio data. The constructed ML model predicts the GIPAW data to within a 3 ppm root-mean-squared error. At this stage, the 133 Cs chemical shifts can be instantaneously calculated from the Cs positions on any clay layers using ML. The inverse analysis, which derives the atomic positions from experimentally observed chemical shifts, is developed from the ML model. The input data for the inverse analysis are the layer structure and the experimentally observed chemical shifts. The Cs positions for the targeted chemical shifts are then output. Inverse analysis is applied to montmorillonite, and the resultant Cs positions are found to be consistent with previous results (Ohkubo, T.; et al. J. Phys. Chem. A 2018, 122, 9326−9337). The Cs positions on saponite clay are also clarified from experimentally observed chemical shifts and inverse analysis.

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“…Additionally, K competes with Cs on the uptake carriers due to the similarity in chemical behavior; hence decreases Cs influx [9,22]. Other elements, like Na, Ca, Al, P may decrease Cs availability to plant [23].Moreover, increasing carbonate content in soil decreases the mobility of cesium [24].Besides, organic matter can affect cesium availability [25]. In this concern, up to 71% of the 137 Cs was found bonded to organic matter in the forest of Japan after Fukushima accident [26].…”

Section: Introductionmentioning

confidence: 99%

Removal of cesium from contaminated soils using EDTA-Na and DTPAchelating agents

Elshazly

Farid

Rizk

et al. 2023

Benha Journal of Applied Sciences

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Soil contamination with Cs possesses a serious environmental threat; and therefore, its remediation is an obligation to ensure environmental safety. The current study aims at evaluating the efficiency of using either EDTA-Na or DTPA as chelating agents for removal of Cs from contaminated soils. Three soils (a clayey oneand two sandy loam soils differing in the organic matter and CaCO 3 contents) were selected to attain this aim.Samples of the soils under study were artificially contaminated with CsCl at three levels i.e. 50, 100, and 200 mg Cs kg -1 . These samples were subjected to sequential extraction pre-and post-leaching to find out Cs redistribution among the different soil fractions after soil washing. The implications of soil washing with the investigated chelating agents on decreasing the risk assessment hazards associated with Cs hazards are discussed in this study. Key results indicated that DTPA was more efficient in removal of Cs from the contaminated soils than the EDTA-Nadidand both decreased considerably soil Cs, particularly from those which are considered the mobile fractions (water soluble and exchangeable fractions) beside of the carbonate bound fractions. Accordingly, the calculated risk assessment code declined noticeably from -very high risk‖ levels (more than 50) to -medium risk‖ levels (ranging from 30 to 50 ) for most spiked soils. In conclusion, DTPA and EDTA-Na are effective chelating agents in reducing the risks associated with Cs contamination in soils.

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Sorption and desorption experiments using stable cesium: considerations for radiocesium retention by fresh plant residues in Fukushima forest soils

Cited by 10 publications

References 57 publications

Radiocesium mobility in different parts of the two major tree species in Fukushima

Radiocesium mobility in different parts of the two major tree species in Fukushima

New Approach To Understanding the Experimental ¹³³Cs NMR Chemical Shift of Clay Minerals via Machine Learning and DFT-GIPAW Calculations

Removal of cesium from contaminated soils using EDTA-Na and DTPAchelating agents

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Sorption and desorption experiments using stable cesium: considerations for radiocesium retention by fresh plant residues in Fukushima forest soils

Cited by 10 publications

References 57 publications

Radiocesium mobility in different parts of the two major tree species in Fukushima

Radiocesium mobility in different parts of the two major tree species in Fukushima

New Approach To Understanding the Experimental 133Cs NMR Chemical Shift of Clay Minerals via Machine Learning and DFT-GIPAW Calculations

Removal of cesium from contaminated soils using EDTA-Na and DTPAchelating agents

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Product

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New Approach To Understanding the Experimental ¹³³Cs NMR Chemical Shift of Clay Minerals via Machine Learning and DFT-GIPAW Calculations