Deposition and Dispersion of Radio‐Cesium Released due to the Fukushima Nuclear Accident: 2. Sensitivity to Aerosol Microphysical Properties of Cs‐Bearing Microparticles (CsMPs)

Kajino, Mizuo; Adachi, Kouji; Igarashi, Yasuhito; Satou, Yukihiko; Sawada, Morihiro; Sekiyama, T. T.; Zaizen, Yuji; Saya, Akane; Tsuruta, Haruo; Moriguchi, Yuichi

doi:10.1029/2020jd033460

Cited by 12 publications

(6 citation statements)

References 70 publications

(222 reference statements)

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“…They also found only 5 %-15 % of pure dust particles and as much as 60 %-80 % of mixtures of mineral dust and sea salt, including dust mixed with a small amount of sea salt and sea salt mixed with a small amount of dust. Mineral dust is hydrophobic and nonspherical when emitted and thus shows high IN activity, is light absorbing, becomes hygroscopic during transport, and invigorates heterogeneous reactions (Kameda et al, 2016). On the other hand, sea salt is highly hygroscopic and is thus an efficient CCN.…”

Section: Aerosol Representationsmentioning

confidence: 99%

Comparison of three aerosol representations of NHM-Chem (v1.0) for the simulations of air quality and climate-relevant variables

et al. 2021

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Abstract. This study provides comparisons of aerosol representation methods incorporated into a regional-scale nonhydrostatic meteorology–chemistry model (NHM-Chem). Three options for aerosol representations are currently available: the five-category non-equilibrium (Aitken, soot-free accumulation, soot-containing accumulation, dust, and sea salt), three-category non-equilibrium (Aitken, accumulation, and coarse), and bulk equilibrium (submicron, dust, and sea salt) methods. The three-category method is widely used in three-dimensional air quality models. The five-category method, the standard method of NHM-Chem, is an extensional development of the three-category method and provides improved predictions of variables relating to aerosol–cloud–radiation interaction processes by implementing separate treatments of light absorber and ice nuclei particles, namely, soot and dust, from the accumulation- and coarse-mode categories (implementation of aerosol feedback processes to NHM-Chem is still ongoing, though). The bulk equilibrium method was developed for operational air quality forecasting with simple aerosol dynamics representations. The total CPU times of the five-category and three-category methods were 91 % and 44 % greater than that of the bulk method, respectively. The bulk equilibrium method was shown to be eligible for operational forecast purposes, namely, the surface mass concentrations of air pollutants such as O3, mineral dust, and PM2.5. The simulated surface concentrations and depositions of bulk chemical species of the three-category method were not significantly different from those of the five-category method. However, the internal mixture assumption of soot/soot-free and dust/sea salt particles in the three-category method resulted in significant differences in the size distribution and hygroscopicity of the particles. The unrealistic dust/sea salt complete mixture of the three-category method induced significant errors in the prediction of the mineral dust-containing cloud condensation nuclei (CCN), which alters heterogeneous ice nucleation in cold rain processes. The overestimation of soot hygroscopicity by the three-category method induced errors in the BC-containing CCN, BC deposition, and light-absorbing aerosol optical thickness (AAOT). Nevertheless, the difference in AAOT was less pronounced with the three-category method because the overestimation of the absorption enhancement was compensated by the overestimation of hygroscopic growth and the consequent loss due to in-cloud scavenging. In terms of total properties, such as aerosol optical thickness (AOT) and CCN, the results of the three-category method were acceptable.

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Section: Aerosol Representationsmentioning

confidence: 99%

Comparison of three aerosol representations of NHM-Chem (v1.0) for the simulations of air quality and climate-relevant variables

et al. 2021

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“…Cesium is one of the main fusion products, which has been stared to release to the atmosphere after the first nuclear bomb at the sixties of the last century [8][9][10]. The following nuclear disasters such as Chernobyl in1986 and Fukoshima in 2011 returns the fear of the negative consequences of Cs on the environment [11][12][13].Cs as a radioactive nuclide ( 137 Cs has about 30 years half-life) risks are higher than the corresponding ones of the stable toxic form [14].Generally, the chemical behavior of 137 Cs is similar to those of Na and K [15]; thusit deposits in the soft tissues of aquatic and terrestrial organisms [16]. In the human body, itharms the central nervous system and causes kidneys and liverfailure [17].…”

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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“…Even after 7 years from the nuclear accident, high levels of 137 Cs have been found in ambient aerosols from some areas of Fukushima especially during rain events [16]. There are possible mechanisms for the high levels of 137 Cs; e.g., re-suspension of dust particles from soil surface [17,18], or other pathways such as biological emission via fungal spore activity. Because the 137 Cs concentrations are often higher during rain, the soil resuspension is not likely.…”

Section: Introductionmentioning

confidence: 99%

Relationship of 137Cs with Fungal Spore Tracers in the Ambient Aerosols from Fukushima after the 2011 Nuclear Accident, East Japan

et al. 2022

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Even after 7 years of the nuclear accident that occurred in 2011 at the Fukushima Dai-ichi nuclear power plant (F1NPP), high levels of 137Cs have been detected in ambient aerosols from some polluted areas of Fukushima. Higher levels of radionuclides were often observed in the atmosphere during and after rain events. We presume that biological processes such as fungal activity associated with higher relative humidity may be involved with a possible emission of radioactivity to the atmosphere, which was originally emitted from the F1NPP accident and was deposited over the ground, forest, soil, etc. Here, we report, for the first time, relationships of 137Cs and organic tracers of fungal spores (i.e., arabitol, mannitol and trehalose) in the aerosol samples collected from Fukushima, Japan. Although we found twice-higher concentrations of 137Cs at nighttime than at daytime, fungal spore tracers did not show a consistent trend to 137Cs, that is, organic tracers at nighttime were similar with those at daytime or were even higher in daytime. This study has not clearly demonstrated that fungal spores are the important source of high levels of 137Cs at nighttime. The current unclear relationship is probably associated with the sampling strategy (four consecutive days with a sampling on/off program for day/nighttime samples) taken in this campaign, which may have caused a complicated meteorological situation.

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Deposition and Dispersion of Radio‐Cesium Released due to the Fukushima Nuclear Accident: 2. Sensitivity to Aerosol Microphysical Properties of Cs‐Bearing Microparticles (CsMPs)

Abstract: The contaminated air mass traveled over Japan and the radionuclides were deposited into and contaminated terrestrial ecosystems; this phenomenon was discovered by field measurements (

Cited by 12 publications

References 70 publications

Comparison of three aerosol representations of NHM-Chem (v1.0) for the simulations of air quality and climate-relevant variables

Comparison of three aerosol representations of NHM-Chem (v1.0) for the simulations of air quality and climate-relevant variables

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

Relationship of 137Cs with Fungal Spore Tracers in the Ambient Aerosols from Fukushima after the 2011 Nuclear Accident, East Japan

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