Abstract
A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study. [Figure not available: see fulltext.].
| Original language | English |
|---|---|
| Article number | 12 |
| Journal | Progress in Earth and Planetary Science |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2018 Dec 1 |
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Keywords
- Atmospheric radioactivity
- Bioaerosol
- Fukushima
- Host particle
- Mineral dust
- Nuclear accident
- Radiocesium
- Resuspension
- Seasonal variation
- Spore
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
Cite this
The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan. / Kinase, Takeshi; Kita, Kazuyuki; Igarashi, Yasuhito; Adachi, Kouji; Ninomiya, Kazuhiko; Shinohara, Atsushi; Okochi, Hiroshi; Ogata, Hiroko; Ishizuka, Masahide; Toyoda, Sakae; Yamada, Keita; Yoshida, Naohiro; Zaizen, Yuji; Mikami, Masao; Demizu, Hiroyuki; Onda, Yuichi.
In: Progress in Earth and Planetary Science, Vol. 5, No. 1, 12, 01.12.2018.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan
AU - Kinase, Takeshi
AU - Kita, Kazuyuki
AU - Igarashi, Yasuhito
AU - Adachi, Kouji
AU - Ninomiya, Kazuhiko
AU - Shinohara, Atsushi
AU - Okochi, Hiroshi
AU - Ogata, Hiroko
AU - Ishizuka, Masahide
AU - Toyoda, Sakae
AU - Yamada, Keita
AU - Yoshida, Naohiro
AU - Zaizen, Yuji
AU - Mikami, Masao
AU - Demizu, Hiroyuki
AU - Onda, Yuichi
PY - 2018/12/1
Y1 - 2018/12/1
N2 - A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study. [Figure not available: see fulltext.].
AB - A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study. [Figure not available: see fulltext.].
KW - Atmospheric radioactivity
KW - Bioaerosol
KW - Fukushima
KW - Host particle
KW - Mineral dust
KW - Nuclear accident
KW - Radiocesium
KW - Resuspension
KW - Seasonal variation
KW - Spore
UR - http://www.scopus.com/inward/record.url?scp=85042440290&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85042440290&partnerID=8YFLogxK
U2 - 10.1186/s40645-018-0171-z
DO - 10.1186/s40645-018-0171-z
M3 - Article
AN - SCOPUS:85042440290
VL - 5
JO - Progress in Earth and Planetary Science
JF - Progress in Earth and Planetary Science
SN - 2197-4284
IS - 1
M1 - 12
ER -