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Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident.

Adachi K, Kajino M, Zaizen Y, Igarashi Y - Sci Rep (2013)

Bottom Line: However, we still do not know the exact physical and chemical properties of the radioactive materials.In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble.Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition.

View Article: PubMed Central - PubMed

Affiliation: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, Japan. adachik@mrijma.go.jp

ABSTRACT
The Fukushima nuclear accident released radioactive materials into the environment over the entire Northern Hemisphere in March 2011, and the Japanese government is spending large amounts of money to clean up the contaminated residential areas and agricultural fields. However, we still do not know the exact physical and chemical properties of the radioactive materials. This study directly observed spherical Cs-bearing particles emitted during a relatively early stage (March 14-15) of the accident. In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble. Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition. The finding of the spherical Cs particles will be a key to understand the processes of the accident and to accurately evaluate the health impacts and the residence time in the environment.

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Related in: MedlinePlus

The distribution of radioactive materials on the filter samples measured with the IP.Black dots indicate the presence of radioactive materials. The outer rims (dotted line) of the filters were added artificially. This study focused on the filter samples from March 14, 21:10 to March 15, 09:10 (upper left), and from March 20, 21:30 to March 21, 09:13 (bottom center).
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f2: The distribution of radioactive materials on the filter samples measured with the IP.Black dots indicate the presence of radioactive materials. The outer rims (dotted line) of the filters were added artificially. This study focused on the filter samples from March 14, 21:10 to March 15, 09:10 (upper left), and from March 20, 21:30 to March 21, 09:13 (bottom center).

Mentions: We measured the radioactive materials that were collected in the filter at ground level on March 14–15 using the IP (Fig. 2). The radioactive materials were distributed spotty, suggesting that the number of radioactive particles was relatively small but that their activity levels were relatively strong. Within this filter sample, we counted approximately 100 spots caused by radioactive materials, suggesting a concentration of approximately 10 radioactive particles per m3. For reference, the average particle number concentration was 4.1 × 107 per m3 for particles larger than 0.5 μm from March 15 (Fig. S1). The spotty distribution in the IP image was also observed in the rooftop filter sample from March 15 (Fig. S3).


Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident.

Adachi K, Kajino M, Zaizen Y, Igarashi Y - Sci Rep (2013)

The distribution of radioactive materials on the filter samples measured with the IP.Black dots indicate the presence of radioactive materials. The outer rims (dotted line) of the filters were added artificially. This study focused on the filter samples from March 14, 21:10 to March 15, 09:10 (upper left), and from March 20, 21:30 to March 21, 09:13 (bottom center).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3757362&req=5

f2: The distribution of radioactive materials on the filter samples measured with the IP.Black dots indicate the presence of radioactive materials. The outer rims (dotted line) of the filters were added artificially. This study focused on the filter samples from March 14, 21:10 to March 15, 09:10 (upper left), and from March 20, 21:30 to March 21, 09:13 (bottom center).
Mentions: We measured the radioactive materials that were collected in the filter at ground level on March 14–15 using the IP (Fig. 2). The radioactive materials were distributed spotty, suggesting that the number of radioactive particles was relatively small but that their activity levels were relatively strong. Within this filter sample, we counted approximately 100 spots caused by radioactive materials, suggesting a concentration of approximately 10 radioactive particles per m3. For reference, the average particle number concentration was 4.1 × 107 per m3 for particles larger than 0.5 μm from March 15 (Fig. S1). The spotty distribution in the IP image was also observed in the rooftop filter sample from March 15 (Fig. S3).

Bottom Line: However, we still do not know the exact physical and chemical properties of the radioactive materials.In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble.Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition.

View Article: PubMed Central - PubMed

Affiliation: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki, Japan. adachik@mrijma.go.jp

ABSTRACT
The Fukushima nuclear accident released radioactive materials into the environment over the entire Northern Hemisphere in March 2011, and the Japanese government is spending large amounts of money to clean up the contaminated residential areas and agricultural fields. However, we still do not know the exact physical and chemical properties of the radioactive materials. This study directly observed spherical Cs-bearing particles emitted during a relatively early stage (March 14-15) of the accident. In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble. Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition. The finding of the spherical Cs particles will be a key to understand the processes of the accident and to accurately evaluate the health impacts and the residence time in the environment.

Show MeSH
Related in: MedlinePlus