scholarly journals Evaluation of Environmental Contamination and Estimated Radiation Exposure Dose Rates among Residents Immediately after Returning Home to Tomioka Town, Fukushima Prefecture

Author(s):  
Masahiko Matsuo ◽  
Yasuyuki Taira ◽  
Makiko Orita ◽  
Yumiko Yamada ◽  
Juichi Ide ◽  
...  

On 1 April 2017, six years have passed since the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, and the Japanese government declared that some residents who lived in Tomioka Town, Fukushima Prefecture could return to their homes. We evaluated environmental contamination and radiation exposure dose rates due to artificial radionuclides in the livelihood zone of residents (living space such as housing sites), including a restricted area located within a 10-km radius from the FDNPS, immediately after residents had returned home in Tomioka town. In areas where the evacuation orders had been lifted, the median air dose rates were 0.20 μSv/h indoors and 0.26 μSv/h outdoors, and the radiation exposure dose rate was 1.6 mSv/y. By contrast, in the “difficult-to-return zone,” the median air dose rate was 2.3 μSv/h (20 mSv/y) outdoors. Moreover, the dose-forming artificial radionuclides (radiocesium) in the surface soil were 0.018 μSv/h (0.17 mSv/y) in the evacuation order-lifted areas and 0.73 μSv/h (6.4 mSv/y) in the difficult-to-return zone. These findings indicate that current concentrations of artificial radionuclides in soil samples have been decreasing in the evacuation order-lifted areas of Tomioka town; however, a significant external exposure risk still exists in the difficult-to-return zone. The case of Tomioka town is expected to be the first reconstruction model including the difficult-to-return zone.

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e114407 ◽  
Author(s):  
Makiko Orita ◽  
Naomi Hayashida ◽  
Hiroshi Nukui ◽  
Naoko Fukuda ◽  
Takashi Kudo ◽  
...  

2015 ◽  
Vol 11 (3) ◽  
pp. 1-9
Author(s):  
Ugochukwu Okoro ◽  
Ijeoma Dike ◽  
Chidiezie Chineke ◽  
Christiana Godwin ◽  
Chiamaka Chukwunyere

2014 ◽  
Vol 111 (10) ◽  
pp. E914-E923 ◽  
Author(s):  
Kouji H. Harada ◽  
Tamon Niisoe ◽  
Mie Imanaka ◽  
Tomoyuki Takahashi ◽  
Katsumi Amako ◽  
...  

Radiation dose rates were evaluated in three areas neighboring a restricted area within a 20- to 50-km radius of the Fukushima Daiichi Nuclear Power Plant in August–September 2012 and projected to 2022 and 2062. Study participants wore personal dosimeters measuring external dose equivalents, almost entirely from deposited radionuclides (groundshine). External dose rate equivalents owing to the accident averaged 1.03, 2.75, and 1.66 mSv/y in the village of Kawauchi, the Tamano area of Soma, and the Haramachi area of Minamisoma, respectively. Internal dose rates estimated from dietary intake of radiocesium averaged 0.0058, 0.019, and 0.0088 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. Dose rates from inhalation of resuspended radiocesium were lower than 0.001 mSv/y. In 2012, the average annual doses from radiocesium were close to the average background radiation exposure (2 mSv/y) in Japan. Accounting only for the physical decay of radiocesium, mean annual dose rates in 2022 were estimated as 0.31, 0.87, and 0.53 mSv/y in Kawauchi, Tamano, and Haramachi, respectively. The simple and conservative estimates are comparable with variations in the background dose, and unlikely to exceed the ordinary permissible dose rate (1 mSv/y) for the majority of the Fukushima population. Health risk assessment indicates that post-2012 doses will increase lifetime solid cancer, leukemia, and breast cancer incidences by 1.06%, 0.03% and 0.28% respectively, in Tamano. This assessment was derived from short-term observation with uncertainties and did not evaluate the first-year dose and radioiodine exposure. Nevertheless, this estimate provides perspective on the long-term radiation exposure levels in the three regions.


2019 ◽  
Vol 184 (3-4) ◽  
pp. 500-503
Author(s):  
K Inoue ◽  
M Arai ◽  
H Tsuruoka ◽  
K Saito ◽  
M Fujisawa ◽  
...  

Abstract Absorbed dose rates in air were measured for the whole area of the Kanto region in 2015, 2016 and 2017 (n = 31 147). The mean absorbed dose rates in air for each prefecture measured by car-borne surveys were from 44 to 67 nGy h−1 (13–289 nGy h−1). The absorbed dose rate in air from artificial radionuclides (134Cs + 137Cs) measured by fixed-point observation (n = 507) was from 1 to 14 nGy h−1 (0–105 nGy h−1), and meaning that the contribution ratios of 134Cs and 137Cs were 3–22%. The deposited location of artificial radionuclides was less than 1000 m from ground level and depended on the topography, wind direction and precipitation field.


1975 ◽  
Vol 18 (10) ◽  
pp. 1535-1536
Author(s):  
V. S. Gorev ◽  
V. A. Kozhemyakin ◽  
M. D. Firsov ◽  
V. A. Fomenko ◽  
A. L. Kholodkov ◽  
...  

PLoS ONE ◽  
2011 ◽  
Vol 6 (11) ◽  
pp. e27761 ◽  
Author(s):  
Satoru Monzen ◽  
Masahiro Hosoda ◽  
Shinji Tokonami ◽  
Minoru Osanai ◽  
Hironori Yoshino ◽  
...  

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