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


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Title: Evaluation of Environmental Contamination and Estimated Radiation Exposure Dose Rates among Residents Immediately after Returning Home to Tomioka Town, Fukushima Prefecture
Authors: Matsuo, Masahiko / Taira, Yasuyuki / Orita, Makiko / Yamada, Yumiko / Ide, Juichi / Yamashita, Shunichi / Takamura, Noboru
Issue Date: 29-Apr-2019
Publisher: MDPI
Citation: International journal of environmental research and public health, 16(9), art.no.1481; 2019
Abstract: 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.
Keywords: air dose rate / difficult-to-return zone / effective dose rate / evacuation order-lifted areas / external exposure risk / Fukushima Daiichi Nuclear Power Station accident / living space / radiocesium / surface soil / Tomioka town
URI: http://hdl.handle.net/10069/39206
DOI: 10.3390/ijerph16091481
Rights: © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/39206

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