Assessment of the Annual Additional Effective Doses amongst Minamisoma Children during the Second Year after the Fukushima Daiichi Nuclear Power Plant Disaster.

Yukio Kanazawa,Tomohiro Morita,Tim A Mousseau,Kikugoro Sakaihara,Tomoyoshi Oikawa,Tatsuo Hanai,Masahiro Kami,Masaharu Tsubokura,Shigeaki Kato,Shuhei Nomura

doi:10.1371/journal.pone.0129114

Abstract

An assessment of the external and internal radiation exposure levels, which includes calculation of effective doses from chronic radiation exposure and assessment of long-term radiation-related health risks, has become mandatory for residents living near the nuclear power plant in Fukushima, Japan. Data for all primary and secondary children in Minamisoma who participated in both external and internal screening programs were employed to assess the annual additional effective dose acquired due to the Fukushima Daiichi nuclear power plant disaster. In total, 881 children took part in both internal and external radiation exposure screening programs between 1st April 2012 to 31st March 2013. The level of additional effective doses ranged from 0.025 to 3.49 mSv/year with the median of 0.70 mSv/year. While 99.7% of the children (n = 878) were not detected with internal contamination, 90.3% of the additional effective doses was the result of external radiation exposure. This finding is relatively consistent with the doses estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The present study showed that the level of annual additional effective doses among children in Minamisoma has been low, even after the inter-individual differences were taken into account. The dose from internal radiation exposure was negligible presumably due to the success of contaminated food control.

Highlights

Radiation exposure can result in potential long-term health risks, such as increased incidence of tumor, depending on effective doses.[1]
The present study showed that the level of annual additional effective doses among children in Minamisoma has been low, even after the inter-individual differences were taken into account
In order to evaluate the levels of chronic radiation exposure among residents near the Fukushima Daiichi nuclear power plant and to clarify inter-individual differences of doses, we examined individual annual additional effective doses among children in Minamisoma, where periodic, consistent internal and external radiation monitoring has been performed

Summary

Introduction

Radiation exposure can result in potential long-term health risks, such as increased incidence of tumor, depending on effective doses.[1]. Doses from chronic radiation exposure can be classified into two types: external and internal radiation exposures. The level of external and internal radiation can be estimated using the data on soil and food contamination as demonstrated in publications by the World Health Organization (WHO)[8] and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).[9] For example, the level of external and internal radiation exposure through inhalation can be estimated using the data on surface radioactivity density, and the level of internal radiation exposure through ingestion can be calculated using the data on food radionuclide concentrations

Methods

Results

Conclusion