Measures against increased environmental radiation dose by the TEPCO Fukushima Dai-ichi NPP accident in some local governments in the Tokyo metropolitan area: focusing on examples of both Kashiwa and Nagareyama cities in Chiba prefecture

Feasibility study of an intervention program to enhance self-confidence of kindergarten teachers who deal with radiation-related health concerns from parents with young children

Background

Following the Fukushima Daiichi Nuclear Power Station accident in March 2011, radiation anxiety was high among residents in affected areas. Enhancing radiation-related health literacy is effective in reducing radiation anxiety. This feasibility study aimed to examine a novel intervention program to enhance the self-confidence of kindergarten teachers who deal with radiation-related health concerns from parents in order to determine the feasibility of conducting a future randomized controlled trial.

Methods

Teachers and administrative staff of two private kindergartens in Fukushima City and members of Media Doctor Japan (a research group for enhancing the quality of health news reporting in Japan) were recruited for study participation. Participants were randomly assigned to intervention and control groups. The intervention group participated in the intervention program, comprised of lectures, group discussions, and presentations. The control group received the same written materials used in the intervention program. The primary outcome of this study was feasibility, assessed via four questions concerning program acceptability and described without quantitative analysis. Secondary outcomes were self-confidence concerning parent consultation (1 question, 4-point Likert scale), radiation-related health knowledge (5 question quiz, 1 point for each correct answer, score: 0–5), and health literacy (assessment developed by Ishilawa, et al., score: 1–5) assessed numerically before and after the intervention. Means and standard deviations of outcomes before and after the intervention and their changes in both groups were reported with groups of participants (kindergartens and the Media Doctor Research Japan) reported separately. No quantitative analyses were performed for secondary outcomes.

Results

Five and six kindergarten workers and seven and seven Media Doctor Japan members participated in the intervention and control groups, respectively. Reported acceptability was generally positive, and only one participant gave a negative response regarding program usefulness. Improved self-confidence was found in kindergarten employee participants. Radiation-related health knowledge was higher after the intervention in both kindergarten teachers and Media Doctor Japan members. The amount of change was higher in the intervention group than in the control group.

Conclusions

The intervention program enhanced self-confidence in kindergarten employees. The feasibility of the intervention program for a larger randomized controlled trial was ascertained. Time to conduct lectures and group discussions should be increased to further enhance health literacy.

Trial registrations

UMIN000042527 [University Hospital Medical Information Network (UMIN) Center] registered on November 25, 2020.

Cooperation process between a local government and experts in official voluntary decontamination of environmental radioactivity

Kashiwa city, inside the Tokyo metropolitan area and located ~200 km south of the Fukushima Dai-ichi Nuclear Power Plant, received a raised environmental ambient radiation dose due to the disaster relative to the rest of area. In this paper, the challenging process of the official voluntary decontamination activity in Kashiwa city, Chiba prefecture, which was carried out with strong cooperation between a local government and experts, is described and reviewed in terms of the effectiveness of the radiation protection. The support system for the official voluntary decontamination work was constructed by the citizens. It was completed within ~15 months after the accident, by way of the following five main steps. (i) A local forum was organized, commencing an open discussion. (ii) (a) Some civic groups started their own activities independent of the national and local governments' policies and measures, and (b) Kashiwa city office held information symposia and risk communication meetings with key persons as a kind of stakeholders as well as education and training of official leaders for voluntary decontamination work. (iii) Joint positive discussion and work projects between civic groups and the local government were started by key personnel. (iv) Local government planned and fixed its official decontamination strategy based on the results of several open discussions. (v) A guidance book for official voluntary decontamination by citizens was distributed by Kashiwa city office. The systematic framework for voluntary decontamination by citizens in Kashiwa city was developed through cooperation between a local government and decontamination experts, which was rare at that time. The authors believe that the process is valuable and should be shared with experts from various fields around the world.

Collaboration of local government and experts responding to increase in environmental radiation level due to the nuclear disaster: focusing on their activities and latest radiological discussion

Activities were introduced in Kashiwa city in the Tokyo metropolitan area to correspond to the elevated environmental radiation level after the disaster of the Fukushima Daiichi nuclear power plant. These were based on a strong cooperation between local governments and experts. Ambient dose rate and radioactivity of foodstuff produced inside of the city have been monitored. Representative ambient dose rates around living environments have almost already become their original levels of the pre-accident because of the decontamination activity, natural washout and effective half-lives of radioactivity. The internal annual dose due to radioactive cesium under the policy of 'Local Production for Local Consumption' is estimated as extremely low comparing the variation range due to natural radioactivity. Systematic survey around a retention basin has been started. All of these latest monitoring data would be one of the core information for the policy making as well as a cost-benefit discussion and risk communication.

Collaboration of local governments and experts responding to the increase of the environmental radiation level secondary to the nuclear accident: a unique activity to relieve residents' anxiety

After the Fukushima nuclear power plant accident, 'hot spots' were found in Tokatsu area in Chiba prefecture. Although ambient radiation dose in this area was too low to harm residents' health, local residents were particularly worried about possible adverse effects from exposure to radiation. To avoid unnecessary panic reactions in the public, local governments in Tokatsu area collaborated with radiation specialists and conducted activities to provide local residents with accurate information on health effects from radiation. In addition to these activities, the authors offered one-to-one consultations with a radiologist for parents of small children and expecting mothers. They herein report this unique attempt, focusing on parents' anxiety and the age of their children. Taken together, this unique collaborative activity between local government and experts would be one of the procedures to relieve residents' anxiety.

Radiation dose rates now and in the future for residents neighboring restricted areas of the Fukushima Daiichi Nuclear Power Plant

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.