Assessment of the risk of medium-term internal contamination in Minamisoma City, Fukushima, Japan, after the Fukushima Dai-ichi nuclear accident

Low dose from external radiation among returning residents to the former evacuation zone in Minamisoma City, Fukushima Prefecture

After the 2011 Fukushima Daiichi nuclear power plant accident, evidence on the real-life conditions of returnees to areas once designated as legal no-go zones, including their radiation dose levels, is scarce. In the present study, using a radiation dosimeter and lifestyle survey, we evaluated the lifestyle characteristics and dose levels in 2017 from external exposure among those who returned to the no-go zones after the evacuation orders were lifted. A total of 112 returnees to Odaka district, Minamisoma City, Fukushima Prefecture, were considered and compared to 266 non-returnees. The proportion of participants with annual additional doses from external exposure above 1 mSv was 7.0% for returnees, and 7.3% and 4.2% for non-returnees living in other districts or outside of the city, respectively. Although caution is required given the very small sample sizes, this implies that as of 2017 doses from external exposure among returnees in Odaka were very low and by scientific consensus would be associated with a very low likelihood of physical effects. We also found that while returnees were older on average than non-returnees, they had similar life conditions (i.e. occupation and time spent outdoors). It should be particularly emphasised that the expected lifetime doses from the incident in addition to the natural background dose are a very small among returnees. This study contributes to enhancing societal debates and risk communication regarding how government can provide returnees with the support they need, improve their outlook for radiation doses, and continue to improve crucial infrastructure in former no-go zones so that communities can be rebuilt.

The Great East Japan Earthquake, Tsunamis, and Fukushima Daiichi Nuclear Power Plant Disaster: Lessons for Evidence Integration from a WADEM 2017 Presentation and Panel Discussion

In April 2017, some of the health impacts of the 2011 Great East Japan Earthquake, tsunamis, and resultant Fukushima Daiichi nuclear power plant disaster (Okuma, Fukushima Prefecture, Japan) were presented at the 19th Congress of the World Association for Disaster and Emergency Medicine (WADEM; Madison, Wisconsin USA) in Toronto, Canada. A panel discussion was then opened by asking audience members about their experiences in their own countries, and how they would suggest taking steps to reach the goals of the Sendai Framework for Disaster Risk Reduction 2015-2030. This paper summarizes the presentation and panel discussion, with a particular focus on the common problems identified in understanding and reducing health risks from disasters in multiple countries, such as the ethical and practical difficulties in decision making on evacuating vulnerable populations that arose similarly during the Fukushima nuclear disaster in 2011 and Hurricane Ike's approach to Galveston (Texas USA) in 2008. This paper also highlights the need for greater integration of research, for example through increased review and collation of evidence from different disaster settings to identify common problems and possible solutions, which was identified in this panel session as a precursor to fulfilling the goals of the Sendai Framework.Leppold C, Ochi S, Nomura S, Murray V. The Great East Japan Earthquake, tsunamis, and Fukushima Daiichi nuclear power plant disaster: lessons for evidence integration from a WADEM 2017 presentation and panel discussion. Prehosp Disaster Med. 2018;33(4):424-427.

Diversity of Concerns in Recovery after a Nuclear Accident: A Perspective from Fukushima

Since the 2011 Fukushima nuclear accident, tremendous resources have been devoted to recovery, and the Japanese Government is gradually lifting evacuation orders. However, public concerns remain prevalent, affecting some people's return to a normal life and threatening their well-being. This study reviews government reports, academic papers, newspaper articles and conference presentations with the aim of obtaining a better understanding of issues which relate to radiation concerns in the recovery process in the aftermath of the accident. It looks extensively at: (1) the current status of the post-accident operations and existing radiation issues in Fukushima, and (2) approaches taken to engage the public during recovery from five previous comparable nuclear and radiological events: Three Mile Island, Buenos Aires (RA-2 facility), Chernobyl, Goiânia and Tokai-mura. The findings indicate that the limitations and emerging challenges of the current recovery operations cause concerns about radiation exposure in various aspects of day-to-day life. Past experiences suggest that long-term management that take a holistic and cohesive approach is critical for restoration of sustainable livelihoods and for social re-integration. Not only actual risks but also public perceptions of risks should be carefully assessed and addressed in the process of environmental remediation.

Radioactively-hot particles detected in dusts and soils from Northern Japan by combination of gamma spectrometry, autoradiography, and SEM/EDS analysis and implications in radiation risk assessment

After the March 11, 2011, nuclear reactor meltdowns at Fukushima Dai-ichi, 180 samples of Japanese particulate matter (dusts and surface soils) and 235 similar U.S. and Canadian samples were collected and analyzed sequentially by gamma spectrometry, autoradiography, and scanning electron microscopy with energy dispersive X-ray analysis. Samples were collected and analyzed over a five-year period, from 2011 to 2016. Detectable levels of ¹³⁴Cs and ¹³⁷Cs were found in 142 of 180 (80%) Japanese particulate matter samples. The median radio-cesium specific activity of Japanese particulate samples was 3.2kBqkg^-1±1.8kBqkg^-1, and the mean was 25.7kBqkg^-1 (σ=72kBqkg^-1). The U.S. and Canadian mean and median radio‑cesium activity levels were <0.03kBqkg^-1. U.S. and Canadian samples had detectable ¹³⁴Cs and ¹³⁷Cs in one dust sample out of 32 collected, and four soils out of 74. The maximum US/Canada radio-cesium particulate matter activity was 0.30±0.10kBqkg^-1. The mean in Japan was skewed upward due to nine of the 180 (5%) samples with activities >250kBqkg^-1. This skewness was present in both the 2011 and 2016 sample sets. >300 individual radioactively-hot particles were identified in samples from Japan; composed of 1% or more of the elements cesium, americium, radium, polonium, thorium, tellurium, or strontium. Some particles reached specific activities in the MBqμg^-1 level and higher. No cesium-containing hot particles were found in the U.S. sample set. Only naturally-occurring radionuclides were found in particles from the U.S. background samples. Some of the hot particles detected in this study could cause significant radiation exposures to individuals if inhaled. Exposure models ignoring these isolated hot particles would potentially understate human radiation dose.

Additional risk of diabetes exceeds the increased risk of cancer caused by radiation exposure after the Fukushima disaster

The 2011 Fukushima disaster led to increases in multiple risks (e.g., lifestyle diseases and radiation exposure) and fear among the public. Here, we assessed the additional risks of cancer caused by radiation and diabetes related to the disaster and the cost-effectiveness of countermeasures against these conditions. Our study included residents of the cities of Minamisoma and Soma (10-40 km and 35-50 km north of the Fukushima Daiichi (N° 1) Nuclear Power Station, respectively). We used the loss of life expectancy (LLE) as an indicator to compare risks between radiation exposure and diabetes. We also estimated the cost-effectiveness of radiation-related countermeasures, including restricted food distribution, decontamination, and whole-body counter tests and interventions. Metformin therapy was selected as a representative management for diabetes. The diabetes-related LLEs among residents were 4.1 (95% confidence interval: 1.4-6.8) ×10-2 years for the whole population and 8.0 (2.7-13.2) ×10-2 years for 40s to 70s in a scenario that considered the additional incidence of diabetes during the first 10 years. The cancer-related LLEs caused by lifetime exposure to radiation were 0.69 (2.5-97.5 percentile: 0.61-0.79) ×10-2 years for the whole population and 0.24 (0.20-0.29) ×10-2 years for 40s to 70s. The diabetes-related LLEs among residents in the above-mentioned scenario were 5.9-fold and 33-fold higher than those attributed to average radiation among the whole population and among the 40s to 70s age groups, respectively. The costs per life-years saved of the radiation countermeasures (i.e., restricted food distribution, decontamination, and whole-body counter tests and interventions) were >1 to >4 orders of magnitude higher than those of general heath checkups and conventional management for diabetes. Our findings indicate that countermeasures to mitigate diabetes are warranted. Policy-makers' and individuals' understanding of multiple risks after any disaster will be essential to saving the lives of victims.

Social isolation and cancer management - advanced rectal cancer with patient delay following the 2011 triple disaster in Fukushima, Japan: a case report

Background

Little is known about the effects of social isolation in the elderly on their process of gaining health information and seeking health care.

Case presentation

In March 2011, Fukushima, Japan experienced an earthquake, tsunami, and nuclear disaster, also known as Japan’s triple disaster. In June 2016, an 80-year-old Japanese man, who lived alone after divorce at the age of 42, presented to our hospital with bloody stools and dizziness. Although his bloody stools initially occurred in May 2015, a year earlier, he did not pursue the possibility of malignancy. He was diagnosed as having stage IIIA rectal cancer. Detailed history taking revealed that he experienced social isolation after the disaster, due to the evacuation of his friends, losing his regular opportunities for socialization. He additionally reported that the current diagnosis of rectal cancer made him feel he had lost his health in addition to his social relationships. Although radical surgery was attempted, it failed to resect the lesion completely, and thereafter his disease gradually progressed. As support from family or friends was not available, he was not able to receive palliative radiation therapy or home-based care in his end-of-life period. He died at a long-term care facility in February 2017.

Conclusions

This case suggests that intense social isolation after the Fukushima disaster was a likely contributor to the patient delay, poor treatment course, and poor outcome of an elderly patient with rectal cancer. Direct communication with family and friends may play an indispensable role in increasing health awareness and promoting health-seeking behaviors, and in the midst of social isolation, elderly patients with cancer may lose these opportunities and experience increased risk of patient delay. Although health care providers may be able to alleviate isolation-induced delay by promoting cancer knowledge and awareness widely among local residents, policy-led interventions at the community level may be essential to reducing social isolation and its health consequences.

Towards a Long-Term Strategy for Voluntary-Based Internal Radiation Contamination Monitoring: A Population-Level Analysis of Monitoring Prevalence and Factors Associated with Monitoring Participation Behavior in Fukushima, Japan

Following Japan’s 2011 Fukushima nuclear incident, we assessed voluntary-based monitoring behavior in Minamisoma City—located 10–40 km from the Fukushima nuclear plant—to inform future monitoring strategies. The monitoring in Minamisoma included occasional free of charge internal-radiation-exposure measurements. Out of around 70,000 individuals residing in the city before the incident, a total of 45,788 residents (female: 52.1%) aged ≥21 were evaluated. The monitoring prevalence in 2011–2012 was only 30.2%, and this decreased to 17.9% in 2013–2014. Regression analyses were performed to estimate factors associated with the monitoring prevalence and participation behavior. The results show that, in comparison with the age cohort of 21–30 years, the cohort of 71–80 and ≥81 years demonstrated significantly lower monitoring prevalence; female residents had higher monitoring prevalence than male residents; those who were living in evacuation zones at the time of the incident had higher monitoring prevalence than those who lived outside any of the evacuation zones; for those living outside Fukushima and neighboring Prefectures post-incident monitoring prevalence decreased significantly in 2013–2014. Our findings inform the discussion on the concepts of radiation risk perception and accessibility to monitoring and societal decision-making regarding the maintenance of the monitoring program with low monitoring prevalence. We also stress the possibility that the monitoring can work both to check that internal contamination levels are within acceptable limits, and as a risk communication tool, alleviating individuals’ concern and anxiety over radiation contamination.

Effects of indoor and outdoor cultivation conditions on 137 Cs concentrations in cultivated mushrooms produced after the Fukushima Daiichi Nuclear Power Plant accident

BACKGROUND

Radiocesium (¹³⁴ Cs and ¹³⁷ Cs) in mushrooms has been a matter of public concern after the accident at Fukushima Daiichi Nuclear Power Plant. To minimize the internal dose by ingestion of cultivated mushrooms, the Japanese government set a guideline level with respect to the radiocesium concentration in bed-logs and mushroom beds; however, the effects of indoor and outdoor cultivation methods on radiocesium concentrations in cultivated mushrooms were not clear.

RESULTS

The effects of indoor and outdoor cultivation on the radiocesium concentrations in mushroom were examined using published food monitoring data. ¹³⁷ Cs concentration data in Lentinula edodes from the Aizu area in Fukushima Prefecture and seven prefectures outside Fukushima were used for the analysis. No statistically significant ¹³⁷ Cs concentration differences were found between these two cultivation methods. Using detected ¹³⁷ Cs data in shiitake, the geometric means from each prefecture were less than one-quarter of the standard limit (100 Bq kg^-1 ) for total radiocesium under both cultivation conditions.

CONCLUSION

It was suspected that re-suspended radiocesium might have been taken up by mushrooms or that radiocesium might have been absorbed into the mushrooms from the soil in the outdoor cultures. However, neither effect was significant for cultivated mushrooms in the areas examined. © 2016 Society of Chemical Industry.

Estimated association between dwelling soil contamination and internal radiation contamination levels after the 2011 Fukushima Daiichi nuclear accident in Japan

OBJECTIVES

Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific.

METHODS

To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10-40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2-3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels.

RESULTS

A total of 7987 people with a mean age of 55.4 years underwent screening of in vivo Cs-137 whole-body counting. A statistically significant association was noted between internal and continuous Cs-137 soil contamination levels (model 1, p value <0.001), although the association was slight (relative risk (RR): 1.03 per 10 kBq/m(2) increase in soil contamination). Analysis of categorical soil contamination levels showed statistical (but not clinical) significance only in relatively higher soil contamination levels (model 2: Cs-137 levels above 100 kBq/m(2) compared to those <25 kBq/m(2), RR=1.75, p value <0.01; model 3: levels above 63 kBq/m(2) compared to those <11 kBq/m(2), RR=1.45, p value <0.05).

CONCLUSIONS

Low levels of internal and soil contamination were not associated, and only loose/small associations were observed in areas with slightly higher levels of soil contamination in Fukushima, representing a clear difference from the strong associations found in post-disaster Chernobyl. These results indicate that soil contamination levels generally do not contribute to the internal contamination of residents in Fukushima; thus, individual measurements are essential for the precise evaluation of chronic internal radiation contamination.

Current Measures on Radioactive Contamination in Japan: A Policy Situation Analysis

BACKGROUND

The Great East Japan Earthquake on 11th March 2011 and the subsequent Fukushima Dai-ichi nuclear power plant disaster caused radioactive contamination in the surrounding environment. In the immediate aftermath of the accident the Government of Japan placed strict measures on radio-contamination of food, and enhanced radio-contamination monitoring activities. Japan is a pilot country in the WHO Foodborne Disease Burden Epidemiology Reference Group (FERG), and through this initiative has an opportunity to report on policy affecting chemicals and toxins in the food distribution network. Nuclear accidents are extremely rare, and a policy situation analysis of the Japanese government's response to the Fukushima Dai-ichi nuclear accident is a responsibility of Japanese scientists. This study aims to assess Japan government policies to reduce radio-contamination risk and to identify strategies to strengthen food policies to ensure the best possible response to possible future radiation accidents.

METHODS AND FINDINGS

We conducted a hand search of all publicly available policy documents issued by the Cabinet Office, the Food Safety Commission, the Ministry of Health, Labor and Welfare (MHLW), the Ministry of Agriculture, Forestry and Fishery (MAFF) and prefectural governments concerning food safety standards and changes to radiation and contamination standards since March 11th, 2011. We extracted information on food shipment and sales restrictions, allowable radio-contamination limits, monitoring activities and monitoring results. The standard for allowable radioactive cesium (Cs-134 and Cs-137) of 100 Bq/Kg in general food, 50 Bq/Kg in infant formula and all milk products, and 10 Bq/Kg in drinking water was enforced from April 2012 under the Food Sanitation Law, although a provisional standard on radio-contamination had been applied since the nuclear accident. Restrictions on the commercial sale and distribution of specific meat, vegetable and fish products were released for areas at risk of radioactive contamination. Monitoring of radioactive materials in food products in the prefectures has been mainly conducted before shipment to restrict the distribution of radio-contaminated foods. Between March 2011 and March 2012, 133,832 tests of non-commercial and commercial products were conducted, and 1,204 tests (0.9%) were found to violate the provisional standards. Since April 2012, 278,275 tests were conducted, and 2,372 tests (0.9%) were found to violate the revised standards. MHLW assessment of representative market baskets of foodstuffs at 15 locations throughout Japan between February and March 2014 found very low estimated dietary intake of radioactive cesium (0.0007-0.019 mSv/year), as did assessments of the contents of an average day's food. Monitoring of fisheries products in coastal areas affected by the nuclear accident found very limited and declining radio-contamination of live fish outside of Fukushima prefecture. Fisheries monitoring is of limited geographical scope and covers only certain fishes.

CONCLUSIONS

Area-specific bans on production and distribution have been effective in preventing radioactive contamination in the Japanese food market. Currently there is no major concern about radioactive cesium concentrations in retail foodstuffs in Japan, and very low levels of contamination at the production and wholesale stage. However, because the residue limits and food safety policies were revised on an ad hoc, emergency basis after the nuclear accident, the monitoring procedure needs to be reviewed based on objective and scientifically rational criteria. A transparent and objective scientific framework is needed for prioritizing foodstuffs for inspection and revising Prefecture-specific restrictions. Monitoring of fishes and other seafood products in the wild should be regularized and the information made more publicly accessible, and monitoring activities expanded to identify foodstuffs that are no longer a food safety risk. Consultation with producers and consumers should be more formalized to ensure their concerns are incorporated into regular policy reviews in an appropriate and transparent manner. However, despite the limited available knowledge on best practice in food control and enforcement of provisional radio-contamination limits after the accident, current Japanese policy is sufficient to protect the Japanese public from major risk of radio-contamination from the commercial food market.

External effective radiation dose to workers in the restricted area of the Fukushima Daiichi Nuclear Power Plant during the third year after the Great East Japan Earthquake

Since the Great East Japan Earthquake on 11 March 2011, Iitate Village has continued to be classified as a deliberate evacuation area, in which residents are estimated to receive an annual additional effective radiation dose of >20 mSv. Some companies still operate in Iitate Village, with a special permit from the Cabinet Office Team in Charge of Assisting the Lives of Disaster Victims. In this study, we measured the annual effective radiation dose to workers in Iitate Village from 15 January to 13 December 2013. The workers stayed in Iitate for 10 h and left the village for the remaining 14 h each working day. They worked for 5 days each week in Iitate Village, but stayed outside of the village for the remaining 2 days each week. We found that the effective radiation dose of 70% of the workers was <2 mSv, including natural radiation; the maximum dose was 3.6 mSv. We estimated the potential annual additional effective radiation dose if people returned full-time to Iitate. Our analysis supports the plan for people to return to their home village at the end of 2017.

Dependence of radiation dose on the behavioral patterns among school children: a retrospective analysis 18 to 20 months following the 2011 Fukushima nuclear incident in Japan

After radioactive incidents, the exposure risk in daily activities among children is a major public concern. However, there are limited methods available for evaluation of this risk, which is essential to future health risk management. To this end, this study assessed the relationship between behavioral patterns of school children and radiation exposure for a period of 18-20 months following the 2011 Fukushima nuclear incident. The assessed population comprised 520 school children from Minamisoma city, located 20 km north of the nuclear plant. Data for the doses were obtained using individual dosimeters and from results of a behavior survey administered by the City Office. The mean value of the doses in the study period was 0.34 mSv, with a standard deviation of 0.14 mSv, indicating an annual dose of ∼1.36 mSv, which includes doses from natural sources. Our results showed that behavior with respect to outdoor activities had no statistically significant relationship to the dose. A 0.1 μSv/h increase in the air dose rate at home was associated with a 10% increase in the dose; however, a 0.01 μSv/h increase in the air dose rate on the school grounds was associated with a 2% increase in the dose. This study indicates that the air contamination levels at the places where children spend most of their day are the significant predictors of the dose, as opposed to the levels at those outdoor locations in which short periods of time spent.

Whole body counter assessment of internal radiocontamination in patients with end-stage renal disease living in areas affected by the Fukushima Daiichi nuclear power plant disaster: a retrospective observational study

OBJECTIVE

To assess internal radiocontamination of patients with end-stage renal disease (ESRD) who were regularly taking haemodialysis (HD) and living in areas affected by the crippled Fukushima Daiichi nuclear plant after the Great East Japan earthquake on 11 March 2011.

METHODS

Internal radiocontamination in 111 patients with ESRD regularly taking HD at Jyoban Hospital in Iwaki city, Fukushima from July 2012 to November 2012 was assessed with a whole body counter (WBC). The maximum annual effective dose was calculated from the detected Cs-137 levels. Interviews concerning patient dietary preferences and outdoor activities were also conducted.

RESULTS

Among the 111 patients tested, internal radiocontamination with Cs-137 was detected in two participants, but the levels were marginal and just exceeded the detection limit (250 Bq/body). The tentatively calculated maximum annual effective dose ranged from 0.008 to 0.009 mSv/year, which is far below the 1 mSv/year limit set by the government of Japan. Relative to 238 non-ESRD participants, patients with ERSD had significantly more opportunities to consume locally grown produce that was not distributed to the market (p<0.01). However, the percentage of patients with ESRD with detectable Cs (1.8%) was lower than that for non-ESRD participants (3.8%), although this difference was not significant (p=0.51).

CONCLUSIONS

These findings suggest that internal radiocontamination levels and the calculated annual additional effective doses were negligible for patients with ESRD taking HD in areas affected by the crippled Fukushima nuclear plant. Although HD is suggested to promote Cs-137 excretion, continuous inspection of locally grown produce together with WBC screening for radiocontamination should be continued for patients with ESRD regularly taking HD.

Minimal Internal Radiation Exposure in Residents Living South of the Fukushima Daiichi Nuclear Power Plant Disaster

Following the Fukushima nuclear power plant disaster, assessment of internal radiation exposure was indispensable to predict radiation-related health threats to residents of neighboring areas. Although many evaluations of internal radiation in residents living north and west of the crippled Fukushima nuclear power plant are available, there is little information on residents living in areas south of the plant, which were similarly affected by radio-contamination from the disaster. To assess the internal radio-contamination in residents living in affected areas to the south of the plant or who were evacuated into Iwaki city, a whole body counter (WBC) screening program of internal radio-contamination was performed on visitors to the Jyoban hospital in Iwaki city, which experienced less contamination than southern areas adjacent to the nuclear plant. The study included 9,206 volunteer subjects, of whom 6,446 were schoolchildren aged 4-15 years. Measurements began one year after the incident and were carried out over the course of two years. Early in the screening period only two schoolchildren showed Cs-137 levels that were over the detection limit (250 Bq/body), although their Cs-134 levels were below the detection limit (220 Bq/body). Among the 2,760 adults tested, 35 (1.3%) had detectable internal radio-contamination, but only for Cs-137 (range: 250 Bq/body to 859 Bq/body), and not Cs-134. Of these 35 subjects, nearly all (34/35) showed elevated Cs-137 levels only during the first year of the screening. With the exception of potassium 40, no other radionuclides were detected during the screening period. The maximum annual effective dose calculated from the detected Cs-137 levels was 0.029 and 0.028 mSv/year for the schoolchildren and adults, respectively, which is far below the 1 mSv/year limit set by the government of Japan. Although the data for radiation exposure during the most critical first year after the incident are unavailable due to a lack of systemic measurements, the present results suggest that internal radio-contamination levels more than one year after the incident were minimal for residents living south of the crippled Fukushima nuclear plant, and that the annual additional effective doses derived from internal Cs contamination were negligible. Thus, internal radio-contamination of residents living in southern radio-contaminated areas appears to be generally well controlled.

An evaluation of early countermeasures to reduce the risk of internal radiation exposure after the Fukushima nuclear incident in Japan

After a radiation-release incident, intake of radionuclides in the initial stage immediately following the incident may be the major contributor to total internal radiation exposure for individuals in affected areas. However, evaluation of early internal contamination risk is greatly lacking. This study assessed the relationship between initial stage evacuation/indoor sheltering and internal radiation contamination levels 4 months after the 2011 Fukushima nuclear incident in Japan and estimated potential pathways of the contamination. The study population comprised 525 participants in the internal radiation screening program at Minamisoma Municipal General Hospital, 23 km north of the Fukushima nuclear plant. The analysed dataset included the results of a screening performed in July 2011, 4 months after the incident, and of a questionnaire on early-incident response behaviours, such as sheltering indoors and evacuations, completed by participants. Association between such early countermeasures and internal contamination levels of cesium-134 were assessed using Tobit multiple regression analyses. Our study shows that individuals who evacuated to areas outside Fukushima Prefecture had similar contamination levels of cesium-134 to individuals who stayed in Fukushima (relative risk: 0.86; 95% confidence interval: 0.74-0.99). Time spent outdoors had no significant relationship with contamination levels. The effects of inhalation from radiological plumes released from the nuclear plant on total internal radiation contamination might be so low as to be undetectable by the whole-body counting unit used to examine participants. Given the apparent limited effectiveness of evacuation and indoor sheltering on internal contamination, the decision to implement such early responses to a radiation-release incident should be made by carefully balancing their potential benefits and health risks.

Health effects of radiation and other health problems in the aftermath of nuclear accidents, with an emphasis on Fukushima

437 nuclear power plants are in operation at present around the world to meet increasing energy demands. Unfortunately, five major nuclear accidents have occurred in the past--ie, at Kyshtym (Russia [then USSR], 1957), Windscale Piles (UK, 1957), Three Mile Island (USA, 1979), Chernobyl (Ukraine [then USSR], 1986), and Fukushima (Japan, 2011). The effects of these accidents on individuals and societies are diverse and enduring. Accumulated evidence about radiation health effects on atomic bomb survivors and other radiation-exposed people has formed the basis for national and international regulations about radiation protection. However, past experiences suggest that common issues were not necessarily physical health problems directly attributable to radiation exposure, but rather psychological and social effects. Additionally, evacuation and long-term displacement created severe health-care problems for the most vulnerable people, such as hospital inpatients and elderly people.

Radiation-driven migration: the case of Minamisoma City, Fukushima, Japan, after the Fukushima nuclear accident

The emigration of residents following the Fukushima nuclear accident has resulted in aging and depopulation problems in radiation-contaminated areas. The recovery of affected areas, and even those areas with low radioactive pollution levels, is still heavily affected by this problem. This slow recovery consequently affects immigration patterns. This review aims to present possible factors that have contributed to this dilemma. We first present an overview of the evacuation protocol that was administered in the study area following the Fukushima accident. We then analyze characteristics of the subsequent exodus by comparing population data for both before and after the accident. Based on the findings of existing literature, we identify three causes of emigration: (1) The health risks of living in a low radiation zone are still unknown; (2) The post-disaster psychological disturbance and distrust of government information promotes the emigration of evacuees; (3) an absence of economic vitality and of a leading industry renders the area less attractive to individuals residing outside of the city. Further research is needed on this issue, especially with respect to countermeasures for addressing this problem.

Who was concerned about radiation, food safety, and natural disasters after the great East Japan earthquake and Fukushima catastrophe? A nationwide cross-sectional survey in 2012

Background

Disaster-related concerns by sub-populations have not been clarified after the great East Japan earthquake and the Fukushima nuclear power plant incidents. This paper assesses who was concerned about radiation, food safety, and natural disasters among the general population in order to buffer such concerns effectively.

Methods

The hypothesis that women, parents, and family caregivers were most concerned about radiation, food safety, and natural disaster was tested using a varying-intercept multivariable logistic regression with 5809 responses from a nationwide cross-sectional survey random-sampled in March 2012.

Results

Many people were at least occasionally concerned about radiation (53.5%), food safety (47.3%), and about natural disaster (69.5%). Women were more concerned than men about radiation (OR = 1.67; 95% CI = 1.35–2.06), food safety (1.70; 1.38–2.10), and natural disasters (1.74; 1.39–2.19). Parents and family care needs were not significant. Married couples were more concerned about radiation (1.53; 1.33–1.77), food safety (1.38; 1.20–1.59), and natural disasters (1.30; 1.12–1.52). Age, child-cohabitation, college-completion, retirement status, homemaker status, and the house-damage certificate of the last disaster were also associated with at least one concern. Participants from the Kanto region were more concerned about radiation (2.08; 1.58–2.74) and food safety (1.30; 1.07–1.59), which demonstrate similar positive associations to participants from Tohoku where a disaster relief act was invoked (3.36; 2.25–5.01 about radiation, 1.49; 1.08–2.06 about food safety).

Conclusions

Sectioning the populations by gender and other demographics will clarify prospective targets for interventions, allow for a better understanding of post-disaster concerns, and help communicate relevant information effectively.

BABYSCAN: a whole body counter for small children in Fukushima

BABYSCAN, a whole body counter for small children with a detection limit for (137)Cs of better than 50 Bq/body, was developed, and the first unit has been installed at a hospital in Fukushima, to help families with small children who are very much concerned about internal exposures. The design principles, implementation details and the initial operating experience are described.

Comprehensive whole-body counter surveys of Miharu-town school children for three consecutive years after the Fukushima NPP accident

Comprehensive whole-body counter surveys covering over 93% of the school children between the ages of 6 and 15 in Miharu town, Fukushima Prefecture, have been conducted for three consecutive years, in 2011, 2012 and 2013. Although the results of a questionnaire indicate that approximately 60% of the children have been regularly eating local or home-grown rice, in 2012 and 2013 no child was found to exceed the (137)Cs detection limit of 300 Bq/body.