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emitter); concentrations of the gamma emitters 60Co, 137Cs, and 129I were also well below the applicable regulatory limit( IAEA, 2022). So that tritium levels also fully satisfy safety standards, the water is diluted with seawater before being discharged, thus reducing the tritium concentration to under 1,500 Becquerels( Bq)/ L, which is approximately one-seventh of the standard set by the World Health Organization for drinking water. ALPS-treated water tanks have been stored inside the FDNPS, and their number is increasing; as of 2024 it exceeded 1,000. To proceed safely with the decommissioning work, the space occupied by the tanks is needed for the construction of new facilities. However, the decision to DTW into the Pacific Ocean drew criticism both in Japan and in some neighboring countries. For instance, China announced a ban on seafood from Japan, and the Republic of Korea expressed protests against DTW from the FDNPS( Huaxia, 2022).
Tomioka and Okuma towns are both located within 20 km of the FDNPS and abut the Pacific Ocean. The FDNPS is located in Okuma town( Fig. 1). As the DTW process is expected to be conducted over 30 years it is therefore essential to assess how it affects former residents’ intention to return. Furthermore, the return rates of former residents of Tomioka and Okuma towns are quite low, compared to some other evacuation order-lifted areas. It has been clarified that the low rate of return to the areas affected by the nuclear accident was linked to residents’ sex, age, level of anxiety about radiation exposure, and mental and physical health( Hande et al., 2023). However, the relationship among social connections, social capital( SC), and the intention to return( ITR) has not previously been clarified. Community connections among the continuous evacuees and the evacuation area might affect their ITR, even more than 10 years after the FDNPS accident.
This study examines the impact of the DTW, SC, quality of life, and radiation risk perceptions on the ITR in the affected areas. In particular, it focuses on people who may have faced great struggles due to the FDNPS accident. The results offer important suggestions for how to provide appropriate support that addresses the specific concerns of former residents of affected areas.
2 Methods
2.1 Study participants
This study was conducted in Tomioka and Okuma towns, on Japan’ s Pacific coast, in the Fukushima Prefecture( Fig. 1). Study participants were people aged 18 years and older who still held resident cards for these towns after the disaster. A few new residents had obtained cards since the accident occurred. Permission to conduct the study was obtained from the municipal governments of both towns, based on a partnership agreement with Nagasaki University. The questionnaire was prepared at the university and then distributed to the towns from the Radiation Health Management Section using the Basic Resident Ledger( Takamura et al., 2021). A questionnaire was enclosed in the public relations magazine sent to potential survey participants who held a resident card for Tomioka and Okuma as of November 2022, based on data from the Basic Resident Ledger. The data collection period was from November 2022 through January 2023. The 702 in Tomioka and 676 in Okuma responses were received from the approximately 7,250 and 4,900 households to which each magazine was distributed in Tomioka and Okuma, respectively. Among the total responses, 678 in Tomioka and 660 in Okuma were regarded as valid after excluding incomplete responses. The study’ s purpose, methods, and ethical considerations were explained using a leaflet, and responding to the questionnaire was considered to indicate informed consent.
2.2 Questionnaire
The questionnaire was formulated based on the Fukushima Health Management Survey and previous research conducted in the area affected by the nuclear accident( Matsunaga et al., 2021). The questionnaire encompassed inquiries on participants’ demographic characteristics, such as age and sex. ITR to Tomioka / Okuma was described as follows: already returned, want to return, undecided, and do not want to return. Questions about the DTR, whether the respondent was concerned about DTR from the FDNPS, and whether the respondent was willing to acquire information about DTW were also asked.
Regarding radiation risk perception, respondents were asked whether they thought genetic effects would occur because of the FDNPS accident and whether they were reluctant to consume local foods from Tomioka or Okuma. These questions were answerable as“ yes,”“ probably yes,”“ probably no,” or“ no.”
After seeking the advice of experts in radiation risk communication, we proposed the following possible responses regarding the way in which the respondents wanted to be informed about the radiological situation in their municipalities: individual consultations, small group meetings( gatherings of less than 10 people) and conferences( groups of more than 10 people). To measure social connections with their latest local community, we applied a Japanese version of a health-related community social capital scale( SC) composed of 11 items on civic participation( five questions), social cohesion( three questions), and reciprocity( three questions)( Takamura et al., 2021). Civic participation was assessed based on participation in five types of community groups: volunteering, sports, hobbies, culture, and skills teaching. We defined“ participation”( scored as“ 1”) as engaging with a social group once per month or more. Civic participation was evaluated as participating in none( 0), participating in one group( low), two groups( middle), or three or more groups( high) among the five types noted above. Social cohesion comprised the degree of community trust and attachment the study participants felt for their local community. It was assessed using three questions:“ Do you think people living in your area can be trusted in general?”,“ Do you think people living in your area often help others?”, and“ What is your level of attachment to the area where you currently live?” Social cohesion was scored“ 0” if respondents did not answer“ very” or“ moderately” to any of the questions. If respondents answered“ very” or“ moderate” to at least one of the questions, it was scored as“ 1.” Replying“ yes” one of the three questions was scored as low( 1), two as medium( 2), and all three as high( 3). Reciprocity was assessed by receiving and providing emotional support and instrumental support from the local community. It was assessed using the