[Perspective on the nuclear power plant accident caused by the great east Japan earthquake and tsunami: health impairment risks due to pollution by radioactive materials from the damaged plant as recognized by experts and by the general population and role of the experts].

Introduction: Large amounts of radioactive materials were leaked into the environment from the Fukushima Daiichi Nuclear Power Plant (FDNPP) of the Tokyo Electric Power Company damaged by the 2011 Great East Japan Earthquake and accompanying tsunami. Increased health impairment risks due to the leaked radioactive materials are of concern over a long period of time and over a wide geographical area. From the results of epidemiologic studies conducted after the Chernobyl accident, the health risks are not anticipated to be very marked. The purpose of the present study is to examine (i) the elevated health risks as viewed by the general population, (ii) tolerance to the risks that the general population suffer from their viewpoint, and (iii) the overall picture as seen by researchers and experts in specialized areas of study after the accident.

Method: Information was obtained from articles in print and on the Internet and by interviewing a psychologist and tens of employees of several corporations.

Results And Discussion: Epidemiologic studies conducted after the severe accident of the nuclear power plant in Chernobyl revealed an elevated risk of thyroid cancer in children due to (131)I while elevated risks due to radioactive materials other than (131)I were not detected. The amount of radioactive materials leaked into the environment from the FDNPP was less than that in Chernobyl. Therefore, it is possible to estimate that health impairment risks due to the leaked radioactive materials from the FDNPP are low. However, it is impossible to conclude a zero risk. It is likely that the general population does not fully understand the health impairment risks due to the leaked radioactive materials from the FDNPP. Although no increased incidences of diseases other than thyroid cancer of children were scientifically shown en masse from studies in Chernobyl, individual risks and results in the future caused by the severe accident of FDNPP cannot be denied. Much of the general population is apt to demand the security of a zero risk from human-generated disasters such as the severe accident of FDNPP. Many are very intolerant of the health impairment risks factors and wish to avoid any risk altogether. The viewpoint of the general population differs considerably from that of epidemiologists and other research experts. Researchers and experts are often well versed in their own specialized areas but ignorant of other areas. Thus, it is difficult to grasp the complete view of an event under consideration. This so-called 'takotsubo' situation is dangerous in human society. Researchers and experts must make effort to understand areas other than their own specialized areas. Scientific researchers usually possess a great deal of conviction from the results of their own studies. They are apt to ignore criticism of their study results from individuals working in other research areas even when the results of their studies are inadequate. When the conditions of their studies are changed somewhat and insufficient information is obtained, the results may not be accurate. Researchers and experts should take full cognizance of this possibility, view with strong skepticism about the results of studies even in their own areas, and listen with humility to criticisms from those working in fields of discipline other than their own.

Conclusions: It should be fully recognized that the viewpoint of the general population is considerably different from that of researchers and experts regarding health risks due to the severe accident of FDNPP. Researchers and experts must make effort to understand the opinions of those working in areas other than their own in order to grasp a true and complete view of an event under consideration.