Public Health Impacts of Fukushima


Japan’s location in the major earthquake
zone makes it particularly vulnerable to natural disasters. March 11th, 2011, a magnitude 9 earthquake
occurred off the east coast of Japan, generating a up to 40m high tsunami that severely
damaged coastal areas and resulted in more than 15,000 deaths
and 2500 missing people. As a consequence of the tsunami, the Fukushima
Daiichi Nuclear Power Station (FDNPS), located along the shoreline, lost its core cooling
capacity which caused severe damage to the reactor’s core and led to a maximum Level
7 nuclear accident on the scale (International Nuclear Event Scale) Substantial amount of radionuclides was released
into the environment following explosions and discharge of coolant water into the ocean. In less than a day after the incident and
the weeks followed, over 150 thousand citizens within a 20 kilometer radius were forced to
evacuate. Residents living in the vicinity of the Plant,
were exposed externally to radiation from the radioactive cloud and ground deposits
and internally from inhalation and ingestion of radionuclides, including iodine-131 (131I)
and caesium-137 (137Cs). 131I has a short radioactive half-life of
eight days and has particularly significant effects to children due to the size of their
thyroid glands and the nature of their metabolism. Meanwhile, 137Cs has a half-life of 30 years
and this implies long term risk of exposure through ingestion and exposure from
ground deposition. Based on a large health survey of the residents
(Fukushima Health Management Survey) and the dose assessments done by World Health Organisation
(WHO) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR),
the average lifetime effective doses for adults in the Fukushima prefecture were estimated
to be around 10 mSv or less, which is well within the annual radiation limit of 20 mSv
As for the nuclear plant cleanup workers, their average effective dose over the first
19 months after the accident was about 12 mSv. Among the 110,000 workers, about 38,500 received
total doses of more than 10 mSv over that period, while 170 received doses of more than
100 mSv, which poses a slightly elevated risk of cancer. Outside Japan, a trace amount of radionuclides
was detected in the air and water of California shortly after the accident, yet it quickly
dissipated, and its effect was claimed to be negligible. This man-made disaster has significant public health consequences. The prompt response actions of evacuation has arguably led to a sharp increase in mortality
among elderlies being placed in temporary housings, deterioration of health in general
due to the lack of access to healthcare, and also an increased risk of non-communicable
diseases like diabetes and mental health illnesses. It is estimated that over 1000 premature deaths
have been caused by maintaining the evacuation beyond a prudent week or so. Disruption to the smooth operation of hospitals,
the exacerbation of pre-existing health problems, and the general ‘mental fatigue’ from dramatic
changes in life situation were the leading causes of these pre-mature deaths. The displaced Fukushima population also suffer
from psycho-social and mental health problems, following relocation, ruptured social links
of people who lost homes and employment, disconnected family ties and stigmatization. A higher occurrence of post-traumatic stress
disorder (PTSD), anxiety, and postpartum depression among the evacuees was assessed as compared
to the general population of Japan. Psychological problems, such as hyperactivity,
emotional symptoms, and conduct disorders have also been reported among evacuated children. There were no acute radiation injuries or
deaths among the workers or the public due to exposure to radiation resulting from the
accident. For the 172 workers who received whole body
effective doses estimated to be over 100 mSv, an increased risk of developing thyroid cancer
and other thyroid disorders was estimated. Considering the level of estimated doses,
the WHO health risk assessment stated that the lifetime radiation-induced cancer risks
other than thyroid are small and much smaller than the lifetime baseline cancer risks. The greatest risk was found among girls
exposed as infants. There were also reports about thyroid cancer
cases being diagnosed among children exposed to low doses of radioactive iodine. Further analysis of epidemiological data will be necessary
to evaluate a potential attribution of thyroid cancer to radiation exposure. In a global health perspective, the health
risks directly related to radiation exposure are low in Japan and extremely low in neighbouring
countries and the rest of the world. Concerning food safety, radioactive iodine
and caesium in concentrations above the Japanese regulatory limits were detected in some food
commodities after the accident. WHO has worked closely with Food and Agriculture
Organization (FAO) through the International Food Safety Authorities Network (INFOSAN)
to ensure that the global community receives the best advice on the matters related to
the radioactive contamination in food. Since the early phase of the emergency, the
Ministry of Health, Labour and Welfare of Japan, which informs INFOSAN about any residual
radioactivity levels in food, have monitored food contamination closely and implemented
protective measures to prevent sale and distribution of contaminated food in Japan and outside of Japan. So far the food that were sold, especially
those exported, are considered safe, to a large extent. Public health lessons learnt from this unprecedented,
triple disasters are crucial to help Japan and all countries better plan, prepare, respond
and recover from potential nuclear accidents. Evacuation aims to minimize or prevent health risks of radiation exposure. However, the process of evacuation itself, especially under the conditions of a severe natural disaster, may pose serious health risks, particularly for vulnerable populations, such as the disabled, elderly, and children. Such relocation has resulted in the aforementioned
health consequences of increased disaster-related deaths, psychosocial and access to health care issues. Some therefore argued that the sustained evacuation
may have caused more harm than allowing the residents to stay – given the relatively low
radiation level and availability of iodine tablets. Thereby, authorities should take account of
the negative health impacts of their response actions, in the case of future incidents. Worse still, disrupted infrastructure, disconnection of evacuees from their municipalities, reduced number of health workers and failure of local public health and medical systems due to relocation made it more difficult to address the deprived health of the displaced population. In hindsight, strengthening of public health
services and improving access to health care are key issues for the well-being of evacuees, in addition to mental health, psychological, behavioral and societal support. Risk communication is also proved to be essential and should be carried out by trained specialists, while better education and training on health
effects of radiation should be provided to the general healthcare workers. Now that 9 years have passed, so what still
could be done? The Fukushima Health Management Survey (FHMS)
is expected to contribute to future health effect assessments. Population health surveillance will permit the identification of additional needs for the delivery of health care. Moreover, as part of the occupational health
programmes, a special protocol for medical follow-up of emergency workers is being implemented. To date, the biggest challenge for the mitigation
in Fukushima is the restoration of the social fabric and social trust. Hence, it is important for disaster reparations to include the
element of social empowerment to restore the public’s faith and strengthen affected communities (as stated in Sendai Framework of Risk Reduction). WHO’s Radiation Emergency Medical Preparedness and Assistance Network, also continues to develop medical countermeasures against similar
nuclear emergencies. REMPAN provides a global network of biodosimetry
laboratory (BioDoseNet). Guidelines are now more clearly in place to
ensure effective response by various parties. WHO partners with countries to ensure international
radiation safety standards are kept. The Sendai Framework also provides important
guidelines for increasing disaster risk management capacity, of which WHO approves. Besides, international organizations like
the IAEA also play a part in emergency response by following arrangements under the
Joint Radiation Emergency Management Plan of the International Organizations. As the take-home message, after the rain, earth hardens. Efforts are needed, both inside and outside Japan, to share the public health lessons learned from Fukushima around the world.

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