Humanitarian Health Action

Japan nuclear concerns

Current risk

What is the current risk of radiation-related health problems in Japan for those residing near the reactor in comparison to those in other parts of Japan?

• During the early phase of the nuclear emergency radiation-related health were dependant on exposure, which is turn were due to several things, including: the amount and type of radiation released from the reactor; weather conditions, such as wind and rain; a person’s proximity to the plant; and the amount of time spent in irradiated areas.
• The Government of Japan’s early actions in response to events at the Fukushima Daiichi nuclear power plant were in line with the existing recommendations for radiation exposure. The Government has evacuated individuals who were living within a 20-kilometre radius around the Fukushima Daiichi plant. Those living between 20 km and 30 km from the plant were asked to evacuate voluntarily. In general, people living farther away of the site of the event are at lower risk than those who live nearby.
• In light of evolving new information on levels of environmental radioactivity in the 20-30 km zone and some surrounding areas beyond the 30km zone, the Government of Japan established new planned evacuation zones from which residents were relocated to temporary housing based on the estimated cumulative doses they may receive in the 1 year following the accident.
• In addition, an emergency evacuation preparedness zone was also identified in which residents were asked to prepare their affairs in case they were asked to evacuate. These zones also follow administrative boundaries and extend beyond the 30 km radius.

Is there a risk of radioactive exposure from food contamination?

• Yes, there is a risk of exposure as a result of contamination in food.
• However, contaminated food would have to be consumed over prolonged periods to represent a risk to human health.
• The radioactive iodine and caesium in concentrations above the Japanese regulatory limits have been detected in some food commodities as a result of food monitoring
• Japanese authorities have advised residents to avoid these food and have implemented measures to prevent their sale and distribution.

Are there health risks to people living outside of Japan from radiation emitted into the atmosphere from damaged Japanese nuclear power plants?

Thus far, there are no health risks to people living in other countries from radioactive material released into the atmosphere from the Japanese nuclear power plants. Radiation levels measured to date in other countries are far below the level of background radiation that most people are exposed to in every day circumstances.

Radiation levels have been monitored by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), which operates 63 surveillance stations around the world.

Ionizing radiation

What is ionizing radiation?

• When certain atoms disintegrate, they release a type of energy called ionizing radiation. This energy can travel as either electromagnetic waves (i.e. gamma or X-rays) or as particles (i.e. alpha, beta or neutrons).
• The atoms that emit radiation are called radionuclides; e.g., radioactive iodine, caesium, and plutonium.
• Ionizing radiation is an essential tool for diagnosis and treatment in medicine, that must be used with rigorous attention to safety.

Human exposure to ionizing radiation

Are people normally exposed to ionizing radiation?

• Human beings are exposed to natural radiation (also known as background radiation) on a daily basis. Natural radiation comes from space (i.e. cosmic rays) as well as from naturally-occurring radioactive materials found in the soil, water and air. Radon gas is a naturally-occurring gas that is the main source of natural radiation.
• People can also be exposed to radiation from man-made sources. Today, the most common man-made sources of ionizing radiation are X-ray machines and other medical devices.
• Radiation doses can be expressed in Sievert (Sv) units. On average, a person is exposed to approximately 3.0 milli Sieverts (mSv)/year, of which 80% (2.4 mSv) is due to naturally-occurring sources (i.e., background radiation), 19.6 % (almost 0.6 mSv) is due to the medical use of radiation and the remaining 0.4% (around 0.01 mSv) is due to other sources of human-made radiation.
• In some parts of the world, levels of exposure to natural radiation differ due to local geology. People in some areas can be exposed to more than 200 times the global average.

How are people exposed to ionizing radiation?

• Ionizing radiation may result from sources outside or inside of the body (i.e. external irradiation or internal contamination).
• External irradiation is produced when a person is exposed to external sources (i.e. X-rays) or when radioactive material (i.e. dust, liquid, or aerosols) becomes attached to skin or clothes.
• Internal contamination may result from breathing in or swallowing radioactive material or through contamination of wounds.

What type of radiation exposure could occur in a nuclear power plant accident?

• In the event a nuclear power plant does not function properly, individuals, land, and structures in the vicinity of the plant could be exposed to a mixture of radioactive products generated inside the reactor, also known as “nuclear fission products”. The main radionuclides representing health risk are radioactive caesium and radioactive iodine.
• Members of the public may be exposed directly to radionuclides, either in the air or if food and water become contaminated by these materials.
• Rescuers, first responders, and nuclear power plant workers may be exposed to radioactive materials and higher radiation doses inside or around the power plant due to their professional activities.

Travel advice

What is the WHO travel advice for Japan?

• WHO has not issued an advise on general restrictions regarding travel to Japan.
• During the early phase of the emergency, travellers were advised to avoid travel to the areas most affected by the earthquake and tsunami because of disruptions to essential services, such as transport and electric power. The ongoing disaster relief activities, including the nuclear power plant emergency response and control activities, would have made travel difficult and could have consumed resources needed by relief workers and residents. Moreover, as indicated by the Japanese authorities, travel within the evacuation and exclusion zones surrounding the Fukushima Daiichi nuclear power plant was prohibited.
• In general, travellers who do not have essential reasons to travel were advised to give careful consideration to deferring travel to any areas where there had been considerable disruption to the normal infrastructure and where authorities were responding to urgent humanitarian needs.
• The situation in Japan has improved. Residents are being temporary allowed access into some areas that had been evacuated, but restrictions still exist. The Government of Japan is monitoring the situation and plans to lift restrictions once safety conditions are met.
• Information on the status of the nuclear facilities in Fukushima can be found on Japan’s Nuclear and Industrial Safety Agency (NISA) website and on the International Atomic Energy Agency (IAEA) website.
• Travellers should be aware of the risk of further earthquakes across Japan. Moreover, there may be areas of power, fuel, food and water shortages.

• International Atomic Energy Agency (IAEA)

Do travellers returning from Japan represent a health risk for others?

At this time, only those involved in the emergency response near the nuclear power plant remain in the area where there are higher levels of radioactivity. For their own safety, all personnel in these areas should undergo decontamination procedures when they leave the site. Travellers returning from Japan who have come from the 20 km evacuation zone surrounding the Fukushima Daiichi nuclear power plant and who have undergone proper screening and decontamination procedures, and travellers from all other areas, do not pose a radioactive health risk to others and do not require screening.

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