Humanitarian Health Action

FAQs: Japan nuclear concerns

September 2011

Health effects

What are the acute health effects of radiation exposure?

  • If the dose of radiation exceeds a certain threshold level, it can produce acute effects, including skin redness, hair loss, radiation burns, and acute radiation syndrome (ARS).
  • In a nuclear power plant accident, the general population is not likely to be exposed to doses high enough to cause such effects.
  • Rescuers, first responders, and nuclear power plant workers are more likely to be exposed to doses of radiation high enough to cause acute effects.

What long-term effects can be expected from radiation exposure?

  • Exposure to ionizing doses of radiation can increase the risk of cancer.
  • Radioactive iodine can be released during nuclear emergencies. If radioactive iodine is breathed in or swallowed, it will concentrate in the thyroid gland and increase the risk of thyroid cancer. Among persons exposed to radioactive iodine, the risk of thyroid cancer can be lowered by taking potassium iodide pills, which helps prevent the uptake of the radioactive iodine.
  • The risk of thyroid cancer following radiation exposure is higher in children and young adults.

Does radiation exposure pose a risk to foetuses?

  • Foetuses are at risk of brain damage from radiation during weeks 8-25 of gestation.
  • Studies have shown brain damage in foetuses following exposure to an acute dose of radiation exceeding 100 mSv during weeks 8-15 and an acute dose exceeding 200 mSv during weeks 16-25. Outside of weeks 8-25, studies have not shown radiation risk to the fetal brain.
  • Foetal exposure to radiation can increase the risk of cancer in childhood. Studies have shown this effect with doses above 100 mSv.

What emotional impact can a nuclear accident have on children? How can they be assisted?

  • Disasters and their aftermath can have a profound emotional impact on children and may result in long term behavioural disturbances. Children exhibiting signs of stress - including difficulty sleeping, loss of appetite, developing new fears, changes in behavior (e.g. clinging, bedwetting), being preoccupied with the crisis - should receive extra time and attention from family members and other caregivers.
  • Children are among the most vulnerable of those affected by a nuclear accident because of their inability to fully understand and process the immediate and long-term effects of the emergency. Family members and caregivers should try to find out what the child thinks and feels about the disaster. If the child is scared because she/he has misunderstood what has happened, then simple explanations should be provided while avoiding alarming details. Children need a chance to play and relax. Encourage older children to be helpful and maintain regular routines.
  • Reactions to stress can depend on developmental level and are generally marked by changes in typical behavior for a specific child or adolescent. Reactions may continue for days, weeks or even months. Children should see a paediatrician or mental health professional if anxiety or grief interferes with their daily functioning, or if these emotions do not reduce with time. Early management of these symptoms can speed recovery and prevent long-term consequences.