When a tsunami hit the Fukushima I Nuclear Power Plant on March 11, 2011, it sent the plant into nuclear meltdown, releasing radioactive material into the surrounding environment. On March 12, over 100,000 people living within 20 kilometers (12 miles) of the disaster site were evacuated, and those within 30 kilometers (19 miles) were warned to stay inside to minimize risk of exposure. Since then, there have been various claims and counterclaims on increased incidences of cancer among local residents.
Months after the incident, the University of Fukushima began an unprecedented screening of children for early signs of thyroid cancer. The disease can be caused by exposure to radioactive iodine 131, and can indicate signs of radiation-related cancers. They screened hundreds of thousands of children, which is the age group most at risk of developing thyroid cancer after exposure, who were living in the Fukushima Prefecture.
What they found was staggering: Almost half of the 300,476 children so far tested had cysts on their thyroids, while over 100 were later diagnosed with cancer, a much higher rate of the disease than had previously been recorded.
Predictably, this data has been seized upon by those wanting to prove the dangers of nuclear power, yet scientists have come out strongly against interpretations that indicate the increase in thyroid cancer diagnoses are due to radioactivity exposure. Instead, they think this increase in rates is simply due to sampling.
As the study examined more children than had ever been looked at previously, they simply found that cysts and nodules on the thyroid are far more common than was previously believed. “The evidence suggests that the great majority and perhaps all of the cases so far discovered are not due to radiation,” Dillwyn Williams, a thyroid cancer specialist from Cambridge University, told Science.
In fact, scientists had already predicted that the risk of cancer in those living near the site was probably quite low. While it is the second-largest nuclear disaster to have ever happened, it was nowhere near the same scale as Chernobyl, belching just a tenth of the radiation, much of which was blown out to sea. Those workers who bore the brunt of the exposure have so far not experienced anything like those who cleaned up Chernobyl, though they will have to be screened every year for the rest of their lives, and one worker has since developed leukemia.
In fact, the biggest threat to the people of the Fukushima Prefecture is not thought to be from cancer, but “mental and social well-being.” The disaster caused massive upheavals, disrupted people’s jobs, and induced heavy mental stress on tens of thousands of people. Those who were evacuated are five times more likely to suffer from psychological distress than the rest of Japan, and over 14 percent are recorded as suffering psychological trauma, compared with just 4 percent of the rest of the population.
Main image: IAEA Imagebank/Flick CC BY-SA 2.0