Why were those children exposed to so much radiation?

One of the great failures of Chernobyl was that the government of the Soviet Union did not immediately take steps to protect the public, especially the vulnerable—children and pregnant mothers—from potential radioactive fallout.

Iodine 131 has a short half-life—eight days—but it fell on the ground. Cows, sheep, and goats ate the grass and ingested small amounts of radioactive iodine, and dairy products made from their milk were given to young children for about a month after the accident. So children were drinking and eating radioactive-contaminated dairy products, and had an enormous concentration of radioactive iodine in their thyroids.

Were Fukushima kids also consuming contaminated food?

The lesson learned from Chernobyl was to immediately shut down food and water sources after the Fukushima accident. Any animal that could be a source of dairy products was banned from food supplies, and water systems were tested for radioactive contamination. So there really was no exposure of children to these high levels of radioactivity.

Are there other precautions for people who live near a nuclear plant?

Public health authorities in the United States have distributed iodine pills to people who live near certain nuclear power plants. In the first 24 to 48 hours [after an accident], if you take a pill and your thyroid is saturated with iodine, radioactive iodine is less likely to get to your thyroid.

Should the Japanese government even be testing children for thyroid cancer?

They wanted to reassure everyone that they’re doing everything they can. Many of these [detected] cancers would have gone undiagnosed, or might not have progressed. The same thing happens with prostate cancer: Most men over a certain age are going to have cancerous cells in their prostate [if they are tested]. But that doesn’t mean there’s any clinical significance.

Is three years after a nuclear accident a reasonable time to test for thyroid cancer?

In Chernobyl, the earliest cases were found about four years after the accident. That’s not where the peak was but where they started noticing a small increase, started saying, “Uh-oh, something’s going on.” Based on Hiroshima and Nagasaki survivors, we would expect this kind of solid [thyroid] tumor to appear somewhere in the four- to six-year range [after an event].

In Chernobyl, did the children with thyroid cancer recover?

I think the mortality was less than one percent.

Will the Japanese kids who have been diagnosed receive treatment?

I’m not a pediatric endocrinologist, and I don’t want to speculate. But I understand a lot of this will be watchful waiting.

I’ve read reports that parents in the Fukushima area don’t let their children go outside and play because they fear the children will be exposed to radiation.

There is no more radioactive iodine. Small amounts of long-lived isotopes, such as cesium or strontium, are of some concern. They have a half-life of 30 years, and they have health effects: Cesium concentrates in fatty tissues, strontium in bones.

But levels in Fukushima are minimal, and no [one there is] living near any serious concentration. That’s not to say there couldn’t be a place where a little bit of radioactivity fell on the ground. But by the same token, [radiation] surrounds us all the time. We live in a radioactive environment, from natural sources and medical/diagnostic exposures. If you fly in a plane over the Poles, you get a higher than average dose. If you have granite countertops in your kitchen, you get a little bit of radiation. If you like bananas, you get a little.

Do you have any predictions of what might happen in Fukushima?

Over the long term I don’t think we’re going to find any health effects related directly to radiation. The primary health concerns are mental health effects—anxiety and fear of living in what people perceive as a contaminated area. That’s where significant efforts need to be directed.