Risks And Dangers Associated With Radiation
ROBERT SIEGEL, host:
The release of radiation in Japan, we hear, is not so great as to post a significant danger to public. But we thought we would check in with someone who studies these things about what the risks are and what the dangers are.
John Boice is an expert in radiation epidemiology. He's a professor at Vanderbilt University School of Medicine and scientific director of the International Epidemiology Institute. Dr. Boice, welcome to the program.
Professor JOHN BOICE (Radiation Epidemiology Expert, Vanderbilt University School of Medicine): Nice to be here.
SIEGEL: And, first, is that accurate that there has been no significant danger to public health from radiation released so far?
Prof. BOICE: Yes, I think that's quite true from everything that I've been able to read and watch on the television. The amount of radiation that has been released into the environment seems to be very small and not really related to any health concerns for the population.
SIEGEL: When we hear that U.S. servicemen were exposed in a few hours to a normal, say, month's worth of radiation, still not a dangerous amount or in that case, potentially dangerous?
Prof. BOICE: Well, it's hard to say. It seemed to indicate, from what I had read, that they were able to wash off any of the radioactive elements just with soap and water and that the levels were exceptionally low.
SIEGEL: Based on the past instances of heavy radiation exposure, whether they were the bombs at Hiroshima or Nagasaki or the Chernobyl accident, is there any rule of thumb or are there some rules of thumb as to how much radiation might cause how many serious cases of illness?
Prof. BOICE: At Chernobyl, there were two major health effects. The first had to do with the workers themselves, the in-plant workers who tried to put out the fire. Twenty-eight of them died within 28 days, because that was a very enormous exposure that they had.
The other source of population concern was related to the release of radioactive iodines from the reactor core. And the radioactive iodine spread throughout the environment and children who drank contaminated milk had a very, very high rate of thyroid cancer. In fact, the number of excess cancers associated with that release was on the order of 6,000. It was quite a large number.
SIEGEL: Professor Boice, I'm curious, Chernobyl happened 25 years ago. Were the likely effects of all this pretty well understood in the late 1980s right after it happened or have epidemiologists like yourself been surprised over the years, either by how many or how few cases of cancers or birth defects there have been?
Prof. BOICE: Well, I guess there were two surprises with regard to effects that we did not anticipate. All the evidence at that time indicated that radioactive iodines were not as effective as x-rays and gamma rays in causing thyroid cancer.
And so, one of the new data acquired from Chernobyl was that the childhood thyroid gland exposed to radioactive iodine was very susceptible and thyroid cancer could result. So that was new knowledge.
The second new knowledge was related to some of these - the emergency workers, you know, the ones that got very high doses. A number of them developed cataracts. So we did acquire new knowledge with regard to radiation-induced cataracts.
In the other circumstances, there was no excess of childhood leukemia. There was no excess cancers in the overall recovery workers. And so, that may not have been a surprise not having the increase because the doses to the population and to the workers were relatively low and not at the level where we've been able to detect, at least at this time, significant increases in cancer.
SIEGEL: Now, as I've read, the plants of the type that we're talking about in Japan might give off not just radioactive iodine, but also cesium, strontium, and I guess in the worst case, plutonium. Is iodine, as you see it, is that still the biggest culprit to worry about in terms of health?
Prof. BOICE: Well, that would be the immediate culprit to be concerned about. Cesium sticks out because it has a 30-year half life. That means half the radioactivity is still around 30 years later. And so, if there was widespread contamination of the environment, there would be a concern about the cesium being there. And because it's radioactive, it decays with gamma radiation and could continually expose the population if they move back there.
SIEGEL: Well, thanks for talking with us.
Prof. BOICE: You bet. My pleasure.
SIEGEL: John Boice, who is a radiation epidemiologist. He spoke to us from Rockville, Maryland, where he's scientific director of the International Epidemiology Institute.
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