|David Crouse, Ph.D.|
Traces of radiation have appeared in the metro area, what should we know about exposure?
Radiation safety guidelines make it clear that any unnecessary exposure should be avoided if possible. Fortunately, the levels of radiation detected in the United States are well below those that should cause concern and appear to be declining. Indeed, they are only slightly above exposure levels that occur naturally in some places in the world or in association with things like intercontinental flights or routine radiographic procedures, like a chest X-ray exam.
With the levels seen in the United States, there would be no expected long-term effects. However, in the region immediately surrounding the reactors in Japan (out to say 15-25 miles), and depending on your exact location, duration and type of exposure (e.g., skin versus ingested), there may be long-term effects. Based on available information and the experience from Chernobyl, you might see a small increase in cancer of the thyroid, particularly in children. Fortunately, the public was largely evacuated from that area, limiting exposure and reducing possible long-term effects.
What are the environmental concerns?
Any additional presence in the environment is not good. That is even more true for long lived isotopes like cesium-137. If present in the soils around the reactor, it may cause, as is true in the Chernobyl area, a very long-term problem that could prevent public occupancy. With respect to the sea in the area, concerns are largely alleviated by the tremendous dilution that would be present. The impact on seafood from the region would likely be transient and so far, has been minimal though concerns remain high.
Is there anything else that people should know?
The effects of the actual earthquake and tsunami in Japan have been enormous and require long-term help. Although there is great concern about radiation effects, their present impact compared to that from the actual physical disaster, is small. One last point, using potassium iodide pills for preventing radiation effects here in the U.S. is a waste of money and possibly a hazard.