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Radiation Exposure Primer

Since the earthquake, Tsunami, and nuclear disaster in Japan there has been a lot of information floating around the Internet; some of it not very accurate. Although there is still very little information about the specific types of ionizing radiation coming from the Fukushima nuclear complex, there are some informed estimates based on the Three Mile Island (TMI) and Chernobyl accidents.

Fukushima Nuclear Complex

Image Source: World Nuclear Association

I can see how the Japanese government might want to avoid a panic, but also the release of accurate information is critical to enable people to make informed decisions about the level and types of risks they are being exposed to. And, with radionuclides, it is critical that the information is isotope-specific….because each type of isotype has a different half-life and each type of isotope puts out different types of radiation (alpha, beta or gamma).

Some of the best information I’ve run across was a series of estimates of radiation exposure that had been calculated by the French nuclear regulatory agency:

“Institut de Radioprotection et de Sûreté Nucléaire (IRSN), estimates the radioactive releases of iodine-131 in Japan had reached about 2.4 million curies by March 22, 2011. That is about 160,000 times the best estimate of the amount released during the TMI accident in Pennsylvania (15 curies) and about 140,000 times the maximum estimate of 17 curies. It is about 10 percent of the estimated amount released during the Chernobyl accident, according to the IRSN. Combined cesium-134 (half-life: about 2 years) and cesium-137 (half life: about 30 years) releases from Fukushima are estimated at about half-a-million curies, about 10 percent of estimated Chernobyl cesium releases.”

Another piece of critical information that members of the public should be informed of is the epidemiological information gained from long-term studies of the human populations exposed from Chernobyl. It appears as though the cases of thyroid cancer that were found years after the Chernobyl incident were from ingestion of iodine-131 through milk and dairy products. The route of exposure was through ingestion, not inhalation of iodine-131. It seems as though the cows in the vicinity ate the grass that had been contaminated, then concentrated the iodine-131 in their milk, which was later consumed by humans.

Geary Interactive, a digital marketing agency has recently developed a graphic about ionizing radiation that is so informative that I’m linking to it here. It is a color depiction of the types of ionizing radiation that effects the human body [In English]. It is also a useful graphic for K-12 education.