Some people are misinformed about how long radioactive isotopes lasts from the nuclear fission, and mistakenly think that it might last seconds in the air; this may be true for certain isotopes such as Nitrogen-16, however this is not the scary isotope that causes a majority of the radiation problems.
Nitrogen-16, the radioactive isotope in coolant vapor, has a short half-life of five to seven seconds and rapidly reacts and decays to non-radioactive oxygen when mixed with water vapor and atmospheric gases. However the isotopes that causes a majority of the problems are Iodine-131 and Cesium-137. I hope that the following will help clear up some confusion and people better understand the radiation thats all over the news in Japan and the United States.
Explanation:
Iodine 131 has a half-life of about 8 days of which will emit beta particles upon radioactive decay (Please remember its half-life, It is the time required for the disintegration of one-half of the radioactive atoms that are present when measurement starts.)
Despite the 8 day half life, in the body, iodine has a biological half-life of about 100 days for the body as a whole. It has different biological half-lives for various organs: thyroid - 100 days, bone - 14 days, and kidney, spleen, and reproductive organs - 7 days.
The half-life of cesium-137 is 30.17 years. Because of the chemical nature of cesium, it moves easily through the environment. This makes the cleanup of cesium-137 difficult.
And remember we are talking about half life!!!!
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| Illustrating the decay of Cesium 137 |
Radioactive iodine can enter the body by ingestion or inhalation. It dissolves in water so it moves easily from the atmosphere into humans and other living organisms. For example, iodine-131 can settle on grass where cows can eat it and pass it to humans through their milk. It may settle on leafy vegetables and be ingested by humans. Iodine isotopes also concentrate in marine and freshwater fish, which people may then eat.
People may also be exposed from contaminated sites to cesium-137:
-Walking on cesium-137 contaminated soil could result in external exposure to gamma radiation. Leaving the contaminated area would prevent additional exposure.
-Coming in contact with waste materials at contaminated sites could also result in external exposure to gamma radiation. Leaving the area would also end the exposure.
-If cesium-137 contaminated soil becomes air-borne as dust, breathing the dust would result in internal exposure. Because the radiation emitting material is then in the body, leaving the site would not end the exposure.
-Drinking cesium-137 contaminated water, would also place the cesium-137 inside the body, where it would expose living tissue to gamma and beta radiation.
I hope you this blog post help you understand the elements a little better.
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