Gutter Sediment From Tokyo Shows Concerning Amount of Americium 241

Many places online were reporting on the high levels of cesium found in gutter sediment from Tokyo. The author of the document compared city park soil levels to what they found in the gutter. Drain pipes, downspouts and gutters will have higher radiation because both soil and contamination in rain and on surfaces will collect there. This could explain the discrepancy between the park and the gutter but the soil analysis done raises a different concern. Significant amounts of americium 241 were found in the gutter. Americium 241 is a particularly worrisome isotope because it has a very long biological half life anywhere between 20 years in the liver, 50 in bones and remains permanently in testicles and ovaries. Americium 241 is an alpha emitter that can be blocked by many common materials, but many of the daughter products that americium 241 changes into are gamma emitters or neutrons with long penetration depth. Americium 241 that becomes bound into the body will remain there decaying very slowly, since americium 241 is radioactive it will promote the formation of cancer cells.

From the sediment sample tested, it converts to 74 Bq/kg of americium 241. The derived intervention level for adults by the FDA is 8.8 Bq/kg of americium 241, 2.0 Bq/kg for infants. Usually people are not dining on gutter sediment but it shows the widespread distribution of americium 241 in significant amounts. The sediment can become airborne as it dries out, gets caught in the wind and young kids could play in the dirt. This does show that there is a significant enough level of americium 241 that there should be some awareness and concern. This kind of accumulation is going on in Tokyo, it makes one wonder what is going on in areas closer to the plant. Cesium is frequently reported and gives an idea of the contamination of an area, but some of these other isotopes are far more dangerous and rarely tested for.

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