Fukushima Incident: Are We In Danger From Cesium-137 and Toxic Fish?


Home / Fukushima Incident: Are We In Danger From Cesium-137 and Toxic Fish?

How radioactive is the bluefin tuna in the Pacific ocean – and how dangerous is the Cesium-137? Image by Decoded Science

The Fukushima incident leaves many squeamish and uneasy with the prospect of nuclear contamination and poisoning. The perception of the way in which the tsunami swept through and affected the Japanese countryside may have heightened anxiety of many individuals with impending doom. However the facts need to speak for themselves:

  • In Fukushima, Japan and the World experienced the first nuclear reactor meltdown since Chernobyl.
  • However, the accident at Fukushima is not on the same scale as Chernobyl.
  • Radioactive Cesium 137 has entered the food chain of the Pacific Ocean.
  • More individuals died from the resulting flood waters in Japan than subsequent exposure to radiation.

What is Cesium-137?

Cesium without the moniker ‘137’ is a chemical element that is atomic number 55. As an element, Cesium reacts with water to ultimately go into solution (dissolve). The radioactive element (Cesium-137) and non-radioactive element undergo the same chemical reactions – however, the radioactive element has the additional nuance of being unstable or radiating particles and energetic gamma rays.

It is the radiation of Cesium-137 that worries the medical community and the average citizen. And it should; the particles and radiation emitted by Cesium-137 are known to cause cancer in exposed individuals. And therein lies the uncertainty, a healthy person who is heavily exposed to Cesium-137 and becomes ill will suffer the effects of radiation poisoning (and rarely death). The onset of cancer could take decades and is ‘dose-dependent.’

Fukushima and Cesium-137: Calculating the Damage

The problems with the uncertainty lie in the amount of exposure and the amount of Cesium-137.

Radioactive materials are unstable (and decay by emission of particles and gamma rays).

During the emission processes, the material decays to a different (and occasionally) less toxic element. The duration of that the initial, unstable element is called a ‘half-life.’  As the name implies, a half-life is just that—the time it takes for half of the element to decay to another element.

Cesium-137: Where Does It Go?

Cesium-137 completely decays to Barium-137 in approximately 150 years (the Barium-137 then quickly decays to a radioactively non-lethal material).

So it takes 150 years to completely degrade one-half of a kilogram of Cesium (or approximately one pound) to a non-harmful state. Some may think, it takes a very long time—(it does in a relative sense)— but remember, Cesium-137 also goes into sea water and dissolves. This Cesium-137 will retain its radioactivity for a while, but it will also be dispersed into a large volume of water.

The latest publications in the American Chemical Society and the American National Academy of Sciences listed only a slight increase in Cesium-137 from 2011-2012 bluefin tuna caught off the California coast. The persons most at risk are the fisherman (as you may imagine) who must stay at sea while bringing in the catch. Statistically speaking, the fishermen’s higher incidence of cancer is estimated to be less than 1%.

The general population of the United States eats far less fish, and researchers estimate the risk to the rest of us to be as if we had one or two more X-rays per year.

Fish Toxicity and Fukushima Fears

Claims of fish toxicity in the States are just claims; the people at or residing near the reactor face a different fate.  Cesium-137 does persist in the soil for that half-life of 30 years.  If the soil is not remediated (cleaned), the soil and the food chain in Japan will affect everyone on the island nation. There is a ‘non-fishing’ zone near the coastline of Fukushima-and if Cesium-137 remains at the coast, then there will be a non-fishing zone there for close to a century.

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