Submitted by George Washington on 12/22/2013
Wikipedia provides some details on the distribution of cesium-137 due to human activities:
Small amounts of caesium-134 and caesium-137 were released into the environment during nearly all nuclear weapon tests and some nuclear accidents, most notably the Chernobyl disaster.
Caesium-137 is unique in that it is totally anthropogenic. Unlike most other radioisotopes, caesium-137 is not produced from its non-radioactive isotope, but from uranium. It did not occur in nature before nuclear weapons testing began. By observing the characteristic gamma rays emitted by this isotope, it is possible to determine whether the contents of a given sealed container were made before or after the advent of atomic bomb explosions. This procedure has been used by researchers to check the authenticity of certain rare wines, most notably the purported “Jefferson bottles”.
As the EPA notes:
Cesium-133 is the only naturally occurring isotope and is non-radioactive; all other isotopes, including cesium-137, are produced by human activity.
What people call “background” radiation is really the amount of radiation deposited into the environment within the last 100 years from nuclear tests and nuclear accidents (and naturally-occurring substances, such as radon).
2,053 nuclear tests occurred between 1945 and 1998:
But the amount of radiation pumped out by Fukushima dwarfs the amount released by the nuclear tests.
As nuclear engineer and former nuclear executive Arnie Gundersen notes, the wave of radioactive cesium from Fukushima which is going to hit the West Coast of North America will be 10 times greater than from the nuclear tests (starting at 55:00).
This graphic from Woods Hole in Massachusetts – one of the world’s top ocean science institutions – shows how much more cesium was dumped into the sea off Japan from Fukushima as compared to nuclear testing and Chernobyl:
(And Fukushima radiation has arrived on the West Coast years earlier than predicted.)
The Canadian government has confirmed in October that Fukushima radiation will exceed “levels higher than maximum fallout” from the nuclear tests.
The party line from the Japanese, Canadian and American governments are that these are safe levels of radiation. Given that those countries have tried to ban investigative journalism and have tried to cover up the scope of the Fukushima disaster, people may want to investigate for ourselves.