Apologists for the type of old, unsafe nuclear reactors
which are leaking in Japan argue that the amount of radiation released
from Fukushima is small compared to the amount of "background
There Are NO Background Levels of Radioactive Caesium or Iodine
Wikipedia provides some details on the distribution of cesium-137 due to human activities:
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. As of 2005, caesium-137
is the principal source of radiation in the zone of alienation around
the Chernobyl nuclear power plant. Together with caesium-134,
iodine-131, and strontium-90, caesium-137 was among the isotopes with
greatest health impact distributed by the reactor explosion.
mean contamination of caesium-137 in Germany following the Chernobyl
disaster was 2000 to 4000 Bq/m2. This corresponds to a contamination of
1 mg/km2 of caesium-137, totaling about 500 grams deposited over all of
Germany.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
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.
So there was no "background radiation" for caesium-137 before above-ground nuclear testing and nuclear accidents such as Chernobyl.
Japan has already, according to some estimates, released 50% of the amount of caesium-137 released by Chernobyl, and many experts say that the Fukushima plants will keep on leaking for months. See this and this. The amount of radioactive fuel at Fukushima dwarfs Chernobyl.
Likewise, iodine-131 is not a naturally occurring isotope. As the Encyclopedia Britannica notes:
only naturally occurring isotope of iodine is stable iodine-127. An
exceptionally useful radioactive isotope is iodine-131...
And New Scientist reports that huge quantities of iodine-131 are being released in Japan:
researchers have used a worldwide network of radiation detectors –
designed to spot clandestine nuclear bomb tests – to show that
iodine-131 is being released at daily levels 73 per cent of those seen after the 1986 disaster.
(Indeed, some experts are saying that the amount of radioactivity released in Japan already exceeds Chernobyl.)
There are, of course, naturally occurring radioactive materials.
But lumping all types of radiation together is misleading ... and is comparing apples to oranges.
the National Research Council's Committee to Assess the Scientific
Information for the Radiation Exposure Screening and Education Program explains:
Radioactivity generates radiation by emitting particles. Radioactive materials outside the the body are called external emitters, and radioactive materials located within the body are called internal emitters.
emitters are much more dangerous than external emitters. Specifically,
one is only exposed to radiation as long as he or she is near the external emitter.
For example, when you get an x-ray, an external emitter is turned on for an instant, and then switched back off.
internal emitters steadily and continuously emit radiation for as long
as the particle remains radioactive, or until the person dies -
whichever occurs first. As such, they are much more dangerous.
As Hirose Takashi notes:
of the information media are at fault here I think. They are saying
stupid things like, why, we are exposed to radiation all the time in
our daily life, we get radiation from outer space. But that’s one
millisievert per year. A year has 365 days, a day has 24 hours;
multiply 365 by 24, you get 8760. Multiply the 400 millisieverts by
that, you get 3,500,000 the normal dose. You call that safe? And what
media have reported this? None. They compare it to a CT scan, which
is over in an instant; that has nothing to do with it. The reason
radioactivity can be measured is that radioactive material is escaping.
What is dangerous is when that material enters your body and
irradiates it from inside. These industry-mouthpiece scholars come on
TV and what to they say? They say as you move away the radiation is
reduced in inverse ratio to the square of the distance. I want to say
the reverse. Internal irradiation happens when radioactive material is
ingested into the body. What happens? Say there is a nuclear particle
one meter away from you. You breathe it in, it sticks inside your
body; the distance between you and it is now at the micron level. One
meter is 1000 millimeters, one micron is one thousandth of a
millimeter. That’s a thousand times a thousand: a thousand squared.
That’s the real meaning of “inverse ratio of the square of the
distance.” Radiation exposure is increased by a factor of a trillion.
Inhaling even the tiniest particle, that’s the danger.
[Interviewer] So making comparisons with X-rays and CT scans has no meaning. Because you can breathe in radioactive material.
That’s right. When it enters your body, there’s no telling where it
will go. The biggest danger is women, especially pregnant women, and
little children. Now they’re talking about iodine and cesium, but
that’s only part of it, they’re not using the proper detection
instruments. What they call monitoring means only measuring the amount
of radiation in the air. Their instruments don’t eat. What they
measure has no connection with the amount of radioactive material. . . .
There are few natural high-dose internal emitters. Bananas, brazil nuts and some other foods contain radioactive potassium-40, but in extremely low doses.
As the American Journal of Public Health noted in 1962:
the radioisotopes originally present in rock-type formations, some may
become internal emitters through natural processes. They may be
leached or dissolved into ground and surface waters, thus gaining
access to man's water and food supply. For either physical or
biological reasons, only a few of the naturally radioactive heavy atoms are important sources of internal radiation exposure.
The three most important are believed to be radium 226, the most
abundant natural isotope of radium; lead 210, a daughter of radium 226
and of radon 222, and radium 228, a daughter of natural thorium.
Radon 222 has a half life of less than 4 days.
Radium has a much longer half-life. However,radium ions do not form
complexes easily, due to highly basic character of ions. Radium
compounds are quite rare, occurring almost exclusively in uranium ores.
parts of the country are at higher risk of exposure to
naturally-occurring radium than others. It is not only those built on
top of uranium mines. For example, the American Journal of Public
Health article notes:
Water derived from surface
sources such as rivers, lakes, or wells penetrating unconsolidated sand
or gravel deposits were, in general, found to contain considerably lower
concentrations of radium 226 than wells penetrating deep sandstone
formations of Cambrian or pre-Cambrian ages.
contrast, cesium-137 - one of the main types of radioactivity being
spewed by the Japanese plants - has a much longer half life, and can
easily contaminate food and water supplies. As the New York Times noted recently:
Over the long term, the big threat to human health is cesium-137, which has a half-life of 30 years.
At that rate of disintegration, John Emsley wrote in “Nature’s
Building Blocks” (Oxford, 2001), “it takes over 200 years to reduce it
to 1 percent of its former level.”
It is cesium-137 that still contaminates much of the land in Ukraine around the Chernobyl reactor.
Cesium-137 mixes easily with water and is chemically similar to
potassium. It thus mimics how potassium gets metabolized in the body and
can enter through many foods, including milk.
As the EPA notes in a discussion entitled " What can I do to protect myself and my family from cesium-137?":
Cesium-137 that is dispersed in the environment, like that from atmospheric testing, is impossible to avoid.
Radioactive iodine can also become a potent internal emitter. As the Times notes:
has a half-life of eight days and is quite dangerous to human health.
If absorbed through contaminated food, especially milk and milk
products, it will accumulate in the thyroid and cause cancer.
bottom line is that there is some naturally-occurring background
radiation, which can - at times - pose a health hazard (especially in
parts of the country with high levels of radioactive radon or radium).
cesium-137 and radioactive iodine - the two main radioactive substances
being spewed by the leaking Japanese nuclear plants - are not
naturally-occurring substances, and can become powerful internal
emitters which can cause tremendous damage to the health of people who
are unfortunate enough to breathe in even a particle of the substances,
or ingest them in food or water. Unlike low-levels of radioactive
potassium found in bananas - which our bodies have adapted to over many
years - cesium-137 and iodine 131 are brand new, extremely dangerous
And unlike naturally-occurring internal emitters like
radon and radium - whose distribution is largely concentrated in
certain areas of the country - radioactive cesium and iodine are
spreading not only nationally, but world-wide.
At the very
least, it is important to note that each individual internal emitters
behaves differently. They each accumulate in different places in the
body, target different organs, mimic different vitamins and minerals,
and are excreted differently (or not at all). Therefore, comparing
radioactive cesium or iodine with naturally occurring radioactive
substances - even those which can become internal emitters - is
incorrect and misleading.
is not to say that we're all going to get cancer. Most of use probably
won't. This is solely an attempt to counter the misleading propaganda
from apologists for old, unsafe nuclear reactors. For background
information on "safe" radiation levels, see this.