Government scientists and media
shills are now "reexamining" old studies that show that radioactive
substances like plutonium cause cancer and arguing that exposure to low
doses of radiation is good for us (a theory called "hormesis").
It is not just bubbleheads like Ann Coulter and pro-nuclear hacks like Lawrence Solomon
are saying it as well. In virtually every discussion on the risk of
nuclear radiation, someone post comments arguing that a little radiation
makes us healthier.
However, the official position is that there is insufficient data to support the hormesis theory: As Wikipedia notes:
reports by the United States National Research Council and the National
Council on Radiation Protection and Measurements and the United Nations
Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) have
upheld that insufficient human data on radiation hormesis exists to
supplant the Linear no-threshold model (LNT). Therefore, the LNT
continues to be the model generally used by regulatory agencies for
human radiation exposure.
The notion of radiation
hormesis has been rejected by the National Research Council's (part of
the National Academy of Sciences) 16 year long study on the Biological
Effects of Ionizing Radiation. "The scientific research base shows that
there is no threshold of exposure below which low levels of ionizing
radiation can be demonstrated to be harmless or beneficial.
Most proponents of the hormesis theory claim
that data from the residents of Nagasaki and Hiroshima shows that
residents exposed to low levels of radiation (i.e. some miles from the
bomb blasts) lived longer than residents who lived so far away that they
were not exposed to any radiation.
However, as Reuters noted in 2000:
survivors of the atomic bomb have their life expectancy reduced by an
average about 4 months, which does not support claims that survivors
exposed to low levels of radiation live longer than comparable
To clarify the question of whether atomic
bomb survivors have enhanced or reduced life expectancy, Drs. John B.
Cologne and Dale L. Preston from the Radiation Effects Research
Foundation, Hiroshima, Japan, studied 120,321 survivors and estimated
their radiation exposure and mortality rates after 45 years of follow
They report in the July 22nd issue of The Lancet that median
life expectancy fell by about 1.3 years per Gy of estimated radiation
dose, and declined faster at higher doses. At doses below 1 Gy, median
life expectancy fell by about 2 months, while exposures of greater
than 1 Gy resulted in a median loss of life of 2.6 years.
Cologne and Preston estimate that at a dose of 1 Gy, 60% of those
exposed died from solid cancer, 30% from illnesses other than cancer,
and 10% from leukemia.
"These results are important in light of
the recent finding that radiation significantly increases mortality
rates for causes other than cancer," they write.
A large study of bone cancer in survivors of Nagasaki and Hiroshima published in March of this year also showed no hormesis, but rather increased cancer risk even at low doses. (See this and this for more evidence that low levels of radiation can cause cancer.)
data has also been misinterpreted by those who advocate that a little
radiation is good for you. For example, the above-quoted Wikipedia
In popular treatments of radiation
hormesis, a study of the inhabitants of apartment buildings in Taiwan
has received prominent attention. The building materials had been
accidentally contaminated with Cobalt-60 but the study found cancer
mortality rates more than 20 times lower than in the population as a
whole. However, this study compared the relatively young irradiated
population with the much older general population of Taiwan, which is a
major flaw. A subsequent study by Hwang et al. (2006) found a
significant exposure-dependent increase in cancer in the irradiated
population, particularly leukemia in men and thyroid cancer in women,
though this trend is only detected amongst those who were first exposed
before the age of 30. This study also found that rate of total cancer
cases was lower than expected.
Even If Hormesis is Real, We've Got Too Much of a Good Thing
Even if the accepted scientific consensus is wrong and hormesis is real, we're getting too much of a good thing.
As I've previously noted:
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:
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.
Similarly, I've pointed out:
The Argonne National Laboratory notes:
all the plutonium on earth has been created within the past six
decades by human activities involving fissionable materials.
testing of nuclear weapons, which ceased worldwide by 1980, generated
most environmental plutonium. About 10,000 kg were released to the
atmosphere during these tests.
Average plutonium levels in surface soil from fallout range from about 0.01 to 0.1 picocurie per gram (pCi/g).
Accidents and other releases from weapons production facilities have caused greater localized contamination.
like radioactive cesium and iodide - which I discussed yesterday -
plutonium doesn't exist in nature in any significant quantity, and so
"background radiation" is a meaningless concept.
In other words, even if a little radiation is good for us, we have already been
getting exposed to a lot more radiation - from nuclear weapons tests,
Chernobyl, Japan and other sources - than our ancestors were ever
Indeed, even if the studies did show that low level
exposure by the survivors of Hiroshima and Nagasaki helped them live
longer, background radiation in 1945 was much lower than after
above-ground nuclear tests, Chernobyl and Fukushima.
Other Toxic Exposures
It's not only apologists for the safety-averse
nuclear power industry which is trying to convince us of hormesis.
Apologists for all big polluters are arguing hormesis as well.
Wikipedia describes the general theory:
Hormesis ... is the term for generally favorable biological responses to low exposures to toxins and other stressors.
if any toxic substances might have a hormesis effect in a vacuum, we
are not exposed to chemicals in a vacuum ... we are exposed to several
chemicals at the same time. Indeed, scientists long ago demonstrated the "synergistic effect" of toxins, where:
combined effect of the substances acting together is greater than the
sum of the effects of the substances acting by themselves .
For example, smokers are much more likely to get cancer from exposure to radioactive radon gas than non-smokers.
even if there is hormesis from a chemical at low doses (hormesis
promoters claim that low level exposures cause our body to produce a
wave of antioxidants and other cancer-fighters), by the time we get
swamped with the myriad of toxic chemicals and radiation exposures
present in modern life, our body's defense mechanisms become so
overextended that any hormesis effect is lost.
The bottom line: Some more radiation from Japan or a new nuclear power plant will not be good for us.