From the Vancouver Observer – April 1, 2011

by Linda Solomon

How do we know how much radiation is reaching Canada from Fukushima?
Physicians for Global Survival asked, in a press release today.  They
added that physicians for Global Survival “would like more openness from
safety regulators and government about all isotopes, honesty about
methods of measurement and regular updates about risks to vulnerable
populations.”

 “Physicians for Global Survival  is deeply
concerned about the long term health of populations exposed due to
accidental or planned releases of radioactivity from Fukushima and from
domestic power plants.”

How the US monitors radiation

“The US uses a system of RadNet monitors,” the release said, adding that:

Radiation monitors are “point source” monitors, meaning that the
radioactive element or ray must actually strike the monitor to be
measured.  They are unlikely to detect radiation as close as twenty five
feet above or beside them.  Apparently there are only about 125 of
these monitors for the entire continental United States, Hawaii and
Alaska.

Feel secure yet?

“News reports mention Iodine-131 and Cesium-137, not because they are
the only radioactive elements discharged from the stricken reactors in
Fukushima, but because they are the easiest to detect and measure,” the
report added. 

“They both give off gamma rays (like x-rays for
which technicians wear little badges) when they decay.  Iodine releases
gamma rays directly and cesium, indirectly when its short-lived decay
product, barium-137m, undergoes further decay.”

 What about Canada?

According
to reports from the Gentilly 2 reactor in Quebec, there are 48
radioactive elements identified in regular emissions and, according to
the Canadian Nuclear Safety Commission, there may be more than 225
radioactive elements produced in a fully functioning nuclear reactor. 
Aside from plutonium, news reports are silent.

 Alpha and beta
radioactivity are more difficult to measure.  RadNet measures them by 
“vacuuming” the air and passing it through a filter.  The amount on the
filter is then measured.  Sources are contradictory about amount of time
between detection, measurement and speed at which the public can be
informed. 

 Because of their poor external penetrance – alpha
particles can’t penetrate skin and beta particles don’t go much further
than a few millimeters – their danger has been discounted.  As internal
emitters, however, their damage can be extensive.  Absorbed in a human
body through eating or breathing, they can change enzymes, dislodge
ions, and upset strands of DNA.     

 Radioactive iodine-131
causes cancer by this type of mechanism.  The human body absorbs iodine
from food for the production of a thyroid hormone that is important for
normal growth, intellectual ability and daily energy – ask anyone who
has had a “low” thyroid.  While in the thyroid, radioactive iodine emits
beta particles.  Cells have genes which determine their rate of growth
and life spans.  Beta particles alter these genes and, eventually, in
those who develop cancer, turn off the “growth control” gene so that
cells grow wildly out of control producing cancer.

 Fortunately
the danger from radioactive iodine is relatively short-lived.  With a
half-life of  eight days, one tonne becomes a mere 62.5 kilograms in a
month.  The danger can be decreased but not eliminated by taking
potassium iodide tablets immediately before exposure.

Iodine-131,
however, is not the only radioactive element released from Fukushima –
or from any nuclear power plant, the group said in the news release.

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