Fallout blamed for thyroid cancer -Reply -Reply

[Charles Willis <CAW@nrc.gov>]

Michael,

I have not seen the full report but I would advise against beiing too cynical.  I made
what I considered to be reasonable assumptions about the radioiodine released to
the atmosphere and the resulting doses.  Then, using the BEIR-V risk factors,
calculated the number of thyroid cancers.  My results were in the range offered by
folk from the Institute of Medicine.

A lot of I-131 was released, about 3 E 10 curies, but much of it was injected into the
stratosphere and the distribution in the troposphere was non-uniform and
un-measured.  The principal pathway to people was via milk, etc., so any dose
calculation is highly uncertain.  The risk factors also are highly uncertain so I belive
the published estimate underestimates the range of uncertainty.  Even the upper
value, about a 25 percent increase in thyroid cancer over the next 50 years would
not be detectable, so we may never now.  Still, the guess does not seem as
unrealistic as one might suppose.

Charlie Willis
caw@nrc.gov
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