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Question 7A
+ It seems that there is great uncertainty about the biological effects of
chronic low doses of radiation on man.
"Permissible levels" are set
' nevertheless. Man is a fa&ly large animal. Is it known what biological
-and genetic effects the same levels of air and water contamination which
are presumed "safe" for man, are having on animals smaller than man?
plants?
Answer
On plankton?
On the oxygen-producing diatoms?
On
{A
‘A number of lines of evidence indicate that exposures "safe" for
man are "safe" for other forms of life.
It is generally true that lower
organisms are progressively less sensitive to radiation than man or other
' mammalian species.
Radiation doses required to kill some of the simpler
forms of life are from hundreds to thousands of times those required to kill
/ Mammals.
.
!
a
Radiation effects on man are closely related to the sensitivity of the
germ cells, of the cells of the bloodforming tissues, and of the cells of
the lining of the gut.
Because these cells of man are as sensitive as any
that have been found in animals or plants, we have no reason to expect that
any organism, regardless of size, would be more sensitive to radiation than
Man.
For radiation doses to man to be considered "safe", probabilities
of serious effects must be extremely small.
It would not be consistent
withour view of the value of animal and plant life to require that exposures
to radiation should carry equally small probabilities of serious effects to
be considered "safe".
Our interest in the safety of the multitude of species
of animal and plant life in any portion of the environment is that exposures