a4
ticular problem in this regard for it becomes quickly concentrated in the thyroi:! gland when taken in with the food.
Thus if a fanma radiation monitor tm a pasture outside the
Nevada Test Site shows a reading of .087 r/hr at 12 hours
following the time of a nuclcur te.*, weasured at three feet
above ground level, this
inlicates the ajparently maxinmun safe
level, since the permissitle standard for continuous exposure
from a source esterna’
te tae tody ix 3.9 r/year (effective
biological jose), which i5 ewivalent to a doce rate of .087 r/hr
at l2 hours fcliowing a test.
however, if a milk cow feeds on
this pasture and its milk is
freshi» tonsumed by a small child,
this concausion tecomes
inval.d.
Under *hese circumstances it
can be shown that this same gamma reading (1.e. .087 r/hr)
probably reflects a concentration of iodine 131 in the grass,
which after passing into the cow's milk and being consumed
by the child may deliver to the child's thyroid gland a radiation dose of 175 to 1200 rads.
This dosage exceeds even the
safety Standards ‘or radiation vorkers (30 rads to the thyroid
per year) by a fertur of 5 to 49 and is so high as to represent a csericus po'2antial cause of thyroid cancer.
Thus she
UU.
conelusi¢cns regarding safety in the Nevada
Test Site region become it.valid if it can be shown that the
readings or which ti-v are based were taken in the reyions
in which cilk cove graz2
cna creduce milk that is freshly
consumed by cnildren localiy.
Our study of a nunber of regions
around the Nevada Test site shows that in many cases fallout sufficleatly intense to contair. such excessive amounts of iodine 131