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e COW 53
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a COW 52
c COW 29
a COW 28
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CONTROLLED ENVIRONMENTAL RADIOIODINE TESTS
9. TST RT ADEPT LPI EL LPI ELIE TRI 2 T2122 2222222225 275227]
WIZ
MELLEL PLES ESET TTI
23.45 67 8 9 1011121314 15 1617 18 19 20 21 22 23 24 25 26 27 28
SEPTEMBER 1964
Fig, 10—Milk activities in second test,
For the first four to five days, the half-life in the cow is about one
day. The ratios reported here are based on an “effective” number of
curies consumed. That is, the grass activity per gram is multiplied
by the amount consumed in grams by the average cow. These numbers
are then corrected in time. One-half of the first day’s activity was
used because the sampling period encompassed one whole day, during
which time only one-half of the activity ingested by the cow on that
day would influence the milk activity levels. Added to this were one-
half of the preceding day’s activity, one-fourth of the day’s before that,
etc. The net result is a composite of all the ingested activity that influences the milk activity levels. These ratios should hold true as long
as the cow’s intake of radioiodine is sustained. The ratio resulting
from the wet-weight data from the first test was 240 + 35, whereas the
second test yielded a ratio. of 135+ 20. The reasons for this changeof
ratio are being investigated.
Portable-instrument Readings
Scintillator readings were taken across the contaminated pasture
immediately following the deposition of the radioiodine. Figure 11
shows an apparent linear relation between grass activity and scintilla-
tor readings.