CONTROLLED ENVIRONMENTAL RADIOIODINE TESTS
823
review of safety-analysis reports. The series of experiments will
provide some insight into the behavior of radioiodine in general. This
paper compares some of the results of the first two releases.*
GENERAL DESCRIPTION OF TESTS AND COMPARISON OF RESULTS
So far, two releases of gaseous molecular 131 have been made.
The first, which was made in the spring of 1963, was over a rolling
open-range natural-grasg terrain (Figs. 2 and 3). The first test was
preliminary in the sens®
that it was necessary to know if the desired
information could be gained: from the basic experimental design prior
to the expenditure of time%ind money to establish an actual dairy setup
in the semiarid desert at the NRTS. The results of the preliminary experiment were encouragimg, and therefore the project proceeded. The
second test, which was mgde in September 1964, utilized the same
quantities, the same velaas#mechanicm, and the same form of "I; the
only major difference was that the iodine was released over an estab-
lished irrigated pasture (Figs. 4 and.@). This paper is primarily a comparison of the data that were gained as a result of the two releases.
Measurements made includeddeposition velocities, ‘apes on the
grass, milk to grass activity rattos, milk activities, goptable=instru-
ment “readings relaiive toMantamination levels, and&
an~thyroid-
uptake fractions. Attempts were alsemade to mefpure theEnechanisms
involved in the differences observed -‘between the physical half-ltfe of
the "I and the observed halfslife o&the grass. Thradioiodine release
mechanism was identical in both cases (Figs. &and @). In eachease,
of five flasks. At release time 10% sodijjgn nittite was added through
the outlets in the suction flaskg,-Pais oxidized the-todide into molecular
iodine gas. Nitrogen sparging was startedy art..the
nitrogen were adjusted“seithat.the ion ware
abguigede.ymin,The release
rz
th,
flowrates of the
Sed over a periéd of
Mefocrstazibe’'tConditions z2
+ “Both tests were*madeacuring moderately undjable conditions. The
yind Speeds were stronger
eerie. test 2; the apemopetersat the4--m
- “Data yedukting!‘from theMecsond release werestill being collected’‘at’ the
time of submiggiog,of.this manuscript. Therefore detailed data, methods of cal-
culation, references to and comparison with other work, and acknowledgments
have been intentionally deleted. Full details will be published in an IDO report.