INTRRNAL DEPOSITION OF RADIONUCLIDES
nord the amatyss ot 4 months represents only
radielagical deray.
Thas, the results are net
directly camparsble te those obtained from ani-
mals which were returned alive, and in which
belagical turnever se well as radiologyal decay
were operating.
The largest fraction of the grom beta activity
In two
of the fish in which bones and muscle were sep-
+ AUPE SRI
arated and analysed, equal amonnts of activity
were found in each fraction. However, the
storage of these fish in formaldehyde for 3
months may have permitted the diffusion of
the radioelements from bone to muscle to take
place. Further studies on fresh fish will clarify
nae nal) enbintnn,
this point.
The contamination of the fish in the lagoon
was considerably greater than that of the land
animals studied. As tish form a large staple
item in the diet of the Marshallese, the high
level of contamination is important.
At the end of a 214-month experimental!
period. the excretion by the chickens of both
bets and gamma activity per 24 hours was 5
percent of the value measured at the start at 37
days post detonation (Fig. 5.1).
Analysis of pig excreta indicated a similar
decrease of activity with time. In a 6-week
period, the yamma activity excreted per 24
hours decreased to about 2.5 percent of the activity excreted at 44 days post detonation.
The excreta of the pigs from Utirik contained
less than 10 percent of the gross beta activity
found in the excreta of the pigs from Rongelap
at the same time.
This ratio of 1 was approx.
imately the same ratio found between the activity of the food, water and soil samples of the
two locations,
Radiochemtral Analysia of Tissues and Erereta. Radiochemical analysis of pig tissues
indicated that t2 percent of the skeletal beta
activity was derived from Se. 7 percent from
Bal. and 10 percent from the rare earth group
at *Z days post detonation (Table “.3). The
radioisotopic composition of the urine at this
time was simular to that of the skeleton, The
distribution of activity in the body of the pig
Ca ee
to ee te TDSSToe
wy represeat the distribution in hamen bemgs.
The sheolute amount of internal contannnetion
m the Rongelap people was, however, only s
tenth of that fownd in the animals.
At 4 months pest detonation, the atkaies
eerie compris ieee thai 2 p<corent of the tated
activity in the clam (Table 5.10). The rece
in the fek was contributed by the concentragon
of radioactive material in the viscera.
8i
earth growp constituted 43 percent of the total
beta activity. The balance of the activity was
contributed chiefly by Zr’* (2! percent) and
Ru'*'* (32 percent).
About 50 percent of the
material found in the viscera of the fish was
of the rare earth group.
Very small amounts
of strontium and barium were found. In the
tissues of the fish, strontium, barium and the
rare earths contributed only about 10 percent of
the total activity.
5.43
Autoradiographs
A number of autoradiographs of the tibiae
and femurs of | chick, 4 pigs, 1 rooster and 2
chickens were prepared beth at the USNRDL
and at the Argonne National Laboratory
(ANIL) to determine the pattern of deposition
of fission products. Contact printaing on X-ray
no-sereen film was found to be the most satifactory method of preparing the autoradiographs. The discussion and conclusions presented below summarize the tindings reported
by Norris (15).
The autoradiograph of a tibia from a chicken
sacrificed at 45 days post detonation (Fig. 5.2)
indicated a relatively uniform distmbution of
the activicy throughout most of the bone, with
the highest concentration of activity in the area
adjacent to the epiphysis. This area of high
uvtivity corresponds to an area of dense trabecular bone.
The tibia and femur of a baby chick, which
died spontaneously 47 days post: detonation,
showed the heaviest concentranion of radioactive material in the diaphysir (Fig. 5.3). The
end regions of the bone, which were laid down
after the animals were removed from the cuntaminated environment, were relatively lacking
Inactivity. The region of greatest activity was
mothe dinphysis, which appeared to be ab-
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