3705 AND Sr RETENTION FROM RONGELAP FOODS
80
TT
TTT
TTT
CUMULATIVE EXCRETED "Sr, %
70 b-
751
TOO
FECES
=
60 F-
4
50 F-
4
40
4
30 P-
4
20 —
10 0
0
URINE
20
40
|
;
{|
|
7
|
|
|
[|
60
80 100 120 140
DAYS AFTER INGESTION
|
Jf
160°
ff
«190
Fig. i—Cumulative urinary and fecal excretions of Sy following in-
gestion of Rongelap food.
Since the integration limits were relatively large initially compared to
the rate of change of excretion level, the cumulative curves were not
extrapolated beyond the point at 10 days after termination of the high-
activity-food consumption. The urinary to fecal '"Cs excretion ratio
averaged 3.5, ranging between 2.8 and 3.8, and the %Sr excretion ratio
averaged 0.06, ranging between 0.05 and 0.07.
The cumulative excretion data were substracted from thetotal
intake to obtain the amount of each radionuclide retained. These re-
sults along with the BNL whole-body '*’Cs measurements are given in
Table 3, When the twosets of '*’Cs data are compared, they appear to
be in reasonably good agreement with each other, The fact that the
whole-body measurements are the more accurate, however, is seen
from the semilog plot in Fig. 5. The expected single exponential fit
demonstrates that the '*’Cs from Rongelap food behaves in a similar
metabolic manner to that observed under other intake conditions?"
The deviations from a single exponential function of the retention data
as derived from excretion measurements may be attributed to inaccuracies in the estimation of the contributions from the normal dietary
intake and the accumulation of errors inherent in the procedure. The
biological half-life as measured by the whole-body counter is 74 days,
whereas the apparent half-life as measured on the initial straight-line
portion of the excretion-data curve is 64 days. When it is considered
that the excretion data underestimate the retention slightly in the early
stages of measurement, the agreement is not unreasonable. It should be
pointed out that the short-lived (one to two days) component that has
14