On the basis of the radiochemical analysis of the urine, the body burden (the radioisotopic
deposition in the tissues) was estimated. The ratio between the activity of the urine and the
amount of isotope fixed in the body is required for this calculation. However, few ratios are
available for the deposition of the various radioelements in humans, so that it was necessary
to utilize ratios obtained from animal studies. Of the animals collected from the islands, the
pig was selected as the closest to the human in size and metabolism. A detailed study was
therefore made on the excretion of these animals and on the radioactive content of various
tissues. Details of the animal study are presented in Chap. 3.
TABLE 2.4—Radiochemical Analysis of Rongelap Urine
(45 days postdetonation)
~ Beta Activity
(dis/min/24 hr)
Sample
Gross beta
activity
sr|
Balé0
1
2
3
4
5
6
1370
1260
1020
1210
1460
1200
490
510
480
626
328
T27
120
130
120
150
110
170
197
244
324
284
474
353
1253
526
134
312
100
42
No.
Av.
Total beta
activity, %
Rare-earth
activity
10.7
25.5
TABLE 2.5—Mean Body Burden of Rongelap Group
Radioisotope
sr®
Activity at
Activity at
Activity at
82 days
1 day
1 day
(uc)
(uc)
(NRDL)
0.19
1.6
0.03
1.2
Ba!40
0.021
131 Gn thyroid)
Ruts
0
Rare-earth group
Café
Fissile material
(NRDL)
2.7
6.4
0
0
0
0
(uc)
(LASL)
2.2
0.34
11.2
0.013
0.019
0.016 (ug)
The estimate of the mean body burden of the Rongelap group at 82 days postdetonation is
presented in Table 2.5. The body burden at 1 day postdetonation was calculated in the following
manner. A formula was obtained from urinary excretion data (reported by Cowan, Farabee,
and Love’) in a case of accidental inhalation of Sr®°. The excretion curve was best represented
by four exponentials. [Very similar results were obtained by approximating the biological decay of strontium with a power function, based on human excretion of the metabolically similar
element, radium (Norris, Speckman, and Gustafson'4 and Looney"’).]
Estimates were made of other radioelements present in significant amounts at 1 day, as
shown in Table 2.5. These estimates were madeonthe basis of the level of Sr® at 1 day
18