224
Health Physics
August 2010, Volume 99, Number 2
model, the decay correction need only to account for the
elapsed time between sampling and counting. This was
1000
the method used by Lessard et al. (1985), Goetz et al.
(1987), and Simonet al. (2010b).
Urine volumes
The distributions of individual urine volumes in the
three groups of samples collected by LASL from
Rongelapese on March 16 (n = 35), March 17 (n = 31),
and April 15 (2 = 21) in 1954 are presented in Table 4
and Fig. 2.***5** The mean urine volumes from the LASL
collections in mid-March 1954 were similar; the average
values were 427 mL (March 16, Rongelap), 448 mL
(March 17, Rongelap), and 385 mL (March 19, Sifo).
The distributions and mean urine volumes of the HASL
samples (Fig. 3) from March were similar in magnitude
to the LASL samples, but slightly higher, 596 mL
(March 24, Rongelap), 523 mL (March 25, Rongelap),
TT
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Daily Urine Volume (mL)
RESULTS AND DISCUSSION
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50
7080 9095
99
99.9 99.99
Cumulative Percent
Fig. 2. Empirical cumulative probability distributions of urine
volumes obtained from two Los Alamos Scientific Laboratory
(LASL) samplings of Rongelapese greater than 16 y old at time of
exposure (see Table 4 for a summary of the data).
756 mL (March 24, Sifo), 603 mL (March 25, Sifo), and
573 mL (April 15, Rongelap) (Cronkite et al. 1956).**
Individual urine volumes from two groups of the
American military weather observers resident on
Rongerik at the time of Bravo whoprovided samples in
1954 on March 19 (n = 9 for beta activity measurements
and n = 10 for Pu activity measurements) are shown in
Fig. 4 and are also summarized in Table 4.***SS
The urine volumes collected from the Marshallese
were, on average, small compared to the usual range of
800 to 2,000 mL d' reported for populations with a
typical fluid intake of about 2 L d| (MedlinePlus 2002).
Not all Marshallese sampled, however, excreted these
extremely small samples. For example, of those sampled
on March 16, the volume for one urine sample was
greater than 800 mL, of those sampled on March 17,
three (12%) were greater than 800 mL, and of those
sampled on June 15, six (30%) were greater than 800 mL.
Lowerthan average urine volumesare, in general, a
result of either reduced fluid intake and subsequent
dehydration or high water losses through feces or, more
commonly, through the skin. Hence, one possible explanation for low urine volumes among the Marshallese was
a well documented drought that had been underway in
the northern Marshall Islands for a number of months
prior to the Bravo test. Sharp and Chapman (1957)
reported that “for many weeks prior to 1 March, the
natives had been rationed to one pint cup per individual
per day.” The shortage of fresh water would have also
affected those on Ailinginae and Utrik. The average
urinary excretion for the American weathermen on
Rongerik was significantly greater compared to the
Marshallese (Table 4) and averaged about 1,100 to 1,200
mL per day.***’°* However, Rongerik, where the Amer-
ican military weather observers were located, had a water
distillation unit and drinking water was available in
5-gallon cans at the time of evacuation (Sharp and
Chapman 1957).
Anotherplausible explanation for the small average
values of urine is the reduction of daily urine volumein
Table 4. Summary statistics of sampled urine volumes (see Table | for references). All values are nominally mL per
24 h (na = not available).
No. of samples
Minimum
Maximum
Mean
Median
Std Error
LA316R
LA317R
35
90
31
140
9
730
10
760
850
1,345
1,525
990
427
360
42
448
415
37
LA319A
1,072
1,130
71
LA319AP*
1,197
1,250
86
Group ID
LA319S NY324R
15
na
na
385
na
na
40
70
980
596
653
47
“LASL sample on March 19 from American (A) military for plutonium (P) analysis.
NY325R
NY324S
NY325S
NY416R
43
95
980
523
480
44
12
320
965
756
805
57
15
90
985
603
750
76
21
47
980
573
540
59