+
T. M. BEASLEY, E. E. HELD and R. M. CONARD
247
‘approximately 1/100th of the maximuni: from the northeast Pacific Ocean cecreased
permissible. body burden which has been estab- eightfold between 1965-1067. Assuming thata
lished for non-occupationally exposed indi- first order reaction governed the remeval of
viduals considering the total] body as thecritical 88Fe from the mixed layer of the ccean {up
pper
organ.") Previous measurements of 53Fe body 100 m) he calculated the efieciive hail-iife for
burdens during a period of increasing °5Fe 530"¢ loss as 11 months. Mezsurements in cattle
fallout generally showed that =5Fe body burdens and rain waters show decreases, but at lesser
of females were higher than those of males.-5) rates."©) Tron-35 body burdens of aduit males
Presumably this is due to higher turnover rates in Richland, Washington, decreased approxiof iron in females than in males, with the result mately 4 fold between 1667 and 1970,
that females are more nearly at equilibrium with corresponding to an efiective **Fe bali-life of
their environment. As environmentallevels of
L.5yr. If the 5Fe turnover rates of Richland,
ment and in humans. Jennines‘® has shown
85Fe body burdens of this latter group from
55Fe decrease, females should, on the average,
Washington, residents are similar to those of
reflect this change by exhibiting lower “Fe insular populations, we conclude that people
body burdens than those of males. Figure 1 from maritime cultures would exhibit similar
shows that more female body burdens tended and perhaps faster turnover rates cf *5Fe
toward values <0.4 uCi, while male body because of the short “‘ecolegical haif-bfe"™*of
burdens were morenormally distributed, about this radionuclide in the marine envirenrent.
a mean of 0.43 wCi. Regression analysis ofage
The highest 55Fe body burdens previously
on body burdens showed a significant corre- measured were in female natives at Pethel,
lation (P <0.001); older individuals had Alaska, during 1966.8) Tke average body
higher *5Fe body burdens. Table 2 shows a burden of 18 females was 1.1 «Ci. During th
tabulation of the average *5Fe body of males same year, the average **Fe body burden of
and females by age groups. The number of females and males at Tokai-mura, Japan was
samples per age group is admittedly small yet 0.92 zCi and 0.63 wCi respectively.) We
the general increase of ®5Fe body burden with determined the ®5Fe bedy burdens cf 32 feage appears qualitatively consistent with earlier males and 37 males from Tokai-mura from
data obtained by analyzing blood from Seattle, blood collected in October 1970; the average
Washington males in 1966.
values were 0.12 and 0.17 respectively. Thus,
Comparison of the *5Fe body burdens of not only do the Rongelapese have significaniy
peoples of different countries‘®) requires knowl- higher ®5Fe body burdens than those of the
edge of the turnoverrates of 55Fe in the environ- Tokai-mura residents, but the decrease in the
that the 55Fe specific activities of salmon taken
Table 2. Average body burden of “Fe in Rongelapese
residents ofdifferent ages
Males
-
Females
Age
Number of
samples
Body burden
(uCi)
16-20
21-31
32-42
43-53
54-64
8
4
5
2
6
0.31
.0.33
0.52
0.58
0.53
6
12
5
7
2
23
0.34
0.33
0.66.
0.57
>G64
16-20
21-31
$2.42
43-53 54-64
>64 -
3
2
1966 to 1970 appears comparable to that for
Richland, Washington, males. .
As previously stated, all of the concrs of the
Rongelap study were subjected to external
radiation during the accidental] contamination of
Rongelap Atoll in 1954. Pecause of the high
levels of radioactivity at the Atoll, the Rorgelap
_natives were moved to Majuro Atoll where they
” resided for 3.5 yr. Followizg exposure in 1954,
0.48
whole body counting and urinalysis disclosed
measurable quantities of internally ceposited
fallout radionuclides. By 1937, however, ine
only radionuclides present in the Rongelapese in
significantly measurable quantities were °*Zn,
0.66
formed at that time so body burdens of this
radionuclide are not known. However, based
WCs and Sr.No Fe analyses were per-