Table 1
Lognormal median concentrations of 2**?*°Pu in fish tissues (pCi g-' dry weight) collected at Enewetak and Kwajalein atolls*
Enewetak Atoll
{all samples)
All fish species
Bone
Muscle
Gut
0.038
0.013)
0.45
(24)
(123)
(6)
Surgeonfish
Muscle
Gut
0.028
0.019
(28)
(26)
Mullet
Muscle
Gut
0.014
0.75
(25)
(19)
Goatfish
Muscle
Gut
0.008
0.093
(2)
(18)
All other fish
Bone
Muscle
Gut
0.038
0.009
0.25
(24)
(49)
(44)
Kwajalein Atoll
Meck Island
Kwajalein Island
3)
(1)
(3)
0.086
0.023
0.051
0.02
0.03
(3)
(2)
0.086
0.024
0.14
(3)
(8)
(1)
0.01
Enewetak Island
(6)
0.01
0.53
0.42
(3)
(2)
0.96
0.43
(h)
(1)
0.40
0.41
(2)
(1)
(6)
*See refs | and 5.
+Values in parentheses are numbers of samples analysed. Average muscle and gut values in pCi g-! dry weight can be converted to average
pCi g~? wet weight by dividing by 3.5.
167 E
concentrations in Table 1, This discrepancy cannot be accounted
for by any possible differences related to trophic levels or
feeding habits. A similar calculation also yields large discrepancies between predicted and measured concentrations for
fish muscle.
SS
La
Excess plutonium at Kwajalein
167°20°
North Pass ¢~” Roi-Namur |
5 4%
9 20’'N
“ “muzu
‘
"hy
eis,
a
would be that Kwajalein Lagoon contains significantly more
“hy ..
ON
plutonium levels in the open ocean in this region. Unfortunately,
our schedule did not allow time to collect fish on. Kwajalein
Atoll.
The water samples were analysed for 7°°-?4Pu and '°’Cs
using the methods described in refs 9 and 10. Our analytical
results are shown in Table 2. Although the lagoon was not
sampled in great detail, the data are sufficient to show that the
average 7°°24°Py concentration in Kwajalein Lagoon (0.45 +0.21
pCi m~?) is nearly the same as the mean for the surface water
of the ocean in the area, and that it agrees reasonably well with
the levels previously predicted from woridwidefallout.
At the time the Kwajalein water samples were being processed we werealso participating in an intercomparison exercise
with Woods -Hole Oceanographic Institution to determine
‘,
"3
Fea
Enewetak Island
oN
>
> Meck Island
2's
i,
aw 4“, Bigej Channel
N
4
:
od
South Pass di Kwajalein Island
equatorial surface waters, to provide information on the
Table 2
“Sty
ar
An alternative explanation to account for these discrepancies
plutonium in its environment than would be expected from
worldwide fallout levels alone. To test this possibility, 551
unfiltered water samples were collected during May and June
of 1975 from the locations shown in Fig. 1. During June, two
samples were also collected outside the Atoll in the north
167° 40°
8 40’N
Fig. 1
Locations of sampling sites (see Table 2). ~
239,240Py Jevels in replicate surface-water samples from one
location in the North Atlantic. The mean value for eight
samples from Woods Hole (V. T. Bowen, unpublished) was
0.63+0.16
pCi m~3,
whereas
ours
for
10
samples
was 0.70+0.30 pCim~3. This analytical agreement (as
well as that in other national and international intercomparisons that we have completed) lends a measure of confidence
to our data. In addition, these comparative data show that, as
expected from worldwide depositional data’’, average plutonium levels are somewhat lower in Kwajalein Lagoon than in
Concentrations of °9*-?*°Pu and 1*°Cs (pCi m~*) in seawater in Kwajalein Lagoon and two locations in north equatorial waters
Station*
Depth (m)
Collection date
1
I
2
3
3
4
5
10°26’N 166°31‘E
11°16'N 165°45’E
Surface
44
Surface
Surface
47
Surface
Surface
Surface
Surface
5/10/75
§/10/75
5/08/75
5/08/75
5/08/75
5/08/75
6/14/75
6/15/75
6/15/75
*Kwajalein stations are shown in Fig. 1.
239.240 Py
0.33
0.87
0.29
0.26
0.33
0.54
0.52
0.36
0.53
(20)t
(13)
(27)
(24)
(25)
(16)
(18)
(32)
(23)
137(C5
137
144
I3E
127
129
129
132
132
143
*Values in parentheses are the lo counting errors expressed as percentages of the listed values.
(3)
(5)
(5)
(3)
(3)
(4)
(4)
(3)
(4)
230.240 Py /237Cs5
0.0024
0.0060
0.0022
0.0020
0.0026
0.0041
0.0039
0.0027
(20)
(14)
(27)
(24)
(25)
(16)
(18)
(32)
0.0037 (23)