64
plutonium resulting from the testing of devices in these areas, as shown in
Fig. 2.
It shoutd be noteu that the region of high activity suggested by the
64.2 pCi/g concentration measured in the sediment collected at Station 8-18
off the Yurochi-Aomoen Isiand complex refers to an area of the lagoon used for
the disposal of contaminated material removed from these same islands (Smith
and Moore, 1972).
The 35.8 pCi/g concentration in sediments
from the eastern-
most lagoon station {B-30) suggests that a denser grouping of sampling
stations may reveal a larger area of contamination around this area.
It was
possible that, at this station, debris from the Baker test was sampled, as
described by Glasstone (1950).
In addition, Station B-30 is in the upwelling
region of the lagoon and may thus be hydrologically different from other
lagoon stations.
If Station B-30 received debris from the Baker test, it is
indeed surnrising that the 3.73 pCi/g concentration measured in sediments
collected even closer to the Baker testing area to the north is so low.
A
possible factor may be that the higher radionuclide concentrations measured
in Station B-30 sediments is related to the fact that these sediments were
collected in 47 meters of water, whereas the low radionuclide concentration
found in sediments at Station B-15 were collected on the slope of the lagoon
terraces at a depth cf 32 meters.
5.1-2
Americium-241]
The distribution of aan across the lagoon (Fig. 12)
systematically related to the pattern found for 2394240, u.
is
The activity
ratios of 2394240 puso tt am in surface sediments of the northwest quadrant vary
between 1.66 and 1.85 in Bravo Crater, and are 1.24 at Station B-2, and about
1.39 jn Station B-20, B-19, Tewa Crater and B-18 surface sediments.
The
ratios found at Central and Northwestern Jagoon stations are closely related,
and range from 1.49 to 1.58.
In the eastern and southern regions of the atoll,