at three of them.
routes
A number of transects of the island and
around the island were made to obtain measurements
with the portable counters.
these meaSurements
The approximate locations of
are shown in Figure 7.
The portable survey instruments indicated exposure
rates from 10 to 60 ur/hr around the edge of the island and
Isolated
from 15 to 160 ur/hr near the center (see Table 1).
areas had much higher radiation levels, particularly the
northeastern section where exposure rates of over 200 pr/hr
were measured.
The spectrometer measurements indicated that the major
contributor to the radiation field was °°Co.
This was the
contamination on the buried metal scrap, but the radioisotope
was also found in @ soil sample taken from the island. The other
major contributor was *~*’cs.
Only small amounts of **°Sb
were present.
The exposure rates due to each isotope and its
percentage of the total is shown below for each location,
along with the total exposure rates measured with the
ionization chamber.
SPECTROMETER AND IONIZATION CHAMBER EXPOSURE RATES
(ur/hr)
Location
1
(Center near
2
(Northeast
3
(Near lagoon
137 a5
e°Co
*25Sb
Total
As
25.8(39%)
39.4 (59%)
1.1 (2%)
66, 3
75.5
60.6(33%)
119.5 (66%)
2.0(1%)
182.1
204.0
18.1(50%)
17. 2 (48%)
. 6 (2%)
35.9
34.1
bunker)
corner)
shore)
4 (Center on
55.3
western
side)
Lee
+
por
ewrere ere +
-
3.
27