OFFICIAL USE ONLY
3.
3.1
RADIONUCLIDES IN ATR, SOIL, AND GROUND WATER
ATR SAMPLES
During the 1970 survey, 9 air samplers were operated, 5 on Bikini,
and 4 on Eneu, for 14 days (see Figures 3 and 4 for locations). Data
from those air samples will be tabulated in the SWRHL/EPA forthcoming
report.
Bikini No. 5 and Eneu No. 1 are considered to be background stations
since they were located on the windward side of the respective islands,
overhanging the beach.
Values for radionuclide concentrations in air were obtained by
analyzing one haif of the filter for each day composited by the station
over the total 14 day sampling period.
centrations ranged from 0.6 x 107%
for Eneu were 0.4 x 1074 pCi/m>.
For Bikini, the 239Pu air con-
to 5.4 x 1074 pci/m3,
All results
For comparison, the average value for
239pu background in the U.S. during 1968 was 0.4 x 10-4 pCi/m3 and the
maximum permissible concentrations for the general public for 239, 240py
is 2x 1072.
The analytical error associated with these results is
approximately + 25 percent at the 2 sigma confidence level.
In order to assess the variation in air concentration, the remaining
half of the daily samples from Bikini No. 1 were analyzed individually.
The range was from less than 0.7 x 10-4 to 7.9 x 1074 pCi/m3 for 239pu,
The average for all samples at station No. 1 was approximately 4 x 1074
pCi/m? which compares quite favorably with 5.4 x 10-4 pCi/m3, the highest
value for Bikini. Although some variation in daily levels is evident
from these data, the distribution of results appear to be about what one
might expect.
In any event, it is extremely doubtful that significantly
higher concentrations would be encountered under any weather conditions
expected to occur in that area.
The results for Bikini No.
1 may be somewhat representative of highest
levels to be expected when the island is reoccupied since this air sampler.
was located adjacent to and downwind of the road and was subjected to
frequent dust clouds stirred up by jeep traffic.
3.2
SOIL SAMPLES
Composite soil samples (15 to 22 individual collections) were taken
in 1970 to a depth of 1 inch from disturbed and undisturbed areas along
rows on Bikini (shown in Figure 4).
On Eneu, soil samples were collected
from the Camp Blandy and North Central areas (shown in Figure 5).
profile samples were taken at well points as shown in Figure 4.
The principal radionuclides in the soils are 137¢s and 99sr.
Soil
Average
values of }3’cs on Bikini ranged from less than 1 to 470 pCi/g dry soil
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