list, respectively, the composite 23°Pu in air results for Bikini and Eneu.
The
composite results were obtained by analyzing one half of the filter for each day
and compositing bv station over the total sampling period.
For Bikini the 239Pu
results ranged from 0.6 x ia pCi /m to 5.4 x 1074 pCi/m>, All results for Eneu
were 0.4 x 10° iu pCi/m>, For comparison the average value for *39Pu background in
the U.S. during 1968 was 0.4 x 1074 pci/m,
In order to assess the daily vari-
ation in air concentration, the remaining one-half of the individual filters from
station No, 1 on Bikini were analyzed separately.
Table 9.
These results are listed in
The results ranged from <0.7 x 1074 pci/m to 7.9 x ia4 oCism,
The
average for ail samples at this station is 4 x 1074 pci/m? which compares quite
favorably with the value of 5.4 x 10 + oCi/m> for the composite.
Although some
variation in daily levels is evident from these data, the distribution of results
appears to be about what might be expected allowing for slight differences in
wind conditions.
It should be noted that station No. 1 is located on the down-
wind side of the lagoon road and was subjected to frequent clouds of dust
stirred up by the survey party's
jeep.
In any event, it is doubtful that
significantly higher concentrations would be encountered under normal weather
conditions.
Although it is assumed that the plutonium us present in the oxide
form (incoluble), when comparison is made to the more stringent FRC guide for
soluble plutonium of 6 x 1074 pCi/m> for an individual in the ponulation, the
above results are lower than the guide by approximately two orders of magnitude.
This 1s not meant to imply however, that unfavorable weather conditions sufficient to create Pu concentrations high enough to be of some radiological concern could not exist during other times of the vear.
SUMMARY AND RECOMMENDATIONS
External radiation levels were measured on all islands of Bikini Atoll as part
of the clean-up program.
The highest exposure rate was measured on Tare(Eneman)
where a low lying algae covered area showed 800 uR/hr.
The maximum exposure
rate encountered on the islands scheduled for rehabilitation, Bikini and Eneu,
was 120 yR/hr in the interior of Bikini.
Other islands exhibiting exposure
rates greater than those found on Bikini were:
Uncle (Enidrik)
- 300 uR/hr
Victor (Lukoj)
180 uR/hr
500 uR/hr
Fox (Lomilik)
500 uR/hr
t
Charlie (Nam)
Lu
cS
ira
4]
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CD |
William (Jelete) - 150 uR/hr