jist, 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 by station over the total sampling period. results ranged from 0.46 x 1074 pCi /m® to 5.4 x 1074 pCi/m>. were 0.4 x 107° pCi/m’, For Bikini the 239Pu All results for Eneu For comparison the average value for 729Pu backaround in the U.S. during 1968 nas 0.4 x 107° 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. These results are listed in Table 9, The results ranged from <0.7 x 107? pCi/m? to 7.9 x 107' pCi/m’, The average for all samples at this station is 4 x 1074 pCi/m> which compares quite favorably with the value of 5.4 x i0 4 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 jagoon 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 quide for soluble plutonium of 6 x 10° 2 oCi/m? for an individual in the ponulation, the above results are lower than the guide by anproximately two orders of magnitude. This is 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 uR/hr in the interior of Bikini. Other islands exhibiting exposure rates greater than those found on Bikini were: Uncle (Enidrik) Victor (Lukoj) 300 uR/hr - 180 uR/hr William (Jelete) - 150 uR/hr Charlie (Nam) - 500 uR/hr Fox (Lomilik) - 500 yR/hr We 5005603 4]