of young cordia trees, and exhibited the highest levels encountered on the O Transect. recorded at Location 8 at Much Lower levels were 1400 ft. The spectrometric results indicate that the predominant radionuclide present in the soil on Bikini was *°’cs with lesser amounts of ®"co and *®®sb. ‘These were the main contributors to the total exposure rate. isotopes, Of these three *37es contributed 76 to 78% of the total exposure rate and °°Co and ~**®sb were each responsible for about 10 to 12%. Objects of scrap steel such as abandoned steel cable reels often showed high °°Co contamination and this produced a higher local total exposure rate. In the analysis of the spectrometer data it has been assumed that the radionuclides are distributed exponentially in the soil with a 2 cm relaxation length. This is consistent with the laboratory analysis of soil samples taken at Locations 5 ard 7 and from the area of the clearing experiment. Non-uniform distribution of the gamma emitters and neglect of minor contributors is reflected in the small discrepancies between the ionization chamber and spectrometer total exposure rates given in the above table. Considering the general non-uniformity in fallout distribution throughout this area, agreement between the two measurements is quite good. For ali the locations, the values agree to within 10%. Exposure rates were also calculated from the results of the laboratory analysis of the soil samples taken at Locations 5 and 7. These values are given below together with the percentage of the total exposure due to each isotope. “2