of the area to determine the degree of uniformity of the exposure rate. The exposure rates obtained were: South side 59.9 wr/hr, East side 68.7 ur/hr, North side 76.8 ur/hr, and West side 83.0 ur/hr. The corresponding field spectra indicated the differences in exposure rates were due to differences in *87 a5, ®° Co, and **©sb contributions, rather than to any new contributors, with the percentage contribu- tions of each isotope remaining fairly constant. These local variations in the isotope distribution pattern seemed to be typical of many areas on Bikini and again indicate the difficulty in obtaining a soil sample representative of the area as a whole. However, the excellent agreement of the sum of the field spectrometric exposure rate estimates with the ion chamber measurements and the agreement of the two independent calculations of the percentage of total exposure rate due to each isotope verifies that the field spectrometer averages out most of these variations. Four HASL TLD dosimeters were exposed at this site for about 8 days duration. The average exposure rates were 56 uxr/hr for two placed in the center, 78 ur/hr for one placed on the northeast side of the clearing, and 65 ur/hr for the fourth which was situated on the southwest side of the clearing. These data agree quite well with the ionization chamber and spectrometer total exposure rate estimates, tabulated above. A study of the Ge(Li) spectrum of the soil obtained from this site indicated, as was the case for the soils obtained on the O Transect, the presence in small amounts of *©®mu, *®° Bu, and ***am in addition to *°’cs, ***°Sb, and 60 Co. Summary of Exposure Rates on Bikini Island - The total gamma- ray exposure rates on Bikini Island ranged from 10 - 120 ur/hr. In general, the areas close to shore were 20 - 40 ur/hr and the island center was 50 - 80 ur/hr while scattered hot spots exhibited levels up to 120 ur/hr. Cosmic rays result in an additional exposure rate of ~3.4 pr/hr at all The primary contributor to these gamma-ray exposure locations. rates was '°’cs, with °°Co and **°Sb the only other signifi- cant contributors. - 28 -