the Bravo crater. Off the southern tip is an isolated concret instrument bunker. The radiation levels on the island were about 15 wr/hr. High tides must frequently wash across the island. Consequent there is little retention of radioactive materials, but traces are still found due to the close proximity of the tests. Samples of sand from the island and some bottom sediments from the Bravo crater were taken for gamma spectral analysis. The sand exhibited mostly °°co, **’cs, and **®sb activity. f° Co appeared to be responsible for about 60% of the exposure rate, **’Cs about 30% of the exposure rate, and +28 sb and other elements the remainder. The bottom sediment sample, while containing all of the above isotopes, also contained considerable *°’Bi activity. 6° I. The major contributor was again Co. Nam Nam, the third largest island, is also located in the northwest part of the atoll. This island exhibited yet another variation of the atoll topography, which caused each island to seem markedly different in appearance. Nam has large open areas covered with fimbrisytlis and ipomea vines. Messerschmidia trees, unsurrounded by thick underbrush, were able to spread out and achieve large sizes. A great number of birds were nesting on the island. , Radiation levels were found to vary widely on Nam. In addition, special problems were presented by pieces of highly active scrap metal scattered about the island. One piece of metal found half-buried near the center of the island approached the activity of a typical laboratory §° Co calibration source - ~500 ur/hr at 1 meter. It is possible that a large number of these metal artifacts are in the soil of this island due to its close proximity to testing areas. A full set of radiation measurements was performed on Nam. Ionization chamber measurements were made at four widely separated locations with spectrometer measurements wet eee a> wow ee eee opeme .