iv LIST OF FIGURES FiGUR coC Major pathways to the production of long lived alpha emitting PY Approximate location of nuclear tests at Bikini Atol] Ww Generalized circulation of Bikini lagoon water in winter... .. 23 &» Distribution of mean grain sizes of sediments in Rongelap lagoon . 27 wm .......4.88-.6 . Location of sediment collection sites .. 1... 2... ewe eae 34 no radionuclides at Bikini Atoll] ...... Schematic diagram of the allocation and processing of sediment samples .... 2. cee ee ew eee hwo eww 38 Representative alpha spectra of a plutonium sample .....-. +s 49 Alpha spectra of a uranium sample 50 . 2. 2 2 se ee ee we we tee Representative alpha spectra of a polonium sample ..-.. «+ Dependence of the absolute counting efficiency of the Ge(Li) and Ge(Intrinsic) detectors with gamma-ray energy ......-... YW Areal distributions of 23942405, in surface sediments of 12 Areal distribution of °*! Am 13 Bikini Atoll] lagoon 2394240, ,241 2... 1 ee ee we we we ew we ee we eww 238 15 Areat distribution of 155 65 67 Eu and the activity ratio 2394240,155 Eu in surface sediments - . . 2. ©. ee e+ ee ee ee 69 Areal distribution of 'W37¢5 and the activity ratio 2394240, 137 Cs in surface sediments . . 2. 2. 2. s+ 6 ee © we we ewe 16 Areal distribution o ¢ 207 Bi and the activity ratio 2394240, ,207 Pu/"~ Bi in surface sediments . 2. 2. 2 2 0 ee ee ew ee 7 Areal distribution of 18 63 Pu and the activity ratio 2394240, u/238py in surface sediments .... 2. 2. 2. ee ee eee . 14 58 and the activity ratio Am in surface sediments . 1... 2 2 «+ + 2 ee eevee Areal distribution of 51 2394240 60 Co and the activity ratio Puc, in surface sediments . . . +. se ee ee ew ewe Ordering sequence of the concentrations of radionuclides in surface sediments by station . 2. 6 6 0 ee ee eee eee ee 70