Contents Page Introduction Radiation readings on the islands of Rongelap and Ailinginae Atolls Procedures used in collecting and processing samples and recording radioactivity Rate of decline of radioactivity in food items Evaluation of radioactivity in the biological samples 13 13 Fish 19 26 Invertebrates Land plants 35 39 45 48 Algae Birds Plankton Water Evaluation of radioactivity in the soils 52 Radiochemical analyses 57 Physical decay of samples 62 Appendix 66 iv