CHAPTER 1 INTRODUCTION As @ result of a mucleardetonation in Operation CASTLE, several atolls in the Marshall Islends were conteminated by radioactive fall-out to such an extent that evacuation of the inhabitants was necessary. Plants, anitcls, water and soil vere collected froa the islanis one month after the fell-out occurred. The liva anirals vere sent to the USKRDL end redfochemical enslycis wag made of thelr tissues to provide informtion on the internal reJintion hazard. A report()) of this study hes been published. As a follow-up to the original study a resurvey of the contaminated Rarshall Ialands wag undertaken. Radtochenical anilysis of food plants, fish, water, soil, coral, algee and birds indicate the natura and extent of the interval radiation hazard ercated by tha residual contamination on the islands. Buch data vere necessary to determine the possibility of the re-occupancy of the contaninated islands. A germs dose rate survey vas conducted to determing the external rediation hazard. The present report presents the data obe teined froa the resurvey of ths contazinated islands one year after Cp2ration CASTLE. 1.1 Objectives ile Atoll Resurvey Project wes entitled "Follow-up Determination of the [xtezt of the Distribution of Fall-out Contacination on Ronzelap end Other Atolls in the Marshall Group." Its specific objectives weres (1) Go provide data upon which a dacision can be based es to whether and wien the evacuated eT hao eefely re-occupied by their forser Le Stuty of the rote) Bee ive Contacrinaticn of Ruzmain Beings and Anirols ord Coatexination of the Environ-ent Resulting from Fall-out in Operatioa CASTL3 Addendica report, Project 4.1 Ogzration CASILE WT-935. r . . l