At Bikini, the early diagenesis toward a steady state condition following each test was complicated by subsequent testing in similar geographical locations. Similarly, redistribution of radioactive materials deposited on the land, reefs, and littoral areas would occur from the action of longshore currents, tides, rainfall, groundwater seepage, waves and storms, including infrequent typhoons in the area. In the review of the literature, the subject material was categorized in ane of six general topics, as follows: (1) the production and occurrence of transuranium elements; (2) the introduction of radioactivity in fallout from the different devices detonated at Bikini Atoll; (3) the physical and chemical properties of plutonium and americium in aqueous solution; (4) plutonium distributions in marine sediments; (5) the physical and chemical nature of Bikini sediments and hydrological transport process; and (6) previous radiological surveys of Bikini and Eniwetok sediments. 3.1 Production and Occurrence of Transuranium Isotopes In 1940 the production and subsequent discovery of plutonium was made by the nuclear reaction 238), (d,2n) 2384, mar 2385,, and was reported by Seaborg and co-workers (1946). al. in 1941 (1946). Plutonium-239 was discovered by Kennedy et In 1942 Seaborg and Perlman (1948) demonstrated the nat- ural occurrence of about 10 -14 ‘g Pu/g U in pitchblende. In several? subsequent investigations the Pu/U ratio {n natural materials has been shown to remain fairly constant at around 107! (Keller, 1971). The work of several investi- gations has since indicated that the ee in responsible for naturally occurring 239Pu is 238 (n,y) 239, ri* Np cit.). saa> 239py (Keller, op. The source of neutrons for these reactions is predominantly from the spontaneous fission of uranium and from {a,n) reactions of alpha particles with nuclei of light elements in the uranium-bearing ore. Small quantities