2) Held et al. (1965) studied the relationship of atoll! soil types and the cistribution of fallout raaionuclides at Rongelap Atoll. They reported: The soils are calcareous, containing no inorganic colloids, and their exchanye capacity is airectly related to organic content. In young soils the highest levels of radioactivity are associated with soil algae found as a surface crust in undisturbed areas and in coral fragments [which were infiltrated with algae] in eroded area. In these soils the rare earth radionuclides V4e6 and V7on generally showed less penetration into the soils than any other radionuclides measured. Noshkin and Bowen (op. cit.) have measured the concentration of 23942405 in sections of six sediment cores from the north and south Atlantic Ocean and the Mediterranea Sea. In a review article, Noshkin (1972) presents plutonium concentration profiles in sediment cores from Buzzards Bay, Mass., and other ‘criinental soils. The profiles presented in these papers show that relative te the surface sediments the concentrations of fallout plutonium are reduced to wery small values in 20 cm, and, typically, in 10 cm in the Atlantic sediFert cores. With the exception of one core profile from the Central North *ciantic, the plutonium concentration in the cores decreases regularly with Ae awes wt po » appears convex in shape, and the plutonium concentration is reduced to c:. £9 of the concentration in the surface layer in roughly the first 5 cm °* secirent. @ee Noshkin (op. cit.) noted that the sediment deposition rate in resion where the Cuzzards Bay core was taken was "too low to account for t* presence of both 2395, and '376, at depth in the core." He concluded: Chemical or biological reactions must be occurring at the sediment-water interface to produce changes in the interstitial waters and solid phases which are sufficiently large to induce redistribution of the plutonium and 137Cs taken up by sedimenting material.