The ocean floor of the EPG as sampled by dredges and coring devices consisted of Radium and K*° were detected in the manganese nodules and 10 to 20 pyc Ra®**/gm were found in the surface of the globigerina ooze. Ce’ and Ru! were detected in the alt, ooze on the level floor. A number of samples of mangarese nodules and basalt rock were obtained in the area. alll coarse coral sand, coral rock and mollusk shells near the atolls, and fine globigerina manganese nodules in amounts roughly proportional to the surface area. No radium wus detected in coral sand or gastropod shells. A gamma energy spectrum analysis (Table 1.13) showed the presence of Ce’ and Ruin most of the sediments with traces Onan Butterfly y Fish (y/min)/gm wet Caudal fin Epidermis Gall bladder 1,620 _ 132 420 1,460 23 Scales _ Spleen Stomach Stomach contents Testes Vertebrae 618 85 Skipjack Tuna P (7/min)/gm wet pyc Zn"/gm 96 21,400 1,080 9,400 Flying Fish Ocean SW of Atoll (y/min)/gm wet 38 45 — 4,500 _ 1,200 980 50 —_ 67 1 27 _ 82 880 172 5,850 _ 30 21 (clam) 52 38 (equid, fying fish) 9,500 8,100 (plankton) —_ io A cross section of Core No. 2 and a cross section of Core No. 4 are illustrated in Figure 1.6. The water trapped over the top surface of the core was filtered through a 0.5 micron millipore filter. ditenwnete = Total Gamma _— 52. 88 760 27 (coral, algae} _ 880 Snapper _ 620 Gills Kidney Liver Muscle zn** The suspended sediment, probably originating from the disturbance of the uppermost surface during the coring operation, was reported as (y/min)/liter of the core water inasmuch as an accurate weight of the residue could not be determined aboard ship. The filtered water over the cores was evaporated and assayed. The cores, which consisted essentially of calcareous globigerina ooze and fine coral sand, were frozen and sliced into 3-mm sections. The outer periphery of the core was cut away and discarded to reduce contamination which may have been transferred from section to section by the barrel of the corer as it penetrated the ocean floor. The sections were assayed, giving the results shown in Figure 1.6. The activity of the core was highest in the top 3-mm layer. It then decreased with depth to a constant value of about 3 (y/min)/gm below 20 to 40 cm. Core No. 4 showed a decrease in gross activity to the 18-mm depth where a sharp, unexplained increase occurred. The activity then diminished at a rate similar to the surface peak. _. Total Gamma a DISTRIBUTION OF RADIOACTIVITY IN VARIOUS FISH FROM AILINGINAE ATOLL IN APRIL 1956 te eee ao create 61 Pe ns iets TTmeee meee TABLE 1.10 _ Ra”* k*and thorium. 5 of Zn®*, Mn™, Sb? and possible Eu'™ as artificial contaminants, in addition to natural