-31- large plankton and Mo 99 99m were higher in small plankton; other- wise the radioisotopic compositions were similar. Analysis of sea water collected shortly after another underwater detonation (Umbrella), inthe lagoon at Eniwetok, showed that Np? Tel32_1132 Ggl43_p,143 , 39 , and Mo®9-'7c99™ were the predominant radioisotopes in the particulate matter (>0.45u) present in the surface water near target zero (Table 8}. Table 8. Percentage of gamma emitting radioisotopes in the particulate (> 0.454) and soluble (<0. 454) form in sea water collected 75 minutes after the Umbrella event (8) Radioisotope Np229 Particulate 106 d/m/1 Per cent of particulate activity Per cent of soluble Soluble 106 d/m/1 activity 5.2 62.5 30.0 75.6 0.02 0.2 4.0 10.1 Tel32_1132 1.9 22.3 1.9 4.7 Mo29--T.99™ 0.48 5.8 3.1 7.8 Cel4l_p,14l 0.028 0.3 Cel43_py}43 0. 66 7.9. Cel44_py!44 0. 0028 Ba!40_1,,140 0.076 237 Some of these isotopes also the <0.45yu fraction (Table 8), 0 : £0.1 0.9 were present 0 0 0.7 in high 1.8 amounts in which could include materials VJ ES, Oe no