Abstract Radiochemical separations were made on selected samples from the Pacific Proving Ground by means of ion-exchange resin column and precipitation techniques. The isotepes in the sepa- rated fractions were identified by their half lives, maximum beta energies, and gamma energies. In addition to radioactive fission products, the non-fission radilolsotopes, Mn", Fe>?, Feo, Co’, samples. C02? 3 C0, and zn°?, also were identified in some The latter lsotopes accounted for almost all of the radioactivity in the zoological samples of marine origin.