Different organisms have been demonstrated to be especially effective 

 in concentrating isotopes of cobalt, iron, manganese, phosphorus, 

 strontium, zinc, ruthenium, yttrium, cerium, etc. The AEC is seeking 

 to learn whether the concentration is repeated at various trophic 

 levels and whether such concentrating ability results in hazard to 

 man as well as whether or not the concentrating power can be used to 

 advantage in decontaminating radioactive areas in the ocean„ Since 

 at least twenty to thirty important isotopes may occur in thousands 

 of significant marine species in variously acceptable chemical states, 

 it would appear that studies must be continued for a long time before 

 the role of radioactivity in the marine environment is determined with 

 reasonable assurance. 



Radioactive materials may go into true solution, they may occur in a 

 colloidal state or they may be particulate in the ocean. Sediment 

 transport and sedimentation phenomena must be studied to permit 

 predictions concerning distribution of oceanic radioactivity. Studies 

 are necessary of the modes of transfer of radioelements from sea water 

 to sediments and from sediments to sea water in order to understand 

 their reactions and to trace geochemical processes that affect their 

 distribution. 



Naturally radioactive elements and cosmic ray produced isotopes are 

 apparently at equilibrium in the ocean with geological time. The 

 movements and effects of introduced radioactivity may be with similar 

 naturally occuring radioactive isotopes; thus, studies of the 

 naturally radioactive materials are necessary,, Since the rates of 

 decay are constant of uranium and thorium as well as their radioactive 

 daughter elements, the absolute quantities of such isotopes can be 

 related to produce an approximate age of sediments and to trace 

 geochemical processes of importance in the materials budget of the 

 earth. 



Biological processes modify theoretical distribution of sediments. 

 Studies of biological processes will give considerable data concerning 

 the relative effectiveness of chemical and biochemical processes 

 in the removal of radioactivity from the ocean water. Investigations 

 of the removal of radioactivity by feeding marine organisms and the 

 binding of such material in their waste products will continue. 



In attempting to explain the actual and potential distribution of 

 radioactive isotopes in the ocean, circulation and mixing processes 

 are studied in various ways. 



Radioactive isotopes from fallout are useful in providing knowledge 

 of the vertical and horizontal mixing of ocean waters. Some isotopes 

 apparently move with horizontal currents and others may show laminar 

 flow along thermal layers. Abundance with depth of radioactive 

 isotopes which were added in a reasonably uniform manner to surface 



-L8- 



