42 



Atomic Radiation and Oceanography and Fisheries 



0.1 



.4 .5 



2 3 4 5 iO 



HALF-LIFE (YEARS) 

 Figure 1 



30 40 50 



100 



However, the effect of the internal mixing 

 rate of the sea in the model adopted, is to cut 

 the activity in the mixed layer down to 12.1 

 dps/liter which is, by coincidence, just equal 

 to the natural activity and which would thus 

 just double the activity in the mixed layer. 



It should be noted that the figures given in 

 the table for the predicted activities in the 

 mixed layer refer only to cross-thermocline mix- 

 ing by physical processes, exclusive of biological 



transfer through the thermocline. However, 

 the figures listed provide a basis for speculation 

 on the hazardous effects of the mixed layer 

 activity, in that comparison may be made with 

 biological concentration factors, discussed else- 

 where in this report, to predict the activity 

 levels in marine organisms. In this way, rough 

 predictions may be made of the hazard to man, 

 not only by direct exposure to the waters of the 

 mixed layer of the sea, but by the activity con- 

 centrated in marine organisms used for food. 



