These are expressed in terms of activity per unit mass as well as volume of sea 

 water . 



TABLE I 



Q. = 100 curies per year 



(km) 



1 

 2 



4 

 10 



20 



40 



100 



[ic/ m^ 



0.21 

 0.15 

 0.10 

 0.07 

 0.05 

 0.03 

 0.02 



|JLC/kg 



.00021 

 .00015 

 .00010 

 .00007 

 .00005 

 .00003 

 .00002 



n. ANALYSIS OF INDIVIDUAL SOURCES 

 A. Instantaneous Source 



For an instantaneous point source in an infinite, isotropic medium in the 

 absence of any mean current 



M. 



C. = 



exp 



\ 4Kt / 



(4) 



^ 8(TrKt)3/2 



where t is tlie elapsed time from the instant of introduction of the isotope i 

 of total radioactivity M^^ , and C. is the concentration of radioactivity due to 

 this isotope at the distance r from the point of Introduction (Sutton, p. 134). 

 Here it is considered that tlie amount of radioactivity M. occupies an infinitely 

 small volume at r = when t = , so that C. is infinite at the source and 

 C. = everywhere else initially. For a finite box source of dimensions 2a, 2b , 



