Zone 3b . Those areas of the outer continental shelf which are 

 not classified as known fisheries areas. For this zone the assumption 

 is made that these areas contribute, either directly or indirectly- 

 through raigratory fish, 20% of the protein requirement of a selected 

 portion of the population. It is also assumed that three-fifths of the 

 maximum permissible dose which this population may receive as a re- 

 sult of sea disposal may be allotted to waste disposal operations from 

 nuclear-powered ships in these waters. 



Zone 4a . The open sea, more than 12 miles from shore and hav- 

 ing depths greater than 200 fathoms, in known fishing areas. For this 

 zone the assumption is made that a selected portion of the population 

 receives 50% of its protein requirement from sesufood harvested in 

 these waters, and that three-fourths of the maximum permissible dose 

 which this population may receive as a result of sea disposal may be 

 allotted to waste disposal operations from nuclear-powered ships in 

 these waters. 



Zone 4b . Those areas of the open sea which are not classified as 

 known fishing areas. For this zone the assumption is made that these 

 areas contribute, either directly or indirectly through migratory fish, 

 10% of the protein requirement of a selected portion of the population, 

 and that three-fourths of the maximum permissible dose which this 

 population may receive as a result of sea disposal may be allotted to 

 waste disposal operations from nuclear-powered ships in these waters. 



Computation of ppc Values for Seafood : A human population which 

 obtained all its protein food from marine sources would eat about 1.5kg 

 per week per person of fish or marine invertebrates. If this food is 

 contaminated with a radioisotope, and if this is the only source of in- 

 gestion of the isotope, w^e can calculate the maximum permissible con- 

 centration in food corresponding to the maximum permissible concen- 

 tration in drinking water by multiplying the latter by the ratio (w^ater 

 ingested per week) / (food ingested per week) = 



2200 X 7 . 



: = 10 . 



1500 



Designate this factor as N^^f . Further, for each of the subdivisions of 

 the marine environment, designate by Np that fraction of the protein 

 requirement which a selected portion of the population receives from 

 seafood harvested there; designate by Nj) that fraction of the maximum 

 permissible dose for this population which can be allotted to waste dis- 

 posal into the sea, and by Ng that fraction of the cillotment to the sea 

 which may be utilized for nuclear-powered ships within the particular 

 marine subdivision. Then the partial permissible concentration in sea- 

 food -which can result from the operation of nuclear-powered ships, for 

 each of the subdivisions of the marine environment, is obtained by 

 multiplying the maximum permissible concentration for drinking water 

 for the general public by the factor N , which is given by 



19 



