mean partial permissible concentration (ppc) values for that waste. If 

 M^ represents the activity in the waste resulting from a given j.sotope, i, 

 and (ppc)j represents the partial permissible concentration for the sub- 

 ject environment for that isotope, then the weighted mean ppc value for 

 the environment, for that waste, is given by 



2M. 



ppc = 



S i/(ppc)-? 



The weighted mean ppc value is utilized with the gross activity result- 

 ing from the isotope mix. It has the advantage of providing a convenient 

 means of including the additive effect of the various isotopes contained 

 in the wastes. 



The maximum number of discharges, N, which may be made into 

 a representative segment of each of the subdivisions of the marine en- 

 vironment during any one month period is determined as a function of 

 (a) the total activity in a single such discharge and (b) the environmental 

 ppc value. These determinations are based on an evaluation of the rates 

 of dispersion and exchange in the marine environment. The limitations 

 to our present knowledge of these phenomena require us to use conserv- 

 ative interpretations of the results. If the permissible number of dis- 

 charges, for a given activity, into a representative segment of the marine 

 environment is computed to be less than one per month, that environment 

 is considered to be unsuitable as a receiver of that particular w^aste. 



Our conclusions and resulting recommendations for each of the 

 environmental subdivisions are as follows: 



Harbors, estuaries, and coastal waters out to 

 two miles from the shoreline (Zone 1): 



The considerable variation in the physical processes of dispersion 

 within, and exchange between, segments of this marine environment, as 

 well as local variations in the biological and geochemical processes of 

 importance to our problein, makes it impossible to present a completely 

 general conclusion regarding waste disposal into harbors, estuaries and 

 other inshore areas. Since these are areas of high human activity, it is 

 evident that solid wastes should not be introduced into such waters. Be- 

 cause of the poor dispersion characterizing tideless harbors which are 

 separated from the sea by locks, it is questionable whether any radioactive 

 wastes should be introduced into such waterways from nuclear -powered 

 ships. 



