24. 



3. Concentration of radioactive isotopes by marine organisms . 

 The extent to which the various isotopes supplied by Oak Ridge are 

 concentrated in the edible parts of marine organisms has been sum- 

 marized by W. A. Chipman and B. H. Ketchum in Appendix VI. Max- 

 imum permissible concentrations of the various isotopes in sea water 

 have been calculated by combining these concentration factors with an 

 estimate of the intake of marine foods by man to obtain the quantity of 

 each isotope ingested. The maximum permissible concentration in 

 sea water is the concentration that will give to man through ingestion 

 of marine fish or shellfish a quantity of activity equal to the amount 

 received by drinking water containing maximum permissible concen- 

 trations. 



It should be noted that ingestion of water at MPC levels and 

 ingestion of food at MPC levels would present twice the permissible 

 quantities of radioisotopes to an individual. 



4. Sorption of radioactive elements by suspended sediments and 

 bottom deposits. 



Inorganic sediment components are known to be effective in removing 



dissolved and suspended radioactive waste components. Although 



these sorption reactions have been studied in the laboratory and have 



been observed in natural aquatic systems, at the present time there 



appears to be no way to interpret them in a quantitative^manner that 



