General Cojisideratiojis 



teria in the sea break down the organic con- 

 stituents. Unless care is exercised, however, this 

 discharge into inshore sea areas may be dele- 

 terious to other resources. Dumping of excess 

 volumes of sewage and industrial wastes, with- 

 out proper regard to the local characteristics 

 of the sea bottom, currents, and other factors, 

 has already resulted in ruining some harbors 

 and beaches for recreation, damage to the living 

 resources of adjacent areas, and even serious 

 problems of corrosion to ships. 



The use of the sea for the disposal of atomic 

 wastes has, fortunately, been so far approached 

 with great caution and with due regard to the 

 possible hazards. The problems, because of the 

 dangerous character of small amounts of atomic 

 wastes, are of a different order of magnitude 

 than those of the disposal of other kinds of 

 wastes. 



III. Potential Hazards From Radioactive 

 Materials 



Direct hazards 



A direct hazard to human beings from radia- 

 tion may exist if the levels of radiation in the 

 environment are sufficiently high. 



The natural radioactivity of the sea is very 

 much lower than that of the land. According to 

 Folsom and Harley (Chapter 2 of this report) , 

 a man in a boat or ship receives only about 

 half a millirad per year from the radio isotopes 

 in the sea, compared with about 23 millirads per 

 year from sedimentary rock or 90 millirads per 

 year from granite. Thus, it would be necessary 

 to increase the radioactivity of the sea many 

 fold to equal the radiation that man normally 

 receives from the land on which he lives. Due 

 to the rather rapid mixing in the upper layers 

 of the sea, and to its very large volume, even 

 large quantities of activity introduced at the sur- 

 face in the open sea become sufficiently dis- 

 persed to constitute no direct hazard after a 

 relatively short time, as has been shown by the 

 dispersion of the activity resulting from weap- 

 ons tests in the Pacific. If the direct hazard were 

 the only consideration, sea disposal of radioac- 

 tive wastes would give rise to difficulties only 

 in small areas near the disposal sites. 



Some radioactive wastes have been disposed 

 of in the sea by placing them in containers de- 

 signed to sink to the sea bottom. In this way, 

 the wastes are isolated and not dispersed by the 

 ocean currents. Direct hazards could arise if 



the containers in some manner were to come 

 into contact with humans, such as through ac- 

 cidental recovery during fishing or salvage op- 

 erations or if, through improper design, the 

 containers were to float to the surface and come 

 ashore. 



Indirect hazards 



The most serious potential hazards to human 

 beings from the introduction of radioactive 

 products into the marine environment are those 

 that may arise through the uptake of radio iso- 

 topes by organisms used for human food. There 

 are several reasons why these indirect hazards 

 are more critical than the direct hazards: (1) 

 The radiation received from a given quantity 

 of an isotope ingested as food is much greater 

 than the dose from the same quantity in the 

 external environment; (2) many elements, in- 

 cluding some of those having radioactive iso- 

 topes resulting from nuclear reactions, are con- 

 centrated by factors up to several thousand by 

 the organisms in the sea; (3) the vertical and 

 horizontal migrations of organisms can result 

 in transport of radioactive elements and thereby 

 cause distributions diflferent from those that 

 would exist under the influence of physical fac- 

 tors alone ; for example, certain elements may be 

 carried from the depths of the sea into the 

 upper mixed layer in greater amounts than 

 could be transported by the physical circulation. 



It is quite certain that the indirect hazard to 

 man through danger of contamination of food 

 from the sea will require limiting the permis- 

 sible concentration of radioactive elements in 

 the oceans to levels below those at which there 

 is any direct hazard. Any part of the sea in 

 which the contamination does not cause danger- 

 ous concentrations of radioactive elements in 

 man's food organisms will be safe for man to 

 live over or in. 



A reduction of the harvestable living re- 

 sources of the sea could conceivably occur 

 through the eff^ects of atomic radiations on the 

 organisms that are the objects of fisheries, or on 

 their food. This might result from mortality in- 

 duced by somatic eflfects, or from genetic 

 changes. There is no conclusive evidence that 

 any of the living marine resources have yet suf- 

 fered from either of these, and they are not 

 likely to be undesirably influenced at radiation 

 levels safe from other standpoints. The knowl- 



