GENERAL CONSIDERATIONS CONCERNING THE OCEAN AS A 

 RECEPTACLE FOR ARTIFICIALLY RADIOACTIVE MATERIALS^ 



Roger Revelle and Milner B. Schaefer, Scripps Institution of Oceanography 



and 

 Inter-American Tropical Tuna Commission, La Jolla, California 



L Introduction 



In this report, we have attempted to sum- 

 marize both the present knowledge and the 

 areas of ignorance concerning the oceans that 

 must be taken into account in considering the 

 biological effects of radiation. 



[The oceans of the world furnish essential 

 sources of food and other raw materials, vital 

 routes of transportation, recreation, and a con- 

 venient place in which to dispose of waste ma- 

 terials from our industrial civilization. These 

 different ways in which men use the sea, how- 

 ever, are not always compatible. (The use of 

 the sea for waste disposal, in particular, can 

 jeopardize the other resources, and hence should 

 be done cautiously, with due regard to the pos- 

 sible effects. jWaste products from nuclear re- 

 actions require special care: they constitute 

 hazards in extremely low concentrations and 

 their deleterious properties cannot be eliminated 

 by any chemical transformations; they can be 

 dispersed or isolated, but they cannot be de- 

 stroyed. Once they are created, we must live 

 with them until they become inactive by natural 

 decay, which for some isotopes requires a very 

 long time. 



Waste products from nuclear reactions arise 

 in two ways: (1) from the slow controlled re- 

 actions involved in laboratory experimentation, 

 in the production of materials for nuclear 

 weapons, the production of reactor fuels, and 

 the "burning" of fuels in power reactors; (2) 

 from the rapid, uncontrolled reactions involved 

 in testing of weapons or in warfare. Up to the 

 present time, the largest quantities of fission 

 products introduced into the aquatic environ- 

 ment have been from weapons tests; most of 

 the products from controlled reactions have 

 been isolated on the land, and only relatively 

 small quantities have been introduced into the 



1 Contribution from the Scripps Institution of 

 Oceanography, New Series, No. 901. 



sea or fresh water. In the future, however, in 

 dustrial nuclear wastes will present difficult dis- 

 posal problems and the sea is a possible dis- 

 posal site, particularly for small, densely popu- 

 lated nations with long sea coasts. We have, 

 therefore, given particular attention to the long- 

 range problems that may arise from the large- 

 scale disposal of both high-level and low-level 

 industrial wastes, as well as to the effects of 

 weapons tests. 



Among the variety of questions generated by 

 the introduction of radioactive materials into 

 the sea, there are few to which we can give 

 precise answers. We can, however, provide con- 

 servative answers to many of them, which can 

 serve as a basis of action pending the results of 

 detailed experimental studies. The large areas 

 of uncertainty respecting the physical, chemical, 

 and biological processes in the sea lead to re- 

 strictions on what can now be regarded as safe 

 practices. These will probably prove too severe 

 when we have obtained greater knowledge. It 

 is urgent that the research required to formulate 

 more precise answers should be vigorously pur- 

 sued. Fortunately, the use of radioactive iso- 

 topes is one excellent means of acquiring the 

 needed information, and the quantities of these 

 isotopes required for pertinent experiments are 

 well within limits of safety. Moderate quanti- 

 ties of the very waste products we are concerned 

 with can, therefore, provide one means of at- 

 tacking the unsolved scientific problems. 



II. The Nature of the Ocean and Its 

 Contained Organisms 



The ocean basins cover 361 x 10'^ square 

 kilometers and have an average depth of 3,800 

 meters, giving a total volume of 1.37x10^ 

 cubic kilometers. They are characteristically 

 bordered by a continental shelf, which slopes 

 gently out to a depth of about 200 meters. In- 

 side it is a steeper slope extending down to the 



