OCEANOGRAPHY IN THE UNITED STATES 327 



tion and retention of fission products on marine organism and their 

 transfer along the food chain to tliose higher species used as food by 

 man. Problems of the eti'ects of severe radiation on fishes are also 

 studied. Such studies are of considerable magnitude when one con- 

 siders that there are hundreds of organisms and at least 24 isotopes 

 of significant occurrence as fission products. 



I should like to include here a chart, which was adapted by Chip- 

 man (1958) from data of Hunter and Ballon (1957) showing the 

 percent of total radioactivity contributed by certain fission products 

 at different times after fission (table I). We have this table pre- 

 pared and ready for presentation, but this information is also included 

 as table I in this report. Bather than present the graph at this 

 time, I shall make reference to the table. 



The significance of the table is that it shows the isotopes that biolo- 

 gists look for in contaminated organisims, and it is also significant in 

 that it point out that the relative abundance of these various isotopes 

 changes with time. At a certain time after the origin of the radio- 

 isotape, one isotope may be important ; and some time later some other 

 isotope may be relatively more important. 



I think it obvious from the table that strontium 90, cesimn 137, 

 and cerium 144 are some of the important radioisotopes to be looked 

 for after 3 years. 



In addition to the radioisotopes from fission, other radioisotopes 

 are also produced by the detonation of nuclear devices or the opera- 

 tion of nuclear reactors. These include zinc 65, cobalt 57 and 60, iron 

 55 and 59, phosphorus 32, copper 64, chromium 51, and arsenic 76, all 

 of which are important biologically. 



Since many of the elements are present in trace amounts we have 

 found it necessary to study the chemical composition of biological 

 organisms. It has been demonstrated that plankton organisms will 

 accumulate large concentrations of mixed radioisotopes. If we were 

 looking for an area in the ocean to see if it had been contaminated by 

 fallout, the easiest way to do this at the present time is to collect a 

 sample of plankton and examine the plankton for radioactivity. 



As a result the Commission has developed a detailed program to 

 discover the effectiveness of these organisms, both from the standpoint 

 of decontamination and that of possible transfer to human food or- 

 ganisms. Some expansion is necessary in the fiscal year 1959 ex- 

 penditure of $170,000 for this type of research. 



A second objective is to evaluate the disposal and transport of ele- 

 ments by the physical processes of mixing and currents, by the geo- 

 chemical processes of adsorption, sedimentation and accumulation 

 in locations where they may be absorbed by bottom dwelling popula- 

 tions and finally by biological transport through accumulation in 

 living matter and the subsequent migration, horizontal and vertical, 

 of the populations. Many kinds of experiments must be designed 

 and completed before the answers are known here. 



When radioactive materials enter the oceans they may g-o into solu- 

 tion, they may precipitate or coagulate, they may interact to attain 

 colloidal size, they may be adsorbed or absorbed by other particles, 

 they may settle to the bottom, or they may be ingested by organisms 

 and enter into the biochemical cycle. 



Wliatever tlie state of suspension or removal from tlie water, radio- 

 elements will be subject to physical forces that affect their ultimate 



