94 



Atomic Radiation and Oceanography and Fisheries 



ment involved and its physiological importance 

 to the organism, (2) the physical and chemical 

 state of the element and its acceptability to the 

 organism, (3) the concentration of the element 

 in the environment and the presence of other 

 elements which may inhibit or enhance its up- 

 take, (4) the morphology of the organism, its 

 life history, and its particular role in the food 

 web, and (5) the physical and chemical char- 

 acteristics of the environment. 



Even though the great majority of research 

 with radionuclides in biological fields has been 

 performed within the past 15 years, enough 

 data have been gathered to serve as a basis for 

 the following general statements. 



1 . Radioactive materials are taken into the body 

 of an organism either through physiological 

 processes and incorporated directly into the tis- 

 sues or they are attached to the surfaces of the 

 organisms through adsorption. 



2. The concentration of certain radioelements 

 reaches a higher level in many of the lower 

 plant and animal forms, such as bacteria, pro- 

 tozoa, and phytoplankton, than in higher forms, 

 such as the vertebrates. In such instances, there 

 is an inverse correlation between the complexity 

 of body structure and the concentration of the 

 radioelement in question. 



3. Certain plants and animals have a predilec- 

 tion for concentrating specific radionuclides in 

 different tissues. For instance, iodine is con- 

 centrated in the thyroid tissue, silicon is con- 

 centrated in the tests of some diatoms, calcium 



.is concentrated as calcium carbonate in the 

 shells of some mussels and as calcium phos- 

 phate in others, calcium and phosphorus are 



also concentrated in the bony skeletons of ver- 

 tebrates, phosphorus in concentrated as adeno- 

 sine triphosphate in the flight muscles of some 

 birds, and potassium and other elements are 

 concentrated in wide variety of tissues. 

 4. Although certain radioelements may occur in 

 amounts acceptable for drinking water, many 

 fresh-water organisms have the ability to con- 

 centrate them to levels which would be harm- 

 ful. Such deleterious effects could range from 

 those in which only the individual organism is 

 involved to those in which the entire popula- 

 tion may be affected. 



Little information is available on the toler- 

 ances of the various aquatic organisms to dif- 

 ferent radioactive materials. Recently, however, 

 D. G. Watson at the Hanford Laboratories has 

 determined that a concentration of 65 /i,c P^^ 

 per gram of bone was lethal to trout in about 

 six weeks. A concentration of 10 /xc P^- per 

 gram was not lethal in 12 weeks but caused 

 some radiation damage. This series of experi- 

 ments is only the first step toward determining 

 the tolerance levels for all radionuclides in each 

 of the animals of the fresh-water fauna. 



The use of radiomaterials as a research tool 

 in fresh-water biology has opened new fields 

 which were almost impossible to explore ade- 

 quately by other means. Determination of the 

 metabolism of many of the elements essential 

 for proper nutrition is now possible. Further- 

 more, the effects of the radioactivity emanating 

 from isotopes deposited in the tissues can be 

 studied. In the field of fresh-water biology, per- 

 haps the greatest benefits from the use of radio- 

 active materials can be derived from studies of 

 the physiological processes of the organisms. 



REFERENCES 



BuGHER, J. C, and Marjorie Taylor. 1949. 

 Radiophosphorus and radiostrontium in 

 mosquitoes. Preliminary report. Science 

 110:146-147. 



Clark, F. W. 1924. The composition of the 

 river and lake waters of the United States. 

 U. S. Geol. Survey, Prof. Paper 135. 



Coffin, C. C, F. R. Hayes, L. H. Jodrey, and 

 S. G. Whiteway. 1949. Exchange of ma- 

 terials in a lake as studied by the addition 

 of radioactive phosphorus. Canad. Jour. 

 Research D. 27:207-222. 



Davis, J. J., R. W. Coopey, D. G. Watson, 

 C. C. Palmiter, and C. L. Cooper. 1952. 



The radioactivity and ecology of aquatic 

 organisms of the Columbia River. In Bi- 

 ology Research — Annual Report, 1951. 

 USAEC Document HW-2502 1:19-29. 



Foster, R. F., and J. J. Davis. 1955. The 

 accumulation of radioactive substances in 

 aquatic forms. Proceedings of the Inter- 

 national Conference on the Peaceful Uses 

 of Atomic Energy, 13 (P/280) : 364-367. 



Foster, R. F. 1955. Tritium oxide absorption 

 and retention in the body water of some 

 aquatic organisms. In Biology Research — 

 Annual Report, 1954. USAEC Document 

 HW-35917:98-100. 



