Chapter 9 



Uptake by Fresh-water Organisms 



89 



which feed on fresh- water organisms, (3) to 

 study the seasonal distribution of the radioac- 

 tive materials throughout the biota, and (4) to 

 determine whether the aquatic forms were ad- 

 versely affected. 



2. A three-year study at the Oak Ridge Na- 

 tional Laboratory, Oak Ridge, Tennessee. That 

 work was performed by the Fish and Game 

 Branch, Division of Forestry Relations, Ten- 

 nessee Valley Authority, under contract to the 

 Atomic Energy Commission and consisted pri- 

 marily in an ecological survey of White Oak 

 Creek and its drainage area. In that study, 

 principal emphasis was placed on the effects on 

 the biota and its environment from radioma- 

 terials that consisted of both fission products 

 and wastes with induced radioactivity from the 

 processing of different materials in the prepara- 

 tion of radioisotopes. 



The Ecological Survey of White Oak Creek 

 was divided into three main categories: botany, 

 limnology, and vertebrate biology (Krumholz, 

 1954). Because of a virtual absence of rooted 

 aquatic plants in the area, the fresh-water bi- 

 ology was largely covered in the studies on 

 limnology and vertebrate biology. That program 

 was designed to find out what radiomaterials 

 had accumulated in the biota of the drainage 

 area, in which organisms and tissues they had 

 accumulated, and what, if any, had been the 

 effects of such levels of accumulation on popula- 

 tion balances and on the various types of indi- 

 vidual organisms. 



3. Many studies of lesser magnitude carried on 

 at other installations of the Atomic Energy 

 Commission and at different colleges and uni- 

 versities throughout the United States. Such 

 studies usually are not integrated with one an- 

 other but are separate studies designed to an- 

 swer specific questions. 



Rather intensive studies of the phosphorus 

 cycle in fresh-water lakes have been carried out 

 by workers at Dalhousie University (Coffin, et 

 al., 1949, and Hayes, et al., 1952), at Yale Uni- 

 versity (Hutchinson and Bowen, 1950), and 

 at Atomic Energy of Canada, Ltd. (Rigler, 

 1956) . These studies have increased our knowl- 

 edge of the role of phosphorus in the economy 

 of fresh-water lakes, particularly at the lower 

 trophic levels. Much work has also been done 

 on the economic aspects of such aquatic insects 

 as the mosquitoes (Bugher and Taylor, 1949; 



Hassett and Jenkins, 1951) and also on such 

 aquatic forms as the frog (Hansborough and 

 Denny, 195 1 ) . These animals have been tagged 

 with radioisotopes (usually radiophosphorus) 

 either by direct feeding of substances which 

 contained the radioactive material, or by im- 

 mersing them in radioactive solutions. 



Concentration of radioactive materials in aquatic 

 organisms 



-^ ■ r (Mc/g of organism) 



The concentration factor ' , — ; — ^ - 



^c/ml of water 



for any radioelement cannot exceed the ratio 

 between the normal concentration of that ele- 

 ment in the organism and the concentration of 

 the element in the surrounding water. Thus, if 

 the element in question is not normally used by 

 a particular organism, it is unlikely that any of 

 the radioisotopes of that element will be con- 

 centrated in the tissues. 



Each organism in each environment has spe- 

 cific requirements for the different chemical 

 elements. However, it is necessary to know the 

 chemical composition of the organism and its 

 parts, as well as that of its aquatic environment, 

 in order to understand those requirements and 

 to interpret the role played by each element in 

 the metabolic processes. At present, there is 

 very little information available on the chemical 

 composition of any of the fresh-water organ- 

 isms or their tissues, and consequently there is 

 virtually nothing known of the concentration 

 factors to be expected for the different elements 

 by the organisms. Some data on the chemical 

 composition of fresh-water lakes and streams 

 are available, but these waters differ so widely 

 from one another that no generalizations can 

 be made. The total dissolved solids in fresh 

 waters range from less than five parts per mil- 

 lion to well over 400 parts per million. In 

 addition, the elements which make up these 

 dissolved solids seldom occur in exactly the 

 same percentage composition in any two bodies 

 of fresh water. The concentration of any par- 

 ticular element in the water is directly depend- 

 ent upon the chemical characteristics in the 

 drainage area. Because of these differences in 

 the requirements of organisms and in the chemi- 

 cal compositions of the different fresh waters, 

 it is necessary to consider each situation as a 

 separate case. 



An indication of the differences in the orders 



