7. 



due to the fact this element is held in the bone in a way similar to calcium, there 

 is an accumulation from year to year. It is thus conceivable that especially in 

 some "hot spot" fallout areas damage to man could eventually result. 



It should also be pointed out that this subject is becoming quite contro- 

 versial and there are those who believe that all radioactivity absorbed by man 

 including that which occurs from natural sources is dangerous. Apparently, 

 however, the atomic energy commission and the majority of scientists do not take 

 this extreme view and believe WE WILL NOT BE SERIOUSLY AFFECTED BY BOMBS TESTED 

 UP TO THIS DATE. 



Martin E. Weeks 



Extension Agronomist 



U.S. DEPARTMENT OF AGRICULTURE RESEARCH ON RADIOACTIVE FALLOUT 



Ronald G. Menzel 



U.S. Department of Agriculture 



Beltsville, Maryland 



Radioactive fallout is not now an urgent problem in soil and water conser- 

 vation. However, in case of nuclear accident or war, it might become more urgent 

 than any other soil and water problem. What should be our attitude toward such a 

 problem? 



Since the possible losses are so great if we do not know how to cope with 

 radioactive fallout in an emergency situation, I believe we must maintain a 

 research program; first, to learn about the behavior of fission products in soils; 

 and second, to devise practical means of combating hazardous situations. Accom- 

 plishment of these purposes requires field trials and applications of the results 

 of laboratory and greenhouse research. 



Importance of Strontium-90 



There is one radioactive fission product, which because of its long half- 

 life, soil chemistry, uptake by plants, and incorporation into animal bodies, is 

 known to be one of the chief hazards in radioactive fallout. This is the 

 ubiquitous strontium-90. 



Some short-lived fission products are greater immediate hazards, but they do 

 not present a land-use problem. The main mode of entry for short-lived fission 

 products into plants and animals is directly from the atmosphere. Soil treatments 

 cannot control this situation. 



Long-lived fission products other than strontium-90 are not taken up readily 

 from soils by plants. 



Strontium-90 can readily be determined both in soil^ and in plant materials 

 by using a Geiger counter. Strontium-90 fallout has been about 10 mc/mi^ annually 

 since 1954. It is usually higher than this in northern United States and lower in 

 southern United States. The amounts presently in 1 kg. of most soils give over 

 100 radioactive disintegrations per minute. 



Determination of Strontium-90 from Radioactive Fallout 



Presently, the amounts of strontium-90 entering crops by uptake from soil 

 and by falling directly on the foliage appear to be roughly equal. Under field 



