14 



AGRICULTURAL HANDBOOK 395, U.S. DEPT. OF AGRICULTURE 



ALTERNATIVES TO TREATING CONTAMINATED SOIL 



lu tlie event of widespread radioactive con- 

 tamination, such as after a nuclear attack, much 

 of tlie contaminated farmland could be needed 

 for crop production before it could be treated. 

 Since the major hazard from farmland contam- 

 ination arises from the entry of radionuclides, 

 especially strontium, into human food, some 

 alternatives to soil treatment have been suggested. 

 Among these are using contaminated land to 

 grow crops that contribute lesser amounts of 

 radionuclides to the human diet; using contam- 

 inated pastures for beef or mutton instead of 

 dairy production; and removing radionuclides 

 from milk and other products by treatment in 

 processing. The main characteristics and limita- 

 tions of these alternatives are important in 

 determining the feasibility of treating contam- 

 inated soil. 



Some crops would contribute little or no radio- 

 active material to the human diet, even if they 

 were grown on highly contaminated soils. Fiber 

 crops, such as cotton and flax, are obvious ex- 

 amples. Sugar and oil crops would have most of 

 the radioactive materials removed from the re- 

 fined products that are part of the human diet. 

 However, in case byproducts, such as cottonseed 

 meal or sugarbeet pulp, are fed to animals, the 

 indirect contribution of radionuclides to the hu- 

 man diet would have to be considered. Since corn 

 has one of the lowest mineral contents of any 

 grain, its content of radionuclides such as stron- 

 tium is very low. Other essential food crops, espe- 

 cially those that contribute important minerals 



to the diet, would have to be grown on land with 

 lesser amounts of contamination. Such crops 

 would include most fruits and vegetables. 



Meat and eggs would contribute little radio- 

 active strontium to the human diet. Thus, when 

 the most hazardous contaminating material was 

 strontium, using the land for beef, pork, mutton, 

 or poultry production would be advantageous. 

 This may not be true when other radionuclides 

 constitute the main hazard. For example, meat 

 contributes almost as much cesium-137 to the diet 

 as does milk (36). 



Ion-exchange treatment of milk could reduce 

 its strontium-90 content perhaps more effectively 

 than decontamination or soil management treat- 

 ments on hay and pasture land. In full-scale tests 

 of ion-exchange treatment in a milk-processing 

 plant, from 90 to 97 percent of the strontium-90 

 was removed from the milk (35). Similar treat- 

 ment may be possible with vegetable and fruit 

 juices and purees, but experimental tests have not 

 been made. 



If the alternatives to ti-eating contaminated 

 soil were used fully, land for nutritionally criti- 

 cal crops could be treated preferentially. Critical 

 crops might vaiy, depending on what crops were 

 normally produced in the highly contaminated 

 areas and the possibility of transporting substi- 

 tutes from other areas. In subsequent years, more 

 land could be treated for producing critical crops. 



In some situations, it might be possible to use 

 very highly contaminated land by treating the 

 soil and then using one of the above alternatives. 



CONCLUSIONS 



Land thai has been contaminated loith radio- 

 active nrnteriah may he treated to remove the 

 contaminant or to reduce its entry into food 

 products. Because these treatments usually re- 

 quire great effort, the objectives and feasibility 

 of various treatments need to be carefully evalu- 

 ated for each contamination incident. Indiscrim- 

 inate use of ineffeetixe treatments could be very 

 costly without much reduction in the radiation 

 hazard to the population. 



Treatment objectives may vary according to 

 the type and extent of contamination. If acci- 



dental contamination is confined to a limited area, 

 it may be removed to pre\ent its spread to other 

 areas. In such cases, an existing or potential 

 radiation hazard may be removed without undue 

 liazard to the decontamination workers. If the 

 contamination is widespread radioactive fallout, 

 it may be physically impossible to remove the 

 entire hazard. Nevertheless, the proper choice of 

 treatments and land areas to be treated could 

 reduce significantly the entry of radionuclides 

 into tlie Inuiian food chain. 



Scraping off the surface soil is the most ef- 



