LONG-TERM CONSEQUENCES OF ^ogr IN RATS AND 

 THE PROBLEM OF CARCINOGENESIS! 



K. SUNDARAM 



Medical Division, Atomic Energy Establishment. Troinbay, India 



Among the fission products released by nuclear explosion, ^°Sr predominates 

 over other long-lived radionuclides from the point of view of biological 

 hazards, since it has the combined characteristics of a high fission yield, long 

 physical and biological half-lives, a long residence time in the bones and a low 

 maximum permissible level, ^°Sr being a moderately powerful /3-emitter, is 

 capable of irradiating a larger volume of bone tissue as weU as the haemato- 

 poietic system. However, a factor of discrimination against strontium with 

 respect to calcium is operative during the passage along the ecological 

 series from soil to bone via the food chain. 



In the present paper, the data reported by Casarett et al. (1961) on the 

 long-term effects of ^°Sr in rats have been analysed both with regard to the 

 fraction retained and the consequent biological effects. Table I summarizes the 



Table I 



Group 



Age at start 



experinK 



in days 



Number of . ^ . , Average age 

 , oi experiment . , ,, 

 ammals . , at death 



Average 



days at 



risk 



Total 



dose 



(/nc) 



Skeletal 



burden at 



5 months 



(/xc) 



380 



372 



254 



106 



330 



650 



790 



464 



11 



33 



results with respect to the administered dose and the amount retained in the 

 skeleton, five months after ten to thirty days of feeding of ^°Sr in the drinking 

 water. 



t Communicated by A. R. Gopal-Ayengar. 

 139 



