Experimental absorption and desorption study on a combination of 60Co, 51Cr, 137Cs, 54Mn and 22Na in the carp (Cyprinus carpio L.)

The study of radionuclide behavior in water shows that about 25% of the 60Co et 98% of the 54Mn are found in particle form, while 96% of the 137Cs and 87% of the 22Na remain in solution. The soluble fraction generally remains cationic except for 60Co, of which over one-fourth becames anionic. The uptake kinetics in the carp vary widely according to the radionuclide. The process is linear for 54Mn, and tends to decrease in time for 137Cs, while an equilibrium state tends to avise with 60Co and 22Na. The fresh weight concentration factors calculated after 65 days of experimentation were 150, 12, 3 and 120, respectively. Contaminated carp placed in non-radioactive water for 57 days lost between 45% and 65% of the 60Co, 137Cs and 54Mn uptake. These elimination rates correspond to biological half-lives of 70-120 days for radioactive cobalt and cesium, and longer than 120 days for 54Mn. The process was much more rapid with 22Na, 95% of which was eliminated in 57 days: this corresponds to two biological half lives of 3 and 15 days. When the fish were deprived of food the process was appreciably slower, but in different proportions for each radionuclide; the effect was more significant for 137Cs and 60Co than for 54Mn and 22Na. The fecal excretion of radionuclides also diminished: smaller quantities of 60Co and 54Mn were eliminated under these conditions than when food was administered. Fecal excretion of 22Na was practically nil in both cases