抄録
In previous paper, the authors reported the presence of a considerable amount of radioactive zinc in the radiologically contaminated fish caught at the Pacific Ocean in 1954. The present paper is concerned with the uptake and accumalation of zinc by aquatic animals.
When the clam Meretrix meretrix luzoria, was immersed in the sea water (Cl1.84%, pH8.1) containing Zn65, the accumulation of it was high in gill, mantle, viscera and other soft tissues (Fig. 1). On the hard tissue (shell), radioactivity was detected only a little, if any. About 40% of radioactivity of clam wa ?? lost in two days after return to normal sea water.
When the carp, Cyprinus carpio, was cultivated in the water containing Zn65 45, 000c/m/l, Zr65 was deposited much in gill and kidney. It was recognized that all other tissues contained also some amount of Zn65 (Table 2, Fig. 2). The accumulation of Zn65 injected into the carp muscle was very high in kidney, followed in hepatopanereas heart, intestine, gill, scale, caudal fin, gall-bladder, skin, vertebra and muscle (Table 3, Fig. 3).
The distribution of Sr90 and Cs137 injected into the carp muscle was also studied for the com-parison with that of Zn65. After forty seven or eight hours, Sr90 was found to be chiefly accumu laced in the hard tissue (Fig. 4), whereas Cs137 was chiefly retained in heart and kidney and found both in soft and hard tissues (Fig. 5).
