Radioecological Studies of 137Cs in Limnological Ecosystems: Accumulation and Excretion of 137Cs in Goldfish, Carassius auratus auratus, from Diets

• Published in: RADIOISOTOPES 1996/06/15, Vol.45(6), pp.360-368
• Main Authors: MIYAKE, Sadaaki, MOTEGI, Misako, OOSAWA, Takashi, NAKAZAWA, Kiyoaki, OGATA, Hiromitsu, IZUMO, Yoshiro, NAKAMURA, Fumio
• Format: Article
• Language: English
• Subjects: bioaccumulation; cesium-137; diet; goldfish; limnology; radioecology
• ISSN: 0033-8303; 1884-4111
• DOI: 10.3769/radioisotopes.45.360

Accumulation and excretion of 137Cs in goldfish, Carassius auratus auratus, from radioactive diets (killifish, Oryzias latipes, meats accumulated 137Cs in the radioactive freshwater) or control diets (killifish meats mixed 137CsCl) were investigated in order to elucidate the accumulation mechanism of the radionuclide in natural living fishes. The accumulation of 137Cs, expressed in concentration ratio, in whole body of the fish showed a increasing tendency in proportion to the rearing time. On the other hand, the excretion of 137Cs, expressed in retention rate, in whole body rearing by administration of non-radioactive commertial diets after the accumulation above for 7 days, demonstrated a rapid decreasing at first few days, and followed a gradual decreasing tendency (the biological half lives were about 1.5 days and 52 days, respectively) . As for the tissues and organs, higher accumulation and higher excretion were found in the viscera than those in the muscle. It is so suggested that the metabolic turnover rate of this radionuclide for the viscera is more rapid than that for the muscle. From the experimental results, it was confirmed that the relative contribution by ingestion of the radioactive diets in the accumulation of 137Cs in natural environmental fish was comparatively higher in comparison with uptake of the radionuclide in the radioactive freshwater. With regard to the difference between the radioactive diets and the control diets, the accumulation of 137Cs in whole body of the fish from the radioactive diets was less than that from the control diets to rearing 5 days, but afterward was not different. The difference of the accumulation between these diets will be attributable to that of the metabolic turnover between these diets.