放射能汚染魚に関する研究-IV

Abstract

Radiochemical studies were made for 25 samples of fishes caught from the fishing ground including the area from longitudes 128° E to 162° E and from latitudes 3° N to 33° N during the season which covered from April 25th to July 7th 1954. It is noticed that the distribution of radioactivity varies widely as to the tissues of same fish sample. In general, liver, kidney, gall bladder and heart were found as the most contaminated parts in the tissues of the animal. Pyloric coeca, stomach and intestine were weaker in their radioactivity than the above organs; further the least activity was observed for skin, bone and muscle. However, the order of strength of radioactivity in these tissues is not always the same if the different kinds of fish are comparedwith ach other. For example, the most radioactive parts detected in dolphin were liver, gall bladder and heart (Table 3), while in albacore, heart was not higher in its radioactivity than otherorgans (Table 7) As the result of radiological examination of stomach contents of Okisawara (Cybiidae sp.) and dolphin, there was found no significant correlation between the radioactivity of stomach contents and that which observed in the tissues of the fish (Tables 2, 3). Even distribution of the activity was proved for the muscles which were taken from different parts of dolphin, big eyed tuna and yellow fin tuna (Tables 4, 5, 6). But dark muscle held always much highr radioactivity than white muscle of the same fish. Sometimes, over ten times of strength was recorded for dark muscle compared with white muscle (Tables 4 to 8).