太平洋と大西洋産キンメダイの ⁶⁰Co/Co・¹³⁷Cs/Cs・⁹⁰Sr/Sr比の不同性

抄録

Specific radioactivities (SR) of ⁶⁰Co/⁵⁰Co ¹³⁷Cs/¹³³Cs, ⁹⁰Sr/^86-8Sr, the elemental abundance of of K, Rb, Fe, Zn, Ag and 14 others were determined on Beryx splendens collected from the southwest coast of the Africa on the Atlantic and at the Emperor Seamounts (E-smt) on the western North Pacific. An overall ratio of ¹³⁷Cs ⁹⁰Sr and their SR was 1:1/4:1/8 in Beryx from Kinmei (K-smt) of E-smt, Valdivian smt (V-smt) on Walvis Ridge and A-smt on Guinea Rise. Muscle content of ¹³⁷Cs was the highest: 0.85Bq/kg wet weight in K-smt Beryx and the lowest: 0.12Bq in A-smt ^Beryx; this reflects well ¹³⁷Cs content in seawater. By the concentration Factor 1.48× 10² (¹³³Cs muscle/¹³³ Cs seawater) and ¹³⁷ Cs muscle, content of ¹³⁷Cs in Beryx habitat was estimated at 6-7mBq/l for K-smt, 1.5-2.0 mBq for V-smt and 0.7-1.0 mBq for A-smt. The strong differences were, first attributed to the different fallout by latitudes. ⁶⁰Co ranging 30-150 mBq/kg wet weight was detected in livers. of Beryx and a similar level of ⁶⁰Co was found in the pectoral dark muscle of Beryx exclusively from the Pacific specimens (K-smt, Sagami Bay, ShichitÔ-IÔjima Ridge, Nanse-shotÔ Ridge, KyÛshÛ-Palau Ridge). Coefficient of variation (CV) of radionuclides and their SR were in 60-100% among A-V-K-smt Beryx. However, CV ranging within 10-34% in the Pacific 6 groups. In most cases, CV of many elements by each part lay less than 45% throagh the three localities, except Ag and Cl. Thus, the benthopelagic Beryx splendens may serve as an indicator reflecting environmental radioactivities in 200-600m depth of the Oceans.