On cobalt-60 in marine sediments.
The analytical method of cobalt-60 in marine sediments are first described : Cobalt-60 in marine sediments were leached from the sediments using heated 8N-hydrochloric acid after the organic materials were decomposed by mixing the sediment with antiformin and by heating, and the leached solution was passed through the anion exchange column. Cobalt was eluated by 4 N-hydrochlotic acid, and it was further purified as it being passed through the cation exchange column which had been equilibrated with hydrochloric acid and tetra-hydrofran mixture. Then, the purified cobalt was electroplated on the copper plate. Determination of the radioactivity and identification of the cobalt-60 were made using the low back-ground beta-ray spectrometer and the Ge (Li)-gamma-ray spectrometer. The determination was made to cobalt-60 in the marine sediments collected at the coastal area of Japan and the deep sea bottom of the western North Pacific Ocean. As the result, cobalt-60 was detected from almost all samples, and the range of cobalt-60 contents was found to be 0-12 pCi/kg of dry mud. As the origin of cobalt-60 in marine sediments, fallout, recent iron materials and cooling water from atomic piles can be pointed out. It is considered that the cobalt-60 from fallout is predominant in the widespread distribution of this nuclide. Cobalt-60 was also detected from the marine sediments collected at the depth of about 3000 m. Hence, it is considered that the cobalt-60 was brought there by precipitation of detritus of plankton which had concentrated the nuclide preliminarily at the surface layer.
| Main Authors: | , |
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| Format: | Journal Contribution biblioteca |
| Language: | Japanese |
| Published: |
1976
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| Online Access: | http://hdl.handle.net/1834/16331 |
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