碩士 / 國立臺灣大學 / 海洋研究所 / 103 / Belonging to the 238U-series, Po-210 and Pb-210 are well known for their particle-reactive characteristics in marine environments. Po-210 contributes a dominant fraction of the radiation dose received by humans, which originated from the accumulation effect of ingested seafood.
Fish is the final chain of aquatic food web and provides important protein source for the human being of the world. In this thesis, demersal fishes were collected from the sea off southwestern Taiwan for the determination of Pb-210 and Po-210 activities. Po-210 activity in fish samples were found to vary from 2.8 to 94.7 dpm/g dry weight and Pb-210 activity were found to vary from 0.3 to 8.5 dpm/g dry weight. The Po-210/Pb-210 ratios in the whole fish ranges from 2.5 to 52.3 and is generally greater than unity, which indicates that Po-210 is preferentially taken up by organisms compared to its progenitor Pb-210. Po-210 and Pb-210 are non-uniformly distributed within these fishes, the highest levels being found in the digestive organs whereas the lowest levels being found in the muscle and bones. Po-210 activity is higher than Pb-210 activity in both of muscle and viscera. Owing to the different component, Po-210 and Pb-210 activities in bones of chondrichthyes are higher than that in osteichthyes. There is no systemic variation found for Po-210 activity in different trophic level, however, Po-210/Pb-210 ratios tend to increase along with the food chain.
The annual ingestion dose of 380 mSv/year due to Po-210 in demersal fish is estimated. The annual ingestion dose in Taiwan is higher than other studies, which may be caused by the higher consumption of fish in Taiwan and the higher Po-210 activities in demersal fishes collected from the sea off southwestern Taiwan.
| Identifer | oai:union.ndltd.org:TW/103NTU05279017 |
| Date | January 2015 |
| Creators | Huei-Chun Tang, 唐慧純 |
| Contributors | Ching-Ling Wei, 魏慶琳 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 48 |
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