鉛-210和釙-210 在海洋中屬於親顆粒性的核種，易被不同顆粒物質所清除，使其母子核種間產生活性不平衡的現象。過去的研究顯示，表水中釙-210/鉛-210的活度比值約為0.2~1，可能反映了鉛-210之大氣落塵來源以及生物生產率和湧升流的影響。為了探討生物性顆粒對於放射性核種分佈的影響，本研究係利用拖網在台灣周圍海域收集表層浮游生物樣品供鉛-210與釙-210之分析，藉以瞭解台灣周圍海域浮游生物對釙-210和鉛-210 之好惡及其富集或排斥現象。
分析結果顯示，台灣東北海域之浮游生物的釙-210及鉛-210活度比值介於23.06~51.40；西南海域浮游生物在測線1之比值介於10.72~43.90，在測線2介於16.40~47.87，在測線3介於13.86~23.37，測線4介於9.35~13.82 。兩種大型藻類(匍枝馬尾藻和長枝沙菜)之活性比值分別介於2.24~8.57與3.76~5.92。這些比值皆遠大於1，而其活度相對於無機顆粒之活度而言，浮游生物對釙-210有富集的能力，對鉛-210則有排斥的現象。至於浮游生物對於親顆粒核種的作用機制，由於生理作用的錯綜複雜，使得目前並未能有更明確的討論。比較釙-210及鉛-210在生物性顆粒上之活度，則發現生物性顆粒明顯富集釙-210且排斥鉛-210，此結果大致與文獻報告相符。

Po-210 and Pb-210 are particle-reactive natural radionuclides which can be removed from seawater by their incorporation with various particulate materials, resulting in radioactive disequilibria with respect to their parent nuclides. Previous studies showed that Po-210/Pb-210 activity ratio in surface seawater ranges from about 0.2 to 1 due to atmospheric input of Pb-210 and effects of biological productivity and upwelling. In order to evaluate the effects of plankton on Po-210 and Pb-210 distributions, plankton samples were collected by surface-trawling of plankton net in Taiwanese water. These plankton samples were analyzed for Po-210 and Pb-210 in order to obtain their concentrations and activity ratio, which may indicate the enrichment or discrimination of these nuclides in the marine planktonic phase around Taiwan.
The results show that the Po-210/Pb-210 activity ratio of planktonic samples ranges from 23.06 to 51.40 in northeastern Taiwan, whereas the activity ratio in southwest Taiwan varies within and outside of the sampleing locations: stations 1, 2, 3 and 4 yield range of 10.72-43.90, 16.40-47.87, 13.86-23.37 and 9.35-13.82, respectively. Two marine algae (Sargassum polycystum C.Agardh and Hypnea charoides Lamouroux) yield values of 2.24-8.57, and 3.72-5.96, respectively. These Po-210/Pb-210 activity ratios are much greater than unity, and their activities comparison to those of inorganic particulates support the contention that the plankton preferentially incorporates Po-210 but discriminates against Pb-210. However, the mechanism or process of Po-210 to be incorporated in the plankton remains unclear. In comparison of the activities between Po-210 and Pb-210 in organic particulates, one finds that Po-210 is effectively enriched while Pb-210 is clearly discriminatied by the organic particulates. These results are consistent with those reported in literatures.

目錄
誌謝…………………………………………………………………………..I
摘要………………………………………………………………………….II
英文摘要……………………………………………………………………III
目錄………………………………………………………………………….V
表目錄……………………………………………………………………..VIII
圖目錄………………………………………………………………………IX
第一章 緒論………………………………………………………………..1
第二章　分析方法…………………………………………………………3
2.1採樣區域……………………………………………………………..3
2.2採樣方法……………………………………………………………..3
2.3樣品的組成及性質…………………………………………………..6
2.3.1浮游動物………………………………………………………….6
2.3.2浮游植物………………………………………………………. . .6
2.4樣品的前處理………………………………………………………..7
2.5 分析方法…………………………………………………………...10
2.5.1 釙-210活性之分析……………………………………………..10
2.5.1.1 自鍍………………………………………………………….10
2.5.1.2. α粒子能譜分析……………………………………………12
2.5.2 鉛-210活性之分析……………………………………………..13
2.5.2.1. 測再生性釙-210之活性……………………………………13
2.5.2.2. 測鉍-210的活性……………………………………………16
2.5.2.3. β計數儀……………………………………………………18
2.6數據整理……………………………………………………………18
2.6.1釙-210數據整理………………………………………………..18
2.6.2鉛-210數據整理…………………………………………….….19
2.6.3釙-210活性修正計算式……………………………………… .20
第三章　結果…………………………………………………………….21
3.1分佈趨勢及探討…………………………………………………...21
3.1.1台灣東北海域浮游生物體釙-210的活度…………………….21
3.1.2台灣西南海域浮游生物體內鉛-210的活度………………….23
3.1.3釙-210在東北海域與西南海域之比較……………………….23
3.1.4藻類之釙-210活性…………………………………………….25
3.2浮游生物之鉛-210分佈趨勢……………………………….….…25
3.2.1台灣東北海域浮游生物體內鉛-210的活度……………….…28
3.2.2台灣西南海域浮游生物體內鉛-210的活度……………….…28
3.2.3藻類之鉛-210活性………………………………………….…28
3.3釙-210/鉛-210的活性比值……………………………………..…29
第四章 討論……………………………………………………… ……33
4.1釙-210富集現象及鉛-210排斥現象……………………………..33
4.1.1東北海域浮游生物釙-210在有機相富集及鉛-210在有機相之
排斥現象………………………………………………………..33
4.1.2西南海域浮游生物釙-210在有機相富集及鉛-210在有機相之
排斥現象……………………………………………………….34
4.2浮游生物及藻類相對於海水之富集現象……………………….37
4.3釙-210及鉛-210活性之變因……………………………………39
4.3.1食物鏈…………………………………………………………41
4.3.2放射性核種的化學性質…………………………………….41
第五章 結論…………………………………………………………..46
第六章 參考文獻……………………………………………………..47

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