鉛-210(Pb-210)及釙-210(Po-210)為鈾系列中均屬親顆粒的母子核種對，但Pb-210傾向與無機顆粒結合而Po-210傾向與有機顆粒結合。在這些特性考量下，本研究針對南海北部及呂宋海峽海域分析表水中浮游生物的Po-210及Pb-210，以了解其活度在此海域的時空分佈及其不平衡狀態。因呂宋海峽提供了黑潮水與南海水交換之通道，此海域同時擁有大洋及邊緣海的特性。
研究區域內浮游生物之Po-210活度大多約10~400 dpm/g，但在聖嬰年期間可高達1200 dpm/g，兩者間是否有相關目前尚不明確。影響浮游生物中Po-210活度的因子主要為表水Po-210活度、生物質量、外來水團帶來的Po-210和含有Po-210的浮游生物。浮游生物之生物量(以表水葉綠素a為指標)越高，其Po-210活度越低，兩者成反比趨勢。由浮游生物中的Po-210分佈可見含高量Po-210的黑潮水及其浮游生物有明顯入侵南海北部的現象。浮游生物之Pb-210活度大多約5~25 dpm/g間，其變化趨勢大致與Po-210相似，但遠低於Po-210，因此Po-210/ Pb-210活度比值遠大於1。與懸浮顆粒相較，浮游生物對Po-210有富集但對Pb-210卻有排斥現象。根據本研究及前人研究結果，生物對Po-210的富集程度(即Po-210/Pb-210活度比值高低)由低到高依序為浮游生物、貽貝類、大型浮游生物及海水魚，即越高等的生物，其活度比值似乎越高，但其Po-210及Pb-210的單位質量活度卻普遍比浮游生物低。高等生物會將食物中的Po-210累積於消化系統中，但部份會隨著排泄物排出體外，不會儲存於體內其他部位。就吸附作用而言，表面積對體積比大的浮游生物，其單位質量可吸附較多的Po-210，其比活度較高；大型生物的表面積對體積比小，故單位質量能吸附的Po-210較低，即比活度較低。各種生物應是以吸收及吸附兩種方式同時富集Po-210，但其比例尚無法估計。
依盒子模式計算，南海北部在水深100公尺以內的水體中，其浮游生物的超量Po-210可達水體中不足的Po-210總量的70%以上，但在呂宋海峽，則兩者可達平衡。因此推論水深100公尺以上，水體中不足的Po-210，主要是因生物的吸收及吸附作用而轉移至生物體內，造成大量Po-210的富集現象。

Pb-210 and Po-210, a parent-daughter pair, are particle-reactive radionuclides. Pb-210 tends to be associated with inorganic particles but Po-210 prefers organic particles. In the context of these characteristics the purpose of this study is to determine Po-210 and Pb-210 in the surface water plankton of the northern South China Sea (SCS) and the Luzon Strait (LS) areas in order to understand their temporal and spatial distributions and the extent of their radioactive disequilibrium. As the LS has provided a pathway for the exchange between the Kuroshio and the SCS waters, the study area has the characteristics of an open ocean and a marginal sea.
The plankton Po-210 activities in the study area are about 10~400 dpm/g, but may reach 1200dpm/g in an El Nino year, the effect of which on Po-210 is not clear at present. The Po-210 in the plankton is mainly affected by the surface water Po-210 , biomass concentration, and the Po-210 in the surface water as well as plankton transported from other area(s). If the biomass concentration (as indicated by Chlorophyll-a) increases, the Po-210 in the plankton decreases, i.e. they are inversely correlated. Based on the planktonic Po-210 distribution, the Kuroshio water which has both high Po-210 and high Po-210-bearing plankton has evidently intruded into the northern SCS. The Pb-210 activities of in the plankton vary from 5 to 25dpm/g; the variation trend is similar to that of Po-210 but with much lower activity, resulting in a Po-210/Pb-210 ratio much greater than unity. Compared to the suspended particles, the plankton is highly enriched in Po-210 but it strongly repels Pb-210. Based on earlier studies and this one, the extent of Po-210 enrichment (as indicated by the Po-210/Pb-210 activity ratio) in various organisms increases sequentially from plankton to mussel, large swimmer and then to marine fish, i.e. the higher the level of organism in the food chain, the higher the ratio becomes. However, the Po-210 and Pb-210 activities per unit mass of these organisms are generally lower than those of plankton. Organisms of higher food-chain level may accumulate Po-210 in the digestive system, but part of it may be excreted. Po-210 accumulation does not occur in other parts of these organisms. In terms of adsorption, the plankton with greater surface area to volume ratio, can adsorb more Po-210 resulting in a higher specific activity, whereas large organisms with smaller surface area to volume ratio can adsorb less Po-210 yielding a lower specific activity. The enrichment of Po-210 in various organisms must have been achieved by absorption and adsorption with unknown proportion.
Based on a simple box model calculation for the northern SCS water within the upper 100m layer, the excess Po-210 in the planktonic biomass can account for about 70% of the total deficit in this layer. But in the LS area, the excess and the deficit are balanced. This suggests that the Po-210 deficit in this surface water is due to absorption and adsorption by organisms as evidenced by their large Po-210 enrichment.

目錄
頁碼
致謝...............................................................................................................I
中文摘要....................................................................................................III
英文摘要.....................................................................................................V
目錄.........................................................................................................VIII
圖目錄........................................................................................................XI
表目錄.......................................................................................................XII

ㄧ、緒論.......................................................................................................1
1.1 前言…....................................................................................…….1
1.2 研究區域背景...............................................................................14
二、研究方法..............................................................................................15
2.1. 浮游生物之採樣及前處理...........................................................15
2.2. Po-210核種分析.......................................................................17
2.2.1 消化樣品...........................................................................17
2.2.1.1 酸煮...........................................................................17
2.2.1.2 微波消化....................................................................17
2.2.2 Po-210的自鍍........................................................................17
2.3 Pb-210核種分析........................................................................18
2.3.1 再生Po-210之分析法(α法)....................................................18
2.3.2 再生Bi-210測量法(β法)........................................................19
2.3.3 β計數儀偵測效率之校正....................................................21
2.4 計算方法.....................................................................................23
2.4.1 Po-210活度計算.................................................................23
2.4.2 Pb-210活度計算.................................................................25
2.4.2.1 再生Po-210法之計算...................................................25
2.4.2.2 以Bi-210活度計算.......................................................25
2.4.3 Pb-210不同偵測方法之比較................................................26
三、結果與討論..........................................................................................28
3.1 不同季節浮游生物之Po-210.......................................................28
3.1.1 南海北部...............................................................................28
3.1.1.1 ORI-688航次(2003年7月，夏)......................................28
3.1.1.2 ORI-707航次(2004年2月，冬)......................................31
3.1.1.3 夏、冬浮游生物之Po-210的比較......................................33
3.1.2呂宋海峽附近...........................................................................34
3.1.2.1 ORI-734航次(2004年10月，秋).....................................34
3.1.2.2 FRI-SCSBGC(2005年4月，春)......................................36
3.1.2.3 ORI-763(2005年8月，夏)..............................................36
3.1.2.4 呂宋海峽秋、春、夏季浮游生物之Po-210之變化.............39
3.2 不同季節浮游生物之Pb-210.......................................................41
3.2.1 南海北部...........................................................................41
3.2.2 呂宋海峽附近....................................................................41
3.3 南海北部與呂宋海峽附近浮游生物之Po-210及Pb-210的比較
.......................................................................................................43
3.4 浮游生物對Po-210的富集現象..................................................43
3.4.1 表水中Po-210的缺乏..........................................................43
3.4.2 造成表水中Po-210不足的原因.................................................44
3.4.3 不同生物種對於Po-210的富集............................................44
3.4.4浮游生物對Po-210可能的吸收或吸附路徑.................................45
3.5 整體區域中Po-210的不平衡現象..............................................47
四、結論......................................................................................................50
參考文獻....................................................................................................52
附錄圖3-1-1 南海北部不同季節之表水溫鹽圖.................................59
附錄圖3-1-2 呂宋海峽附近不同季節之表水溫鹽圖.........................60
附錄圖3-2 各航次之表水葉綠素a濃度圖.............................................62
附錄圖3-3 各航次之雨量圖....................................................................63
附錄圖3-4 各航次期間颱風路徑圖.........................................................64
附錄表3-1 歷年聖嬰年及反聖嬰年時間表............................................65













圖目錄
頁碼
圖1-1 Pb-210與Po-210在海水中的傳輸示意圖....................................2
圖2-1 研究區之海底地形及站位圖.........................................................16
圖2-2 樣品分析流程圖.............................................................................20
圖2-3 Beta計數儀之偵測效率圖..............................................................23
圖3-1 南海北部及呂宋海峽不同季節浮游生物之Po-210活度分佈圖
..............................................................................................................30
圖3-2 各航次測站浮游生物之Po-210活度圖......................................40
圖3-3 各航次測站浮游生物之Pb-210活度圖......................................42
圖3-4 本研究區各航次測站浮游生物之Po-210/Pb-210活度比值圖
.......................................................................................................45


表目錄
頁碼
表1-1南海北部、呂宋海峽及台灣周圍表水之Po-210活度Pb-210活度及Po-210/Pb-210活度比值............................................................4
表1-2 全球各大洋表水的Po-210活度Pb-210活度及Po-210/Pb-210活度比值(Nozaki et al., 1998).............................................................6
表1-3 前人研究表水之Po-210/Pb-210活度比值.....................................7
表1-4 各大洋沉降顆粒的Po-210/Pb-210活度比值.................................8
表1-5 浮游生物之Po-210與Pb-210活度及Po-210/Pb-210比值之比較
..........................................................................................................9
表1-6 貽貝類及海水魚(肌肉) 之Po-210與Pb-210活度及Po-210/Pb-210比值之比較...........................................................10
表1-7 Saduria entomon(甲殼類)體內各部位的Po-210活度及Po-210/Pb-210活度比值(Stepnowski, 2000)................................11
表1-8 貽貝類樣品中消化腺體、排泄物及整體的Po-210活度(Bustamante, 2002)........................................................................12
表1-9 貽貝類樣品中消化腺體及整體的Po-210活度............................13
表2-1 各採樣航次站位表.........................................................................16
表2-2 Beta計數儀偵測效率測定結果...................................................22
表2-3 α法與β法比較實驗結果...........................................................27
表3-1-1 南海北部在ORI-688(2003年7月)航次各測站浮游生物中Po-210、Pb-210及Po-210/Pb-210活度比..................................29
表3-1-2 南海北部在ORI-707(2004年2月)航次各測站浮游生物中Po-210、Pb-210及Po-210/Pb-210活度比..................................32
表3-1-3 南海北部及呂宋海峽在ORI-707(2004年10月)航次各測站浮游生物中Po-210、Pb-210及Po-210/Pb-210活度比..................35
表3-1-4 南海北部及呂宋海峽在FRI-SCSBGC(2005年4月)航次各測站浮游生物中Po-210、Pb-210及Po-210/Pb-210活度比..........37
表3-1-5 南海北部及呂宋海峽在ORI-763(2005年8月)航次各測站浮游生物中Po-210、Pb-210及Po-210/Pb-210活度比......................38
表3-2 ORI-734航次(2004年10月)不同區域水深100公尺以上Po-210的不平衡現象................................................................................48

參考文獻
中文部份
吳宗恩，2002，南海北部海域水體中Pb-210與Po-210活性不平衡狀態，國立中山大學海洋地質研究所碩士論文，共63頁。
邱薰慧，2000，台灣周圍海域浮游生物之釙-210和鉛-210含量及釙-210之富集現象，國立中山大學海洋地質研究所碩士論文，共61頁。
洪國緯，台灣東北海域陸坡區之沉降顆粒：通量、粒徑分佈及鉛釙不平衡，國立中山大學海洋地質研究所博士論文，共210頁。
蘇育田，2005，呂宋海峽北部水體中210Pb與210Po之活性不平衡狀態，國立中山大學海洋地質研究所碩士論文，共65頁。

英文部分
Al-Masri, M.S., Mamish, S., Budeir, Y., Nashwati, A., 2000. 210Po and 210Pb concentrations in fish consumed in Syria. Environmental Radioactivity 49, 345-352.
Aysun, U., Güngör, Y., Asiye, B., 2002. Trace metals and 210Po(210Pb) concentrations in mussels (Mytilus galloprovinvialis) consumed at western Anatolia. Applied Radiation and Isotopes 57, 565-571.
Bacon M.P., 1977. 210Po and 210Pb result from F.S. “Meteor” curise 32 in the North Atlantic, “Meteor” Forschungs Ergebnisse A 19, 24-36.
Beasley, T.M., Heyraud, M., Higgo, J.J.W., Cherry, R.D., Fowler, S.W., 1978. 210Po and 210Pb in zooplankton fecal pellets. Marine Biology 44, 325-328.
Brewer, P.G., Nozaki, Y., Spencer, D.W., Fleer, A.P., 1980. Sediment trap experiments in the North Atlantic; isotopic and elemental fluxes. Journal of Marine Research 38, 703-728.
Bustamante, P., Germain., P., Leclerc., Miramand, P., 2002. Concentration and distribution of 210Po in the tissues of the scallop Chlamys varia and the mussel Mytilus edulis from the coasts of Charente-Maritime (France). Marine Pollution Bulletin 44, 977-1002.
Carvalho, F.P., 1988. 210Po in marine organism: a wide range of natural radiation dose domains. Radiation Protection Dosimetry 24, 113-117.
Carvalho, F.P., Fowler, S.W., 1994. A double-tracer technique to determine the water and food as sources of polonium-210 to marine prawns and fish. Marine Ecology Progress Series 103, 251-264.
Carvalho, F.P., 1995. 210Po and 210Pb intake by the Portuguese population: the contribution of seafood in the dietary intake of 210Po and 210Pb. Journal of the Health Physics Society 69(4). 469-480.
Chen, J.C., Chung, Y., 1997. 226Ra, 210Pb and 210Po Distributions at the Sea off Souyjern Taiwan: Radioactive Disequilibria and Temporal Variations. Terrestrial, Atmospheric and Oceanic Sciences (TAO) 8, 255-270.
Cherry, R.D., Shannon, L.V., 1974. The alpha radioactivity of marine organism. Atomic Energy Review 12, 45.
Cherry, R.D., Heyraud, M., 1981. Polonium-210 content of marine shrimp: variation with biological and environmental factors. Marine Biology 65, 167-175.
Cherry, R.D., Heyraud, M., 1982. Evidence for high natural radiation doses in certain mid-water oceanic organisms. Science 218, 54-56.
Chung Y., Finkel, R., 1988. 210Po in the western India Ocean: distributions, disequilibria and partitioning between the dissolved and particulate phases. Earth Planetary Science Letters 88, 232-240.
Chung, Y., Wu, Y.M, 1995. Radioactive Disequilibria Among 226Ra, 210Pb and 210Po at the sea off Northeastern Taiwan. Academisch Centrum Tandheelkunde Amsterdam 34, 15-29.
Cochran J.K., Bacon, M.P., Krishnaswami, S., Turekian, K.K., 1983. 210Po and 210Pb distributions in the central and the eastern Indian Ocean. Earth Planetary Science Letters 65, 433-452.
Flynn, W.W., 1968. The determination of low levels of polonium-210 in environmental materials. Analytica Chimica 43,221-227.
Friedrich, J., Rutgers Van Der Loeff, M.M., 2002. A two tracer(210Po-234Th) approach to distinguish organic carbon and biogenic silica export flux in the Antarctic Circumpolar Current. Deep-Sea Research 49,101-120.
Güngör, N., Topcuoglu, S., Kirbasoglu, C., 2001. 210Po and 210Pb concentrations in biota from the Turkish coast of the Black Sea and Marmara Sea. Rapp. Comm. int. Mer Médit.36, 132.
Harada, K., Tsunogai, S., 1986. Fluxes of 234Th, 210Po, and 210Pb determined by sediment trap experiments in pelagic oceans. Journal of Oceangraphical Society of Japan 42, 192-200.
Heussner S., Cherry, R.D., Heyraud, M., 1990. 210Po, 210Pb in sediment trap particles on a Mediterranean continental margin. Continental Shelf Research 10, 989-1004.
Heyraud, M., Cherry, R.D., 1979. Polonium-210 and lead-210 in marine food chain. Marine Biology 52, 227-236.
Heyraud, M., Cherry, R.D., 1983. Correlation of 210Po and 210Pb enrichments at the sea-surface microlayer with neuston biomass. Continental Shelf Research I, 283-293.
Kadko, D., 1993. Excess 210Po and nutrient recycling with the California coastal transition zone. Journal of Geophysical Research 98, 857-864.
Li, Y.H., Santschi, P.H., Kaufman, A., Benniger, L.K., Feely, H.W., 1981. Natural radionuclides in water of the New York Bight. Earth Planetary Science Letters 55, 217-228.
Lin, Y.N., Chung, Y.,1991. Pb-210 and Po-210 Distributions and Their Radioactive Disequilibria in the Kuroshio Waters off Eastern and Northeastern Taiwan. Terrestrial, Atmospheric and Oceanic Sciences (TAO) 2, 243-265.
McDonald, P., Fowler, S.W., Heyraud, M., Baxter, M.S., 1986. Polonium-210 in mussel and its implications for environmental Alpha-autoradiography. Journal of Environmental Radioactivity 3, 293-303.
McDonald, P., Baxter, M.S., Scott, E.M., 1996. Technological enhancement of natural radionuclides in the marine environment. Journal of Environmental Radioactivity 32(1-2), 67-90.
Narita, H., Haradam, K., Tsunogai, S., 1990. Lateral transport of sediment particles in the Okinawa Trough determined by natural radionuclides. Geochemical Journal 24, 207-216.
Nozaki, Y., Thompson, J., Turekian, K.K., 1976. The distribution of 210Pb and 210Po in the surface waters of Pacific ocean. Earth Planetary Science Letters 32, 304-312.
Nozaki, Y., Tsunogai, S., 1976. 226Ra, 210Pb and 210Po disequilibria in the Western North Pacific. Earth Planetary Science Letters 32, 313-321.
Nozaki, Y., Dobashi, F., Kato, Y., Yamamoto, Y., 1998. Distribution of Ra isotopes and the 210Pb and 210Po balance in surface seawaters of the mid Northern Hemisphere. Deep-Sea Research I 45, 1263-1284.
Nozaki Y., Ikuta, N., Yashima, M., 1990. Unususally large 210Po deficiencies relative to 210Pb in the Kuroshio Current of the East China and Philippine Sea. Journal of Geophysical Research 95, 5321-5329.
Nozaki Y., Tsubota, H., Kasemsupaya, V., Yashima, M., Ikuta, N., 1991. Residence time of surface water and particle-reactive 210Pb and 210Po in East China and Yellow Seas. Geochimica et Cosmochimica Acta 55, 1265-1272.
Radakovitch, O., 1994. Po-210 and Pb-210 in the water column of the western part of Gulf of Lion. Proc. of the MARINA-Med seminar: The radiological exposure of the population of the European community from radioactivity in the Mediterranean Sea, Roma, 281-290.
Richie, G.D., Shimmield, G.B., 1991. The use of 210Po/210Pb disequilibria in the study of the fate of marine particulate matter. In: Radionuclides in the study of marine processes. (ed) Elsevier London, New York 389, 142-153.
Santschi, P.H., Li, Y., Bell, J., 1979. Natural radionuclides in the water of Narragansett Bay. Earth Planetary Science Letters 45, 201-213.
Sarin, M.M., Rangarajan, R., Somayajulu, B.L.K., 1994. Natural radionuclides in the Arabian Sea and Bay of Bengal: distribution and evaluation of particle scavenging processes. Earth Planetary Science Letters 103, 211-235.
Shannon, L.V., Orren, M., 1970. A rapid method for the determination of Polonium-210and Lead-210 in sea water. Analytica Chimica Acta 52, 166-169.
Stepnowski, P., Skwarzec, B., 2000. Tissue and subcellular distributions of 210Po in the crustacean Saduria entomon inhabiting in the southern Baltic Sea. Journal of Environmental Radioactivity 49, 195-199.
Thomopson, J., Turekian, K.K., 1976. 210Po and 210Pb distributions in ocean water profiles from the Eastern South Pacific. Earth Planetary Science Letters 32, 297-303.
Tsunogai, S., Nozaki, Y., 1971. Lead-210 and Polonim-210 in surface water of Pacific. Geochemical Journal 5, 165-173.
Yamamoto, M., Abe, T., Kuwabara, J., Komura, K., Takiza, Y., 1994. Polonium-210 and lead-210 in marine organisms: intake levels for Japanese. Journal of Radioanalytical Nuclear Chemistry 178, 81-90.
Zuo, Z., Eisma, D., 1993. 210Pb and 210Po distributions and disequilibrium in the coastal and shelf waters of the southern North Sea. Continental Shelf Research 13, 999-1022.