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標題: | 淡水河流域224Ra同位素之變化 The variation of 224Ra activity in Danshuei River Watershed |
作者: | Fu-Yun Chen 陳馥韻 |
指導教授: | 蘇志杰(Chih-Chieh Su) |
關鍵字: | 放射性同位素示蹤法,鐳,地下水,淡水河, radioisotope tracer method,radium,groundwater,Danshuei River, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 本研究旨在以放射性同位素224Ra作為示蹤劑,調查淡水河流域地下水輸出之情況。研究於2017年11月3-5日分別在關渡碼頭及淡水河下游進行224Ra活度之空間與潮時分布差異分析,並於2018年1-5月間在非感潮河段上游採集地表水及陸域地下水進行活度分析,另外利用海研一號1176航次採集之近岸水體進行分析。
空間分布結果顯示,超量224Ra活度介於6.0至10.1 dpm/100L之間,位於八里堤防外及重陽大橋河段的採樣點超量224Ra活度皆偏高。然而,淡水河流域上游(非感潮河段)主要支流的超量224Ra活度皆低,因此推估淡水河下游可能受到地下水輸入至河川之影響。此外海研一號1176航次分析結果顯示,靠近淡水河出海口之站位亦有超量224Ra活度高值(12.6±1.7 dpm/100L),由此推測淡水河沿岸海域可亦能受海底地下水輸入之影響。以T3站為例,透過質量守恆箱型模式估算地下水輸出流量範圍約為103-147 m3/s。 潮時時序觀測分析結果顯示超量224Ra活度介於低於偵測極限至10.0 dpm/100L之間,高值(10.0±1.8 dpm/100L)出現在低潮前3小時,低值(低於偵測極限)則出現在高潮時。超量224Ra活度大致與潮位高低呈現負相關之現象,顯示此地區之地下水輸出驅動力受到潮汐震盪的影響。 This study aims to investigate the input of groundwater to the riverine water of Danshuei River through radioisotope tracer, 224Ra, method. Water samples were collected from Guandu Wharf and downstream of Danshuei River during Nov. 3-5, 2017; while fluvial water from upstream of Danshuei River as well as fresh groundwater were sampled in January, 2018 and May, 2018. In addition, seawater samples off the Danshuei River were collected on boat R/V Ocean Researcher I during OR1-1176 cruise(2017/9/18-2017/9/24). The results of spatial distribution showed that the activities of excess 224Ra ranged from 6.0 to 10.1 dpm/100L with the higher excess 224Ra activities found in Bali dike and Chongyang Bridge. However, the fluvial water samples collected from upstream of Danshuei River tributary showed much lower excess 224Ra activities. It indicated that the downstream of Danshuei River might be influenced by groundwater input. As well, higher activity of excess 224Ra(12.6±1.7 dpm/100L)in seawater off the Danshuei River estuary implied an effect of SGD on coastal water. Through mass balance models of radium isotopes, the groundwater discharges were estimated approximately 103-147 m3/s. Furthermore, the results of temporal distribution show that the activities of excess 224Ra ranged from under detection limit to 10.0 dpm/100L with the higher value(10.0±1.8 dpm/100L)at low tide and, the lower one at high tide. The activities of excess 224Ra were negatively correlated with the tidal level, indicating that input groundwater in our study area is mainly affected by tidally driven oscillation. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/72328 |
DOI: | 10.6342/NTU201803748 |
全文授權: | 有償授權 |
顯示於系所單位: | 海洋研究所 |
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