本文研究東海陸棚沉積物總砷之濃度，以OR1-499、OR1-551與OR1-815三個航次之沉積物樣品來探討東海陸棚中沉積物砷之分佈與地化。沉積物的分析使用王水和氫氟酸加熱消化後使用石墨式原子吸收光譜儀分析砷元素濃度。
研究結果顯示，東海陸棚表層沉積物總砷濃度範圍為4.05~18.77 μg /g，平均值為8.04μg /g。東海陸棚中以靠近長江出海口及其內陸棚海域的砷濃度較高，而且砷濃度由內陸棚向中外陸棚遞減。砷在表層沉積物中顯示出總砷濃度與沉積物顆粒大小、總有機碳(TOC)以及鐵、錳等金屬有良好關係。砷在東海陸棚區各測站的垂直分佈無太大變化，顯示東海陸棚區之成岩作用不明顯且在過去並無受到顯著的汙染。
在東海陸棚中，砷在富集現象(enrichment factor)上的分佈呈現由長江出海口和靠近中國大陸的內陸棚逐漸向中外陸棚遞減，內陸棚富集值略高於中外陸棚，富集因子範圍為0.74~3.43，平均為1.29。此結果顯示東海陸棚並無明顯的砷汙染。
本研究分析所得的砷濃度與引用文獻之東海質量累積速率資料，估算砷元素在東海陸棚的年沉降通量。本文將東海陸棚劃分成五個區域，面積約為東海總面積的50%。砷沉降通量為3.2-32.17×103 tons y-1，平均為13.54×103 tons y-1，而內陸棚區約佔68.5%，顯示出主要沉積於東海內陸棚區。

The spatial distribution and vertical profile of arsenic concentration in sediments of the East China Sea (ECS) were studied in the present work. The sediment samples of the ECS were collected by Ocean Research Vessel I under three cruises OR1-499, OR1-551 and OR1-815. The sediment samples were totally digested using aqua regia and the hydrofluoric acid. The total concentrations of arsenic in the digested solution were determined by furnace atomic absorption spectrometry. In addition, the annual sediment flux of As in the ECS was also estimated.
The total concentration of As in surface sediments of the ECS ranged within 4.05-18.77μg/g, with an average 8.04 μg/g. The spatial distribution of As exhibited higher concentration located at the Changjiang estuary and inner shelf, and decreased with seawards. In surface sediment samples, the As concentration inversely correlated well with the grain size, but had a good correlation with the concentrations of total organic carbon, and Fe as well as Mn concentrations. The vertical profiles of As at some studied stations showed minor variation, suggesting that the diagenatic processes were not obvious during the sediment burial and that no As pollution event occurred before in the ECS. The enrichment factor of As in the ECS ranged within 0.74-3.43, with an average 1.29, indicating that the ECS was still free-contaminated by As, except the inner shelf where was slightly contaminated.
Based on the data of mass accumulation rate from the literature and the As concentration obtained in this study, the annual sedimentation fiux of As in the ECS was calculated. The annual average sedimentation flux of As in the ECS is approximately 13.5 ×103 tons and about 69% of the flux is deposited in the inner shelf.

目錄

中文摘要..................................................................................................Ⅰ
英文摘要..................................................................................................Ⅲ
表目錄......................................................................................................Ⅶ
圖目錄......................................................................................................Ⅷ
第一章 緒論............................................................................................1
第二章 研究區域....................................................................................9
2-1 東海地理位置及概況................................................................9
2-2 水文概況..................................................................................11
2-3 東海沉積物的分佈概況..........................................................13
2-4 東海沉積物中重金屬分佈概況..............................................18
第三章 研究方法..................................................................................20
3-1 樣品採集..................................................................................20
3-2 樣品前處理..............................................................................24
3-3 分析試劑..................................................................................24
3-4 沉積物樣品總消化處理..........................................................25
3-5 儀器設備..................................................................................25
3-6 分析品質評估..........................................................................27
第四章 結果與討論..............................................................................29
4-1 表層沉積物砷濃的之分佈......................................................29
4-2 富集因子的探討......................................................................41
4-3 東海陸棚沉積物砷之垂直變化..............................................45
4-4 砷元素之沉降通量..................................................................52
第五章 結論..........................................................................................58
參考文獻..................................................................................................59


























表目錄

表2-1、中國大陸流入東海海域主要河川之流域面積、年輸水量及
年輸砂量………………………………………………………14
表2-2、東海表層沉積物與長江懸浮物、沉積物中金屬元素之比較19
表3-1、採樣測站之位置經緯度與底深………………………...…….21
表3-2、石墨式原子吸收光譜儀偵測砷元素之程序…………………26
表3-3、加拿大海洋沉積物參考樣品之分析精確度及準確度測試…28
表4-1、東海陸棚表層沉積物砷之濃度……………………………....32
表4-2、各近岸海域表層沉積物砷濃度與本研究相比較………....…35
表4-3、東海陸棚表層沉積物種類及總碳含量分析……………...….38
表4-4、As、TOC與沉積物粒徑大小之間的相關係數…………..….40
表4-5、東海陸棚表層沉積物砷之富集因子………………....……….43
表4-6、東海陸棚沉積物砷之沉降通量…………………….…...…….56
表4-7、東海陸棚沉積物砷通量與文獻之比較.....................................57









圖目錄

圖1-1、砷在沉積物中的氧化還原作用循環概要圖…………………..8
圖2-1、東海海底等深線圖……………………………………………..10
圖2-2、東海海流分佈圖……………………………………………....12
圖2-3、東海海域沉積物分佈圖………………………………………17
圖3-1、各航次採樣測站位置圖………………………………………23
圖4-1、東海陸棚區表層沉積物砷濃度分佈…………………………33
圖4-2、東海陸棚表層沉積物砷濃度等值圖…………………………34
圖4-3、東海表層沉積物砷之富集因子等值圖………………………44
圖4-4、東海內陸棚各測站沉積物砷濃度之垂直變化………………48
圖4-5、東海中陸棚各測站沉積物砷濃度之垂直變化………………49
圖4-6、東海陸棚沉積物砷、鐵、錳之深度變化……………………50
圖4-7、測站M17、18、19、20中砷與鐵、錳濃度之相關性……...51
圖4-8、東海陸棚區域劃分圖…………………………………………55

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