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The distributions of arsenic and selenium in the Danshuei River Estuary
|Authors: ||Liu, Yi-Jia|
|Contributors: ||NTOU:Department of Marine Environmental Informatics|
Danshuei River Estuary;liquid-liquid extraction;arsenic;selenium
|Issue Date: ||2020-01-20T06:20:35Z
|Abstract: ||本研究分別於106年7月、12月與107年4月，於淡水河主流與基隆河採集水樣，而107年4月多採取沉積物，分析水樣中溶解態、懸浮態與沉積物中砷與硒的濃度。此外本研究亦探討使用APDC/Freon液相萃取法濃縮樣水中溶解態硒濃度，其最佳萃取pH值為5.5，萃取率不受鹽度影響。淡水河河口海域樣品分析結果其溶解態砷濃度範圍為0.32-3.28μg/L與鹽度有良好的相關性，正/負相關性似乎由採樣時河水砷濃度決定。溶解態硒濃度範圍為<0.006-3.50 μg/L，在12月份調查之濃度明顯比7月與4月調查濃度高。懸浮態砷與硒的濃度範圍分別為ND-57.97mg/kg與ND -43.67 mg/kg，三次採樣砷的最高濃度均出現在基隆河處。沉積物砷與硒的濃度範圍分別為5.52-23.55 mg/kg與0.034-2.831 mg/kg，中、下游濃度比上游高。沉積物的非殘餘相砷濃度佔總砷濃度約28-53%，而硒的非殘餘相濃度佔總濃度百分比約大都< 30 %，顯示沉積物中的砷比較不穩定，對底棲生物的潛在危害及汙染環境的可能性比較高，而硒比較穩定不易改變，對生物的潛在危害可能性較低。計算砷與硒元素在溶解態與懸浮態間之分佈係數，砷與硒之倆相分佈係數log值範圍分別為3.2-4.8與2.7-5.1，倆元素之分佈係數值似乎未隨鹽度改變，而水中倆元素總濃度，主要存在於溶解態濃度。|
The estuarine water samples were collected from the Danshuei River Estuary and its tributary, the Keelung River, in July and December of 2017, and April of 2018. In addition, the surface sediment samples were also collected in April, 2018. The water samples were analyzed for the dissolved and particulate concentration of As and Se, and their partitioning between these both phases were also discussed. In addition, the pre-concentration of dissolved Se was also studied by the extraction method of APDC/Freon. The better extraction pH value was at ca. 5.5 and the extraction efficiency was not influenced by the salinity factor. The dissolved As concentration of the estuarine water samples ranged within 0.32-3.28μg/L and had a good positive/negative correlation with salinity, depending on the riverine As concentration. The dissolved Se concentration of the estuarine water samples ranged within <0.006-3.50μg/L and the concentration obtained in December survey was higher than that of the July and April surveys. The particulate As and Se concentrations of the estuarine water samples ranged within ND-57.97mg/kg and ND -43.67 mg/kg, respectively, and higher concentration appeared at the Keelung River region. The As and Se concentrations in the sediment samples ranged within 5.52-23.55 mg/kg and 0.034-2.831 mg/kg, respectively, and higher concentration generally located at the middle and the lower estuary. The leachable concentrations of As and Se in the sediment samples accounted for 28-53% and <30% of the their total concentrations, suggesting that As was more labile and Se was inert in the sediment. The partitioning log values of As and Se in the dissolved and particulate phases ranged within 3.2-4.8 and 2.7-5.1, respectively, and the both values were independent with salinity. Finally, the total concentrations of both elements in the water samples were mainly present in the dissolved phase rather than the particulate phase.
|Appears in Collections:||[海洋環境資訊系] 博碩士論文|
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