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年度	106	專案性質	實驗性質
專案類別	研究專案	研究主題	評估
申請機構	中興大學	申請系所	土壤環境科學系
專案主持人	劉雨庭	職等/職稱	助理研究員/助理教授
專案中文名稱	烏溪流域底泥砷型態分布與環境因子之關係
中文關鍵字	環境因子,砷物種,底泥,同步輻射,X光吸收光譜
專案英文名稱	Correlation Between Distributions of Arsenic Species and Environmental Factors in the Wu River Sediments
英文關鍵字	Environmental Factors , Arsenic Species, Sediments, X-ray Absorption Spectroscopy
執行金額	800,000元
執行期間	2017/1/9 至 2017/11/30
計畫中文摘要	台中之筏子溪、烏溪及台中榮總、澄清醫院、精密科學園區、台中工業區、台中科學園區二期之放流口等 17 處從 2014 年 03 月到 2015 年 08 月的 pH、電導度其數值變化並未隨著時間有趨勢性的改變。氧化還原電位排除2015年06月烏溪樣品中極高的數值，筏子溪在整治的情況是高於烏溪樣品的。筏子溪樣品總有機碳濃度平均高於烏溪樣品，推測烏溪的河面較大，流速較快導致有機物無法沉積。無定型鐵鋁濃度分佈亦與總有機碳分析之結果比較類似。水樣總砷濃度平均約為 1.39 μg L-1，是遠低於監測標準值的，且差異性並不大。而有幾個底泥樣品的總砷濃度高出底泥品質指標下限值，表示水體的流動會稀釋總砷濃度，但底泥在水體流動下會持續的累積總砷濃度，導致砷濃度不斷放大。筏子溪樣品 F6 為筏子溪中底泥總砷濃度最高的，可能從上游累積至下游 F6；烏溪樣品以 W5 的底泥總砷濃為最高，可能因 W5 為S5 的下游累積的，而 S5 的底泥總砷濃度為樣品中平均底泥總砷濃度最高的，導致 W5 的底泥總砷濃度也較高。筏子溪底泥樣品 F1 圖譜 LCF 結果顯示，此區域的底泥砷的來源主要為地質環境的砷，其他為移動性較高吸附型態的砷。烏溪底泥樣品的砷，主要為吸附型態的砷。S5 可能是中科排放出的砷與此處底泥吸附錯合，表示其底泥中的砷可能往下游移動，因此W5 為台S5 的下游，底泥砷濃度相對高，表示 W5 底泥砷能度可能由 S5 累積而來。由 Person 相關性分析結果顯示底泥砷濃度與河水 As 濃度及無定型 Fe 氧化物濃度之間亦具有顯著相關，烏溪下游各採樣點與中科廢水排放口的底泥、河水中砷濃度與無定型 Fe 氧化物濃度較上游筏子溪高，且底泥砷濃度與河水砷、底泥無定型 Fe 氧化物是有相關，並將 W2、W4、W5、W6 與 S5 分為同一群，明顯受水體砷濃度影響。而其餘的環境因子與水體、底泥中的砷濃度間並未呈現顯著相關。孵育實驗結果顯示，孵育系統 pH 5.5 與 7.5 的鐵溶出量與砷的溶出曲線是有顯著相關的，且兩者溶出時間趨勢相似。其中，砷最高溶出量出現時間點隨著添加葡萄糖濃度而變化，添加葡萄糖濃度愈高時，出現砷最高溶出量時間愈久，pH 5.5 孵育系統明顯有此趨勢。孵育系統 pH 7.5 在孵育第 14 天後，又觀察到砷有再次溶出的現象，而且 pH 9.5 系統也有此類似趨勢出現。pH 9.5 下添加三種葡萄糖濃度的孵育系統，因鐵氧化物在高 pH 值系統下以沉澱態為主，使得 pH 9.5 系統的鐵溶出量極低，砷的溶出主要應是底泥表面吸附被釋出，因此pH 9.5 系統沒有像 pH 5.5 與 7.5 系統有明顯的沉澱態鐵與砷溶解的變化情形。本研究成果顯示主要控制底泥砷濃度的環境因子為水體砷濃度與無定型鐵氧化物含量。
計畫英文摘要	The Arsenic (As) release from the semiconductor industry might result in a significant biomagnification effect even a very small amount. The pH and EC in the sampling sites at the Fazih River (F1~F6), the Wu River (W1~W5) as well as the effluent outlet of hospitals, the Taichung Industrial Park, the Taichung Precision Machinery Innovation Technology Park, and the Central Taiwan Science Park (S1~S5) have not shown a clear change during the period of March 2014 to August 2015. Except the extremely high ORP value in samples collected from the Wu River in June 2015, the ORP in the Fazih River is generally higher than that in the Wu River. In terms of the amount of TOC, that in the Fazhi River is averagely higher than the Wu River, possibly due to the greater flow rate in the Wu River that hinders the TOC accumulation in sediments. The distribution of amorphous Fe and Al follows the similar pattern of TOC. The average concentration of As in water samples is 1.39 μg L-1, below the regulated limit. However, As concentrations in few sediment samples are greater than the lower limit of the sediment quality index, suggesting a continuous accumulation of As in sediments. Results of linear combination fitting (LCF) for the As X-ray absorption spectroscopy (XAS) data indicate that As originated from the intrinsic geological environments dominates the As inventory in the upstream of the Fazih River (F1). However, the major species for other sediment samples is As sorbed on minerals, which shows a greater mobility than As precipitates. Sediments at W5 received the effluents from the Central Taiwan Science Park (S5), resulting in a greater amount of As accumulation. Only a portion of As analyses in terms of quantification and qualification have been done currently. Finishing analyses including As XAS for the rest samples will be the key emphasis afterward. In addition, the redundancy analysis will be used to determine the relationship between As accumulation and environmental factors. Person correlation matrix and principal component analysis data showed that As concentrations in sediments had a significant correlation to As concentrations of water and amorphous Fe oxides, and As concentrations in sediments, waters and amorphous Fe oxides from the Wu Rriver and the Central Taiwan Science Park were higher than those from the Fazhi River. In the incubation experiemnets, the trends of the dissolved As concentration were similar with the dissolved Fe concentrations in the systems incubated at pH 5.5 and 7.5. Besides, it was observed that the dissolved As concentrations in pH 7.5 systems were increased again in 14 days incubation, and there were the similar trends in pH 9.5 systems. However, the iron oxide was mainly precipitated under the pH 9.5 system, and thus the dissolved Fe amounts were low. The adsorbed As was released from the sediments in pH 9.5 incubation systems. This study pointed that As concentrations of water and amorphous Fe oxides were the major factors to control the As concentration in sediments.