底泥添加黃酸對灌溉水體及底泥重金屬有效性影響之研究

Effective of Fulvic Acid Added to Sediment on the Availability of Heavy Metals in Irrigation Water and Sediment

林澤佑(Ze-you Lin)

指導教授 ： 王敏昭

朝陽科技大學/理工學院/環境工程與管理系/碩士(2013年)

摘要

一般河川灌溉渠道底泥重金屬全量皆以全量值作為管制標準，河川灌溉渠道底泥中重金屬污染，若處理不當，將使污染更嚴重。本研究比較以王水消化法與XRF(X - ray fluorescence)所測得重金屬全量。底泥中重金屬具有不同型態，主要可區分為可交換態、碳酸鹽態、鐵錳氧化態、有機態及殘留態，各型態重金屬對環境衝擊亦有所差異，以序列萃取分析方法進行底泥重金屬之型態測定。以過去發生過鎘米事件之彰化縣東西二圳為背景，採集受重金屬污染之底泥，進行pH值之調配，分別為4.00、6.00及8.00，再添加黃酸(fulvic acid, FA)，於常溫下觀察反應系統中重金屬與黃酸之鍵結反應。
東西二圳中游底泥重金屬為Cr及Pb超過底泥品質下限值，且Cu、Ni及Zn超過底泥品值上限值，在下游則是Pb超過底泥品質下限值，其餘Cd、Cr、Cu、Ni、Pb、Zn均超過底泥品值上限值；重金屬型態分佈：以對環境影響最大之可交換態及碳酸鹽態而言，Cd之兩型態佔總量84 %，其次為Zn(41 %)、Ni(26 %)；就對環境影響最小之殘留態及有機態而言，Pb之此兩型態佔71 %，Cr為65 %。在試驗中發現將pH調高時對重金屬濃度之移動並無影響，調低時明顯有重金屬從底泥釋出至水體的情況，pH改變對不同型態Pb及Cr無明顯之影響。其餘重金屬在酸性環境中，易使水體重金屬濃度提高至超過灌溉水質之限值。
底泥吸附重金屬與有機物含量關係密切，有機物中以黃酸之溶解性最佳，本實驗顯示以添加2%黃酸於底泥中有助於重金屬之穩定，但高量之黃酸並不會使底泥吸附重金屬量增加。

關鍵字

XRF ； 序列萃取 ； 黃酸 ； 重金屬 ； 底泥

並列摘要

Sediment of heavy metal in irrigation canals controls in total amount according to the statute. The method uses for the purpose nowadays. It remains pollution cause the hazard of environment. If the treatment of the pollution is improper. And it may produce the severe pollution. In this study, we use aqua regia digestion and XRF(X – ray fluorescence) to detect the heavy metal in contrast. The heavy metal transfers different fractionations in sediment, exchangeable, carbonate-bound, Fe/Mn-oxide bound, organically bound and residual. It causes variously impact to environment. We use sequential extraction (Tessier et al., 1979) to analyze fractionation. The sediment used in this study was provided from a contaminated site of heavy metal at Dung-xi 2nd of Changhua. This site had been contaminated by Cadmium. The sediment balance pH at 4.00, 6.00 and 8.00 .Then add fulvic acid (FA) to observe reaction systems of heavy metal and fulvic acid of bound reaction.

There was found the experiment in this study, in the middle of river, Cu, Ni and Zn risk contaminating environment. Cr and Pb are in potential. But in the downriver, Cd, Cr, Cu, Ni, Pb and Zn risk contaminating environment. Pb is in potential. To heavy metal fractionations, exchangeable and carbonate-bound are the more influence of environment. And Cadmium is the most of the hazard. The two fractionations contain 84% in total. The next are Zn (41 %) and Ni (26 %).Organically bound and residual fractionations are the lowest influence of environment. Pb contains in 71 % and Cr contains 65 %.In pH 8, it''s no influence of heavy metal transfer. But in pH 4, heavy metal transfer from sediment to the water except Cr and Pb. Then cause the heavy metal concentration reach the hazard of the statute.
Adsorption of heavy metals and organic content of the sediment close, organic matter to fulvic acid solubility in the best, the experiments show that fulvic acid to add 2% of heavy metals in the sediment helps stabilize, But the high concentrations of fulvic acid does not cause increased sediment adsorption of heavy metals.

並列關鍵字

sequential extraction ； XRF ； Heavy Metals ； Fulvic acid ； Sediment

參考文獻

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