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年度	107	專案性質	實驗性質
專案類別	研究專案	研究主題	整治
申請機構	中央大學環工所	申請系所	中央大學環工所
專案主持人	林居慶	職等/職稱	副教授
專案中文名稱	利用具環境友善之地球化學調控及吸附材添加現地降低受污染稻田土中親硫金屬(汞和鎘)之植作生物有效性
中文關鍵字	親硫金屬,稻田,地化調控,吸附材添加,植作生物有效性
專案英文名稱	Mitigating phytoavailability of chalcophile metals (Hg & Cd) in contaminated paddy soils through in situ ecofriendly geochemical- and sorbent-amendments
英文關鍵字	chalcophile metals, rice paddies, geochemical control, sorbent amendments, phytoavailability
執行金額	820,000元
執行期間	2018/1/10 至 2018/11/30
計畫中文摘要	本計畫藉由零價鐵與硫酸鹽添加的地化調控，以及利用農業廢棄物經由不同合成方法所製成的碳系吸附材料的添加調控，希望能有效限制親硫重金屬鎘與汞在稻作覆水生長時的生物有效性，以期最終能降低鎘與汞在米粒的累積。從地化調控的稻作植栽試驗結果裡雖可觀察到孔隙水的重金屬濃度不論是鎘、汞、鋅、銅等在稻田覆水時期皆有顯著降低的趨勢，即使整個過程硫酸鹽並未受到微生物的利用而生成硫化物，代表零價鐵本身對於這類重金屬的土壤穩定作用具有一定的效果；不過當檢驗所收成的糙米內的鎘與汞含量時，卻仍然發現具有金屬累積的現象，代表孔隙水中鎘濃度的大幅度降低仍無法顯著降低稻作對於鎘的攝取量。而在碳材方面，含有較多官能基的水熱合成碳及生物碳在對於高濃度鎘的吸附能力雖表現出較活性碳優的情形，但在低鎘濃度時活性碳於去離子水環境的鎘吸附能力卻普遍較其餘兩者佳；不過，當環境改為低鎘濃度的孔隙水時反而讓水熱合成碳的鎘吸附能力有所提升，推測或許跟溶解性有機碳與重金屬配位錯合後所造成的吸附行為轉變有關。另外，當碳材在去離水中對於鎘的等溫吸附試驗所得的分配系數套用在平衡模式時，雖預測出孔隙水中的鎘濃度顯著降低，但此預測值在活性碳組別中卻無法於縮模試驗中驗證。
計畫英文摘要	In this study, we attempted to minimize phytoavailability of mercury (Hg) and cadmium (Cd) to rice plants during the growth phase when rhizosphere is under anaerobic conditions via (i) addition of zero-valent iron particles and sulfate into rice paddies – the geochemical amendment approach, as well as (ii) addition of carbon-based adsorbents synthesized using agricultural wastes – the sorbent amendment approach. After geochemical amendments on the pot soils, while Cd and Hg concentrations in pore water were significantly decreased during the soil submergence phase, such decreases in the phytoavailability of metals to rice roots did not significantly lead to the mitigation on the accumulation of both Cd and Hg in the harvested brown rice, suggesting that the decreasing fold might not be enough to decrease Cd-uptake by rice. As for the interaction of Cd vs. carbonaceous sorbents in DI-water, it was observed that surface functional groups played a key role in Cd adsorption when Cd concentrations were at the ppm level, resulting in hydrochar exhibiting higher sorption capacity than biochar and activated carbon. However, at the ppb level, the trend was reversed, except when the adsorptive experiments were carried out in the porewater environment. Using the equilibrium distribution model, it was predicted that application of these agricultural waste-derived sorbents in situ to the contaminated soil may result in significant decreases in Cd concentrations in porewater. Yet, this prediction was not able to be completely validated by the results from activated carbon-treated soil incubation experiments.