零價鐵與硫酸鹽的添加對於水田根圈環境汞 之生物有效性與菌相組成的影響;Influence of zero-valent iron and sulfate amendments on mercury bioavailability and indigenous bacterial community composition in the paddy rhizosphere

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Title:	零價鐵與硫酸鹽的添加對於水田根圈環境汞之生物有效性與菌相組成的影響;Influence of zero-valent iron and sulfate amendments on mercury bioavailability and indigenous bacterial community composition in the paddy rhizosphere
Authors:	陳欣妤;Chen, Hsin-Yu
Contributors:	環境工程研究所
Keywords:	稻作植栽;零價鐵;硫酸鹽;汞甲基化基因( hgcAB);菌相組成
Date:	2019-12-11
Issue Date:	2020-01-07 14:39:58 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究藉由施加零價鐵(亞鐵在現地間接生成)及硫酸鹽的地球化學調控法，進行土壤植栽試驗探究此調控方法是否能夠有效降低稻田土壤中親硫金屬汞的生物可利用性，以及是否對於此系統具有環境友善性。土壤植栽試驗結果顯示，孔隙水中總汞的變化量在各個處理組中皆有下降的趨勢且較相似，而在孔隙水中甲基汞的變化量以添加零價鐵的組別具有明顯的下降趨勢，只添加硫酸鹽組別甲基汞雖然也有下降的趨勢，但與添加零價鐵的組別仍有程度上的差異。在整個植栽試驗期間，添加硫酸鹽的試驗組別並未依照預期的模式將重金屬轉化為金屬硫化物沉澱在土壤中。在稻作收成結果中，添加鐵確實可以降低糙米中甲基汞的濃度與累積，使其符合法規食米標準；但添加硫酸鹽使糙米中甲基汞累積上升，甚至在只添加硫酸鹽的組別其糙米中甲基汞濃度超過法規標準。各個處理組的菌相組成以及物種多樣性與控制組相似，表示本次所使用的地球化學調控手法對於環境具有友善性。藉由汞甲基化基因(即hgcAB)的表現量加以佐證汞的生物有效性是否降低，在只添加零價鐵的組別中hgcA基因的含量與控制組相比有顯著的下降，表示零價鐵的添加可以有效降低生物可利用之無機汞，因此藉以佐證上述地球化學中所觀察到的結果，證明此地球化學調控手法對於降低汞的生物有效性有著顯著的成功。;We applied a geochemical control method of addition to zero-valent iron and sulfate and investigated whether this control method can effectively reduce the bioavailability of mercury in paddy soil by soil planting experiments. And whether it is environmentally friendly for this system. The results of soil planting experiments showed that the changes of total mercury in pore water had a downward trend and were similar in each treatment group, while the changes of methylmercury in pore water with the addition of zero-valent iron had obvious downward trend effects. The methylmercury in the sulfate-only group also has a downward trend, but there is still a degree of difference from the group with zero-valent iron. Throughout the planting experiment, sulfate did not convert heavy metals into sulfides and precipitate in the soil according to the expected pattern; in the rice harvest results, the addition of iron did reduce the concentration of methylmercury in rice. Degree and accumulation to make it meet the regulations of rice standards; however, the addition of sulfate increased the accumulation of methylmercury in brown rice, and even in the group added only sulfate, the concentration of methylmercury in brown rice exceeded the legal standard. The composition of the bacteria and the species diversity are similar to the control group, indicating that the geochemical control method used is friendly to the environment; the microbial with the mercury methylation gene hgcAB is evidenced by the mercury bioavailability, the content of hgcA gene in the group added only zero-valent iron has a significant decrease compared with the control group.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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