高濃度砷污染土壤之型態劃分及作物之砷累積能力

Species fractionation of soil in high arsenic contaminated soil and accumulation of arsenic in the crops

謝佳霖(Chia-Lin Hsieh)

指導教授 ： 陳庭堅 ； 余伍洲

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2016年)

摘要

砷(arsenic, As)是世界上最受注目的環境有毒物質之一，依其型態特徵以不同的相貌存在，型態的解離不同，但影響重金屬對環境與生物的危害量，因此序列萃取法（sequential extraction procedure）廣泛用以評估重金屬在環境的危害性。本研究採集嘉義民雄與關渡平原農田土壤以及台北瑞芳煉銅廠廢煙道周邊土壤，分析較高濃度砷污染土壤，以及Wenzel序列萃取法分析土壤之砷型態；民雄農田作物分析砷總量，藉由生物累積因子及轉移因子，評估作物砷累積能力。研究結果顯示不同地區及不同濃度之砷土壤都與游離鐵、錳、無定型鐵、錳、陽離子交換容量、黏粒含量、有機質呈現顯著正相關。生物累積因子及轉移係數，得知水稻及青花菜之生物累積因子值均小於1.0，表示對砷的累積能力不佳；各部位轉移係數比值皆小於1.0，表示砷在植體各部位的傳輸能力不佳。從序列萃取結果顯示70%以上之總砷含量固定於無定型鐵鋁氧化物及結晶型鐵鋁氧化物鍵結型態，對於環境衝擊較高的非專一性吸附型態，民雄和關渡地區平均值皆小於1%，瑞芳地區平均值約10%，推測前兩個地區屬於水稻田，因反覆耕作乾溼交替溶解釋放於環境中。使用複迴歸分析(Multiple regression analysis)民雄農田土壤各基本性質與總砷，可發現顯著性差異p值僅有游離鐵Fed、無定型錳Mno小於0.05，亦即具有顯著性。

關鍵字

砷 ； 型態 ； 序列萃取 ； 生物累積因子 ； 轉移係數

並列摘要

Arsenic is one of the most toxic substances in the world. It exists with different species due to different characteristic patterns. The species affects the potential solubility and results in different hazards to the environment. The Wenzel sequential extraction procedure is a widely applied method used to assess the hazard extent of heavy metals in the environment. This study collected soil samples from farmlands in Minsyong Township, Chiayi County and Guandu Plain, Taipei, as well as from surrounding soils from the Taipei Ruifang copper smelter wasted-gas tunnels. The soil samples were analyzed for total arsenic concentrations and arsenic patterns were extracted with the Wenzel sequence extraction method. In addition, the total arsenic in the field crops was analyzed in Minsyong field to calculate the transfer and bioaccumulation factors to assess the capacity of arsenic accumulation in crops. The results showed that different regions and different concentrations of total arsenic significantly and positively correlated with the soil properties including Fed, Mnd, Feo, Mno , cation exchange capacity, clay content, and organic matter. Bioaccumulation factors and transfer coefficients for both broccoli and rice were less than 1.0, which suggested the crops had a poor ability to accumulate arsenic. In addition, the transfer coefficients were less than 1.0, which also suggested arsenic had low transmission capacity in various parts of the crops. The percentages of As extracted with the sequential extraction method showed that more than 70% of As was mainly fixed to both amorphous and crystalline Fe/Mn oxides. The non-specific adsorption species, having higher environmental impact, was less than 1% in the Minsyong and Guandu soils but the Ruifang soils averaged s about 10%. The former two soils were collected from paddy fields because of alternating wet and dry processes resulting in As being dissolved to the environment.
Keywords: Arsenic, species, sequential extraction procedure, bioaccumulation factors, translocation factor.

並列關鍵字

Arsenic ； species ； sequential extraction procedure ； bioaccumulation factors ； translocation factor

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