- 期刊
EDTA、DTPA、EDDS及檸檬酸四種螯合劑添加對提升土壤重金屬銅鋅污染植生復育成效研析
Effect of Chelating Agents on Copper and Zinc Uptake by Sunflower, Chinese Cabbage, Cattail, and Reed for Different Organic Contents of Soils
摘要
國內土壤及地下水污染整治法公告施行已近十年，土壤重金屬整治主要以酸洗法及翻轉稀釋法為主，其有效性及對土壤質地之衝擊常為詬病，綠色整治技術植生復育法近來於國內外受到高度重視。本研究係藉盆栽實驗評析4種植物（向日葵、油菜、香蒲、蘆葦），在含不同有機質含量土壤，於添加4種螯合劑EDTA、DTPA、EDDS及檸檬酸，探討其銅鋅去除效益之差異。實驗結果顯示螯合劑萃取土壤重金屬銅鋅結果以DTPA效果最佳，其次為EDTA、EDDS，檸檬酸則最差。土壤由有機質含量區分為高有機質土壤及低有機質土壤，其中低有機質土壤重金屬弱鍵結比例較高有機質土壤多。在添加螯合劑改變土壤與重金屬銅鋅鍵結型態結果以DTPA提升弱鍵結比例最佳，其次依序為EDTA、EDDS及檸檬酸。植體吸收重金屬結果，4種試驗植物中以向日葵吸收重金屬效益最佳，其次為油菜，而香蒲及蘆葦則係最差；高有機質土壤在銅鋅方面，其累積量如下：向日葵為94、613 mg/kg；油菜為120、464 mg/kg；香蒲為76、364 mg/kg；蘆葦為53、364 mg/kg；另外在低有機質土壤在銅鋅方面，其累積量如下：向日葵為205、2,092 mg/kg；油菜為180、1,350 mg/kg；香蒲為128、741 mg/kg；蘆葦為103、722 mg/kg。添加螯合劑可大幅提升植物根部重金屬吸收，其中以添加DTPA效果最佳，其次依序為EDTA、EDDS，添加檸檬酸則僅有些許之提升。另螯合劑添加對於植體重金屬傳輸性提升方面，以添加EDDS對於植物重金屬傳輸效益最為顯著，其原因為EDDS與重金屬之錯合物可穿透植體根部卡氏帶，進而提高植體對於重金屬之傳輸。本研究結果以添加適量螯合劑可有效提升土壤重金屬銅鋅之植生復育成效，地下水污染關切問題可藉由螯合劑種類選擇及添加量有效控制。
並列摘要
Phytoremediation is a green remediation technology for clean-up contaminated soils. The effect of chelant addition including EDTA, DTPA, EDDS, and citric acid on phytoextraction of metals within different organic contents of soil into sunflower (Helianthus annuus), Chinese cabbage (Brassica campestris), cattail (Typha latifolia), and reed (Phragmites communis) was investigated in this pot experiment study. The application of chelants redistributed the soil Zn and Cu to the more bioavailable fractions, which is essential for phytoextraction enhancement. Soil organic matter had a negative effect on mobilized heavy metals. The application of 5 mmol/kg EDTA and DTPA had inhibitory effects on the growth of the plants. The uptake of metal into tested plants and translocation to aerial plant parts via DTPA and EDTA was prominent compared with that in the control. The essential metals Cu and Zn uptake by sunflowers were most significant within four tested macrophytes. Chelating agent could enhance phytoextration to remediate heavy metal contaminated soil with proper application of chelants and selection of macrophytes.