110

2,450 千元

提升土壤及地下水污染調查及整治技術工作

2021/02/23

2021/12/31

王尚禮

環檢所

溫淑媛

國立臺灣大學

土壤及地下水

重金屬、土壤鉻污染、X光吸收光譜法、序列萃取法、金屬物種分布、空間分布

Heavy metals, Soil chromium contamination, X-ray absorption spectroscopy, Sequential extraction, Chemical speciation, Spatial distribution

莊宗儒

02-33664808#

r10623019@ntu.edu.tw

本計畫以同步輻射X光吸收光譜配合序列萃取法，發展土壤鉻物種型態分析方法，進一步分析污染農地土壤鉻物種空間分布和轉變傳輸機制，以及探討耕犁工法是否可能導致重金屬物種型態轉變或擴散。自桃園和彰化各一塊選取重金屬污染場址，採集耕犁工法整治前後不同距離和深度之土壤樣品進行分析。結果顯示土壤中鉻的主要物種為三價鉻的氫氧化物和氧化物。X光吸收光譜之物種分布和序列萃取法的金屬型態空間分布，呈現類似的趨勢。殘餘態的相對量和氧化鉻相對量的趨勢相同，皆隨距離和深度而增加，而其他物種型態之趨勢則相反，顯示越接近入水口，人為污染的貢獻越高。經過整治的土壤，土壤的鉻濃度，以及不同距離和深度之鉻物種型態分布趨於相近，鉻溶解度下降，顯示耕犁工法的成效，惟仍需要考慮地下水還原環境對鉻物種轉變的可能影響。在方法學上以X光吸收光譜分析少數關鍵樣品的物種組成資訊，配合序列萃取法分析大量樣品來獲得定量分析之資訊，應為探討污染場址土壤中鉻物種型態轉變之最有效方式。

重金屬、土壤鉻污染、X光吸收光譜法、序列萃取法、金屬物種分布、空間分布

109-03-25.pdf

9MB

期末報告定稿

2022/1/1 上午 12:00:00

This project aimed to develop X-ray absorption spectroscopic (XAS) method coupled with sequential extraction method to determine the chemical speciation of chromium (Cr) in contaminated farmland soils before and after the soils were remediated using the tillage method. The information was further used for evaluating the potential risk of Cr in the soils after the remediation. Soil samples were collected from different locations in two contaminated farmlands in Taoyuan and Changhua, respectively, before and after remediation. The XAS results of the soils showed that the predominant Cr species in the soils are Cr hydroxides and oxides. The chemical speciation and fractionation, obtained using XAS and sequential extraction methods, showed similar trends in terms of their spatial distributions in the contaminated sites. The relative contents of Cr oxides or residual phase increased with increasing the distance from the irrigation water inlets of the farmlands or increasing soil depth, while the other species and phases exhibited an opposite trend. The highest contents of the hydroxide species or reducible/oxidizable phases in the soils near the irrigation water inlets revealed the input of Cr from anthropogenic sources. After remediation, the total content and the chemical speciation/fractionation in the soils at different locations became similar, and the solubility of Cr in the soils decreased. These results indicated the positive effects of the tillage remediation method on decreasing the potential risk of soil Cr contamination. However, further investigation is required to consider the potential release of Cr from the reducible Cr phase in groundwater after tillage remediation. The complementary information from combining the XAS and sequential extraction method allows the effective identification of the predominant Cr-associated phases in soils and understanding their chemical transformation under certain conditions in the environment.

Heavy metals, Soil chromium contamination, X-ray absorption spectroscopy, Sequential extraction, Chemical speciation, Spatial distribution