111

2,460 千元

提升土壤及地下水污染調查及整治技術工作

2022/01/13

2022/12/31

王尚禮

環檢所

溫淑媛

國立台灣大學

土壤及地下水

重金屬、土壤銅污染、X光吸收光譜法、序列萃取法、生物有效性、金屬物種分布

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

莊宗儒

02-33664808#

f10623019@ntu.edu.tw

本計畫以同步輻射X光吸收光譜配合序列萃取法，發展重金屬污染土壤之銅物種型態分析方法，以探討污染農地土壤銅物種空間分布和轉變傳輸機制，以及耕犁工法是否可能導致銅物種型態轉變或擴散所產生的風險。自桃園和彰化各一塊選取重金屬污染場址，於耕犁工法整治前後採集不同距離和深度之土壤樣品進行分析。結果顯示土壤中銅的主要物種為腐植酸鍵結、硫酸鹽和硫化物，或類似鍵結構造之物種。序列萃取法的金屬型態和X光吸收光譜之物種分布，具有類似的趨勢，反應土壤母質貢獻之殘餘態的濃度基本上不隨空間變化，在不同樣品的量大致接近。高移動性和生物有效性之物種型態於入水口最高，隨離入水口之距離和深度而減少，顯示越接近入水口，人為污染的貢獻越高。經過整治的土壤，土壤的銅濃度，以及不同距離和深度之銅物種型態分布趨於相近，表土銅溶解度下降，顯示耕犁工法的成效。高移動性物種之人為移動，仍需要考慮深部土壤環境對銅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銅物種型態轉變之最有效方式。

重金屬、土壤銅污染、X光吸收光譜法、序列萃取法、生物有效性、金屬物種分布

110_03_18.pdf

12MB

2023/1/31 上午 12:00:00

This project aimed to develop the X-ray absorption spectroscopic (XAS) method to determine the chemical speciation of copper (Cu) in contaminated farmland soils before and after the soils were remediated using the tillage method. The information was further used to evaluate the potential Cr risk in the soils after the remediation. Soil samples were collected from different locations in two contaminated farmlands in Taoyuan and Changhua before and after remediation. The XAS results of the soils showed that the predominant Cu species in the soils are humic-acid associated Cu, and Cu sulfate and sulfite. 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 contents of the residual phase were relatively constant over the contaminated sites, while those of the other species and phases with higher mobility and availability increased with decreasing the distance from the irrigation water inlets of the farmlands or soil depth. The highest contents of mobile species in the soils near the irrigation water inlets revealed the input of Cu from anthropogenic sources through irrigation water. After remediation, the total content and the chemical speciation/fractionation in the soils at different locations became similar, and the solubility of Cu in the surface soils decreased. These results indicated the positive effects of the tillage remediation method on reducing the bioavailability and associated risk of soil Cu contamination. However, further investigation is required to consider the potential release of Cu from mobile species at deeper soils after tillage remediation. The complementary information from combining the XAS and sequential extraction method allows the effective identification of the predominant Cu-associated phases in soils and the understanding of their chemical transformation under certain conditions in the environment.

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