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年度	100	專案性質	實驗性質
專案類別	模場試驗	研究主題	調查
申請機構	國立中央大學	申請系所	應用地質研究所
專案主持人	陳家洵	職等/職稱	教授
專案中文名稱	監測井多深度地下水採樣方法發展
中文關鍵字	雙封塞多深度採樣；垂直濃度分佈；場址調查
專案英文名稱	Development of Multilevel Groundwater Sampling Techniques in Monitoring Wells
英文關鍵字	Double-Packer Multilevel Groundwater Sampling；Vertical Concentration Distributions；Site Investigation
執行金額
執行期間	2011/11/26 至 2012/11/25
計畫中文摘要	含水層由不同水力傳導係數的地質材料組成，污染團濃度自然呈現三維空間 變化，其分布可自數個監測井內污染物垂直濃度變化得知。傳統地下水採樣方法 提供垂直平均濃度無法反映深度變化，且低估污染程度易造成實務與法律責任爭 議。本計畫的目的是發展監測井雙封塞多深度地下水採樣技術，包括建立洗井方 法和採樣步驟，評估取樣段長度(lS)對採樣結果影響，與直接貫入多深度地下水採 樣結果進行比較驗證。使用微洗井採樣方法調查雙封塞系統井內移動對井水造成 之影響，同時對微洗井多深度採樣方法進行評估。雙封塞技術屬封井採樣，微洗 井技術屬通井採樣，直接貫入法無須使用監測井直接自含水層採樣，屬井外採樣。 依本計畫研擬的雙封塞採樣步驟在一LNAPL 污染場址四口監測井使用不同測試 段長度(lS =1.0, 0.5, 0.4, 0.2 m)進行36 次不同深度的雙封塞採樣、25次微洗井採樣、 及10 次直接貫入法地下水採樣，共71 次不同深度地下水採樣。發現(1)本計畫建 立的雙封塞洗井及採樣步驟並未造成井內不同深度明顯的水質混合情況，適合用 於監測井多深度採樣。(2)雙封塞測試段長度越短，採樣濃度垂直平均效應越小， 越能反映井內污染物濃度垂直變化，建議使用lS =0.2 m 以獲得高解析度的污染物 濃度分布。(3)雙封塞與直接貫入法所得的污染物濃度垂直分布相當一致，證實雙 封塞方法可用於監測井多深度採樣，反映污染濃度垂直變化。二者所獲得的污染 物濃度不必然相同。在高滲透性地層雙封塞採樣方法所得污染濃度大於直接貫入 結果，在低滲透性地層則小於直接貫入結果。(4)微洗井多深度地下水採樣仍屬通 井採樣，無法避免垂直平均效應，未能有效反映井內污染物濃度垂直變化，不建 議使用。
計畫英文摘要	Due to the fact that aquifers are composed of geological materials of different hydraul ic conduct ivi t ies, the contaminant plums natural ly exhibi ts three-dimensional concentrat ion dist ribut ions , of which the invest igat ion can be made use of vert ical concent rat ion dist ribut ions in a number of moni toring wel ls. The convent ional groundwater sampl ing techniques yield ver t ical ly-averaged concent rat ion that fai ls to provide the necessary vert ical vari at ion as wel l as underest imates the contaminat ion, thereby creat ing pract ical concerns and legal l iabi l i t y. This project aims to develop the double -packer mul t i level groundwater sampl ing technique used in moni tor ing wel ls. The work includes the establ ishment of the purge method and the sampl ing procedure, the evaluat ion of the inf luence of the sampl ing length ( lS) on the sampl ing resul ts, and to verify the sampl ing resul ts by comparison to the resul ts obtained by the direct -push sampl ing method. Influence of the movement of the double-packer system on wel l water is invest igated using the micropurge sampl ing method, of which the appl icabi l i ty to mul t i level sampl ing is evaluated. The double-packer technique deals wi th open-wel l sampl ing, whi le the micropurge t echnique is for closed-wel l sampl ing. The di rect -push technique, however, di rect ly takes groundwater samples from the aqui fer wi thout using moni toring wel ls; an out -wel l method. In a LNAPL si te, 36 t imes double-packer ( ls=1.0, 0.7, 0.4 and 0.2 m), 25 t imes micropurge, and 10 t imes di rect -push methods were implemented to gather water samples in four wel ls . It is discovered that (1) The purging and sampl ing procedures developed for the doublele-packer system does not create signi ficant mixing of wel l water at different dpths, and are sui table for mul t i level sampl ing in moni toring wel ls . (2)The shorter the ls the less the vert ical mixing and the more representat ion of the ver t ical variat ion, and i t is recommended that l S=0.2 m be used for a bet ter resolut ion of the concent rat ion profi le. (3) The vert ical concent rat ion profi les of the double-packer and the di rect -push methods are in simi lari t y, indicat ing the double -packer method to be avai lable for mul t i level sampl ing. The concentrat ion values obtained by the se two methods are unnecessari ly to be the same. Rather, the double -packer method yields higher concentrat ion values under higher permeable condi t ions, whi le lower concent rat ion under lower permeable condi t ions. (5)As an open-wel l sampl ing technique, the micropurge mul t i level sampl ing method cannot avoid the vert ical mixing, and the resul ts obtained do not reflect the vert ical variat ion. It is not recommended to use the micropurge technique to handle the mul t i level sampling.