REMChlor為可同時考慮含氯有機溶劑污染地下水的污染源與污染團整治的篩選級別的解析解模式。美國環保署地表下模式支援中心發展出REMChlor的圖形使用者介面，方便使用者能輕易操作並快速地執行計算。REMChlor模式因為其解的基礎為Domenico的近似解析解，因此只不能應用於大的縱向延散係數值。且因其採用來分離互相耦合偏微分方程式的除耦技巧使得REMChlor只能適用每一個含氯有機溶劑物種有相同的遲滯因子。本專案目標為發展出一個可以同時結合污染源區以及溶解相污染團整治的評估模式，此模式可適用大的縱向延散係數值與每一個含氯有機溶劑物種有不同的遲滯因子的限制。污染源區整治模式考量計算污染源質量之溶解作用以及污染源整治的清除及破壞所造成之一階衰減反應。污染源區整治模式將耦合至溶解相污染團整治模式，溶解相污染團整治模式考慮的傳輸機制包括一維的移流、三維延散、由母物種至其子物種產物的一階序列生衰減反應與線性平衡等溫吸附等機制過程。所發展的解析解模式主要是藉由三個積分轉換法與解二階常微分方程的數學方法依序求解一組由序列衰減反應耦合的傳輸方程式。解析解與其計算FORTRAN程式的正確性將與進階的數值解演算法求解相同的偏微分方程式比較加以確認。本研究所發展的解析解模式將利用來評估REMChlor中用來展現的8個教學範例的適用性。最後，所發展之解析解模式將結合健康風險模式，進一步計算人類因飲用、洗澡或是居家使用暴露在這些受污染地下水中致癌污染物造成的人體致癌風險。所發展的致癌健康風險評估模式將可評估整治活動可相對減低的風險。 ;The REMChlor is a screen-level analytical model that is widely used for simulating the transient effects of coupled source and dissolved plume remediation of groundwater contaminated with chlorinated solvents. The Center for Subsurface Modeling Support (CSMoS) at USEPA has developed a Graphical User Interface (GUI) for REMChlor that fa-cilitates the user to quickly and easily execute the calculation. The analytical solution em-bedded in the REMChlor was derived based on the Domenico’s approximate analytical so-lution and is invalid for large longitudinal dispersion coefficients. Moreover, the decompo-sition method used for separating a set of coupled partial differential equations leads that REMChlor analytical solutions are only valid for each individual species having identical retardation factor. In this the project, we target to propose a novel analytical model that couples source and dissolved plume remediation of groundwater contaminated with chlo-rinated solvents. The newly derived model will be valid for large dispersion coefficient and different retardation factors for each individual species. The source model accounts for de-pletion of mass by processes of dissolution and first-order decay reactions resulting from removal or destruction of source mass by remediation. The source model will be coupled to a plume remediation model that considers 1-D advection, 3-D dispersion, first-order decay reaction of parent compound into daughter product and linear isothermal equilibrium sorp-tion. The analytical solutions will be obtained using three integral transformation tech-niques in combination with the mathematical method for solving second-order ordinary dif-ferential equations in sequence. The correctness of the mathematical model and its auxilia-ry FORTRAN computer program code will be established with a comparison between the derived novel analytical model and a numerical model that solves the same differential equations using an advanced numerical scheme. Then, the performance of REMChlor will be evaluated using our derived analytical for 8 tutorials examples designed to demonstrate the robustness of the REMChlor. Ultimately, the derived novel analytical model coupled with the health risk assessment model for calculation of cancer risk posed carcinogenic species in the plume assuming the contaminated water is used in a house for drinking, bath-ing and other household uses. The developed cancer heath risk assessment model will allow for an assessment of the relative reductions in risks that various remediation activities would have.
