Experimental Study of Two-dimensional Migration and Distribution of Non-Aqueous Phase Liquid in Unsaturated and Saturated Porous Media

概要

論文の詳細を見る
To elucidate the two-dimensional migration and distribution of non-aqueous phase liquids (NAPLs) in soils, downward migration and lateral spreading of pure 1,1,1- trichloroethane (TCA) and toluene through a layer of glass beads was observed. In particular, the behavior of both fluids in the unsaturated zone and in the vicinity of a water table was investigated, by considering mass balances (residual NAPL distributions, dissolution and volatilization). In a 24-hour experiment, about 21 % to 24 % of TCA (50 mL) volatilized,0.4 to 2 % dissolved, and about 75 % remained as pure liquid in the layer of glass beads. In a 24-hour experiment, about 5 % of toluene (50 mL) volatilized,0.02 to 0.2 % dissolved, and about 95 % remained as pure liquid. The amount of pure TCA remaining above a water table (in the unsaturated zone and saturated capillary zone), which apparently acts as a barrier for NAPL infiltration, reached 30 to 48 %. Lateral spreading of pure TCA above the water table was found to be very small and negligible. A further experiment simulating groundwater fluctuations suggested that pure toluene, even if its migration has stopped, would be transported downgradient again when a water table falls.
Japanese Association of Groundwater Hydrologyの論文