Author(s): R. R. Giri; K. Sato
Linked Author(s):
Keywords: TCE; Seasonal change; Vadose zone; Bare soil; Soil-atmosphere interaction
Abstract: Dense Non-aqueous Phase Liquid (DNAPL) subsurface contamination has been an important environmental problem in industrialized countries. Understanding of DNAPL subsurface behaviors is essential in site remediation. The objective of this paper is to get insight of seasonal dependency on the fate of volatile organic compounds, e.g. trichloroethylene (TCE), in vadose zone. One-dimensional vertical numerical simulation on simultaneous heat, moisture and TCE transport (gas and aqueous phase) was carried out for winter, spring and summer seasons with solar radiation, atmospheric temperature and pressure as input field data from Saitama, Japan. A uniformly contaminated thin soil layer was placed below the ground surface as an initial condition. The results disclosed that seasonal change significantly affects heat and moisture budgets, and contaminant redistribution as well as vertical transport in vadose zone. Vaporization from water phase, and gaseous-aqueous partitioning are found as two important factors governing contaminant redistribution and vertical movement. Increased subsurface temperature in spring and summer resulted in aqueous concentration depletion, increase of gas concentration and TCE vertical movement.
Year: 2003