【Paper】
Analysis of Vaporization and Diffusion of Chlorinated Organic Solvents in Soil
Takeshi Kobayashi*, Yuka Matsushima** and Kohei Urano**
* Faculty of Engineering, Yokohama National University
** Graduate School of Environment and Information Sciences, Yokohama National University
† Correspondence should be addressed to Takeshi Kobayashi:
Faculty of Engineering, Yokohama National University
（79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501 Japan）

Abstract
The vaporization and diffusion of volatile chlorinated organic solvents, such as tetrachloroethylene and trichloroethylene, in contaminated soil were analyzed to predict the expansion of contamination and to clean them up more effectively. The vaporization rate of PCE liquid in soil was very high. The gas concentration reached saturated vapor pressure within 1.1 seconds of contact time. Therefore, it was shown that, if there are liquid chlorinated organic solvents in soil, strainers must be located to the liquid depth with high flow rate to clean them up effectively. The effective diffusion coefficients in soil were about 0.17 times that of the molecular diffusion coefficients, and the tortuosity factors were 1.8-2.5.

Key words: vaporization, diffusion, chlorinated organic solvent, tortuosity factor