Air sparging was applied to a site contaminated with tetrachloroethylene, toluene and other volatile substances. In this study site, a long term field test was conducted to examine the effects of removal mechanisms as well as the spread of contaminants from the test site. The results obtained in this study were the following; in many monitoring wells, the contaminant concentrations in groundwater smoothly decreased and were below detection limit after about 150 days. The groundwater disturbance arising from air injection induced the mixture and dilution of groundwater within and outside the region of injected air flow and consequently resulted in enlargingthe zone of influence of injected air. The decrease in toluene concentration in groundwater was faster than tetrachloroethylene, because toluene was easily degraded by increasing dissolved oxygen concentration in groundwater due to air injection. Finally, this operation for air injection did not induce the spread of contaminants from the test site.
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