SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Site Background Information: Chapin Brothers Investments, Inc. Page 4 of 19 wells at several intervals during the test. Groundwater samples were collected from the sparging observation wells at the termination of the test to measure changes in hydrocarbon concentrations. SOIL VAPOR EXTRACTION/AIR SPARGING FEASIBILITY Between 22 and 40 inches of water vacuum was maintained at VE-1 throughout the pilot test. The induced vacuum was measured in VE-2, VE-3, VW-1, ASO-1, ASO-2, MW-3 and MW-4. The greatest vacuum measured in the vapor extraction observation wells was 2.4 inches, at well VE-3, located approximately 15 feet northeast of VE-1. However, after three hours of the test, a vacuum of 0.02 inches was measured in MW-3,more than 90 feet east of VE-1. Concentrations of TPH in the extracted vapors ranged from 35,000 µg/1 to 56,000 µg/1. Converting these values to parts per million volume(ppmv),concentrations ranged from 9,800 ppmv (at 6 hours) to 15,680 ppmv(at 12 hours). Generally, a vacuum of 0.10 is required to successfully volatilize subsurface hydrocarbons. The maximum vacuum measured at each well was plotted versus the distance of each well from the extraction well.Drawing a"best fit"line through the three data points will determine the effective radius of influence at this site, the effective radius of influence at the site appears to be approximately 37 feet. It appears that vapor extraction, using an IC engine, would successfully remove a significant volume of petroleum hydrocarbons from impacted soil at the site. Furthermore, it is likely that extraction on VE-2 (slant boring) will have a positive influence on impacted soil in the vicinity of MW-3. Dissolved oxygen and ground water depth data collected during the pilot study indicate that IAS, combined with SVE should provide a viable alternative for remediation of impacted ground water at the site. The ground water depth was increased (depressed) as much as 1.44 feet in ASO-1 (located approximately 3 feet from AS-1);groundwater depth decreased as much as 0.20 feet in ASO-2. No significant change in ground water depth was anticipated in ASO-3 and therefore, ground water depth was measured only once. Dissolved oxygen in ground water was measured in the IAS observation wells at several intervals throughout the IAS test. In ASO-1,dissolved oxygen ranged from 84.1%to 87.4%;in ASO-2,dissolved oxygen ranged from 16.0%to 32.9%;dissolved oxygen was measured at 62.4%in ASO-3.It appears that the effective radius of influence for the air sparging wells on-site may be as great as 20 to 30 feet. The increased dissolved oxygen and the change in groundwater depths indicate that the injected air had an influence on all IAS observations wells at the site.Although the concentration of petroleum hydrocarbons increased in two of the three observation wells,this may be a results of desorption of hydrocarbons from the impacted soil in the smear zone or sample collection techniques. Advanced GeoEneironmental,Inc.