SITE INFORMATION AND CORRESPONDENCE

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I 14 September 2009 AGE-NC Project No. 08- 1607 Page 2 of 3 water monitoring wells MW -4 through MW - 10 and MW - 121) . However, ground water monitoring well MW -8 has been reported as properly destroyed on 11 April 2003 . Additionally, a reduced ground water sampling and monitoring plan has been in place as directed by SJCEHD since 2003 as follows : • Quarterly sampling of ground water monitoring wells MW- 1 through MW -4, MW - 11 and MW - 12D and soil vapor extraction well SV-4; • Annual sampling of ground water monitoring wells MW -5 through MW -7, MW-9 and MW -10 ; • No sampling requirements for soil vapor extraction wells SV- 1 through SV-3 and SV-5 through SV-9 . AGE concurs with SJCEHD for semi-annual sampling for ground water monitoring wells MW - 1 through MW -3 and annual sampling for ground water monitoring well MW -11 and biennial sampling for groundwater monitoring wells MW-4 through MW -7, MW -9, MW - 10 and MW - 12D . However, the inclusion of nine soil vapor extraction wells for semi-annual sampling is not economically feasible or technically justified. Soil vapor extraction wells SV- 1 through SV-9 are clustered within an approximately 27-foot radius surrounding soil vapor extraction well SV -5 . The SVE wells were installed approximately 15 feet on center from each other. Each of the soil vapor extraction wells are reported to be constructed the same: total depth 52 feet below surface grade (bsg); 40-foot length/0.040 -inch slotted well screen with a pea gravel filter pack and the bottom of the screen located at approximately 49 feet bsg. Each of the soil vapor extraction wells are now partially screened in the saturated zone with recent average depth to water measurements between 34 feet and 38 feet bsg . Additionally, ground water samples collected from each soil vapor extraction well have been reported impacted with dissolved hydrocarbons with the highest concentrations reported from soil vapor extraction well SV-4 . Soil vapor extraction well SV-4 is located within 10 linear feet of impacted ground water monitoring well MW - I . Ground water monitoring well MW - 1 is screened from 25 feet to 45 feet bsg as compared to the screen interval for each of the soil vapor extraction wells at 9 feet to 49 feet bsg. Essentially, the screens of ground water monitoring well MW - 1 and each of the soil vapor extraction wells are each partially penetrating the saturated zone with a bottom screen length difference of only 4 feet. The purpose of the SVE wells was remediation not monitoring nor delineation of the plume and the ground water data collected from the remediation wells represents an average high dissolved concentration, due to the lack of successful remediation. If a soil vapor extraction well should be sampled, then the most distal and isolated well in the cluster, soil vapor extraction well SV - 1 , will provide the most useful information concerning plume delineation . Advanced GeoEnvironmental, Inc.