ARCHIVED REPORTS_QUARTERLY MONITORING AND REMEDIATION REPORT - FIRST QUARTER 2007

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24 April 2007 AGE-NC Project No. 04-1207 Page 5 of 9 to 2000-hr. Since its start-up on 05 February 2007,the SVE system has been monitored approximately weekly. At each monitoring event,the flow rate of extracted soil-vapor(influent)was measured using a flow meter. The organic vapor concentration in the extracted soil-vapor stream was measured before entering the blower(influent stream)and after exiting the final carbon vessel(effluent stream)using an OVM equipped with a PID. Monitoring data is included in Table 2. Soil-vapor samples were collected at start-up on 05 February 2007 and weekly, thereafter. The samples were collected into Tedlar vapor bags from a sample port on the influent line and from the effluent stream.The samples were labeled,placed in a cooler,and transported under chain of custody to CTEL for analysis for: • TPH-g in accordance with EPA Method 8015M and • BTEX and MTBE in accordance with EPA Method 8260B. 3.0. FINDINGS The mass of TPH-g extracted by the SVE system was calculated from the recorded flow rates and laboratory analytical data of soil-vapor samples. Depth to ground water data is based on field measurements taken on 18 January 2007.The hydrocarbon impact to groundwater was characterized from laboratory analytical data of ground water samples. 3.1. GROUNDWATER GRADIENT AND FLOW DIRECTION At the time of the January 2007 ground water monitoring event,depths to ground water ranged from 47.67 feet(MW-4) to 48.70 feet (MW-2)below the well heads. Ground water elevation at the site ranged from 3.25 feet (MW-1) to 3.01 feet (MW-2) above mean sea level (MSL) and averaged approximately 3.14 feet above MSL, indicating an increase in elevation of 0.56 feet since the last monitoring event in October 2006. During the January 2007 ground water monitoring event,ground water at the site was inferred to be flowing from a southeast-trending ground water ridge under a relatively uniform hydraulic gradient of approximately 0.004 foot/foot(ft/ft). Figure 4 illustrates the contoured ground water elevations as measured on 18 January 2007. Advanced GeoEnvironmental,Inc.