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' 24 July 2002 • AGE-NC Prod ect No 01-0827 ' Page 4 of 6 ' The analytical results of SVE air flow samples are summarized in Table 2 The laboratory reports (MAI Lab Numbers 9062011, 0203257-0011002, 0204286-001/002, 0205180-001/002, 0206183- 001/002) Quality Assurance and Quality Control (QA/QC) reports and chain-of-custody forms are ' included in Appendix B ' 33 MASS OF RECOVERED HYDROCARBONS The hydrocarbon mass (TPH-g) removed during the operating period was calculated using the ' following equation M =C•Q•t where M= cumulative mass recovered (kg) ' C = sail-vapor concentration (kg/m') Q = extraction flow rate (m'/hr) t = operational period, in hours ' The estimated mass of hydrocarbons y s rem v o ed was based on laboratory analysis of soil-vapor '• samples,the flow rate and operational time The mass of extracted hydrocarbons was calculated for the time penod using average hydrocarbon concentrations of influent soil-vapor sample data, averaged air flow rates and duration of operation The operational results are summarized on Table 1 ' Approximately 25 kg or 8 5 gallons of hydrocarbons were extracted and destroyed by the SVE network between 18 February and 11 June 2002 The volume and mass calculations are attached in Appendix C 3 4 GROUND WATER GRADIENT AND FLOW DIRECTION The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed well casing elevations (Table 3) Depths to ground water ranged from 20 65 to 22 28 feet below the well casing tops The ground ' water elevations at the site ranged from 10 75 feet (MW-5) to 11 03 feet (MW-2) below mean sea level(MSL) The ground water flow was towards the east at the north edge of the site and northeast at the southern portion on the site(Figure 3) The hydraulic gradient in the former UST area was calculated 0 001 feet/feet or 5 3 feet/mile, directed toward the northeast • IAdvanced GeoEnvironmental,Inc