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1 ' 30 December 1999 AGE-NC Project No 95-0104 ' Page 4 of 7 ' 4 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT During the November 1999 monitoring event, depths to ground water in wells MW-i through MW-6 ' and VW-I were measured between 60 80 and 62 00 feet below the tops of well casings,between the July 1999 and November 1999 ground water momtonng events, ground water elevation at the site decreased an average 2 41 feet The ground water elevation data for wells MW-1 through MW-6 and ' VW-1 during the November 1999 ground water monitoring event is depicted in Figure 3 and shown on Table 1 ' Ground water flow direction was generally toward the northeast at a gradient of 0 002 ft/ft, or approximately 11 feet per mile (Figure 3) Ground water was approximately 144 feet above the screen interval at MW-5 and 5 80 feet above the screen interval at MW-6 Therefore these wells are ' "drowned", and may yield samples more representative of deeper ground water conditions rather than that of shallowest ground water, which is commonly the more intensely impacted by petroleum hydrocarbons Monitoring well MW-1 and vapor extraction well VW-1 are screened across the top ' of the saturated zone '• 42 ANALYTICAL RESULTS OF GROUND WATER SAMPLES ' A total of four ground water samples were submitted to a DHS-certified laboratory in November 1999 TPH-g was detected in a water sample collected from well MW-5 at a concentration of 87 micrograms per liter(ug/1) 1 BTEX compounds were detected from ground water samples collected at MW-6 and VW-1 at concentrations ranging as high as 7 Acg/l Benzene was only detected in the ground water sample ' collected from MW-6 at a concentration of 7 4g/1 Fuel oxygenated compounds were not detected in any ground water samples Analytical results of ' the ground water samples are summarized in Table 2 The laboratory reports (McCambell Analytical Inc Lab I D No 24751 through 24754) and chain-of-custody forms are presented in Appendix C ' F V EXTRACTION PILOT 4 3 RESULTS O VAPOR EXT T TEST O O ' Between 27 August 1999 and 14 December 1999,the SVE pilot test was operational for 2,520 hours During the operational period, flow rates ranged from 42 to 45 standard cubic feet per minute (scfin) ' at a differential pressure of 0 60 to 0 70 inches of water, the induced vacuum stabilized at approximately 0 60 inches of water during this portion of the pilot test Hydrocarbon concentrations • were measured at regular intervals at the VES inlet prior to air dilution A general trend of declining ' PID field measurements is noticeable between the August to December PID field measurements ' Advanced GeoEn{lronmenlal.Inc