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I i30 May 2001 AGE-NC Project No 95-0143 Page 5of8 3 1 GROUND WATER ELEVATION AND GRADIENT The elevation of ground water in each of the twelve wells was calculated by subtracting the depth to water from the surveyed casing elevation (Table 1) Ground water elevations increased in the monitored wells an average 0 54 feet between the November 2000 and February 2001 monitoring events Ground water was within the screened Intervals of MW-17 and inferred to be within the screened Interval of each vapor well Ground water ianged from 0 04 feet to 7 50 feet above the screened interval in the other eight monitoring wells The inferred flow direction was toward the I northeast at the subject property Ground water elevation contours for the February2001 monitoring event are illustrated in Figure 3 A portion of the screened interval of vertical vapor extraction well VW-3 appears to have collapsed During the February monitoring event, clean sand was encountered at approximately 15 below the top of the well casing The sand is similar to filter pack material and differed in color from the native sand found at the site 3 2 ANALYTICAL RESULTS OF WATER SAMPLES During the February 2001 monitoring event, TPH-g was detected in samples collected from I monitoring wells MW-3,MW-6,MW-7 and MW-9 at concentrations ranging from 100 µg/l(MW-6) to 160,000 µg/l(MW-3) BTEX compounds were detected in wells MW-3, MW-6, MW-7, MW-9 MW-16 and MW-17 at concentrations as high as 34,000 µg/l (xylenes in the sample from MW-3) I MTBE was not detected in samples collected from the site during the February 2001 sampling event Figure 4 illustrates the approximate extent of TPH-g and benzene contamination in ground water I Measurable free product was not encountered in any of the wells on the site Analytical results of ground water samples collected during the February 2001 monitoring event are summarized on Table 2 Analytical results of historical ground water samples are summarized on Table 3 The laboratory report (MAI Laboratory IDs 61124 through 61132) and chain-of-custody forms are included in Appendix B Dissolved oxygen levels recorded during the January and February 2001 monitoring events fluctuated, no distinguishible pattern could be discerned from the data collected Dissolved oxygen data are summarized on Table 4 I 3 3 ANALYTICAL RESULTS OF SOIL VAPOR SAMPLES Concentrations of TPH-g, MTBE and BTEX compounds were not detected above laboratory reporting limits in the one soil vapor sample extracted from the inlet port of the SVE system Advanced GeoEnvironmeatal,Inc