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T a . 27 September 1999 AGE-NC Project No 95-0167 Page 7 of 9 concentrations of 3 9 mg/kg, 33 mg/kg, 17 mg/kg and 110 mg/kg, respectively BTEX compounds were also detected in two other soil samples collected from boring MWA Toluene,ethyl benzene and total xylene were detected in sample MW1-30 at concentrations of 0 012 mg/kg, 0 005 mg/kg and 0 028 mg/kg, respectively BTEX compounds were detected in sample MW1-35 at concentrations of 0 008 mg/kg, 0 024 mg/kg, 0 007 mg/kg and 0 037 mg/kg, respectively Soil samples collected from the other soil boring did not contain detectable concentrations of petroleum hydrocarbons The oxygenated compound MTBE was not detected to the soil samples analyzed Analytical results of soil samples are summarized in Tables 1 The laboratory report(MAI Laboratory ID 13585 through 13596), quality assurance and quality control (QA/QC) reports and chain-of-custody form are in Appendix B 5 3 GROUND WATER ELEVATION, FLOW DIRECTION AND GRADIENT A California state-licensed survey engineer from Baumbach&Piazza Inc surveyed a reference point on the top of each ground water monitoring well at the site to the nearest 0 01-foot relative to the City of Stockton Bench Mark Datum # HS0396 The results of the monitoring well survey are contained in Table 2 The surveying report (Baumbach & Piazza) is presented in Appendix C The relative ground water elevation in each well was calculated by subtracting the depth to ground water from the surveyed relative casing elevations The depths to ground water and relative ground water elevations are tabulated in Table 2 The depth to ground water ranged from 13 44 feet below the well casing (bwc) in MW-4 to 13 70 feet bwc in MW-2 The relative ground water elevation at the site ranged from-4 40 feet below mean sea level (msi) In MW-3 to -4 61 feet ms] in MW-2 The ground water gradient was approximately 0 0025 or 13 feet per mile, over the distance from the up gradient well (MW-3) to the east edge of the site (MW-2) The relative ground water elevation Isocontours are depicted In Figure 3 54 ANALYTICAL RESULTS OF GROUND WATER SAMPLES TPH-g was detected in samples collected from monitoring wells MW-I and MW-2 at concentrations of 56,000 micrograms per liter (fig/1) and 2,900 ,ug/1, respectively Benzene was detected In samples collected from wells MWA, MW-2 and MW-3 at concentrations of 6,800 jig/l, 240,.g/l and 0 72 pg/I, respectively Other BTEX compounds were detected in water Advanced Geo£mironmental,Inc