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' 31 May 2005 . AGE-NC Project No 04-1239 ' Page 4 of 7 ' 23 WELL HEAD SURVEY On 03 May 2005, a California state-licensed surveying engineer from Baumbach & Piazza, Inc ' surveyed the location and elevation of monitoring wells MW-9 through MW-11, the global positioning system(GPS)location was surveyed to the nearest 0 1-foot relative to coordinate datum NAD 83 (1986), and the elevation at the notch In the top of the well casing was surveyed to the ' nearest 0 01-foot relative to City of Stockton benchmark #101 The elevations of wells MW-9 through MW-11 were determined to be 10 12 feet, 10 70 feet,and 10 54 feet below mean sea level (MSL), respectively The results of the monitoring well survey are recorded in Table 1 The ' surveying report Is presented in Appendix E 3.0. FINDINGS Soil stratigraphy and ground water elevation,flow direction,and gradient were determined from field data The contaminant impact to soil and ground water was quantified from laboratory analysis i 3 1 STRATIGRAPHY In general, silty clay, clayey silt, and sandy silt were encountered from surface grade to between 20 feet and 25 feet bsg From approximately 25 feet bsg to the total depth of the borings(40 feet bsg) sand, silty sand, sandy silt,and silt were encountered Saturated soil was not observed in recovered soil samples until a depth of 25 feet bsg Boring logs are provided in Appendix B Geologic cross- sections of the site are illustrated on Figures 3 and 4 32 ANALYTICAL RESULTS OF SOIL SAMPLES A total of fourteen soil samples were analyzed for the constituents listed in Section 2 1 1 + TPH-g was detected in soil samples MW9-25, MW9-30,MW9-35,and MW9-40 at concentrations ranging from 14 milligrams per kilogram (mg/kg) to 2,400 mg/kg Cross-sections illustrating the estimated extent of adsorbed TPH-g are illustrated on Figures 5 and 6 BTEX compounds were detected in samples MW9-25, MW9-30, MW9-35, and MW9-40 at maximum concentrations In sample MW9-35 of 17 mg/kg toluene, 59 mg/kg ethylbenzene, and 352 mg/kg total xylenes • No additional analytes were detected at or above laboratory detection limits in the soil samples Advanced GeoEnvironmenw,Inc