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i 03 September 2004 AGE-NC Project No 98-0448 Page 5of13 ' TPH-g was detected at 25 feet bsg from VW-6 at a concentration of 260 milligrams per kilogram (mg/kg),TPH-g was detected at 25 feet and 3 5 feet bsg from AW-5 at concentrations of 1,700 mg/kg and 130 mg/kg, respectively r y r Various BTEX compounds were detected from the above three soil samples at concentrations as high as 2 5 mg/kg benzene, 40 mg/kg toluene, 20 mg/kg ethylbenzene and 170 mg/kg xylenes ' No other fuel components were detected by laboratory analysis The analytical results of selected soil samples are summarized in Table 1 The laboratory reports (MAI Work Order 0405226) and chain ' of custody forms are included in Appendix C, GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix D ' 2 6 SURVEYING OF GROUND WATER MONITORING WELLS ' On 26 August 2004, a state of California state-licensed survey engineer from Baumbach&Piazza, Inc (BPI) surveyed/resurveyed reference points on the top of the well casings from wells MW-1 through MW-8 to the nearest 0 01-foot relative to known City of Stockton benchmark datum no 101 Additionally,BPI utilized global positioning system (GPS)techniques to identify latitude and longitude for tracking wells MW-1 through MW-8,VW-1 through VW-6 and AW-1 through AW-5 ' on the State Water Resources Control Board (SWRCB) GeoTracker database system The results of the monitoring well survey are contained in Table 2, GeoTracker confirmation pages of the submitted GPS well casing survey EDF files are included in Appendix D,the surveying report(BPI ' Job No 97970-56) is presented in Appendix E ' 3.4. SOIL VAPOR EXTRACTION/IN-SITU AIR SPARGE REMEDIATION Between 28 January and 22 June 2004, an SVE remediation system was continuously operated at ' the site, utilizing a regenerative vacuum blower to selectively apply an induced vacuum to wells VW-1 through VW-5 and MW-4A During this time, IAS remediation was continually operated at the site on wells AW-1 through AW-4 (screened 25 to 30 feet bsg) and MW-413 (scr`eened 45 to 5u ' feet bsg) utilizing an air compressor to inject air beneath the water table Newly installed wells VW-6 and AW-5 were incorporated into the SVE/IAS remediation system on 03 June 2004 Operation and design of the SVE and IAS systems for the site were described in Remedial Action Work Plan (dated 07 July 2000), and in Remedial Action Work Plan Addendum (dated 19 March 2004) During a routine SVE operation and maintenance site inspection on 10 March 2004,AGE discovered that repairs were necessary at the valve and manifold piping at SVE well MW-4A Therefore, _ l Advanced GeoEnviron mental,Inc 1