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Ms Lori Duncan Project No 880-039 1A 01010000 <br /> May 12, 2004 <br /> Page 3 <br /> The groundwater samples were analyzed by Severn Trent Laboratory (NELAP#01119CA) <br /> in West Sacramento, California, for TPHg using U S Environmental Protection Agency <br /> (EPA) Method 8015M, and for BTEX and MTBE using EPA Method 8021B The <br /> results of laboratory analyses indicate that TPHg were present in wells MW4R-S, <br /> MW-4R-D, VW-1D, VW-2, and VW-4 at concentrations ranging from 320 to 56,000 <br /> micrograms per liter (µg./L) Unidentified TPHg range hydrocarbons were reported in well <br /> MW-1R at concentrations of 350 ttg/L Benzene was reported in wells MW-1R, MW-4R- <br /> S,MW-4R-D, VW-ID, VW-2 and VW-4 at concentrations ranging from 2 6 to 7,200µg/L <br /> MtBE was not detected during this event Copies of the chain-of-custody records and <br /> laboratory analytical report are included in Appendix C <br /> On February9, 2004, the shallow water table beneath the site appeared to form a trough <br /> Pp g <br /> trending northeast across the site (Figure 2) Groundwater flow north of the site was to <br /> the southeast at a gradient of 0 04, and beneath the southeast portion of the site, <br /> groundwater flow was to the northwest at a gradient of 0 1 Groundwater analytical data <br /> are summarized on Table 1 TPHg and benzene concentrations are shown on Figure 3 <br /> REMEDIATION SYSTEM STATUS: FIRST QUARTER 2004 <br /> k <br /> The remediation system consists of four shallow zone and three deep zone soil vapor <br /> extraction (SVE) wells, from which soil vapors are extracted using a Stealth Bobcat <br /> Catalytic Oxidizer rated at 100 cubic feet per minute (cfm) Startup of the remediation <br /> system occurred on February 3, 2000, under the supervision of regulatory personnel <br /> Subsequently, Shaw staff perform weekly system O&M, collect influent and effluent air <br /> samples monthly in accordance with air board permit requirements, and report quarterly <br /> to the air board <br /> Sampling Results <br /> On January 05, February 08, and March 10, 2004, vapor samples were collected from <br /> treatment system's influent and effluent Samples were submitted to Severn Trent <br /> Laboratories for analysis of TPHg and BTEX using Method EPA-19 TO-3 A summary <br /> of TPHg and benzene results are summarized in Tables 2 and 3 Laboratory analytical <br /> reports and chain-of-custody documentation are included in Appendix D <br /> ' N\sacDP120041Prj%880%880039IA 4ab doc SHAW ENVIRONMENTAL,INC <br />