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Mr James Barton ProjectNo 880-039 IA01050000 <br /> October 22, 2003 <br /> Page 3 <br /> service station sites Free product was not observed in groundwater monitoring wells (see <br /> Table 1 and Appendix A) Shaw used the third quarter 2003 data to evaluate changes in <br /> concentrations of dissolved petroleum hydrocarbons in the groundwater Shaw sampling <br /> and analysis procedures are presented in Appendix B <br /> Ther <br /> g oundwater samples were analyzed by Severn Trent Laboratory(NELAP 401119CA) <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 MW-4R-S, <br /> MW-4R-D and VW-21), at concentrations ranging from 4,500 to 63,000 micrograms per <br /> liter(µg/L) Benzene was reported in wells MW-3R, MW-4R-S, MW-4R-D and VW-2D at <br /> concentrations ranging from 5 6 to 6,800 µg/L MTBE was not detected in any of the six <br /> wells sampled Copies of the chain-of-custody records and laboratory analytical report are <br /> *, presented in Appendix C <br /> The analyses for BTEX and MTBE for samples collected from wells MW-4RS, VW-2D, <br /> and VW-4 were performed outside of hold time because they required secondary <br /> analysis due to over range analyte concentrations Shaw reviewed the results and <br /> determined that due to results consistent with previous events, the data is useful for <br /> assessing current conditions beneath the site <br /> The groundwater gradient was approximately 0 008, with groundwater flow to the <br /> north-east (Figure 2) Groundwater analytical data are summarized on Table 1 TPHg <br /> and benzene concentrations are shown on Figure 3 <br /> REMEDIATION SYSTEM STATUS- THIRD QUARTER 2003 <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 /> 4 <br /> N\SacDP120031Prj188018800391A Sag doe Shaw Environmental,Inc <br />