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Mr Tom Busenbark Project No 880-039 lA January 29, 2003 Page 3 GROUNDWATER MONITORING: FOURTH QUARTER 2002 On November 13, 2002, a Shaw technician was on-site to measure depth to groundwater and collect groundwater samples from wells MW-1R, and VW-2 through VW-4 for laboratory analyses Shaw coordinated point quarterly sampling with the adjacent service station sites Free product was not observed in groundwater monitoring wells (see Table 1 and Appendix A) Shaw used the fourth quarter 2002 data to evaluate changes in concentrations of dissolved petroleum hydrocarbons in the groundwater Shaw sampling and analysis procedures are presented in Appendix B The groundwater samples were analyzed at Sparger Technology (ELAP #1614) in Sacramento, California, for TPH-g using US Environmental Protection Agency (USEPA) Method 8015M, and for BTEX and MTBE using USEPA Method 8020M Copies of the chain-of-custody records and laboratory analytical report are presented in Appendix C The results of laboratory analyses indicate that dissolved hydrocarbons were present in all four wells sampled TPH-g were reported at concentrations ranging from 75 (well VW-4) to 120,000 (well VW-2) micrograms per liter (µg/L) Benzene was reported in wells ' MW-1R, VW-2, VW-3 and VW4 at concentrations of 12, 6,700, 1,400, and 2 9 pg/L, respectively MTBE was only reported in the groundwater sample from well VW-4 at a concentration of 2 0 pg/L by USEPA Method 8020M Results of laboratory analyses are summarized in Table 1 The gradient was approximately 0 006 with groundwater flow to the east (Figure 3) Groundwater analytical data are summarized on Figure 4 REMEDIATION SYSTEM STATUS: FOURTH QUARTER 2002 The remediation system consists of four shallow zone and three deep zone soil vapor extraction (SVE) wells, from which soil vapors are extracted using a Stealth Bobcat Catalytic Oxidizer rated at 100 cubic feet per minute (cfm) Startup of the remediation N 1sacDP\20031Pr}188018800391 A 3aa doc Shaw Environmental,Inc. ' (01050000)