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• Mr Travis Bryant August 9, 2001 Page 2 Project No 2002-1426-01 In the vicinity of the site are a former ARCO Service Station, a Chevron Service Station, a Texaco Service Station, The Transmission Shop, and a former Colombo Bakery, all of which have or previously had UST's Based on data collected from subsurface investigations performed at the former ARCO Service Station, the Chevron Station, The Transmission Shop, and the Texaco Service Station, residual and dissolved hydrocarbons have been detected beneath these facilities, and a commingled plume exists beneath Charter Way and Lincoln Street It is our understanding that the groundwater flow direction near the intersection has generally been toward the east and northeast The groundwater plume has not been delineated, but reportedly, extends down gradient as far as Van Buren Street A work plan to further evaluate the extent of hydrocarbon impact, dated January 28, 2000, was submitted to San Joaquin County Department Public Health Services, Environmental Health Division (PHS/EHD) The scope of work included vertical assessment using Cone Penetrometer Test (CPT) followed by discreet soil and groundwater sampling to a total depth of approximately 120 feet below ground surface (bgs) GROUNDWATER MONITORING On May 17, 2001, a representative from Stratus measured depth to groundwater and collected groundwater samples from the two onsite groundwater monitoring wells for subjective and laboratory analyses Floating product was not observed in any of the groundwater monitoring wells The locations of the monitoring wells are presented on Figure 2 Groundwater Elevation Second quarter 2001 groundwater levels were measured on May 17, 2001, using an electronic sounding device, and recorded on the field data sheets presented in Appendix A Table 1 presents the historical and second quarter 2001 groundwater elevation data At the time of the second quarter 2001 monitoring event, groundwater was encountered in MW-1 and MW-2 at 19 28 and 19 48 feet bgs, respectively Groundwater flow direction and gradient were not calculated as data from only two monitoring wells is available Sampling, Analysis, and Monitoring Program Results Groundwater samples were collected from wells MW-1 and MW-2 on May 17, 2001 Appendix B presents the sampling procedures used Samples were forwarded to Alpha Analytical Laboratory, a state certified laboratory, for analysis with appropriate chain-of-custody documentation Groundwater samples were analyzed for TPHG using USEPA Method 801 SB/DHS LUFT, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX), and for methyl tertiary butyl ether (MTBE), tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE), and ethyl tertiary butyl ether (ETBE) using USEPA Method 826013 C Troject FileslI B C\Stockton\Qrt]yVBC Stockton-2Q01 doc STRATUS