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• Mr Travis Bryant May 6, 2002 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 USTs 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-northeast and east-southeast The groundwater plume has not been delineated, but reportedly, extends downgradient 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 of Public Health Services, Environmental Health Division (PHS/EHD) The scope of work included vertical assessment using Cone Penetrometer Testing (CPT) followed by discrete soil and groundwater sampling from two soil borings to a total depth of approximately 120 feet bgs Status retained Gregg Drilling and Testing, Inc , and the work was completed on May 30, 2000 Results of the investigation were presented in a findings report dated October 27, 2000 GROUNDWATER MONITORING On February 14, 2002, a Stratus representative 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 First quarter 2002 groundwater levels were measured on February 14, 2002, using an electronic sounding device, and recorded on the field data sheets presented in Appendix A Table 1 presents the historical and first quarter 2002 groundwater elevation data At the time of the first quarter 2002 monitoring event, groundwater was encountered in MW-1 and MW-2 at depths of 20 25 and 20 41 feet bgs, respectively Groundwater elevations increased approximately 125 feet (MW-1) and 128 feet (MW-2) since the previous sampling event (December 6, 2001) Groundwater flow direction and gradient were not calculated, as data from only two monitoring wells is available Sam_phn�, Analysis, and Monitoring Program Results Groundwater samples were collected from wells MW-1 and MW-2 on February 14, 2002 Appendix B presents the sampling procedures used Samples were forwarded for analysis, with appropriate chain-of-custody documentation, to Alpha Analytical Laboratory, a California state certified laboratory Groundwater samples were analyzed for TPHG using USEPA Method 8015B/DHS LUFT, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX), methyl tertiary butyl ether P 11 B C\Stockton\Qrtly120021TBC Stockton-i Q02 doe STRATUS