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M&MAutomotrve August 31 2000 • Reconnaissance Groundwater Sampling Groundwater from each borehole was sampled using a GeoProbe designed discrete water- sampling device in the uppermost aquifer Depth to groundwater measurements were made to the nearest one-one hundredth of one foot from existing grade, and also checked for the presence of separate phase product The groundwater sample was carefully collected with a clean disposable bailer and poured into the appropriate laboratory prepared container with minimum cavitations and headspace Each water sample was labeled, logged onto a chain-of-custody form, and placed in a chilled ace chest on crushed ice for transport to the laboratory Subsurface Conditions One exploratory boring was drilled at the location shown on Figures 1, and was advanced to a termination depth of 32 feet The boring initially revealed a pea gravel backfill from the excavation activity This backfill extended to about 10feet Silty clay underlies the backfill to a depth of 14 feet, which was stained gray and displayed petroleum vapor and odor These strata are underlain by a clayey sand to sand to a depth of about 21 feet The staining and vapors decreased with depth, with none observed by 19 feet A sample was lost at 19 to 21 feet, but sand and salty sand strata underlie the clayey sand Thin clay interbeds occurred in the silty sand at depths of 31 to 3 2 feet Groundwater occurred at depths of about 15 feet and rose in the encased boreholes to a depth of 9 35 feet, suggesting the aquifer strata may be unconfined to weakly confined Historic groundwater data shows flow to the north Regional lithologic lateral and vertical variation are present in the shallow aquifer strata, which are typical for raver and floodplain deposits in this portion of the San Joaquin Valley (see Geologic Cross Section, Figure 3) While lateral and vertical variation are present in the aquifer strata, these strata as a whole form the uppermost water bearing aquifer (or hydro-) stratigraphy between about 10 to 30 feet in the area explored Chemical Analysis Five soil samples, and two groundwater samples were analyzed at a Chromalab, Inc State certified analytical Iaboratory from the exploratory borings These samples were tested for the following, Total Petroleum Hydrocarbons as Gasoline (TPHG), Benzene (B), Page 3 St7lmso/cust/m&m