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ff ASSOCIATE S INC constituents at this depth were observed in SB1 and include TPHg (9,500 mg/kg), toluene (65 mg/kg), ethyl benzene (82 mg/kg), and xylenes (470 mg/kg) The petroleum hydrocarbons appear to attenuate rapidly with depth as indicated greatest by soil samples from SB 1 at 45 5 feet bgs and SB2 at 55 5 feet bgs which contained only trace or nondetectable concentrations of petroleum hydrocarbons Total lead was detected at 5 5 mg/kg in the soil sample collected from ' SB 1 at 25 5 feet bgs Neither benzene, fuel oxygenate additives, nor VOCs were detected above laboratory method detection limits in any of the soil samples analyzed ' Petroleum hydrocarbon constituents, including TPHg and BTEX, were detected in initial groundwater grab samples collected from borings SBI and SB2 Only benzene, which was reported at concentrations of 7 6 ug/l and 12 ug/l, exceeded California's Maximum Contaminant Level(MCL) for drinking water In correspondence dated October 9, 1998, San Joaquin County Public Health Services, Environmental Health Division (PHD/EHD) requested additional work be performed at the project site 1 2.0E�'H D ID PROCEDURESIVI ® S AM To further evaluate subsurface conditions beneath the site, a total of three soil borings were advanced at the site and completed as groundwater monitoring wells All field activities were performed in accordance with ATC's Workplan for Additional Subsurface Investigation at Three Palms Grocery located at 6732 East Highway 88, Stockton, California submitted to PHS/EHD on December 8, 1998 2.1 Soil Boring Advancement and Sampling On June 15 and 16, 1999, a total of three soil borings (MW1 through MW3) were advanced at the site in the vicinity of the "closed" or former underground storage tanks (USTs) to evaluate determine the lateral extent of petroleum affected soil and groundwater Drilling was conducted 1 by V & W Drilling, Inc (State C57 license no 720904) utilizing a hollow stem auger drill rig The soil samples from the soil borings, each advanced to approximately 91 feet bgs, were collected at five-foot intervals or significant changes in lithology, using a 2-inch diameter split- spoon sampler containing three brass tubes A field geologist logged drill cuttings and soil samples utilizing the Unified Soil Classification System The drill cuttings were characterized for soil type, moisture content, and visual evidence of petroleum hydrocarbons A flame ionization detection meter (FID) was used as a field screening device for the detection of petroleum hydrocarbon vapors in drill cuttings and cored samples Drill cuttings were temporarily stored on site, encapsulated in plastic sheeting pending disposal Descriptions of soil types encountered and sample collection intervals are included on the w 1148851reports\Supp1 Invest doc 2