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Beacon Station No. 513 January 19, 1998 Lodi,California Tank Removal/Clo urge Report BTEX (between 0.0086 ppm and 0.56 ppm), and MTBE (between 7.7 ppm and 17 ppm) only in the sample collected from between and beneath dispensers 4 and 5. • Stockpiled Soil Analytical results of soil samples collected from the stockpiled soils generated from the excavation of the former tank cavity indicated TPHg, MTBE and xylenes. Analytical results of soil samples collected from the stockpiled soils generated from the product pipeline trenches and the dispenser islands indicated detectable concentrations of MTBE and xylenes. Analytical results of soil samples collected from the stockpiled soils generated from the overexcavation for the new, larger USTs, the air and water line trenches, and the remodeling activities indicated no detectable hydrocarbons. • Groundwater Sampling Analytical results of groundwater samples collected on November 21, 1997 indicated no detectable hydrocarbons as TPHg, MTBE, and BTEX. CONCLUSIONS & RECOMMENDATIONS In June 1993, Remediation Testing Design conducted a soil vapor survey and reported on July 1, 1993 that no petroleum hydrocarbon vapors were detected in the shallow soil beneath the site. In August 1993, Delta Environmental Consultants, Inc. (Delta) conducted a subsurface investigation which included soil borings and groundwater monitoring well installations. Delta reported that no hydrocarbons were detected any of the borings, except the angled boring SB-3 under the west dispenser island at 26 feet below surface grade (bsg). >i Sample SB-3-7 indicated TPHg (17 parts per billion (ppb)), ethylbenzene (0.32 ppb) and xylenes (2.0 ppb). (Delta, November 5, 1993, Hydrogeologic Investigation, Beacon Station No. 513, 401 West Kettleman Lane, Lodi, California. (Delta Project No. 40-93-942). The November 1997 groundwater sampling by Doulos indicated no detectable hydrocarbons. Based on data generated from previous investigations and from the current UST removal and groundwater sampling activities, it is Horizon's opinion that no further work is warranted at this site and that the site be granted closure and the three monitoring wells be decommissioned. LIMITATIONS The methods and procedures utilized for this work are the generally-accepted standards of the practice of geology and environmental science in California at the time of the investigation. This site investigation was conducted solely for the purpose of evaluating soil conditions adjacent to former UST locations with respect to gasoline-related hydrocarbons. No soil engineering or geotechnical references are implied nor should any such references be inferred. The evaluation of geological conditions at the site, for purposes of this investigation, was made utilizing a limited number of observation points. Subsurface conditions may vary some distance away from the available observation points. This report 1513-11.tcr 4 HORIZON ENVIRONMENTAL. INC.