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Site History Jackpot Food Mart, 1434 W Yosemite Ave,Manteca, CA Time Oil Property No D4167 Remediation Activities In order to determine if bioattenuation is occurring in hydrocarbon-impacted soils beneath the subject site, a Geoprobe sampling system was used to collect soil samples on July 5, 1996 Continuous-core samples were collected from three locations to a depth of 15 feet below ground surface Samples from the probe locations were submitted to a laboratory and analyzed for TPH-g, BTEX, hydrocarbon-utilizing bacteria, heterotrophic bacteria, and several other chemical and physical parameters to assist in evaluating if bioattenuation is occurring SECOR will prepare a report which documents field activities and contains analytical reports If appropriate, site closure will be requested Time Oil's Second Quarter 1996 status report and SECOR's "Bi-annual Monitoring Report, January- June 1996" dated July 22, 1996 were forwarded to the PHS/EHD and CRWQCB on July 31, 1996 Quarterly Status Report - Third Quarter 1996 and Submittal of Confirmation Sampling Report and Request for Site Closure Groundwater Sampling -Second Half 9996 The Second Half 1996 groundwater sampling event will be scheduled for November or December 1996 Remediation Activities- Third Quarter 1996 Because groundwater at the subject site had not been Impacted, and soil Impacts appeared to be residual, Time contacted the PHS/EHD in early 1996 to discuss the need for active site remediation and continuation of the quarterly groundwater monitoring program The PHS/EHD agreed that semi-annual groundwater monitoring would be sufficient, and that a remediation system for soils might not need to be Installed if it could be shown that bioattenuation was occurring in the site's soils Accordingly, a workplan was forwarded to the PHS/EHD on April 22, 1996, which presented a scope of work to evaluate bioattenuation Verbal approval of the workplan was received from the PHS/EHD prior to the initiation of site activities In order to determine if bioattenuation was occurring in hydrocarbon-impacted soils beneath the subject site, a Geoprobe sampling system was used to collect soil samples on July 5, 1996 Continuous-core samples were collected from three locations to depths of up to 16 feet below ground surface (bgs) Each sampling location corresponded to the approximate location of hydrocarbon-impacted soils encountered during previous activities Corresponding Point No Former Samples Location/Former Findings GP-1 W-3, P2 North pump island Up to 13,000 ppb at 4 5 feet bgs and 0 71 ppm at 14 5 feet bgs GP-2 W-2 East of existing pump islands Up to 100 ppm gasoline at 5 feet bgs GP-3 W-1. T3 East portion of former lank bed Gasoline up to 460 ppm at 14 5 feet bgs As in previous site investigations, soils were found to consist of fine to medium sands to a depth of approximately 15 feet This strata was underlain by clay Because previous investigations indicated that the clay unit may be acting as an aquitard, all Geoprobe points were discontinued at a depth of 15 feet to 16 feet below ground surface to prevent possible impacts to groundwater Samples collected from each probe location at depths of 4 5 - 5 feet bgs, 9 5 - 10 feet bgs, and 14 5 - 15 feet bgs were analyzed for TPH-g and benzene, toluene, ethylbenzene, and xylenes (BTEX) Additionally, samples collected from the bottom of each Geoprobe location were analyzed for total organic carbon (TOC) Samples collected from GP-3 were also analyzed for gasoline-utilizing bacteria, BTEX-utilizing bacteria, and total heterotrophic bacteria (THB) to confirm that intrinsic bioremediation is 8