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24 November 1997 AGE-NC Project No. 97-0351. . Page 2of5 . One 4,000-gallon.gasoline UST(East UST Area),was re owed from the site on 13 November 1997. . The UST was located in Lindsay Street, between the._ orthern. and "southern blocks of buildings. Upon removal.of the UST, holes were noted at thewestern. end and in'the'.bottom of the UST. Hydrocarbon_odors, were not observed in 'soil above'.elevenfeet .below surface grade (bsg).- Approximately five bsg)..Approximately-five cubic yards of hydrocarbon d soil were removed and stockpiled during the UST removal sampling. Soil samples were collected from two feet below.the UST, at depths of twelve feet bsg. The overburden soil was used to back fill the lowest portion of the excavation. 'Analytical results of soil samples collected from UST excavation indicated that an unauthorized' release of-hydrocarbons had occurred at the western edge of the UST. Total petroleum hydrocarbons quantified as gasoline were detected in sample Ti=W at 90 mg/Kg,(milligrams per kilogram or parts per million: ppm). TPH-g was not detected.inthe soil swnple collectedfrom the eastern end of the UST.. 2.3. . PREVIOUS SITE INVESTIGATION - WEST UST AREA On 14 November 1,996 and 16 January, 1097, a total of fifteen soil probe,borings (PI through P15) were advanced at the site,under the supervision of the P S-EHD. Soil probe borings were advanced . in the vicinity of.the West UST area', removed.in 1986 from in the City of Stockton right-of-way; at the western edge of the site and in the vicinity of the T lating shop on the site. Locations of the soil ,probe borings are illustrated on Figure 2.` Hydrocarbon-impacted soil in the vadose zone,associat d with the West UST area within San Jose, Street was.limited to a narrow zone from depths of al proximately 5 to 15 feet bsg, immediately surrounding the:UST. The detection of MTBE in soi samples collected from probe boring P indicate the release,of gasoline to be relatively recent, ossibly within,the past twenty years. Gasoline-impacted ground water is present around the West UST area.The dissolved gasoline plume-. appears to extend to approximately 50 feet.northeast affid.50 feet southwest from the former West UST area,'and has an approximate width of 40 feet.The estimated extent of the gasoline-impacted ground water is depicted in Figure 3. 2.4.' REGIONAL GROUND WATER .The estimated depth,to ground water at this gropertY is approximately 20 feet bsg, based on information from Lines of Equal Depth of Water.Wel , Fall 1995 published by the San Joaquin County Flood Control District and Water Conservation District. However, the PHS-EHD records indicted that the highestground.water was observed t the site in 1986 at 10 feet.bsg:, During Advanced dcoEnvironmental,Inc,