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1 <br /> Site Background Information Five Star Marina <br /> . Page 2 of 3 <br /> t <br /> Hydrocarbon odors were not detected in soil above eleven feet below surface grade (bsg) <br /> ' Approximately five cubic yards of hydrocarbon-impacted soil were removed and stockpiled during <br /> the UST removal Soil samples were collected from two feet below the UST at a depth of twelve feet <br /> I ' bsg The overburden soil was used to backfill the lowest portion of the excavation <br /> Analytical results of soil samples collected from the East UST Area excavation detected total <br /> petroleum hydrocarbons quantified as gasoline(TPH-g) in the sample collected at the western end <br /> of the UST T1-W at 690 mg/kg TPH-g was not detected in the soil sample collected from the <br /> eastern end of the UST <br /> PREVIOUS SITE INVESTIGATION <br /> On 14 November 1996 and 16 January 1997, a total of fifteen soil probe borings (P1 through P15) <br /> were advanced at the site, under the supervision of the EHD Probe borings P 1 to P5 and P 10 to P 14 <br /> were established surrounding the West UST area and along the boundary of the sub/ect property with <br /> the Texaco facility The West UST was removed in 1986 from the City of Stockton right-of-way at <br /> the western edge of the site Locations of the soil probe borings are illustrated on Figure 2 <br /> Total petroleum hydrocarbons as gasoline {TPH-g}, benzene toluene eth lbenzene and xylenes <br /> ' (BTEX) and methyl tertiary butyl ether(MTBE) were detected in soil samples collected from the <br /> probe borings advanced in the area of the West UST excavation at concentrations as high as 3,700 <br /> mg/kg Hydrocarbon-impacted soil associated with the West UST area appears to be of limited <br /> ' lateral extent, limited to a narrow zone from depths of approximately 5 to 15 feet bsg, immediately <br /> surrounding the UST The detection of MTBE in soil samples collected from probe boring P 1 <br /> indicates the release of gasoline to be relatively recent,possibly within the past twenty years <br /> TPH-g was detected in four of ten grab ground water samples collected from the West UST area at <br /> concentrations ranging from 84 to 44,000 micrograms per liter (pg/l) Various BTEX compounds <br /> were detected in six of ten samples analyzed at concentrations ranging from 0 60 to 7,800 µg11 <br /> TPH-g-impacted ground water appears to extend to approximately 50 feet northeast and 50 feet <br /> southwest from the former West UST area, and has an approximate width of 40 feet <br /> 1 <br /> 1 <br /> 1 <br /> 1 <br />