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Ms Vicky McCartney <br /> Page 6 of 6 <br /> approximately 15 feet bgs, but the contamination does not extend vertically to 20 feet bgs, <br /> which was free of contaminants <br /> • Soil samples collected from boring SB2, which was drilled downgradient of the former USTs, <br /> contained no detectable petroleum hydrocarbons <br /> • Groundwater samples collected from boring SB 1/SB l a contained moderate levels of gasoline <br /> constituents Contaminant concentrations were greatest at the top of the water table (within <br /> the former tank pit) and lower at the base of the upper water-bearing unit (approximately 21- <br /> 24 feet bgs) <br /> • Groundwater samples collected from monitoring well MW3, which was also drilled through <br /> the tank pit, contained only very low levels of TPHg and ethylbenzene and are considered <br /> more representative of actual conditions beneath the former USTs <br /> • The groundwater sample collected from boring SB2 downgradient of the former USTsj wk3 <br /> contained no detectable hydrocarbons <br /> 5.2 Conclusions <br /> • The remaining volume of contaminated soil is estimated at a maximum of approximately 145 <br /> cubic yards, all within the saturated zone, containing an estimated 155 pounds of gasoline <br /> • Residual soil contamination beneath the site does not extend deeper than approximately 15 <br /> feet bgs <br /> • Less than 0 1 pound of gasoline constituents remain in the groundwater beneath the site <br /> • Dissolved groundwater contamination does not extend significantly downgradient, as <br /> evidenced by the non-detectable results in the water sample collected from boring S132 <br /> 6.0 RECOMMENDATIONS <br /> I <br /> Based upon the evidence obtained from investigations conducted at the subject site, Ground Zero <br /> believes that the site should be closed with no further action required <br /> Please contact Ground Zero at (209) 838-9888 if you have any questions or comments regarding <br /> this submittal <br /> Respectfully, \c3'tE�SD GOl0 <br /> Ground Zero Analysis, Inc G� <br /> jONN P <br /> LANE <br /> No 6795 <br /> (P Q <br /> John P Lane, <br /> CA Registered Geologist No 6795 F OF CA,\'� <br /> Attachments <br /> i <br /> G\GROUNDZE\Souza\ReportslADD_SUBSURF_SUM doe <br />