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Quarterly Groundwater Monitoring,Results of Verification ' Sod Borings,and Closure Request Report Moore Petroleum, 1399 E Yosemite,Ave,Manteca,CA July 1, 1996 ' Page 3 started in July of 1995 and was shut down in August of 1995, at which time mfluent vapors dropped below laboratory detection limits for total petroleum hydrocarbons(TPH), ' as gasoline, and benzene,toluene, ethylbenzene and xylenes(BTEX) At this time the carbon system was pulsed on a monthly basis through December of 1995 at which time hydrocarbon vapors were not detected in the influent stream The vapors extraction system was then removed from site 2.0 GROUNDWATER MONITORING ' 2.1 Groundwater Levels On April 23, 1996, Apex personnel collected groundwater-level measurements from all six ' monitoring wells All groundwater elevations were measured to the nearest 0 01 foot, referenced to the surveyed top-of-casing elevations, and conducted according to the Apex Standard Operating Procedures(SOP) included as Appendix A Liquid-level measurements collected since January 1993 are summarized in Table 1 Hastoncal liquid level measurements are contained in AppendixB Figure 3 is a potentiometric surface map of the shallow water-bearing zone on April 23, 1996 ' 2.2 Groundwater Sampling and Analysis ' On April 23, 1996, Apex personnel collected groundwater samples from all six monitoring wells (MW-1B, MW-2 through MW-6) The samples were submitted, under cham-of-custody, to Sparger Technology, Inc , of Sacramento, California (Sparger), a state-certified analytical ' laboratory The wells were sampled for total petroleum hydrocarbons(TPH), as gasoline, benzene, toluene, ethylbenzene and total xylenes(BTEX) All samples were collected according to the Apex SOP mcluded in Appendix A All Analytical results since January 1992 for TPH, as ' gasoline, BTEX and methyl-tert-butyl-ether(MTBE) are summarized in Table 2 Historical analytical results for the subject site are included in Appendix C The April 23, 1996 laboratory analytical reports and cham-of-custody form are included in Appendix D All six groundwater samples collected on April 23, 1996, were below laboratory detection limits for TPH, as gasoline, and BTEX for the fourth consecutive quarter 3.0 VERIFICATION SOIL,BORINGS Apex personnel supervised the drilling of two sort borings in the area of the former underground gasohne storage tanks (VSB-1 and VSB-2) The two soil borings were drilled on April 5, 1996, at the locations indicated on Figure 4 The borings were drilled by Woodward Drillmg Company,