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1 <br /> PKXLEM ASSESSMENT R83MT <br /> 14800 West Frontage Road Manteca Calftornia <br /> I3.0 RESULTS <br /> 3.1 Soil Boring and Sampling <br /> On November 15, 1991, one additional soil boringwas drilled to approximately 43 feet <br /> pp Y <br /> below surface The soil boring was completed as 4-inch-diameter groundwater <br /> monitoring well MW-9 The boring was drilled using 10-inch-diameter hollow-stem augers <br /> During drilling, the subsurface soils and alluvial materials of the unsaturated zone were <br /> sampled at 5-foot intervals A log of the soil boring was generated based on field <br /> descriptions, and is included as Appendix B Soil samples were screened in the field <br /> using a PID Results of the PID screening are indicated on the boring log <br /> 3 2 . Analytical Results Soil <br /> A total of two soil samples were collected from the boring for MW-9 One soil sample was <br /> collected from the cuttings stockpile The samples were submitted under chain-of- <br /> custody to NET Pacific, Inc , of Santa Rosa, California, a state-certified laboratory The <br /> samples were analyzed for concentrations of <br /> • TPH, as gasoline, by GC/FID Method 5030, <br /> • BTEX, by EPA Method 8020, and, <br /> Itotal lead by EPA Method 7421 <br /> I The analysis indicated concentrations of both TPH, as gasoline, and BTEX were below <br /> the respective detection limas Concentrations of total lead were indicated at 3 7 ppm in <br /> the boring sample collected at 29 feet below surface and 5 4 ppm in the sample collected <br /> I from the cuttings stockpile The sal sample analytical results are summarized in Table 2 <br /> The laboratory analytical reports and chain-of-custody forms are included in Appendix C <br /> 3 3 Groundwater Monitoring Well Installation Development, and Surveying <br /> I Groundwater monitoring well MW-9 was installed at the location shown on Figure 2 Well <br /> construction details are included in Appendix B Based on water levels observed during <br /> drilling, the perforated casing was set from 23 to 43 feet below grade The well was <br /> I capped with a locking wellhead cap and secured by a water-tight, traffic-rated wellhead <br /> vault The top-of-casing elevations above mean sea level of MW-1 through MW-8 were <br /> surveyed, by Tom Morrow Surveying, a licensed surveyor Monitoring well MW-9 was <br /> later surveyed with reference to the other wells by a professional geologist <br /> I90-097A PAR 6 <br />