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supervision of Russell W Juncai , Cdl. ornia Registered <br /> Geologist Number 3861 and Nora H Kataok3, California <br /> Registered Civil. Engineer Number 38322 <br /> 4 3 RESUL"S OF J;NVESTIGATION <br /> 4 I Laboratory Analysis <br /> Speci`ically selected soil samples from all five soil. <br /> ` borings were submitted to FGL Environmental for analysis <br /> ?results are Summar: zed on Taole 1. Laboratory reports and <br /> et chain-o£-custody forms are contained in AppendiA C <br /> 4. 2 Quality Assurance/Quality Control. Evaluation <br /> 114 Standard laboratory QA/QC was followed for analysis of soil <br /> r samples. Laboratory spikes and duplicates provide an <br /> est-mate of sample ana3ysiz -rariance in order to r,stablisn <br /> variance related to field sampling and laboratory handling <br /> The laboratory qualit.! control reports for soils _ndicate <br /> very low analytical variance <br /> � y 4 3 Site Stratigraphy <br /> All five borings encountered stiff to very stiff lean clay <br /> in the upper 10 to 20 feet, coarse grained material (sands <br /> and gravels) from about 15 to 35 feet, and very stiff Lean <br /> clay beginning at 35 to 40 feet below grade. although <br /> coarse grained material was encountered during drilling, the <br /> � Leg-onally ooserved fine grained soil (clay) was encountered <br /> deeper in the section which retarded vertical contaminant <br /> movement. <br /> Hai 4.4 Extent of Soil Contamination <br /> Soil samples were collected at five-foot intervals from each <br /> new soil boring. Selected samples were submitted for <br /> analyses. analytical results for aTEX and TPH confirmed <br /> field observations in that the highest contaminant levels <br /> were in soil borings number 1 and number 2, closest to the <br /> northern edge of the former tank excavation, which was the <br /> locat:.on for the former gasoline tank fill openings . <br /> However, the low to non-detectable constituent <br /> concentrations dad not confirm olfa,;tory indications of p7j <br /> hydrocarbon presence in soil boring number 5 and selected <br /> samples in borings number 1 and number 2. <br /> Discussions Frith the laboratory analyst at FGL Environmental <br /> revealed that hydrocarbons were observed on the <br /> chromatogr"ph, but were below minimum method detection <br /> limits so a value was not assigned. The ratio of <br /> 6 <br />