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CJeaCogicaf7echnics 2nc. 1.,.I *.Md Page 2 Soil Groundwater Investigation Report Moresco Project No.251.3 w. June 7, 1999 �. 2.0 SUMMARY OF INVESTIGATION In accordance with the approved work pian and for the purpose of further investigation of the �. vertical extent of soil impacted with gasoline range petroleum hydrocarbons, Geological Technics Inc. installed one monitoring well to 110 feet below grade. This well was installed to determine if contamination had migrated into groundwater. '•' 2.1 Soil Boring Installation In an effort to further define the vertical extent of gasoline range petroleum hydrocarbons, �. one (1) soil boring was advanced. The boring was drilled to 110 feet below grade and converted into a monitoring well. The soil boring was drilled using a 10-inch outside diameter (o.d.), continuous flight, hollow stem auger owned and operated by V&W Drilling (C57# 720904). A monitoring well permit was secured from. SJC PHS/EHD and the agency was notified 48 hours prior to commencing work. The subsurface was cleared of underground utilities by L' notifying Underground Service Alert. Soil cuttings and drilling decontamination water were placed in DOT-17 55-gallon drums 6.0 and moved to along side the building until their disposal can be arranged. 2.1.1 Soil Sampling Procedure 4.0 Soil samples were collected for geological and analytical evaluation at five-foot intervals. A professional geologist working under the supervision of a registered geologist maintained a boring log providing sediment description using the USCS and field observations. Soil samples were collected in 6.0-inch brass liners using a 2.0 inch modified California split La spoon sampler. All soil samples were sealed with Teflon sheets, capped with plastic end caps, labeled, and placed in a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol. Because every soil sample collected was not submitted for laboratory analysis, a screening process was used to gather additional information through field observation. The field screening included: a sediment type, especially grain size and clay content • moisture content • visible evidence of contamination (i.e., color change due to reduction of iron or �. discoloration from hydrocarbons and other pollutants) • measurements above background on an organic vapor meter (OVM) The OVM is a portable photo ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 eV (hydrocarbon range). Details on the geology encountered during the completion of the sampling event as well as the field observations are included in Section 3.2, Geology and Field Observations. 2.1.2 Soil Laboratory Analyses �. Based on field screening observations seven soil samples from the borehole were submitted to Kiff Analytical of Davis, CA (State Certified Laboratory 42236) for the following analysis: