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' GeoCogua1TecFuucs Inc Page 3 Soil& Groundwater Investigation Report ' J M Equipment Project No 507 2 June 9, 1999 2.1.1 Soil Sampling Procedure 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 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 Since only selected soil sample collected were submitted for laboratory analysis, a screening ' process was to gather additional information through field observation noting the following • 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 ■ readings above background on a 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 2.12 Soil Laboratory Analyses Based on field screening observations, one to two soil samples from each shallow borehole and five soils samples from the deep borehole were submitted to Sherwood Laboratories of Hilmar(State Certified Laboratory #1400) for analysis of O benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020), G methyl tertiary butyl ether (MTBE by EPA method 8020 with confirmation by EPA method 8260) O gasoline range petroleum hydrocarbons (TPH-G by EPA method 8015(m)) The detection limits for these compounds are listed below A Chain of Custody was completed for all samples collected and tracked to ensure sample integrity Detection Limits S_01 µg g , 2.2 Monitoring Well Installation ITo investigate the lateral definition of gasoline range petroleum hydrocarbons in the groundwater at this site, Geological Technics Inc installed three water table groundwater monitoring wells to the northeast, south and southeast of the former UST's (Figure 2, Site Map) The monitoring wells were constructed using 2 0-inch diameter PVC casing with flush I threads The screened intervals extended from the water table to twenty feet below the water table Groundwater was encountered at approximately 15 feet bgs A #3 sand filter pack surrounded and extended two feet above the 0 020 inch screened interval and was topped by a two foot bentonite chip transition seal installed on top of the filter pack and hydrated A