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Geo(og afTechnics1=. Page 4 Soil Groundwater investigation Report C&B Equipment Project No.: 336..2 December 22, 1997 carefully emptied using a bottom emptying device thus reducing the possibility of sample ?' agitation and volatilization. Once the sample container (40 ml VOA) was filled and capped, the bottle was inverted, tapped, and checked for head space bubbles. The sample container was identified and labeled with a unique designation, inserted into foam holders and placed ._ in an ice chest cooled to 4°C for transport to the laboratory 2.1.2 Laboratory Analyses Based on field screening observations, two soil samples from each shallow borehole and three soil samples from the deep borehole were submitted to Sherwood Laboratories of Hilmar (State Certified Laboratory #1400) for analysis for benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020), gasoline range petroleum hydrocarbons (TPH- ' -� Gasoline 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. Results of the soil analysis are summarized in Table 1 of Appendix A. The one pore water sample collected by the SimulProbe sampling tool at 28-28.5 inch bgs was submitted to Sherwood Laboratories of Hilmar for BTEX and MTBE analysis by EPA method 602 and TPH-Gasoline by EPA method 5030/8015(m). The detection limits for these compounds are listed below. Results of the soil pore water analysis are summarized in Table 1 of Appendix A. DetectionLimits: 131 hX MTBE TPH-Uasotine Soil (µg/Kg) Water µ 2.2 Monitoring Well Installation =� To investigate the lateral definition of gasoline and diesel range petroleum hydrocarbons in L' the groundwater at this site, Geological Technics Inc. installed four shallow groundwater monitoring wells to the northwest, northeast, cast and west of the former UST's and one deeper, discretely screened, monitoring well on the edge of the former UST pit (Figure 2, 1 Groundwater Gradient Map). Shallow Wells The shallow monitoring wells were constructed using 2.0 inch diameter PVC casing with -:. flush threads. The screened intervals extended from approximately two feet above the current water table to thirteen feet below the water table. Groundwater was encountered at =� approximately 7 feet below grade. A #3 sand filter pack surrounded and extended one foot _j 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 surface seal was achieved by pumping a neat cement grout (augmented with C4% bentonite) on top of the transition seal. The wells were secured with locking watertight caps encased in flush mounted traffic rated well boxes. _ Deeper Well I The deeper monitoring well was constructed using 2.0 inch diameter PVC casing with flush i. threads. The screened intervals extended from 26 to 28.5 feet below ground surface, or about 19 to 21.5 feet below the water table. Groundwater was encountered at approximately 7 feet below grade. A 93 sand filter pack surrounded and extended two feet above the 0.020 inch screened interval and was topped by a two foot weighted bentonite pellet transition seal installed on top of the filter pack. A surface seal was achieved by pumping a neat cement j