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Monitoring Well Installation Report <br /> Quik Stop Market No 121 <br /> Page 7 <br /> was encountered From approximately 60 to 62 feet, more silty clay was encountered Below 62 <br /> feet and extending to the bottom of the bore hole, a very dense sand to silty sand was <br /> encountered The boring was terminated at 75 feet <br /> Groundwater was encountered at approximately 19 feet in all five monitoring wells The depth <br /> to groundwater was measured on January 10, 2000 at depths ranging from 16 27 feet at MW-4 to <br /> 17 35 feet below the top of the PVC casing at MW-1 However, hydrostatic pressure in <br /> monitoring well MW-6, screened between 65 and 75 feet, pushed the static water level to <br /> approximately 10 35 feet below the ground surface (Table 1) The groundwater flow direction <br /> within the shallow aquifer is calculated to be toward the north to northeast, at a gradient of <br /> approximately 0 003 feet per foot (Figure 3) <br /> Surveying <br /> A licensed land surveyor was retained to survey the monitoring wells accurately and to determine <br /> the elevation of each well casing The survey ensures accuracy so that the plot plans will portray <br /> the data in a manner useful for determining groundwater flow direction The survey included <br /> both horizontal and vertical measurements Elevation readings were measured to the nearest 0 01 <br /> foot and corrected to mean sea level A copy of the survey measurements is attached in Appendix <br /> C <br /> Laboratory Analysis <br /> CCI submitted a total of 17 soil samples and 8 water samples to North State Environmental of <br /> South San Francisco, California, a state-certified laboratory, for analysis All samples were <br /> analyzed for total petroleum hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene <br /> and xylenes (BTEX), using EPA Test Methods 8015 and 8020, and fuel oxygenates using EPA <br /> Test Method 8260 Results of the soil and groundwater sample analysis are summarized in <br /> Tables 2 and 3 The laboratory reports and chain-of-custody forms are attached in Appendix D <br /> Discussion <br /> Soil Conditions <br /> A review of the soil sample analyses collected from monitoring wells MW-4, MW-5, MW-6, <br /> MW-7 and recovery well RW-1 indicated 10 of the 17 soil samples were impacted with <br /> petroleum hydrocarbons Specifically, recovery well RW-1, located on the east side of the <br /> existing fuel tanks, was reported by the laboratory to contain TPHg Six soil samples collected <br />