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BTEX The laboratory did not filter any of the ground water samples <br /> prior to analysis <br /> Because the data from the Phase I investigation indicated that lead and <br /> EDB were not of concern, the Phase II samples were analyzed for TPH <br /> as gasoline and diesel and BTEX only Trip blanks were collected and <br /> analyzed for TPH as gasoline and BTEX <br />' Inv <br /> The findings of the Phase I and Phase II Investigations at Site #2 have <br /> provided information regarding the site geology and hydrogeology and <br /> have characterized the lateral and vertical extent of the petroleum <br /> product release at the site A discussion of the investigation findings is <br /> provided below <br /> Geology: The information obtained during the installation of <br /> monitoring wells and soil borings indicates that the site is underlain by <br /> clays, silts and sands Figures 3-5 and 3-6 represent cross-sections of <br /> Former Tank Site #2, the locations of the cross-sections are provided in <br /> Figure 3-4 Fill was encountered in varying thicknesses in all of the <br /> borings It occurred in the first 2-to-3 feet of MW-1A, MW-3A, MW- <br /> 5A, B1-A, B2-A, and B4-A, and in the first 7 feet of MW-2A and <br /> MW-4A In general, semiconsolidated silty and clayey soils extend <br /> from beneath the fill to a depth of approximately 10-to-20 feet Below <br /> the silts and clays, unconsolidated fine-to-coarse-grained sands are <br /> present These sands contain localized layers of silt and gravel <br /> Hydrogeology. During drilling, ground water was initially encountered <br /> at approximate depths ranging between 9 5 and 19 feet below the <br /> ground surface After the wells stabilized, ground water was <br /> encountered at an approximate depth of 5 feet bgs Therefore, ground <br /> water at Site #2 appears to be confined The potentiometric surface <br /> defined during the investigations and subsequent quarterly monitoring <br /> events suggests that the ground water gradient is towards the south- <br /> southwest This is consistent with data obtained from Site #1 The <br /> flow gradient may vary because of tidal water-level fluctuations in the <br /> nearby Stockton Deep Water Channel <br /> Perched ground water is locally situated beneath the former tank <br /> location in the vicinity of MW-2A It appears that the ground water at <br /> MW-2A is perched and is not in communication with the ground <br /> water that was encountered in the other monitoring wells This <br /> inference is based upon observations during drilling and supported by <br /> the fact that the ground water elevation is higher at this point than in <br /> the surrounding wells <br /> 3-5 <br />