ARCHIVED REPORTS XR0000155 - Laserfiche WebLink

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vAmes ►.,� o r... SACRAMENTO A filter pack consisting of #3 sized washed silica sand was installed from the bottom of the slotted casing to approximately ' one foot above the top of the slotted casing in each well. Approximately 18 inches of bentonite chips were then placed on ' the filter pack and hydrated. After the bentonite layer was observed to hold water, the remaining annular space, from the top of the bentonite layer to just below ground level, was sealed ' using a cement/bentonite grout. Locking, watertight plugs were placed in the top of each PVC well casing. A traffic cover was then set in concrete around each well . The traffic boxes were mounted slightly above grade to prevent water from entering the ' boxes. All of the casing plugs were locked with keyed-alike locks. ' 3 . 3 Laboratory Analytical Results West analyzed a total of sixteen soil samples from the four boreholes. The sixteen samples consisted of three samples from BH6, four samples from BH7 , three samples from BH8 and six ' samples from BH9 . Each sample was analyzed for TPH-D and BTEX. West reported that four samples contained TPH-D ' concentrations above the method's detection limit of 2 milligrams per kilogram (mg/kg) . The 25-foot sample from BH6 contained the ' highest concentration of TPH-D, at 4 ,900 mg/kg. The 10-foot and 15-foot samples from BH7 contained 180 mg/kg and 89 mg/kg of TPH-D, respectively. The samples above and below the 10-foot and ' 15-foot samples did not contain any TPH--D concentrations above the method' s detection limits. The 10-foot sample from BH8 ' contained 11 mg/kg of diesel . West reported that none of the samples analyzed for BTEX contained BTEX concentrations above the method' s detection limits. A summary of the analytical results are presented in Table 1. The analytical laboratory report and Versar' s chain of custody document are included as Appendix C. 9