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northeast, southwest, and southeast corners of the excavation, respectively, at depths ranging <br /> . from 5 to 6 feet below grade These samples were analyzed for TPHd <br /> 2 Samples 5A and 5D were reported to contain 210 and 16 mg/kg of TPHd, respectively <br /> TPHd was reportedly not detected in samples 5B and 5C Based on the reported <br /> concentration of TPHd in sample 5A, an additional 1 foot of soil was removed in this <br /> area and sample 5A-1 was collected at a depth of approximately 6 feet TPHd was <br /> reportedly not detected in sample 5A-1 <br /> 3.5 FORMER FUELING FACILITY <br /> 1 Discolored surficial soil was observed around the track pans associated with the former <br /> fueling facility This area was excavated to a total depth of approximately 2 5 to 4 feet below <br /> grade, until discolored soil was no longer observed Samples 4A, 4B, 4C, 4D, 4E, 4F, and <br /> 4G were collected from the excavation and were analyzed for TPHd The sample locations <br /> are shown in Figure 4 <br /> . 2 The samples were reported to contain concentrations of TPHd ranging from 2 2 to 22 mg/kg, <br /> with the exception of sample 4G, which was reported to contain 1,400 mg/kg Based on the <br /> reported concentration of TPHd in sample 4G, an additional 3 feet of soil was removed from <br /> this area and sample 4G-1 was collected TPHd was reportedly not detected in sample 4G-1 <br /> 3.6 EXCAVATION BACKFILLING <br /> 1 For safety reasons, and per San Joaquin County directions, the tank cavities were partially <br /> backfilled between November 14 and November 16, 1990 The former gasoline tank and <br /> wastewater tank excavations were backfilled with gravel, and the former diesel tank <br /> excavation was backfilled with sand Final backfilling and compaction using engineered <br /> fill occurred between November 27 and November 30, 1990, following final confirmation <br /> sampling <br /> 2 The former fueling facility, inspection pit, and former remote fill line areas were backfilled <br /> using engineered fill and compacted to 95 percent relative compaction (compaction was <br /> confirmed in the field using a nuclear density gauge) <br /> 8 <br /> ENVIRONMENTAL SOLUTIONS <br />