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E S T E R \ G E O L O G I C RES O C R C E S , I X C J. Munoz/3 Apr 1989 7 �2 was encountered in the excavation at a depth of about 9.25 ft,; Sj.nong1 hydrocarbon odors and traces of floating hydrocarbons were noted in the open excavation. Gravel removed from the pit were slightly stained, but ' _4 hydrocarbon staining was not observed on the excavation walls. `-`Since" groundwater was encountered in the tank pit, only a water sample was collected for analysis. Water sample TP-W-1 , which was analyzed by B&C, contained xylenes at 1 . 1 ppb (Table 2) . 15 October 1987 - Julian Munoz. Safeway a Between 12 and 14 August 1987, WA installed monitoring wells MW-1 through MW-3. From ground surface to between 24 to 26 ft below grade, low- estimated permeability silty clay and clayey silt were observed. These were underlain to 33 ft below grade by moderate- to high-estimated permeability silty sand and clean sand. Groundwater was encountered at about 18 ft below grade. TFH and BTX were not detected in soil samples collected during drilling of the borings or in groundwater samples collected after completion of the wells. Analytic results for the soil and water samples are included in Tables 1 and 2, respectively, and well locations are presented in Figure 3. Geologic cross-sections A-A' and B- B' , which include analytic results and PID readings measured during drilling, are presented in Figures 4 and 5, respectively. 10 February 1988 - Julian Munoz Safeway On 23 and 24 January 1988, pea gravel , which contained fuel hydrocarbons and had been stored in the excavation after the removal of the storage tanks, was removed for aeration on site. Approximately 750 cubic yards of pea gravel were stockpiled at the northwest corner of the Safeway facility. Pea gravel was not removed from beneath or around a 10- inch diameter water main and 14-inch diameter storm drain, which trend across the northern side of the excavation. A continuous cement slab, used to tie down the storage tanks was encountered at about 13.5 ft below grade (Figure 3). Two samples of the pea gravel TP-B-2 and TP-B-3, which were composited for analysis, were collected to determine the concentration of TFH present in the north side of the excavation. Native soil samples TP- N-1, TP-N-4, TP-N-5, TP-N-6, and TP-N-7 were collected along the southern half of the excavation (Figure 3) . The composited pea gravel samples, which were analyzed by B&C, contained 450 ppm TFH. TFH were not detected in samples TP-N-1A and TP-N-4A. The highest concentration of TFH was detected at 3,700 ppm in sample TP-N-7 collected from the southwestern corner of the excavation. Analytic results for native samples and pea gravel are presented in Tables 1 and 3, respectively. 07611 ma9 "a