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'-�,Y., �Hu,+.a^'%. "� w '.,,�..,�. �` w ,w+. � +s4, ��..�. •��'Q. .'� `0 y,.,!tl?- �J'+'. Sk4r�i,`",..�,. `n .r,s.`..,, :�v �• �;r ,'''�� :rs TAT;}; 1.05LIRE A�1 OitT 620 West Charter Way,Stockton, California Delta Project No.40-S-9.566 Page 7 trenches were submitted for laboratory analysis. The sampling locations are indicated in Figure 2, and laboratory r,.sults are summarized in Table 2. As shown in Table 2, TPH concentrations ranged from nondetectable in product lice sample #1, to 64 ppm in product line sample #3. 4.5 New Tank F-xcnvnllnn and Sam lin The new tank area was excavated during the week of November 13, 1989. Soil samples collected in soil borings SB-5 and SB-7 in February 1989,were used to define the condition of soils on the western side- of ideof the tank excavation (Figure 2). Copies of certified laboratory results for analysis of soil samples collected from borings SB-5 and SB-7 are presented in Appendix B. soil sample analytical results from these borings are compiled in fable 3. Five additional samples were collected from the base of the new tank hole during excavation in November 1989. These samples are identified in Figure 2,and the laboratory results are included in Table 3. Copies of certified laboratory report., are contained in Appendix A. TFH concentrations in soil samples SB-5, SB-7,north end and south end of the new excavation were all below detection limits. The highest TPH -MID collected in the center of the new tank excavation at concentration was detected in soil sample SS a depth of 19 feet below grade. This soil sample was collpcted almost directly ben:ath the western end Soil samples collected in the northeast (sample SS- of the former northernmost pump island(Figure 2). ,M. NE) and southeast(sample.SS-SE) corners of the tank excavation showed TPH concentrations of 2.5 and 320 Fpm, respectively. i4.. ,., Verbal approval was obtained from the San Joaquin County Local Health District to place the new tanks w« in the excavation,despite the presence of petroleum hydrocarbons in soils. Two 12-inch diameter surface casings were placed between two of the tanks as indicated in Figure 2 in order to allow future access to ' oses. These wells will be installed following install extraction wells :o be used for soil venting purp completion of building construction and paving at the site. Taree new 12,00Q gallon, doubles fiberglass tanks were installed on November 21, 1939. The tank excavation was then b�cl�lled with pea double-walled t �. gravel and will be capped by a concrete pad. 4.6 NV&sle 011 Slime,.and Mist Sam lin 1lesults One soil sample each was collected beneath the waste oil tank, the sump,and the two service bay hoists and submitted to Sequoia Analytical for analysis of the parameters listed in Section 3.2. The