ARCHIVED REPORTS_XR0002443 - Laserfiche WebLink

Home Browse Search

1 J I 02 June 1997 AGE-NC Project No 95-0105 ' Page 3 of 11 r water was encountered in the excavation at a depth of approximately 8 feet below surface grade(bsg) ' but eventually stabilized at 6 5 feet bsg Samples were not collected from the excavation in April 1995 The excavation limits are depicted on Figure 3 - Excavation And Trenching Plan ' On 25 May 1995,trenching was performed to determine the extent of impacted soil Trench T 1 was installed next to Parker Avenue west of the building, trench 72 was installed at the northwest corner ' of the site, trench T3 was installed near Grant Line Road at the northeast corner of the former tank excavation B, trench T4 was installed at the northwest comer of the building One soil sample was collected from each of trenches Tl,T2 and T4 Two samples were collected from trench T3 Three ' samples were also collected from the April 1995 soil stockpile Trenching and sampling locations are shown on Figure 3 ' Excavation was resumed on 26 June 1995 The April 1995 excavation was extended northward toward Grant Line Road, westward toward Parker Avenue and southward along Parker Avenue Approximately 125 cubic yards of soil were removed during the June 1995 excavation Seven soil ' samples were collected from the side walls of the excavation at depths between 5 5 to b feet Excavated soil, including soil excavated in-April 1995, was transported and disposed at Forward Landfill in Manteca, California The limits of the excavation and sample locations are shown on Figure 4 -Final Excavation Plan 2 6 ANALYTICAL RESULTS OF TRENCHING, EXCAVATION AND' STOCK PILE SAMPLES TPH-g was detected in trenching samples T1-1, T2-1, T3-2 and T4-1 at concentrations of 150 ppm, 780 ppm,2 7 ppm and 2,700 ppm, respectively Sample T2-1 was found to contain benzene at 1 1 ' ppm, while benzene was not detected in samples T1-1 or T4-1 Other BTE&X compounds were detected at low concentrations in samples T1-1, T2-1 and T4-1 BTE&X compounds were not detected in sample T3-2 The highest concentration of TPH-g in an excavation sample was detected in excavation sample NW-2, at 1,600 ppm Benzene was also detected at 1 2 ppm Excavation samples NW-3, WW-1, ' WW-2 and SW-2 were found to contain TPH-g at concentrations of 14 ppm, 53 ppm, 330 ppm and , 23 ppm, respectively Petroleum hydrocarbons were not detected in samples NW-I or SW-I The ' remaining excavation samples contain low to moderate concentrations of various aromatic hydrocarbons The analytical results of soil samples are summarized in Table 1