ARCHIVED REPORTS_XR0005664 - Laserfiche WebLink

Home Browse Search

1 • initial soil sample locations are presented on Figure 2 Analytical results of soil samples ' collected during removal of the USTs are summarized in Table 1 ' As an interim abatement measure, the excavation was lined with 6-mil plastic sheeting and the soil was returned to the excavation hole On September 23, 1998, Jim Thorpe Oil, Inc ' excavated approximately 166 cubic yards of impacted soil The soil was transported directly to Forward Inc landfill for disposal A strong petroleum odor and some visible discoloration were ' noted in the upper portion of the removed soil As soil removal continued, the bottom of the excavation began to clean up, and the west and south walls appeared to have only occasional ' areas of minor contamination However, the north and east walls still showed evidence of discoloration William J Hunter, RG, of Wm J Hunter & Associates, supervised the removal of ' the contaminated soil On September 23-24, 1998, approximately 369 cubic yards of clean fill dirt and 54 cubic yards of gravel base was brought in to fill the pit created by removing the USTs ' and over-excavating The soil was compacted as required by San Joaquin County ' Previous subsurface assessments were performed by Ground Zero in November 1998 and October 1999 The first investigative phase consisted of drilling two pilot borings (CPT1 and CPT2) using a cone penetrometer testing (CPT) ng and three soil borings (SB 1, SB2, SB3) to characterize subsurface stratigraphy and sample soil and groundwater The second investigative phase consisted of drilling six soil borings (SB4, SB5, MW 1, MM2, MW3, MW4) and installing four groundwater monitoring wells (NMI-MW4) to further Investigate the vertical and lateral ' extent of soil and groundwater contamination Figure 3 presents locations of borings and groundwater monitoring wells The investigations indicated that relatively low levels of residual gasoline constituents remain in the ' unsaturated soil beneath the former USTs from approximately 30 feet bgs to groundwater at approximately 60 feet bgs Soil samples collected from the capillary fringe zone in each boring/well contained low levels of residual gasoline constituents including methyl tert butyl ether (MTBE) Low level soil contamination in the saturated zone appeared to be limited to the depth interval between 60 feet bgs and approximately 75 feet bgs in the perimeter borings However, low level contamination including benzene and MTBE were detected in soil at 95 feet bgs in the pilot 5 data/pr oundz eftuieburg/reports/mud_has_wel[report,doc I