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�l dispenser islands TPH-G concentrations were detected to soil samples ranging from ND to 19,000 ppm Benzene concentrations were detected in soils ranging from ND to 280 ppm Monitoring wells MW-1 through MW-3 were installed to evaluate ground water quality Sods from these well borings contained TPH-G ranging from ND to 28 ppm and benzene ranging from ND to 0 38 ppm Vapor extraction well VEW-2 soils contained TPH-G ranging from 2,800 to 12,000 ppm and benzene ranging from 18 to 110 ppm Soil analytical results are presented in Table 1 - Analytical Results Soil (Fugro West, Inc, December 1995) In late 1991 and early 1992, a 75-day vapor extraction feasibility test was performed at the subject site using wells VEW-1, VEW-2, and MW-3 Wells VEW-1 and VEW-2 were tested to evaluate their feasibility to addressing petroleum hydrocarbons detected below the former USTs location Well MW-3 was selected based on previously detected separate-phase hydrocarbons (SPH) in this well However, SPH has not been detected in well MW-3 since August 1993 In September 1995, four geoprobes (GEOI through GEO4), were driven to depths up to 56 fbg and sampled Soil samples obtained from these probes contained TPH-G ranging from ND to 7,000 ppm and benzene ranging from ND to 10 ppm These soil data were obtained from samples collected from depths ranging from 16 to 49 fbg It appears that petroleum hydrocarbons in soil are primarily contained within a limited area beneath the former UST complex and along portions of the former product piping (3 fbg) Petroleum hydrocarbons were not detected in unsaturated soils analyzed from Borings MW-3, B-6, GE01, and GEO4, located down-gradient from the former UST location Petroleum hydrocarbons were not detected in unsaturated soils analyzed from up-gradient wells MW-1 and MW-2, Borings B-2, B-5, and GEO3 Petroleum hydrocarbons were also not detected in unsaturated soils analyzed from the new USTs location, Borings B-1, B-9, B-10, B-1 1, B-12, B-13 and B-14 Based on these data and the quarterly ground water monitoring reports, the SJCPHS requested that an additional soil and ground water investigation be performed The results of this investigation are presented below FIELD PROCEDURES s Exploratory Soil Borings Eight exploratory sod borings were drilled and sampled using hollow- stem auger drilling equipment Four soil borings (SB-1 through SB-4) were drilled on July 2, 1997 for the purpose of delineating the vertical extent of petroleum hydrocarbons in on-site soils Four soil borings (MW-4 through MW-7) were drilled between September 16, and 18, 1997 for the purpose of delineating the extent of petroleum hydrocarbons in on/off-site soils and ground water After drilling, Borings MW-4 through MW-7 were converted to ground water monitoring wells The boring . and well locations are shown on Plates 2 and 3 374 2