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[F{fi TABLE 1 <br /> =7 <br /> UST OVEREXCAVATION:SOIL SAMPLE ANALYSES <br /> Village West Marina,Stockton-San Joaquin County <br /> Results expressed in mg/Kg <br /> :., 1P+4 Method EFA Method 60-21-- Ck LTJJ"P <br /> g4�5 med INV: <br /> ;:Sample Bate 3 Yotal Organic. <br /> 1Yo Sa led, TPFI g: &enaenc TvltlnG k'Jhylbt Xylenes Leash: <br /> N-Bottom 07/20/93 4.3 0.065 0.038 0.14 0.57 ND <br /> S-Bottom 07/20/93 340 5.8 13 8.9 44 ND <br /> N-Wall 07/20/93 330 0.69 0.44 3.4 15 NA <br /> S-Wall 07/20/93 4.7 0.6$ 0.016 0.46 1.2 NA <br /> E-Wall 07/20/93 ND ND ND ND ND NA <br /> W-Wall 07/20/93 ND ND ND ND ND NA <br /> Reporting 1 mg/Kg 0.005 mg/Kg 0.05 <br /> Limits mg/Kg <br /> ND Not detected above the reporting limit of the laboratory test. <br /> NA Not analyzed <br /> i_ Laboratory analyses by Sequoia Analytical of Concord <br /> The excavation was backfilled in May, 1994 subsequent to collection of stockpile soil samples <br /> for single-sample-composite analyses in order to detect residual TPH-g and TRPH-d analytes. <br /> Favorable results (all analytes were nondetectable) allowed for stockpile backfill were approved <br /> :. 1 in a letter dated May 10, 1994 from Specialist Collins to Mr. Dwight Davis of the Pegasus <br /> `! Group. <br /> HydropunchTm Sampling <br /> ._s <br /> Under the supervision of Specialist Collins, three Hydropunch'm boreholes (HP-1, HP-2, and HP- <br /> ; _ 3 shown on the Site Sketch, Figure 2 and the Ground-Water Gradient Map, Figure 3) were <br /> drilled near the north, east, and west flanks of the overexcavation. Borehole soil samples were <br /> logged at five-foot intervals by the W.W. Irwin, Inc. field geologist; the samples were chilled <br /> and retained for laboratory analyses, but the analyses were not required by the SJCPHS EHD. <br /> Ground water was encountered at an average depth of 23.7 feet below surface grade (bsg). <br /> When analyzed, the ground-water samples collected from HP-1 and HP-2 revealed BTEX <br /> analytes in nondetectable or fractional concentrations; the sample from HP-1 exhibited 86 pg/1 <br /> of TPH-gasoline. When analyzed, the sample collected from HP-3 exhibited TPH-g at 360 <br /> pg/Q, and a benzene concentration of 160 µg1f, prompting the SJCPHSEHD to order the <br /> completion of three monitoring wells for ground-water direction and gradient determination, and <br /> possible definition of the contaminant migratory path. See Table 1A for analytical results. <br /> d <br /> W.W. Irwin, Inc. <br /> Project No. 33016.06 <br /> i `' February 1996 3 <br />