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1 v <br /> 0 <br /> ASS OCIATES I N C . <br /> feet bgs. The petroleum hydrocarbons appeared to attenuate rapidly with depth as indicated <br /> greatest by soil.sample from 35.5 feet bgs, which contained only trace levels of isopropylbenzene, <br /> 1 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene. Trace amounts of petroleum hydrocarbon <br /> constituents were also detected in the groundwater sample collected from soil boring SB 1. <br /> 1 2.0 SOIL EXCAVATION ACTIVITIES <br /> To remove the majority of the impacted backfill soil from the location of the former 1,000-gallon <br /> ' UST, ATC supervised the excavation and disposal of approximately 70.5 tons of soil. All.field <br /> activities were performed in accordance with ATC's Revised Workplan for Soil Excavation and <br /> Additional Subsurface Investigation at Inland Paint, 117 West Harding Way, Stockton, <br /> ' California, dated July 6, 1998. This workplan was approved by PHS/EHD with minor <br /> modifications. <br /> 2_1 Soil Excavation and Sampling <br /> ' On September 11, 1998, ATC personnel supervised the excavation of the impacted backfill <br /> material located in the former UST location by Bob Evans Trucking (license # ). Excavated <br /> backfill material was field screened with a flame ionization detector (FID) as it was removed from <br /> the excavation. One four-tube composite soil sample and one grab sample were collected from <br /> the excavated material prior to its immediate transportation from the site. Approximately 70.5 <br /> tons of impacted soil was excavated from the site under the supervision of Ms. Lori Duncan of the <br /> PHS/EHD. <br /> ATC personnel collected two soil samples from the bottom of the excavation, at the north end of <br /> ' the excavation and at the south end of the excavation. An area of discolored soil was also <br /> observed on the north wall of the excavation at a depth of approximately 12 feet bgs and a sample <br /> was collected from that location. The excavation area and sample locations are shown on Figures <br /> ' 2and 3. <br /> 2.2 Soil Analytical Results - Excavation Activities <br /> ' Soil samples were laced on ice and trans orted under chain-of-custody documentation to State- <br /> certified Sequoia Analytical laboratory (FLAP #1210) in Redwood City, California for analysis. <br /> Samples were analyzed for TPHg, TPHd, benzene, toluene, ethylbenzene, and xylenes (BTEX, <br /> EPA Method 8020), total petroleum hydrocarbons as Stoddard Solvents (TPHss, EPA Method <br /> 1 8015), chlorinated hydrocarbons (EPA Method 8010), oxygenate fuel additives (EPA Method <br /> 8260), and total lead. <br /> 1 Soil samples SP(1-4), SB-5, SB, NB, and NW contained no detectable concentrations of <br /> chlorinated hydrocarbons or oxygenate fuel additives. TPHd and TPHg were detected in all soil <br /> samples at elevated concentrations, but the chromatogram patterns did not match gasoline or <br /> diesel. TPHss was detected in all soil samples at elevated concentrations and the chromatogram <br /> pattern did match Stoddard Solvents. Soil samples SB, NB, and NW contained trace amounts of <br /> w:117295VY,Wrtslsumii.doc 2 <br />