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Vapor Extraction Test Report <br /> Former Thrifty Oil Service Station N 172 <br /> September 14, 1995 <br /> 4.4 LABORATORY ANALYSIS OF VAPOR SAMPLES <br /> Laboratory analysis of influent air samples collected from VW-A, VW-B, VW-C indicate <br /> hydrocarbon concentrations as follows. <br /> Test Well VW-A: Beginning of Test End of Test <br /> • Purgeable hydrocarbons: 4,400 ppmv 4,800 ppmv <br /> • Benzene: 120 ppmv 120 ppmv <br /> • Toluene: 32 ppmv 31 ppmv <br /> • Ethylbenzene: 110 ppmv 120 ppmv <br /> • Xylene: 360 ppmv 310 ppmv <br /> Test Well VW-B: Beginning of Test End of Test <br /> 1 Purgeable hydrocarbons: 1,700 ppmv 2,300 ppmv <br /> • Berme: 58 ppmv 72 ppmv <br /> • Toluene: 17 ppmv 23 ppmv <br /> • Ethylbenzene: 41 ppmv 54 ppmv <br /> • Xylene: 45 ppmv 62 ppmv <br /> Test Well VW-C: Beginning of Test End of Test <br /> • Purgeable hydrocarbons: 8,600 ppmv 9,500 ppmv <br /> • Benzene: 320 ppmv 350 ppmv <br /> • Toluene: 62 ppmv 68 ppmv <br />' 0 EthyIbenzene: 310 ppmv 330 ppmv <br /> • Xylene: 250 ppmv 240 ppmv <br />' 5.0 CONCLUSIONS AND RECOMMENDATIONS <br /> • The transmissibility and permeability to air values calculated from all three tests are <br /> indicative of sandy and silty sand soils (Freeze & Cherry, 1979). <br />' • The average effective radius-of influence is estimated to be approximately 33 feet for a <br /> flowrate of 16-17 cfm in the test wells. <br /> • Laboratory analysis of air samples from the test wells indicate that significant concentrations <br /> of hydrocarbons can be recovered by soil vapor extraction from VW-A, VW-B and VW-C. <br /> At the flow rates tested, the estimated gasoline hydrocarbon removal rates were <br /> approximately 31 pounds per day (lb/day) for VW-A, 15 Ib/day for VW-B, and 61 Ib/day <br /> for VW-C. <br /> 5 <br />