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JkVeFr�►,�eglINC. SACRAMENTO <br />' velocities, and temperatures were noted during regular system <br /> checks. The operational data are presented in Table 2 . <br /> 4 . 5. 1 Hydrocarbon concentrations <br /> Hydrocarbon concentrations in vapor samples collected from <br /> the vapor extracted from EW6 were measured periodically during <br /> the pilot study. Vapor samples were collected in 280--cubic <br /> centimeter evacuated cylinders (supplied by Applied Science Labs) <br /> using a NalgeneTM hand-operated sampling pump. The samples were <br />' sent to the laboratory via courier, under Versar' s chain of <br /> custody document. Soil-vapor samples were also analyzed in the <br /> field using a ThermoEnvironmental Instruments Model 580A Organic <br /> Vapor Meter (OVM) equipped with a 10. 0 electron volt lamp. The <br /> OVM was calibrated using an isobutylene gas standard. The <br /> response factor of the OVM was set for isobutylene for the <br /> calibration procedure and subsequent measurements. The total <br /> hydrocarbon concentrations measured in samples collected before <br /> the carbon treatment system are included in Table 3 . <br /> 4 . 5. 2 Laboratory Analytical Methods <br /> The soil-vapor samples were analyzed by Trace Analysis <br />' Laboratory (Trace) of Hayward, California. The following <br /> analyses were performed by Trace: <br />' A. Total Petroleum Hydrocarbons as Gasoline <br /> (TPH-G) [DHS Leaking Underground Fuel Tank <br /> (LUFT) Field Manual Method; <br /> and <br /> B. Benzene, Toluene, Ethylbenzene and Total Xylenes <br /> ' (BTEX) (Modified EPA Method 8020] . <br /> The laboratory analytical results are presented in Section <br /> 4 . 6. Although diesel fuel was released at the site, the samples <br /> were analyzed for TPH-G. The SVE system methodology is designed <br /> to remove the lighter volatile fraction from the impacted soils, <br /> ' leaving the heavier less mobile fraction as a residual. The <br /> ' 12 <br />