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i I30 October 2002 AGE-NC Project No 01-0827 IPage 2 of 5 ' Soil-vapor samples were collected to document trends in concentrations of hydrocarbon vapor in the soil-vapor extracted by the SVE network and to determine the treatment system hydrocarbon destruction rate Soil-vapor samples from the Influent and effluent streams were collected in Tedlar I vapor bags on 17 July and 20 August 2002 The samples were labeled,placed in pre-chilled coolers and transported under chain-of-custody to McCampbell Analytical,Inc (MAI),a State of California Department of Health Services (DHS)-certified analytical laboratory The samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline (TPH-g) and diesel (TPH-d) in ' accordance with EPA Method 8015 Modified and • Benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary butyl ether (MTBE) in accordance with EPA Method 8020, The results of the laboratory analysis are summarized in Table 2 I2 2 WELL MONITORING AND EVACUATIONS � . On 30 August 2002, a Solmst water level meter was used to measure the depth to ground water in ground water monitoring wells MW-1, MW-3 and MW-5 and vapor wells VW-1, VW-2d, VW-3 and VW-5d After water levels were gauged, a dedicated disposable bailer was used to purge these wells of a minimum of three casing-water volumes (approximately 3 5 to 16 gallons) of ground water Temperature,pH, and conductivity were measured at regular intervals during purging using an Oakton model water analyzer Purged water was stored on-site in 5 5-gallon drums The field data Isheets are included in Appendix A On 04 September 2002, depth to ground water was measured in monitoring wells MW-1 through MW-5 with the Solinst water level meter The groundwater elevations and gradient were determined from this data(Table 1) 2 3 GROUND WATER SAMPLE COLLECTION Water samples were collected from each monitoring well using new disposable bailers after allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume Each sample was I transferred into three 40-m1 EPA-approved volatile organic analysis (VOA) vials and one 1-liter amber bottle Samples were stored in a chilled container and transported under chain-of-custody to Precision EnviroTech (PET) of Stockton, a DHS-certified analytical laboratory Each sample was Ianalyzed for • TPH-g and TPH-d in accordance with EPA Method 8015 Modified, IAdvanced Geo Environmental,Inc I