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! 05 May 2005 AGE-NC Project No 99-0645 ! Page 2 of 6 ! 22 SOIL-VAPOR EXTRACTION The SVE system was observed or maintained weekly and monitored monthly During each ! monitoring event, the flow rate of extracted soil-vapor (influent) was measured using a totalizing- flow Blue White roto-meter Vacuum potential was measured at the 2-inch influent line by the magnehelic vacuum gauge In addition, the organic vapor concentrations in the Influent stream (before entering the blower) and the effluent stream (after exiting the carbon unit) were measured using the OVM A Magnehelic vacuum gauge was temporarily attached to the inlet of the blower to measure vacuum pressure exerted on the extraction well, and a cumulative flow meter was utilized ' downstream of the carbon canisters to monitor air flow Sampling ports were installed upstream of the knockout vessel and downstream of the 1,500-1b carbon vessels to recover influent and effluent SVE air flow samples used to monitor the efficiency of hydrocarbon removal, in addition, the influent and effluent streams were monitored routinely for the presence of organic vapor using an organic vapor meter(OVM)equipped with a photo-ionization detector(PID Thermo Environmental 580, 10 0 eV, calibrated to isobutylene) Field measurements,recorded at regular intervals between ' 17 December 2004 and 23 March 2005, are summarized in Table 1 • Influent and effluent soil-vapor samples were collected on 21 January, 16 February and 08 March I2005, an effluent soil-vapor sample was collected on 23 March 2005 The influent vapor samples were collected from within a vacuum chamber directly into Tedlar vapor bags,the effluent samples were collected directly out of the effluent stream The samples were labeled, placed in a cooler and transported under chain of custody to Cal Tech Environmental Laboratories(CTEL) in Paramount, a State of California Department of Health Services(DHS)-certified analytical laboratories The soil- vapor samples were analyzed for • Total petroleum hydrocarbons quantified as gasoline (TPH-g) 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 23 MONITORING WELL EVACUATION AND MONITORING On 25 January 2005,the water level in each of three monitoring wells was measured relative to the top of the well casing using a Solinst water level meter After water levels were measured, a dedicated, disposable plastic bailer was used to purge each well Four and one-half to five gallons (a minimum of three well volumes) of water were removed from the wells Temperature, pH and conductivity of the purged water were measured at one-and-one-half gallon Intervals using an • Oakton water analyzer during purging The values had generally stabilized by the end of the purging Advanced GeoEnvironmental,Inc r