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r06 November 2002 . AGE-NC Project No 97-0290 ' Page 2 of 6 ' 2 2 COLLECTION OF GROUND WATER SAMPLES Water samples were collected from the monitoring wells using the dedicated disposable plastic ' bailers after allowing the wells to achieve a minimum 80%recovery of the pre-purge water volume Each water sample was transferred into 40-m1 volatile organic analysis (VOA)vials containing 0 5 ml 18%hydrochloric acid as a sample preservative The samples were properly labeled, placed in a ' chilled container and transported under chain-of-custody to CalTech Environmental Laboratory (CTEL), a California Department of Health Service (DHS) - certified laboratory in Paramount, California The samples were analyzed for ' 0 Total petroleum hydrocarbons as gasoline (TPH-g) in accordance with EPA Methods 8015 Modified and ' 0 Benzene,toluene,ethylbenzene and xylene(BTEX)and methyl tertiary-butyl ether(MTBE) in accordance with EPA Method 8020 23 SOIL-VAPOR EXTRACTION AND IN-SITU AIR-SPARGING lie A soil vapor extraction / in-situ air sparging (SVE/IAS) system composed of 1) an SVE unit consisting of a 2 5-horsepower regenerative vacuum blower and three 55-gallon carbon canisters, and 2) an IAS system, utilizing an air compressor, was in operation during the quarter The SVE system was monitored monthly and inspected or maintained weekly during operation In addition, because the SVE unit utilizes 55-gallon carbon-filled canisters to adsorb hydrocarbon vapor from ' the extracted soil-vapor, the carbon median was monitored and changed on a regular basis during the quarter to maximize hydrocarbon adsorption/destruction During each monitoring event, measurement of the SVE flow rate, vacuum (potential), ' concentrations of hydrocarbons in the extracted soil-vapor and collection of a set of soil-vapor Y p samples were conducted by AGE personnel The flow rate of soil-gas-vapor was measured using a ' Blue-White direct measure flow roto-meter or Dwyer pressure flow meter Vacuum(potential)was measured at vapor extraction wells using a Magnehelic vacuum gauge The organic-vapor ' concentration in the extracted soil-vapor stream was measured before entering the SVE vacuum blower(influent stream) and after exiting the carbon vessels using an organic vapor meter(OVM) equipped with a photo-ionization detector PID (Thermo Environmental 580B, 10 OeV, calibrated ' to isobutylene 100 ppb) The IAS system was maintained and the air-sparging flow rate was adjusted to approximately ' 4 standard cubic feet per minute (scfm) and to a pressure of 6 pounds per square inch (psi) at each well during each monitoring event, a YSI-55 dissolved oxygen meter was utilized to check the IAdvanced CeoEnvironmental,Inc I