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20 October 2004 <br /> AGE-NC Project No 95-0109 <br /> Page 2of5 <br /> 2 2 WELL MONITORING AND PURGE PROCEDURES <br /> On 09 September 2004, twenty three on- and off-site ground water wells were monitored for depth <br /> to water and fourteen monitoring wells (MW-7, MW-8, MW-9, MW-11, MW-12 and MW14 <br /> through MW-22) were purged and sampled A Solmst water level meter was used to measure the <br /> depth to groundwater to the nearest 0 01-foot in all twenty-three wells relative to the tops of the well <br /> casings The ground water elevation In each well was calculated by subtracting the depth to ground <br /> water from the surveyed well casing elevation (Table 1) <br /> After water levels were measured, wells MW-7, MW-11, and MW-14, were purged using new <br /> disposable plastic bailers Wells MW-8,MW-9,MW-12 and MW-15 through MW-22 were purged <br /> using a Waterra inertial pump <br /> Between 4 0 and 6 5 gallons of water were removed from wells that were purged by disposable <br /> bailers Approximately 2 5 to 28 gallons were removed from the wells that were purged by the <br /> Waterra inertial pump MW-8 and MW-9 drew down before the full purge volume was reached <br /> Temperature, pH and conductivity of the purge water were measured at regular purge-volume <br /> intervals using an Oakton water analyzer and the readings were recorded on field logs Field data and <br /> work sheets are included in Appendix A The purged water was containerized in 55-gallon <br /> DOT-approved drums and stored on-site <br /> 23 COLLECTION AND ANALYSIS OF GROUND WATER SAMPLES <br /> The depth to water was re-measured after purging to ensure a minimum of 80 percent recharge of <br /> the initial water level in each well prior to sampling Afterwards,water samples were collected from <br /> wells MW-7,MW-11 and MW-14 using the disposable plastic bailers and from the remaining wells <br /> using the Waterra Inertial Pump Immediately upon retrieval,the samples were transferred into 40-m1 <br /> EPA-approved volatile organic analysis (VOA) vials containing 0 5-ml 18% hydrochloric acid as <br /> a sample preservative <br /> The samples were labeled, stored on ice, and transported in a chilled container, under chain of <br /> custody, to McCampbell Analytical, Inc (MAI) of Pacheco, a State of California Department of <br /> Health Services-certified analytical laboratory <br /> All ground water samples were analyzed for <br /> • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> • Methods 5030/8015M, and <br /> Advanced GeoEnvironmental,Inc <br />