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' 12 October 1995 <br /> AGE-NC Project No. 95-0112 <br /> Page 3 of 6 <br /> 3.2. LOGGING <br />' Soil was extruded from the second brass sleeve and screened for the presence of organic vapors using <br /> a photo-ionization detector(PID: Thermo Environmental 580A, 10.0 eV, calibrated to isobutylene), <br /> and the readings were recorded on the boring logs. The soil was then describe in accordance with the <br /> Unified Soil Classification System (see Boring Logs, Appendix A). <br />' 3.3. BORING COMPLETION <br />' Borings SW-1 and SW-2 were completed as air sparging injection wells using five feet of 2-inch <br /> diameter, 0.020 slotted PVC casing. The slotted casing was set at depths between 68.6 to 73.5 in <br /> SW-1 and depths between 70 and 75 feet in SW-2. Blank PVC casing was installed above the slotted <br /> tcasing to surface grade in each sparging well. <br />' The sand pack was installed from total depth to one foot above the screened intervals. A five-foot <br /> bentonite plug was installed above the sand pack and the borings were backfilled to surface grade <br /> with Portland Cement. <br /> 3.4. MONITORING WELL PURGE PROCEDURES <br /> ' On 11 July 1995, a Solinst water level meter was used to measure the depth to ground water in each <br /> well except MW-2 relative to the top of each casing. The relative ground water elevations and <br /> ' hydraulic gradient were determined from these data (Table 2). <br /> After depth to ground water measurements, monitoring wells MW-1 and MW-3 to MW-8 were <br /> ' purged using pre-cleaned PVC bailers to remove a minimum of three (3) well casing volumes. <br /> Approximately 18 gallons of water were removed from MW-1; 2 gallons were removed from.MW-3; <br /> 4 gallons were removed from MW-7; and 7 to 8 gallons were removed from wells MW-4, MW-5, <br /> ' MW-6 and MW-;8. Because of poor recharge, three well volumes could not be removed from MW-3. <br /> Ground water stabilization parameters were measured at regular intervals using an ICM water <br /> ' analyzer. Purged water was stored on-site in 55-gallon drums. Stabilization data and field logs are <br /> included in Appendix C. <br /> 3.5. COLLECTION OF GROUND WATER SAMPLES <br /> ' Water samples were collected from each purged well using new disposable bailers. The samples were <br /> transfered into 40-m1 EPA vials preserved with hydrochloric acid and transported in a chilled <br />