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24 <br /> August I995 <br /> AGE-NC Project No 95-0144 <br /> Page 2 of 8 <br /> ' The lateral extent of impacted soil remains undefined to the north, east and south Petroleum <br /> hydrocarbons were detected in soil samples collected from bonngs SB 1, SB2, MW-1, MW-4 and <br /> MW-5 The PHS/EHD is requiring further investigation to define the lateral extent of impacted soil <br /> and ground water <br /> ' <br /> 3.0. PROCEDURES <br /> i <br /> 3 1 MONITORING WELL PURGE PROCEDURES <br /> On 1 <br /> � 1 May 1995, a Solinst water level meter was used to measure the depth to ground water in each <br /> well relative to the top of the casing The relative ground water elevations and hydraulic gradient <br /> were determined from these data (Table 1) <br /> f - F <br /> ' Each well was then purged using a 2-stage purge pump The purge pump was decontaminated <br /> ' between each well using an Alconox solution Approximately 10 gallons of water were removed from <br /> MW-1, MW-2, MW-4 and MW-5, approximately 35 gallons of water were removed from MW-8 <br /> (minimum of three well volumes) Temperature, pH and conductivity were measured at two-gallon <br /> intervals (five gallon intervals for MW-8) using an ICM model 52200 water analyzer All purged <br /> water was stored in 55-gallon drums on-site Stabilization data and field logs are included in <br /> Appendix A <br /> 3 2 COLLECTION OF GROUND WATER SAMPLES <br /> Water samples were collected from each well using new disposable bailers Immediately upon <br /> retrieval, the samples were transferred into 40-m1 EPA vials preserved with hydrochloric acid and I- <br /> hter amber bottles The samples were transported in a chilled container to McCampbell Analytical Inc <br /> (MAI) in Pacheco and analyzed for total petroleum hydrocarbons as gasoline, motor oil and <br /> transmission oil (TPH-g, TPH-mo, TPH-to) and volatile organics (benzene, toluene, ethylbenzene <br /> iand total xylenes, BTE&X) in accordance with EPA methods 5030 and 602, respectively The <br /> laboratory reports and chain-of-custody forms are presented in Appendix B <br /> 33 GEOPROBE PROBINGS <br /> ,i <br /> Seventeen probings were installed at the site on four separate days between 16 June to 17 July 1995 � <br /> ' (Figure 2) The probings were advanced using a van-mounted Geoprobe 5400 soil probing machine <br /> equipped with 1 125-inch diameter rods <br /> E�1 <br /> I <br />