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�Y Because of their small diameter,piezomelers PI and P2 were developed using a PVC bailer, From 30 to 60 gallons of water were removed from each well during development. Purged water was stored on the site in 55-gallon drums and then properly disposed of by a licensed hazardous materials management company. 3.6 GROUNDWA'T'ER SAMPLING Groundwater has been sampled twice since the new wells were installed. Groundwater was sampled on 30 January 1991 and included new wells IW1,RW 1,RW2, RW4, and MWIO. Well RW3 had about one foot of LPPI-I and was not sampled, Samples were;submitted to Pace Labo- ratories under chain-of-custody, where they were analyzed for TPH as gasoline and for BTEX by DHS-modified EPA Methods 8015 and 8020,as appropriate. The second round of sampling was conducted on 2 May I99I after all proposed wells had been installed. This round included monitoring wells MW8, MW10, MWl1, and MW12, recovery wells RWI, RW2, and RW4 (RW3 had 0.54 of LPPI.1), piezometers PI and P2, injection well IW I, and vapor recovery wells V1, V3,and V4. Samples were analyzed by Med-Tox Associ- ates,Inc. To provide the information necessary for the treatment system being designed,samples were analyzed for TPH (light and heavy), for BTEX, and for volatile and semi-volatile organics using EPA Methods 8015, 8020, 8240, and 8270, as appropriate. Additionally, samples from recovery wells were analyzed for priority pollutant metals,general minerals, BOD,and anions. 3.7 WELL LOCATION,SURVEYING,AND GAUGING The new wells were located relative to the site boundaries, and elevations of the tops of the casings were surveyed,using afire hydrant on the west side of Pershing Avenue and a previous- ly surveyed well, RW2, as benchmarks. Labels summarizing pertinent information about the wells and their construction were placed in the well boxes. Depths to water were gauged from a mark on the casing,and the thickness of LPPH was meas- ured in the new wells- About 0.5-1 foot of LPPH has been measured on the water in RW3. An adjusted water depth was reported for RW3 on 30 January 1991 because the layer of LPPH depresses the water table slightly. The correction for water table depression was calculated using the equation of Lenhard and Parker(1990),and the corrected depth to water was used for water table determination. The correction calculation is included in Appendix C. e6y..(,734�N�.+91N 9