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magnitude of 0 009 (Figure 1), which is consistent with previous data Groundwater <br /> elevations have increased an average of 0 39 feet since the previous quarter Field documents <br /> are included as Appendix A <br /> After the depths to water were measured, selected wells (MW 1, MW8, MW 10, MW 13, <br /> RW1—RW3, P1, and P2) were purged by vacuum truck and sampled At least four well <br /> casing volumes of purge water were removed from each well except for MW1, MW8, and <br /> MW 10, which completely dewatered at 3, 2 2, and 2 6 casing volumes, respectively After <br /> purging, groundwater samples were collected with disposable polyethylene bailers which had <br /> been cleaned at the factory EA field personnel rinsed the bailers three tunes with deionized <br /> water prior to collecting a groundwater sample The water was placed in 40-m1 VOA vials <br /> Vials were labeled and preserved in an ice-filled cooler for storage and transported under <br /> appropriate chain-of-custody procedures Samples were sent to Pace Incorporated and <br /> analyzed for Total Petroleum Hydrocarbons as gasoline (TPH-g) by DHS-modified EPA <br /> Method 8015 and for benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA <br /> Method 8020 <br /> The analytical results for the samples collected on 17 February are presented in boldface type <br /> in Table I with results of previous analyses The laboratory analytical report is included as <br /> Appendix B The air sparging wells (SWI and SW2) are noted as AS and AS2 in the <br /> laboratory analytical report <br /> Concentrations of TPH-g in samples ranged from 130 µg/L in MW1 to 70,000 pg/L in RW3 <br /> (Figure 1) Concentrations of benzene ranged from <0 5 µg/L in MW1 to 9,600 pg/L in <br /> RW3 (Figure 1) Onsite petroleum hydrocarbon concentrations were lowest in the sample <br /> collected from MW 1, located along the western boundary of the site The concentration of <br /> TPH-g in the sample collected from MW8, located adjacent to the Shell service station and <br /> upgradient of P1 and P2, was 44,000 pg/L Concentrations of TPH-g have decreased in all <br /> wells except for RWI, which had a slight increase LPH has not been detected in any well <br /> since October 1992 <br /> 4. WORK PROPOSED FOR NEXT QUARTER <br /> Water elevations in groundwater monitoring wells will be measured and groundwater samples <br /> collected in June 1994 The samples will be analyzed for petroleum hydrocarbons The soil <br /> vapor extraction and air sparging system will be in operation <br /> 73942Q294 2 2 <br />