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1 <br /> 5. STATUS OF SOIL REMEDIATION <br /> On behalf of Exxon, EVAX Technologies has begun operation of a soil vapor extraction and <br /> treatment system at the site. The system went into operation in February 1991. Monitoring and <br /> progress reporting for this system are done separately by EVA.X. <br /> 6. DEFINITION OF LIQUID-PHASE HYDROCARBONS <br /> Liquid-phase hydrocarbons (LPH) have not been detected at the site. <br /> 7. DEFINITION OF DISSOLVED CONSTITUENT PLUME <br /> Groundwater in wells MW1, MW2, MW6, MW7, and MWS was sampled 10 .Tune 1991. The <br /> samples were analyzed by Pace Incorporated for Total Petroleum Hydrocarbons as gasoline <br /> (TPH-g) by EPA Method 8015 and for aromatic hydrocarbons,benzene, toluene,ethylbenzene, <br /> and xylenes (BTEX) by EPA Method 8020. Concentrations of petroleum hydrocarbons greater <br /> ' than the method detection limits were measured in the samples taken from well MW6(Table 3). <br /> MW6,which replaces MW3, is located in the former tank field and is surrounded on four sides <br /> a e, <br /> by the other wells. Analytical results of samples collected 10 dune are presented in Table 3 and <br /> are cumulatively summarized with earlier results in Table 4. Copies of the laboratory report o <br /> analyses are included as Appendix A. <br /> Groundwater sampling has been done on an approximately quarterly schedule since late 1986. <br /> Groundwater sampled from well MW3 (and its replacement, MW6) during this time has <br /> contained higher concentrations of petroleum constituents than water from the other four wells <br /> (Table 4). Because MW3 and MW6 are surrounded by the other four well locations and no <br /> concentrations of TPH-g greater than 50 pg/L and no concentrations of BTEX greater than 0.5 <br /> pg/L have been detected in samples of groundwater from the outlying wells, the dissolved <br /> constituent plume appears to remain limited to the area immediately around MW3 (and MW6), <br /> directly beneath the former tank field (Figure 2). <br /> S. STATUS OF DISSOLVED CONSTITUENT REMEDIATION <br /> Groundwater remediation is not currently planned. <br /> 9. WATER LEVEL RECORDS AND GRADIENT DETERMINATIONS <br /> The depth to groundwater in each well was measured at the timeof sampling,.using.att.optical_, .. <br /> interface probe. Groundwater elevations calculated using these data and surveyed top-af-casi,nl <br /> wp5iRi05IXs)R'renun9cfrx.4 3 <br />