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1 <br />' hydraulic gradient of approximately 0 004 ft/ft, although an apparent groundwater depression <br /> existed in the vicinity of well MW4 The apparent groundwater depression suggests that the <br /> water level in well MW4 is either influenced by pumping in the water supply well, or that some <br />' vertical leakage of the shallow aquifer is occurring through the water supply well A <br /> potentiometnc surface map of the shallow aquifer generated using the October 25, 2000 well <br />' monitoring data is presented on Figure 7 Groundwater monitoring data sheets and purge logs are <br /> included in Appendix III <br />' 5.2 Soil Analytical Results <br />' No TPHg or BTEX constituents were detected in the capillary fringe or bottom-hole samples <br /> collected from borings MW5 through MW8 MTBE was detected in boring MW6 at a <br />' concentration of 0 018 ppm in the sample collected at 55 feet bgs and at a concentration of 0 009 <br /> ppm in the sample collected at 72 feet bgs No other oxygenated gasoline additives or lead <br />' scavengers were detected No gasoline constituents were detected in the soil sample collected at a <br /> depth of 110 feet bgs from boring MW9 Soil analytical results are summarized in Tables 2 and <br /> Table 3 Chain of custody documentation and laboratory data sheets are included in Appendix 1V <br /> 5.3 Groundwater Analytical Results <br /> Of the newly installed wells, only wells MW5 and MW6 contained any detectable concentrations of <br />' gasoline constituents Well MW5 contained only MTBE at a concentration of 55 parts per billion <br /> (ppb) Well MW6 contained 1,900 ppb TPHg, 0 6 ppb benzene, and 20,000 ppb MTBE No <br />' gasoline constituents were detected in the groundwater sample collected from deep well MW9(B) <br /> Nitrates were detected at concentration of 8 ppm in well MW9(B) Groundwater analytical results <br />' are summarized in Tables 4 and 5 The estimated extent of dissolved benzene contamination and <br /> dissolved MTBE contamination beneath the site are shown on Figures 8 and 9, respectively Chain <br />' of custody documentation and laboratory data sheets are included in Appendix IV <br />' 6.0 WASTE DISPOSAL <br /> No detectable gasoline constituents were present in the soil cuttings, drilling mud, or wastewater <br /> generated during drilling activities The cuttings and drilling mud were spread upon the ground <br /> surface within property boundaries pursuant to correspondence from PHS/EHD dated December 4, <br /> 11 <br /> data/groundzeAulsburg/reports/mud_has_weI(report.doc <br />