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GUARWnLY Ofal3NOWA1L771AoMtKING$91"11 <br /> 1505 South EI 0clailo.5Soco2on.caufomla <br /> On July 2, and 3, 1991, Aegis conducted soil borings, sampling, and installation of <br /> monitoring wells MW-1, MW-2, and MW-3 (Figure 2). Results of soil borings, sampling, <br /> and well installation were reported by Aegis to Exxon in a "Phase I Subsurface <br /> Investigation Results Report," dated September 13, 1991. <br /> t <br /> 4.10 GROUNDWATER MONITORING <br /> E� <br /> 4.1 Grg�! 1dwatar <br /> On Oc�ober 17, 1991, Aegis personnel collected measurements of the depths to <br /> since <br /> groundwater in wells MW-1, MW-2, and MW-3. Over the past 3 months, since <br /> drop <br /> July 11, 1991, groundwater levels have fallen in the three wells {Figure 3}. p <br /> ranged from 1.26 to 1.23 feet (Table V. On the basis of the October 17, 1991, <br /> measurements,groundwater is estimated to flow to the southeast at an average gradient <br /> Pa of a' <br /> proximately 0.0007 ft/ft. Figure 3 is a potentiometric surface map of the shallow <br /> water-bearing zone on October 17, 1991. <br /> Previous groundwater levels are summarized in Table 1. All groundwater elevation <br /> a, measurements were made from the referenced wellhead elevations, measured to the <br /> nearest 0.01 foot, and conducted according to the Aegis standard operating procedures <br /> Jy . (SOP) Included as Appendix A. <br /> 4.2 Water Sarnplinc� and Anal►�sis <br /> 1.� <br /> i.a <br /> On October 17, 1991, Aegis personnel collected groundwater samples from the three <br /> wells at the site. The samples were collected according to the Aegis SOP included in <br /> ain-of-custody to Face Laboratories, incorporated of <br /> Appendix A, and delivered under ch <br /> y ; Novato, California, a state-certified analytical laboratory. The samples were analyzed for i <br /> concentrations of: a) TPH, as gasoline, by EPA Method 8015; b} BTEX by EPA <br /> 1 k Method 602;c) ethylene dibromide and ethylene dichloride by Method 5030(GC,FID)and <br /> Method 8010; and d} total Lead by. EPA Method 7421. The analytical results are <br /> summarized in Table 2. The analytical reports and chain-of-custody forms are included <br /> I' in Appendix B. Concentrations of TPH, as gasoline, and benzene reported in Table 2 are <br /> 60 also shown on Figure 4. <br /> Y» <br /> 6v <br /> i. <br /> ttif <br /> 91.aaaCAFT <br />