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Second Quarter 1998 Status Report - Former Discovery Chevrolet <br /> July 23, 1998 <br /> (April, 1997), and have never been detected in well MW-5. Historical quarterly <br /> groundwater monitoring and chemical analytical data are summarized in Table 1. <br /> PRESENT QUARTER FIELD ACTIVITIES <br /> Quarterly monitoring and sampling of the groundwater monitoring wells for the second <br /> quarter 1998 was performed on June 5, 1998. Field monitoring and chemical analytical data <br /> from the current quarter are summarized in Table 1. Groundwater sampling procedures are <br /> summarized in Appendix A. Copies of the field data sheets are presented in Appendix B. <br /> Copies ol'the laboratory analytical report and completed chain-of-custody form are presented <br /> in Appendix C. Well MW-3 is scheduled for annual sampling during the first quarter of <br /> each calendar year only. <br /> Groundwater Monitoring and Gradient Evaluation <br /> Depth-to-water (DTW) measurements were obtained from groundwater ;monitoring wells <br /> MW-1 through MW-5, and on-site supply well DW, prior to well purging and sample <br /> collection. Static groundwater levels were measured from the north edge of the top of each <br /> well casing and recorded to the nearest ±0.01 foot. Groundwater was measured between <br /> 4.85 and 10.69 feet bgs. Water-Ievel data collected from wells MW-1 through MW-5 were <br /> -;i used to construct a Potentiometric Map (Figure 3). Based on these data, the shallow <br /> groundwater beneath the subject site appears to flow toward the north at a gradient of <br /> approximately 0.004 ft/ft. Each well was inspected for the presence of floating product. <br /> Floating product or a product sheen was not observed in any of the groundwater monitoring <br /> wells this quarter. <br /> Laboratory Analytical Data <br /> The groundwater samples were collected in sample containers supplied by the laboratory. <br /> Samples from wells MW-1, MW-2, MW-4, MW-5, and DW were analyzed for TPHg by <br /> Environmental Protection Agency (EPA) Method 5030/GC-FID, and for benzene, toluene, <br /> ethylbenzene, and total xylenes (BTEX) and methyl test-butyl ether (MTBE) by EPA Method <br /> 8020. The samples were analyzed by American Environmental Network (FLAP #/1172) <br /> located in Pleasant Mill, California. <br /> TPHg, benzene, or MTBE were not detected in the groundwater samples collected from <br /> WON MW-4 or MW-5. MTBE was not detected in the groundwater samples collected from <br /> MW-1 or MW-2. TPHg were detected in wells MW-1 (80 ppb) and MW-2 (80 ppb), <br /> Benzene was also detected in these samples at 10 and 12 ppb. These data have been used <br /> to construct a TPHg/Benzene/MTBE Concentration Map (Figure 4). <br /> 948146.05-5 3 <br />