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c i rf� Former Discovery Chevrolet fl7 June 27, 1995 f Quarterly monitoring and sampling of the monitoring wells begin in March 1995. 4{� Groundwater was measured between 10.05 and 10.65 feet bgs, and appeared to flow toward the north-northwest at a gradient of approximately 0.003. Floating product was not observed in the monitoring wells. TPHg were detected in wells MW-1 (3,900 ppb)'and MW-2 (1,000 ppb), benzene was detected in wells MW-1 (730 ppb) and MW-2 (180 ppb), and TPHd were detected in well MW-3 (200 ppb). Quarterly groundwater and sampling data are summarized in Table 1. PRESENT QUARTER FIELD ACTIVITIES Quarterly monitoring and sampling of the groundwater monitoring wells for the second quarter 1995 was performed by G-R on May 17, 1995. Mr. Steve Sasson of the S7CEHD was present to observe the measuring, purging, and sampling of the.groundwater monitoring wells. Field monitoring and chemical analytical data from the current quarter are summarized in Table 1. The G-R groundwater sampling procedures are summarized in kk Appendix A. Copies of the G-R field data sheets are presented in Appendix B. Copies of f the laboratory analytical report and completed chain-of-custody form are presented in Appendix C. Groundwater Monitoring and Gradient Evaluation E Depth-to-water (DTW) measurements were obtained by G-R from groundwater monitoring wells MW-1 through MW-3 prior to well purging and sample collection. Static groundwater levels were measured from the north edge of the top of each well casing and recorded to the nearest ±0.01 foot. Groundwater was measured between 10.02 and 10.66 feet bgs. These water-level data were used to construct a Potentiometric Map (Figure 3). Based on these data, the shallow groundwater beneath the subject site appears to flow toward the north- northwest at a gradient of approximately 0.003. Each well was inspected for the presence of floating product. Floating product or a product sheen was not observed in any of the groundwater monitoring wells this quarter. Laboratory Analytical Data F F The groundwater samples were collected in sample containers supplied by the laboratory. F The samples from well MW-1 through MW-3 were analyzed for TPHg by Environmental Protection Agency (EPA) Method 5030/GC-FID, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX) by EPA Method .8020. The sample from well MW-3 was also E analyzed for TPHd by EPA Method 50301GC-FID, and for Oil and Grease (O&G) by I Standard Method 5520BF. The samples were analyzed by American Environmental Network (ELAP #1172) located in Pleasant Hill,,California. 8146.02.2 3