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Fourth Quarter 1996 Status Report=Former Discovery Chevrolet January 3, 1997 Quarterly monitoring and sampling. of the monitoring wells begin in March .1995. Historically, depth to groundwater has fluctuated between 9.86 and 11.53 feet bgs. Groundwater appears to flow toward the north-northwest at a gradient of approximately 0.003 to 0.005. Floating product has not been observed in the monitoring wells. TPHg, BTEX,,or Oil and Grease have not been detected in well MW-3: TPHg concentrations•in wells MW-1• and MW-2 have ranged from 60 to 17,000.ppb', and benzene concentrations. ` have. ranged from 10 to 3,100 ppb. Historical.'quarterly groundwater monitoring and chemical analytical data are summarized:intable'!. PRESENT QUARTER FIELD ACTIVITIES Quarterly monitoring and sampling of the groundwater monitoring wells for the fourth quarter 1996 was performed by G-R on November 21, 1996.. Field monitoring and chemical analytical data from the current quarterare summarized in Table 1. The G-R groundwater sampling procedures are summarized in,Appendix A: Copies of the G= field data sheets are presented in .Appendix B. Copies of the•laboratory analytical report' and completed chain-of-custody form: are presented in Appendix C. Groundwater Monitoring and Gradient_Evaluation >� 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 9:87 and 10.46 feet bgs.. These water-level data were used to construct a Potentiomeiric 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 The groundwater samples were collected in sample containers supplied by the laboratory. The samples from wells MW-1 and MW-2 were analyzed for TPHg by Environmental Protection Agency (EPA) Method 5030/GC-FID, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX) and Methyl Tertiary Butyn Ether (MTBE) by EPA Method 8020. The sample from well MW-3 was analyzed for MTBE and for TPHd by EPA Method 5030/GC-FID, and chlorinated hydrocarbons (C1=HCs) by EPA.Method 8010. The samples were anaIyzed,by American Environmental Network('FLAP #1172) located in Pleasarit Hill, California. - 1 9146.93A 3 .