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E /1.+. Former Discovery Chevrolet March 28, 1995 PRESENT QUARTER FIELD ACTIVITIES Quarterly monitoring and sampling of the groundwater monitoring wells for the first quarter 1995 was performed by G-R on March 8, 1995. Mr. Steve Sasson of the S3CEHD was present at the site on March 8, 1995, 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 Appendix A. Copies of the G-R field data sheets are presented in Appendix B. Copies of the laboratory analytical report and completed chain-of-custody document 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 10.05 and 10.65 feet bgs. These water-level data were used to construct a quarterly 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 F presence of floating product. Floating product or a product sheen was not observed in any of the groundwater monitoring wells this quarter. Mr. Sasson noted that the well casings were not marked as to the location of the survey point from which the well elevation was measured. A letter report dated March 9, 1995, from Mr. Virgil Chavez (PLS No. 6323), the surveyor who originally measured the elevations of the well casings, is attached as Appendix D. This letter report indicates that the elevations of the well casings were measured on the approximate north side of the casing, and that the locations were marked at the time of the survey with hashes using a black marker. Laboratory Analytical Data The groundwater samples were collected in sample containers supplied by the laboratory. The samples from well MW-1 and MW-2 were analyzed for TPHg by Environmental Protection Agency (EPA) Method 50301GC-FID, and for benzene, toluene, ethylbenzene, and total xylenes (BTEX) by EPA Method 8020 The sample from well MW-3 was analyzed for TPHg, BTEX, Total Petroleum Hydrocarbons as diesel (TPHd) by EPA. Method 5030/GC-FID, and for Oil and Grease (O&G) by Standard Method 5520BF. The samples were analyzed by American Environmental Network (ELAP #1172) located in Pleasant Hill, k California. 8146.42-1 3 f: