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II tl, 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On June 25, 2004, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the three monitoring wells at the site 21 Groundwater Monitoring Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- groundwater was measured to within 0 01 feet using a water level indicator The static depth to the groundwater table, as measured in the three groundwater monitoring wells, ' ranged from 25 38 feet bgs in MW-2 to 25 60 feet bgs to MW-3 The corresponding groundwater surface elevation ranged from a high of 11 27 feet above mean sea level (msl) at MW-2 to a low of 11 04 feet above msl at MW-3 The resulting groundwater surface appears as a regular plane dipping to the north-northeast at a gradient of approximately 0 0025 foot/foot A groundwater surface contour map is included as Figure 3 The well construction details, wellhead elevations rand groundwater monitoring data are summarized in Table 1 22 Groundwater Sampling and Analysis Following groundwater level measurements, all three wells were purged and sampled The wells 1 were purged using a pump and dedicated disposable tubing, until at least three well casing volumes were extracted and/or after groundwater temperature, pH and electrical conductivity values had stabilized The sampling information field sheets are included in Appendix A Following well purging and recharge, groundwater was sampled from the wells using dedicated disposable bailers and laboratory-supplied containers The groundwater samples were transported in an iced cooler with chain-of-custody documentation to Excelchem Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory (Certification #2119) Excelchem analyzed each of the groundwater samples for TPH-as-diesel, TPH-as- gasoline, benzene, toluene, ethylbenzene, and xylenes (BTEX) by EPA Method 8020/8015M, and ' for methyl tertiary butyl ether (MTBE), di-isopropyl ether(DIPS), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether(TAME) and tertiary butanol (TBA) and 1,2-DCA by EPA Method 82606 ' 7 1