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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On April 25, 2005, to comply with quarterly groundwater monitoring requirements, Ramage NEnvironmental monitored and sampled the three monitoring wells at the site 1 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 19 20 feet bgs in MW-2 to 19 30 feet bgs in MW-1 The corresponding groundwater surface elevation ranged from a high of 17 45 feet above mean sea level (msl) at MW-2 to a low of 17 36 feet above msl at MW-1 and MW-3 The resulting groundwater surface appears as a regular plane dipping to the northwest at a gradient of approximately 0 0014 foot/foot A groundwater surface contour map is included as Figure 3 The well construction details, wellhead elevations and 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 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 (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME) and tertiary butanol (TBA) and 1,2-DCA by EPA Method 82608 7 i