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1 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On June 21, 2006, to comply with quarterly groundwater monitoring requirements, and to monitor the plume of impacted groundwater, Ramage Environmental monitored and sampled the three wells 21 Groundwater Monitoring Depth-to-groundwater was monitored to within 0 01-foot using a water level indicator The static depth to the groundwater table, as measured in the three monitoring wells, ranged from 12 30 feet below grade in MW-1 to 24 42 feet below street grade in MW-3 The groundwater surface ' elevation in the three wells ranged from a high of 12 16 feet below mean sea level (msl) at MW-1 to a low of 12 86 feet below msl at MW-3 The resulting groundwater surface appears as a regular plane dipping to the northeast at a gradient of approximately 0 0083 foot/foot A groundwater surface contour map is included as Figure 4, the groundwater monitoring data are summarized in Table 3, and the sample information field sheets are included in Appendix A Between March 15, and June 21, 2006, the groundwater surface rose an average of 1 47 feet, the M groundwater gradient decreased from 0 0113 to 0 0083 foot/foot, and the groundwater flow direction remained toward the northeast During th'T quarter, the groundwater surface elevation was at its highest level, since the monitoring wells were installed in July 2002 Otherwise, these ' groundwater surface characteristics are consistent with historical and seasonal trends ' 22 Groundwater Sampling and Analysis Following groundwater level measurements, the wells were purged and sampled The wells were ipurged with a pump and dedicated disposable tubing until at least three well casing volumes had been removed and/or after groundwater temperature, pH and electrical conductivity values had stabilized Groundwater was sampled from the wells using disposable polyethylene bailers and laboratory-supplied containers Each sample container was 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 groundwater sample for TPH-as-gasoline and benzene, toluene, ethylbenzene, xylenes (BTEX) by EPA Method 8021 B/8015M, and for MTBE, di-isopropyl ether (DIPS), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) by EPA Method 8260B r 7