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2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On November 25, 2002, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the three wells 21 Groundwater Monitoring Depth-to-groundwater was monitored using a water level indicator capable of measurements to within 0 01 foot The static depth to the groundwater table, as measured in the three monitoring wells, ranged from 15 11 feet below grade in MW-1 to 27 43 feet below street grade in MW-3 The groundwater surface elevation in the three wells ranged from a high of 14 94 feet below mean sea level (msl) at MW-2 to a low of 15 87 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 0107 foot/foot A groundwater surface contour map is included as Figure 4, and the groundwater ' monitoring data are summarized in Table 3 2.2 Groundwater Sampling and Analysis Following groundwater level measurements, the wells were purged and sampled The wells were purged 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 #2219) Excelchem analyzed each groundwater sample for TPH-as-gasoline and benzene, toluene, ethylbenzene, xylenes (BTEX) by EPA Method 8020/8015M, and for MTBE, di-isopropyl ether (DIPS), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether(TAME), and tertiary butanol (TBA) by EPA Method 8260B Only the groundwater sample collected from MW-1 contained detectable concentrations of gasoline hydrocarbons This sample contained 25,000 micrograms per liter (µg/l) of TPH-as- gasoline, 1,000 µg/1 of benzene, 2,400 µg/I of toluene, 1,200 �ig/l of ethylbenzene, 3,700 fcg/l of xylenes, and 19 µg/I of MTBE The groundwater sample analytical results are summarized in Table 2, the distribution of gasoline in groundwater is shown on Figure 5, and the laboratory reports are included in Appendix A r 6