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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On December 11, 2003, to comply with quarterly groundwater monitoring requirements, 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 15 98 feet below grade in MW-1 to 28 37 feet below street grade in MW-3 rThe groundwater surface elevation in the three wells ranged from a high of 15 84 feet below mean sea level (msl) at MW-1 to a low of 16 81 feet below msl at MW-3 The resulting groundwater surface appears as a regular plane clipping to the northeast at a gradient of approximately 0 0114 foottfoot A groundwater surface contour map is included as Figure 4, and the groundwater monitoring data are summarized in Table 3 22 Groundwater Sampling and Analysis Followinggroundwater level measurements the wells were purged and sampled The wells were g P 9 P 1 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#2119) Excelchem analyzed each groundwater sample for TPH-as-gasoline and benzene, toluene, ethylbenzene, xylenes (STEX) by EPA Method 8020/8015M, and for MTBE, di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), and 1,2-dichloroethane (1,2-DCA) by EPA Method 8260B A)ssj )!2.-di brr rx4 IV BZ44 B, ✓rsti Only the groundwater sample collected from MW-1 contained detectable concentrations of gasoline hydrocarbons This sample contained 15,000 micrograms per liter (µg/1) of TPH-as- ' gasoline, 1,900 pg/1 of benzene, 170 µg/l of toluene, 1,800 µg/l of ethylbenzene, 4,600 gg/I of xylenes, and 20 gg/I of MTBE The groundwater sample analytical results are summarized in Table 2, the distribution of gasoline in groundwater is shown on Figure 5, the laboratory reports . are included in Appendix A, and the sample information field sheets are included in Appendix B 6 M