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1 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On February 19, 2003, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the four 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 four groundwater monitoring wells, ranged from 23 31 feet bgs in MW-1 to 24 45 feet bgs in MW-3 The groundwater surface elevation in the four wells ranged from a high of 12 18 feet below mean sea 1 level (msl) at MW-1 to a low of 12 83 feet below msl at MW4 The resulting groundwater surface appears as an irregular plane dipping to the east-southeast at a gradient of approximately 0 022 foot/foot A groundwater surface contour map is included as Figure 4, and the groundwater monitoring data are summarized in Table 3 r' 22 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 #2119) Excelchem analyzed each of the samples for TPH-as-motor oil, TPH-as-diesel, TPH-as-gasoline and BTEX by EPA 1 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 82606 The groundwater samples collected from MW-1, MW-2 and MW-3 contained detectable concentrations of petroleum hydrocarbons, including TPH-as-gasoline and BTEX compounds The groundwater sample collected from MW-4 was free of petroleum hydrocarbons MTBE was not detected in any of the four groundwater samples The groundwater sample analytical results are summarized to Table 2, the distribution of gasoline and benzene in groundwater is shown on Figure 5, and the laboratory reports are included in Appendix A i 6 1 1