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2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On November 25, 2002, to comply with quarterly groundwater monitoring requirements, Ramage <br /> Environmental monitored and sampled the four wells <br /> 21 Groundwater Monitoring <br /> Depth-to-groundwater was monitored using a water level indicator capable of measurements to <br /> within 0 01 foot The static depth to the groundwater table, as measured in the four groundwater <br /> monitoring wells, ranged from 23 64 feet bgs in MW-1 to 24 83 feet bgs in MW-3 The <br /> groundwater surface elevation in the four wells ranged from a high of 12 51 feet below mean sea <br /> level (msl) at MW-1 to a low of 13 11 feet below msl at MW-4 The resulting groundwater surface <br /> appears as an irregular plane dipping to the east-southeast at a gradient of approximately 0 022 <br /> foot/foot A groundwater surface contour m p is included as Figure 4, and the groundwater <br /> monitoring data are summarized in Table311- '1�" <br /> 22 Groundwater Sampling and Analysis <br /> Following groundwater level measurements, the wells were purged and sampled The wells were <br /> purged with a pump and dedicated disposable tubing until at least three well casing volumes had <br /> been removed and/or after groundwater temperature, pH and electrical conductivity values had <br /> stabilized Groundwater was sampled from the wells using disposable polyethylene bailers and <br /> laboratory-supplied containers Each sample container was transported in an iced cooler with <br /> chain-of-custody documentation to Excelchem Environmental Labs (Excelchem), a state of <br /> California-certified hazardous waste testing laboratory (Certification #2119) Excelchem analyzed <br /> each of the samples for TPH-as-motor oil, TPH-as-diesel, TPH-as-gasoline and BTEX by EPA <br /> Method 802018015M, and for MTBE, di-isopropyl ether (DIPS), ethyl tertiary butyl ether (ETRE), <br /> tertiary amyl methyl ether(TAME), and tertiary butanol (TBA) by EPA Method 82606 <br /> ' Theroundwater samples collected from MW-1 MW-2 and MW-3 contained detectable <br /> 9 P e <br /> concentrations of petroleum hydrocarbons, including TPH-as-gasoline and BTEX compounds <br /> The groundwater sample collected from MW-4 was free of petroleum hydrocarbons MTBE was <br /> not detected in any of the four groundwater samples The groundwater sample analytical results <br /> are summarized in Table 2, the distribution of gasoline and benzene in groundwater is shown on <br /> Figure 5, and the laboratory reports are included in Appendix A <br /> �1 <br /> 6 <br /> r <br />