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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On December 29, 2004, to comply with quarterly groundwater monitoring requirements, Ramage <br /> PY <br /> Environmental monitored and sampled the six monitoring wells The on-site domestic water <br /> supply well was not sampled because it was taken out of service, when the site was converted to <br /> city water service <br /> 2.1 Groundwater Monitoring <br /> Depth-to-g roundwater was measured to within 0 01-foot in the six monitoring wells using a water <br /> level indicator The depth to the groundwater table ranged from 20 73 feet bgs in MW-6 to 22 68 <br /> feet bgs in MW-4 The corresponding groundwater surface elevations ranged from a high of <br /> 15 89 feet above mean sea level (msl) at MW-1 to a low of 15 04 feet above msl at MW-5 The <br /> resulting groundwater surface appears as an irregular plane dipping to the north-northeast at a <br /> gradient of approximately 0 0065 foottfoot A groundwater surface contour map is included as <br /> Figure 5 The well construction details and groundwater monitoring data are summarized in Table <br /> 1 <br /> 2.2 Groundwater Sampling and Analysis <br /> Following groundwater level measurements, the six wells were purged and sampled The <br /> monitoring wells were purged with a pump and dedicated disposable tubing until at least three <br /> well casing volumes had been removed and/or after groundwater temperature, pH and electrical <br /> conductivity values had stabilized Groundwater was sampled from the monitoring wells using <br /> dedicated and disposable polyethylene bailers and laboratory-supplied containers All sample <br /> containers were transported in an iced cooler with chain-of-custody documentation to Excelchem <br /> Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory <br /> (Certification #2119) <br /> Excelchem analyzed each of the groundwater samples for TPH-as-gasoline, benzene, toluene, <br /> ethylbenzene and xylenes (BTEX) by EPA Method 802018015M, and for MTBE, di-isopropyl ether <br /> ' (DIPE), ethyl tertiary butyl ether(ETBE), tertiary amyl methyl ether(TAME), tertiary butanol (TBA), <br /> and 1,2-dichloroethane (1,2-DCA) by EPA Method 8260B <br /> . 7 <br />