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1 <br /> 2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On September 12, 2005, to comply with quarterly groundwater monitoring requirements, Ramage <br /> Environmental monitored and sampled the nine 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 /> I21 Groundwater Monitoring <br /> Depth-to-groundwater was measured to within 0 01-foot in the nine monitoring wells using a water <br /> level indicator The depth to the groundwater table ranged from 20 50 feet bgs in MW-6 to 22 55 <br /> ' feet bgs in MW-2 The corresponding groundwater surface elevations ranged from a high of <br /> 15 94 feet above mean sea level (rnsl) at MW-1 to a low of 15 14 feet above msl at MW-7 The <br /> resulting groundwater surface appears as an irregular plane dipping to the north at a gradient of <br /> approximately 0 0064 foot/foot A groundwater surface contour map is included as Figure 5, and <br /> the well construction details and groundwater monitoring data are summarized in Table 1 <br /> ' 22 Groundwater Sampling and Analysis <br /> Following groundwater level measurements, the nine 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 8021 B18015M, and for MTBE, di-isopropyl <br /> ether (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butanol <br /> (TBA), and 1,2-dichloroethane (1,2-DCA) by EPA Method 8260B <br /> 8 <br /> • <br /> 1 <br />