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2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> ' On September 26, 2002, to comply with quarterly groundwater monitoring requirements, Ramage <br /> Environmental monitored and sampled groundwater at the site <br /> ' 21 Groundwater Monitoring <br /> ' Depth-to-groundwater was measured in all four groundwater monitoring wells to evaluate <br /> groundwater flow and gradient characteristics The depth to the groundwater table, ranged from <br /> ' 22 56 feet below ground surface (bgs) in MW-1 to 23 41 feet bgs in MW-2 and MW-4 The <br /> corresponding groundwater surface elevation ranged from a high of 14 96 feet above mean sea <br /> level (msl) at MW-1 to a low of 14 45 feet msl at MW-4 A different well construction for MW-2 <br /> tmay cause the groundwater elevation in this well to be incompatible with the elevations in the <br /> three other wells The resulting groundwater surface appears as a regular plane dipping to the <br /> ' northeast at a gradient of approximately 0 0060 foot/foot A groundwater surface contour map is <br /> included as Figure 4 The well construction details, wellhead elevations and groundwater <br /> monitoring data are summarized in Table 1 <br /> 22 Groundwater Sampling and Analysis <br /> Following the groundwater level measurements, three of the four wells were purged and sampled <br /> Monitoring well MW-2 was not sampled due to insufficient groundwater in the well The wells <br /> ' (MW-1, MW-3 and MW-4) were purged using a pump and disposable tubing until at least three <br /> well casing volumes were extracted and/or after groundwater temperature, pH and electrical <br /> ' conductivity values had stabilized Following well purging and recharge, groundwater was <br /> sampled from MW-1, MW-3 and MW-4 using dedicated disposable bailers and laboratory- <br /> supplied containers A groundwater sample was also collected from the on-site water supply well, <br /> ' after pump activation and allowing the water to run for approximately 15 minutes <br /> ' Each sample was labeled, packaged in an iced cooler and transported with chain-of-custody <br /> documentation to Excelchem Environmental Labs (Excelchem), a state certified hazardous waste <br /> testing laboratory (Certification #2119) Excelchem analyzed each of the groundwater samples <br /> ' for Total Petroleum Hydrocarbons (TPH)-as-gasoline, benzene, toluene, ethylbenzene and <br /> xylenes (BTEX) by EPA Method 8020/8015M, and for MTBE, di-isopropyl ether(DIPE), ethyl <br /> ' tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), and 1,2- <br /> dichloroethane (1,2-DCA) by EPA Method 82608 <br /> ' 5 <br />