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2 0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS <br /> On March 26, 2003, to comply with quarterly groundwater monitoring requirements, Ramage <br /> Environmental monitored and sampled the three existing monitoring wells at the site <br /> 21 Groundwater Monitoring <br /> Depth-to-groundwater was monitored using a water level indicator capable of measurements to <br /> 9 P <br /> within 0 01 foot The static depth to the groundwater table, as measured in the three monitoring <br /> wells, ranged from 20 44 feet bgs in MW-2 to 20 54 feet bgs in MW-1 The corresponding <br /> groundwater surface elevations ranged from a high of 16 21 feet above mean sea level (msl) at <br /> MW-2 to a low of 16 11 feet above msl at MW-3 The resulting groundwater surface appears as a <br /> regular plane dipping to the northwest at a gradient of approximately 0 0015 foot/foot A <br /> groundwater surface contour map is included as Figure 3 The well construction details and <br /> groundwater monitoring data are summarized in Table 3 <br /> Between December 19, 2002 and March 26, 2003, the groundwater surface rose an average of <br /> 0 54 feet, the groundwater gradient decreased from 0 0033 to 0 0015 foot/foot, and the <br /> groundwater flow direction shifted less than 5 degrees toward the west Between March 2002 and <br /> March 2003, the groundwater surface has dropped an average of 2 47 feet, and the groundwater <br /> flow direction and gradient have remained relatively consistent <br /> Groundwater Sampling and <br /> 2 2 Gro p 9 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 monitoring wells using dedicated and disposable <br /> polyethylene bailers and laboratory-supplied containers All sample containers were transported in <br /> an iced cooler with chain-of-custody documentation to Excelchem Environmental Labs <br /> (Excelchem), a state of California certified hazardous waste testing laboratory (Certification#2119) <br /> Excelchem analyzed each groundwater sample for Total Petroleum Hydrocarbons (TPH)-as-diesel, <br /> TPH-as-gasoline and BTEX by EPA Method 8020/8015M, and for methyl tertiary butyl ether <br /> (MTBE), di-isopropyl ether(DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether <br /> (TAME), tertiary butanol (TBA) and 1,2-DCA by EPA Method 8260B <br /> 7 <br />