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i • 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On May 9, 2003, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the on-site monitoring wells In addition, Ramage Environmental continued to remove free product from MW-1, on a reduced schedule 21 Groundwater Monitoring Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- groundwater was measured to within 0 01 foot in each of the wells using a water level indicator A free product sheen was observed in MW-1 The depth to static groundwater across the site ranged from 46 08 feet bgs in MW-3 to 47 40 feet bgs in MW-1 The corresponding groundwater surface elevation ranged from a high of 27 44 feet below mean sea level (msl) at MW-3 to a low of 28 19 feet below msl at MW-1 The resulting groundwater surface appears as a regular plane dipping to the west-southwest at a gradient of rapproximately 0 0068 foot/foot A groundwater surface contour map is included as Figure 4 The well construction details and groundwater monitoring data are summarized in Table 1 22 Groundwater Sampling and Analysis P 9 Y Following the groundwater level measurements, MW-2 and MW-3 were purged and sampled Due to the presence of a free product sheen, MW-1 was not sampled The wells (MW-2 and MW- 3) were purged using a pump and dedicated disposable tubing, until at least three well casing volumes were extracted, and/or after groundwater temperature, pH and electrical conductivity values had stabilized Following well purging and recharge, groundwater was sampled from MW- 2 and MW-3 using dedicated disposable bailers and laboratory-supplied containers Each sample container was transported in an iced cooler with chain-of-custody documentation to Excelchem Environmental Labs (Excelchem), a state of California certified hazardous waste testing laboratory (Certification#2119) Excelchem analyzed each of the groundwater samples for TPH-as-gasoline and BTEX by EPA Method 802018015M, and for methyl tertiary butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETRE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), and 1,2-dichloroethane (1,2-DCA) by EPA Method 82608 • 5