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2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS • ' On November 25, 2002, to comply with quarterly groundwater monitoring requirements, Ramage Environmental monitored and sampled the seven monitoring wells 2 1roun water Monitoring G d g Upon arrival at the site, each of the wellheads was inspected, unlocked and opened Depth-to- groundwater was measured in each of the wells using a water level indicator capable of measuring groundwater to within 0 01 foot The static depth-to-groundwater ranged from 42 58 feet bgs in MW-7 to 44 10 feet bgs in MW-1 The corresponding groundwater surface elevations ranged from a high of 24 54 feet below mean sea level (msl) at MW-6 to a low of 25 24 feet below msl at MW-2 The resulting groundwater surface appears as an irregular plane dipping to the east-southeast at a gradient of approximately 0 0024 foot/foot As shown on the groundwater surface contour map (Figure 4), a groundwater depression observed at MW-2 is not consistent with the regional groundwater surface In MW-2, a layer of separate-phase hydrocarbons (free product) approximately 0 01 feet thick was observed, prior to purging the well The groundwater monitoring data are summarized in Table 1 22 Groundwater Sampling and Analysis Ramage Environmental purged and sampled all seven monitoring wells The wells were purged using a pump and disposable tubing until at least three well casing volumes were removed and/or ' after groundwater temperature, pH and electrical conductivity had stabilized Following well purging, groundwater was sampled from the wells using dedicated disposable bailers and laboratory-supplied containers, which were transported in an iced cooler with chain-of- custody documentation to Kill Analytical, LLC (Kiff), a state of California certified hazardous waste ttesting laboratory (Certification#2236) Kiff analyzed the groundwater samples for TPH-as- gasoline, BTEX, MTBE, di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butanol (TBA), and 1,2-DCA by EPA Method 82606 1 7 r