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2,0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS On July 30 2001 Ramage Environmental monitored and sampled groundwater at the site 21 Groundwater Monitoring Depth-to-groundwater measurements were taken in six of the nine groundwater monitoring wells to evaluate groundwater flow and gradient characteristics Monitoring wells MW-1, MW-2, and MW-4 were not accessible due to temporary coverage by burial vaults Groundwater surface elevations were not calculated for the two deep sod vapor extraction wells (VW-1 and VW-2), because their wellhead elevations were moved during the installation of the former sod vapor extraction and air sparging system These wellheads will be re-surveyed during the next phase of site investigation work ' In the six wells monitored, the depth-to-groundwater beneath the site ranged from 40 14 feet below ground surface (bgs) in VW-1 to 43 46 feet bgs in MW-7 MW-7 is completed above- grade and protected with a monument casing The groundwater elevation beneath the site ranged from a high of 25 05 feet below mean sea level (MSL) to MW-3 to a low of 25 33 feet below MSL in MW-5 The cumulative groundwater monitoring data are summarized in Table 1 The groundwater flow direction and gradient are illustrated on the groundwater surface map (Figure 3) The groundwater gradient was calculated at approximately 0 004 foot/foot in a northeasterly direction This is consistent with the historical groundwater gradient and flow direction 22 Groundwater Sampling and Analysis p g Y Groundwater was sampled from four of the seven monitoring wells (MW-3, MW-5, MW-6, and MW-7), the two deep soil vapor extraction wells (VW-1 and VW-2), and Irrigation Well#2 Each of the monitoring wells was purged of at least three well volumes using a pump and disposable tubing Following purging and recharge, groundwater samples were collected from the wells using dedicated and disposable sampling bailers Irrigation Well #2 was allowed to flow at the wellhead until the downhole pump was automatically activated A groundwater sample was collected directly at the wellhead through a sample port groundwater samples were contained in laboratory-supplied containers labeled The g p , and packed in an iced cooler for transport with chain-of-custody documentation to Kiff Analytical, LLC (Kiff) a state of California certified analytical laboratory (#2236) 5