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' 2.0 GROUNDWATER MONITORING, SAMPLING AND ANALYSIS i On May 18, 2001, Ramage Environmental monitored and sampled groundwater at the site ' 2.1 Groundwater Monitoring Depth-to-groundwater measurements were taken in eight of the nine groundwater monitoring wells to evaluate groundwater flow and gradient characteristics Monitoring well MW-4 was not accessible due to temporary coverage by a burial vault Groundwater surface elevations were ' not calculated for MW-1 and 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 eight wells monitored, the depth-to-groundwater beneath the site ranged from 36 79 feet below ground surface (bgs) in MW-1 to 40 52 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 22 17 feet below mean sea level (MSL) in MW-2 to a low of 22 39 feet below MSL in MW-5 Groundwater levels rose an average of 0 14 feet, since groundwater levels were last measured on February 17, 2001 Since May 1992, the groundwater levels have risen approximately 29 4 feet The current and historical 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 0 00143 foot/foot in a northeasterly direction This is consistent with the historical groundwater gradient and flow direction 22 Groundwater Sampling and Analysis Groundwater was sampled from six of seven monitoring wells (MW-1 through MW-7, except MW-4), Irrigation Well #2, and the two deep sod vapor extraction wells (VW-1 and VW-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 5