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' Geo(v ica(Technus Inc Page 2 g , Groundwater Monaonng Report Project No 724 2 April 17,2000 of groundwater under the site was —16 30 feet below mean sea level The water level has risen over 22 75 feet at the site since October of 1992 Depths to water were approximately 32 feet bgs ' Figure 2 is a groundwater gradient map for the March 8, 2000 monitoring event Table 1 in Appendix A contains the groundwater elevations and gradients for all events back to October 1992 Groundwater historically flowed predominately to the east at an average of 0 0033 ft/ft The steepness of the gradient at this event is at a historic low but is similar to that observed in the last monitoring event A different choice of wells used to calculate the gradient (MW-1, MW-3 and MW-4) would have increased the gradient steepness but would also have reversed its direction 12 Groundwater Sampling Procedure On March 8, 2000, Del-Tech Geotechnical Support personnel arrived on-site, opened the wells, and measured the depth to water with an electrically actuated sounding tape The ' water level reading was recorded to an accuracy of 0 01 foot In wells where free floating product was suspected, a clear disposable bailer was used to gauge the interface No floating free product was observed during this monitoring event Stagnant water in the well casing was purged using a purger pump as recorded in the field logs (Appendix C) The rate of well purging was monitored The wells were purged of at ' least three casing volumes until the groundwater parameters (temperature, conductivity, and pH) had stabilized (Appendix C) This indicated that water, representative of actual aquifer conditions, was entering the well Groundwater parameter stabilization was characterized by ' three successive readings within 10% Before a sample was collected, the water level was allowed to recharge to at least 80% of the initial level All water removed from the monitoring well and not used as a sample was placed in a 55 gallon DOT (Department of Transportation 17-H) approved container that was ' properly labeled and is temporally stored on-site A 4" stainless steel bailer was used to collect each sample Bailer cleanliness was assured by ' collecting a bailer blank (pouring distilled water through the bailer and collecting it in a VOA vial) prior to collecting the analytical sample ' Extreme care was exercised while collecting samples to prevent agitation of the water contained in the bailer Water samples were transferred from the bailer into 40-m1 VOA vials preserved with hydrochloric acid using a bottom-emptying device that minimizes sample ' aeration during transfer of the sample All samples were checked for headspace bubbles, labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to ' the laboratory