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Geological Techmcs Inc Page 4 Groundwater Monitoring Report Project No 425 2 January 25, 2002 ' order of magnitude greater than horizontal The relationship of upward and downward vertical gradients in the shallow/intermediate well pair is plotted in Figure 8 It should be ' noted from Figure 8 that the depth to groundwater is on a steady decline since project start, with annual late summer temporary rises in 1998, 1999, and 2000 ' Refer to Table 3 of Appendix A for a summary of the vertical gradient calculations ' 1.2 Groundwater Sampling Procedure On December 3, 2001, 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 Free ' product was evident in well MW-2 Stagnant water in the well casing was purged using a Centrifugal 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 or until the groundwater parameters (temperature, conductivity, and pH) had stabilized (Appendix C) indicating that water, representative of dc,tual aquifer conditions, were entering the well Groundwater parameter stabilization was characterized by three successive readings within 10% Before a sample was collected, the well's water level was allowed to recharge to at least 80% of its initial level All water removed from the monitoring wells and not used as a ' sample, was placed in a 55 gallon DOT (Department of Transportation 17-H) approved container that is properly labeled and temporarily stored on-site ' A stainless steel bailer was used to collect each 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 ' The sampling technician wore disposable gloves while collecting all samples p g ' A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from field to the laboratory, thereby providing a means to track ' their movement and insure their integrity 0