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1 C'Cotogka'rechtcs/Ac Page 4 Groundwater Monitoring Report Project No 723 2 June 15,2004 ' For the March 21, 2004 event, the vertical gradient for the MW-3/MW-201 pair was negative (or downward) at -0 001 ft/ft Previous calculations have revealed both positive ' and negative gradients but additional monitoring is needed to determine long-term trends 1.2 Groundwater Sampling Procedure ' On March 21 2004 Del-Tech Geotechnical Support personnel arrived on-site opened the > PP p p wells and measured the depth to water with an electrically actuated sounding tape The water level readings were recorded to an accuracy of 0 01 feet In wells where free-floating product is suspected, a clear disposable bailer is Used to gauge the interface During this monitoring no free product was noted Due to the tube twist problem mentioned above, the new CMTrm wells were not sampled on --� March 21 The field technician had difficulty with Waterra hoses "kinking" due to friction on the chamber sidewalls A second mobilization was conducted on March 23, 2004 with an adaptor to prevent the hoses from "kinking" during sampling The new wells were successfully sampled on that day - Stagnant water in the well casing was purged using a Waterra pump as recorded in the field logs (Appendix C) The rate of well purging was monitored The wells were purged of approximately three casing volumes and until the groundwater parameters (temperature, conductivity and pH) had stabilized (Appendix C) indicating 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 well's water level was allowed to recharge to at least 80% of the initial level The purge water was placed in a properly labeled 55-gallon DOT (Department of Transportation 17-H) approved container and temporarily stored on-site The dedicated Waterra pump was used to collect each monitoring well sample Extreme ' care was exercised while transferring the sample into 40-m1 VOA vials preserved with hydrochloric acid All samples were checked for headspace bubbles, labeled, inserted into foam holders and placed into an ice chest cooled to 4°C for transport to the laboratory The sampling technician wore disposable gloves while collecting all samples A chain of custody document, listing all samples collected and their intended analyses, accompanied the samples from the field to the laboratory, thereby providing a means to track the movement of the samples and ensure their integrity 1 i