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GeologxoI eclutics Inc Page 2 Groundwater Monitoring Report Project No 723 2 November 7,2001 Figure 2 is a groundwater gradient map for the September 12, 2001 event Figure 3, ' Groundwater Gradient Rose Diagram includes historical groundwater directions and gradients ' This is the eighth event during which the deep discretely screened well, MW-101, was monitored A shallow well has not yet been installed next to MW-101 so a vertical gradient cannot easily be calculated The groundwater head in MW-101 was less (0 18 — 0 52 feet) ' than the head in nearby wells MW-2 and MW-3, so it appears there may have been a significant vertical gradient on September, 2001 ' Table 1 in Appendix A contains the groundwater elevations and gradients for the site ' 1.2 Groundwater Sampling Procedure On September 12, 2001, Dei-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 readings were recorded to an accuracy of 0 01 foot In wells where free-floating product was suspected, a clear disposable bailer is used to gauge the interface During this Nmonitoring no free product was noted 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 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 is properly labeled 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 in 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 field to the laboratory, thereby providing a means to track their movement and ensure their integrity