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RA 4 CJeologicaf?edmzcs Inc. C&B Equipment Page 2 Ground water Monitoring Report Project No.336.2 January 13, 1997 92.34 feet (referenced to a 100 foot arbitrary plane). The gradient was North 07° West with a slope of 0.00375 ft/ft. Table 1 of Appendix A summarizes the ground water level measurements to date. Ground r._ water gradient calculations show that the dominant ground water flow is in a north- IL northwesterly direction with the slope ranging from 0.0072 ft/ft to 0.00375 ft/ft. Figure 3 is a ground water gradient map from this latest sampling event. Figure 4 is a rose diagram of the _ gradients from the three monitoring events. 1.2 Ground water Sampling Procedure : 3 On December 6, 1996, Del-Tech Geotechnical Support personnel arrived on-site, opened the well, 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 is used to gauge the interface. Stagnant water in the well casing was purged using either a Grundfos pump or electronic bailer as recorded in the field logs (Appendix C). The rate of well purging was monitored. The well was purged of at least three casing volumes and until the ground water parameters (temperature, conductivity, and pH) had stabilized {Appendix C) indicating that water, representative of actual aquifer conditions, was entering the well. Ground water 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 it's 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 temporally stored on-site. >3 A 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 1 contained in the bailer. Water samples were transferred from the bailer into 40 ml VOA vials preserved with hydrochloric acid using a bottom emptying device which minimizes sample aeration during transfer of the sample. All samples were checked for head space bubbles, labeled, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to ' the laboratory. Disposable gloves were worn by the sampling technician while collecting all samples. �i