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Cjeofogica(Techmcs Inc Page 3 Groundwater Monitoring Report Project No 425 2 February 9, 1999 11.2 Vertical Groundwater Gradients Vertical groundwater gradients were not calculated using MW-2 and MW-102 because the floating product in MW-2 prevented an accurate depth to water measurement However, past events has shown the vertical gradient to be 1 75 to 2 times greater then horizontal and in a downward direction See Table 3 of Appendix A The groundwater elevation in MW-202 is 0 68 feet higher then the groundwater elevation in MW-102 This indicates an upward flow of the deeper groundwater 1.2 Groundwater Samphng Procedure On November 13, 1998, 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 is used to gauge the interface 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 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 it's 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 temporally stored on-site 1 A 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 1n 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-mi 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 while collecting all samples wore disposable gloves