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Geological Tedwks Inc. Page 2 Groundwater Monitoring Report Project No. 1030.2 August 27,2004 mean sea level (MSL). Site-specific groundwater bearing and slope were calculated and p found to be S850E @ 0.0058 ft/ft. Groundwater elevation increased 1.22 feet since the ' January 2004 monitoring event. These results are consistent with average historical groundwater bearing and slope for this site. Vertical groundwater gradients were calculated for the site using the MW-i/MW-101 well pair and found to be positive. The site-specific vertical groundwater gradient is 0.0024 ftlft. MW-1 is screened from 5 to 20 feet bgs and MW-101 is screened from 29.5 to 34.5 feet bgs. ' Vertical groundwater gradient calculations have been performed at regular intervals since the installation of MW-101 on April 12, 2002. The vertical groundwater gradient calculated for ' the April 2004 monitoring event mirrored the calculated horizontal groundwater gradient. The historical vertical gradients have been positive and approximately one order of magnitude less than the horizontal gradients. Groundwater elevation, bearing and slope were calculated using data gathered from MW-2, MW-3 and MW-4 during the April 19, 2004, monitoring event and the results are summarized in Table 1 of Appendix A. Table 2 of Appendix A summarizes the vertical groundwater gradient calculations. 1.2 Groundwater Sampling Procedure On April 19, 2004, Del-Tech Geotechnical Support Service 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. If free floating product had been suspected, a clear disposable bailer would have been used to gauge the interface. No floating product was observed during this sampling event. Stagnant water in the well casing was purged using a Waters@ pump and dedicated tubing. The rate of well purging was monitored. The well was purged of at least three casing volumes until the groundwater parameters (temperature, conductivity and pH) had stabilized (Appendix Q 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 from each well, the water level was allowed to recharge to at least 80% of its initial level. All water removed from the monitoring well and not used as a sample was placed in a 55 gallon DOT approved container that is properly labeled and ' temporarily stored on-site. ' A Waterra@ pump and dedicated tubing were used to collect each sample. Extreme care was exercised while collecting samples to prevent agitation of the water contained in the Waterra pump. With minimal sample aeration, water samples were transferred from the pump into 40-m1 VOA vials preserved with hydrochloric acid. All samples were checked for headspace