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""tog"'Techxcaw Page 4 Groundwater Monitonng Report Project No 770 2 November 19,2003 r 18 at-0 007 and —0 012 ft/ft, respectively The MW-61106 well pair vertical gradients were negative (a downward direction) at—0 001, -0 001 and —0 002 ft/ft, respectively, on July 22, ' August 20 and September 18, 2003 Both positive and negative vertical gradients have been calculated for previous events ' Similar to the historical lateral directions, the direction of groundwater in the vertical plane also fluctuates at the site The magnitude of vertical groundwater flow direction ranged ' from—0 02 to 0 0097 for the site investigation 1.2 Groundwater Sampling Procedure On July 22 and August 20, 2003, Del-Tech Geotechnical Support Services staff mobilized to the site to measure depth to groundwater in the site's monitoring wells On September 18, 2003, Don Light of Dei-Tech Geotechnical Support Services again mobilized to the site to complete the quarterly groundwater monitoring and sampling of the site's monitoring wells Before sampling was attempted, the wells were sounded for depth to water and then a clear disposable bailer was used to determine if floating product was present No free product or sheen was noted in the site's wells for the event although sheen has been present in certain wells in the past The wells were purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball assembly and '/2 inch tubing Purging continued until the temperature, conductivity and pH of the groundwater tstabilized (<10% variation among three readings) indicating that formation water representative of aquifer conditions was entering the wells These water quality parameters were measured at intervals of each well volume purged Once purging was complete, a water sample was collected from the Waterra tube Care was taken to minimize sample agitation Once the sample container was filled and capped, the bottle was inverted, tapped and checked for headspace bubbles The sample container was identified and labeled with a unique designation, inserted into foam holders and placed into ' an ice chest cooled to 4°C for transport to the laboratory All non-disposable sampling equipment was decontaminated using a hot water washer and ' detergent before and between uses Disposable gloves were used by the technician to collect all samples and were changed with each sample collection ' A chain of custody document, listing all samples collected, accompanied the samples from field to laboratory, thereby providing a means to track their movement and insure their integrity