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Geofogrcaf?echnics Inc Wage 3 Groundwater Monitoring Report Project No 770 2 May l4,2002 For the March 11, 2002, monitoring event, a vertical gradient was calculated for the MW- 5/MW-105 pair The vertical gradient was negative (a downward direction) and equal to the horizontal gradient of shallow wells MW-I through MW-3 (0 0004) The vertical gradients calculated for previous events are negative on August 28, 2000, June 27, September 19 and December 7, 2001, and positive on December 29, 2000, and March 15, 2001 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 ranges from —0 0004 to — ' 0 0236, in a negative direction, for the last four monitoring events 1.2 Groundwater Samphug Procedure On March 11, 2002, Don Light of Del-Tech Geotechnical Support Services mobilized to the site to conduct groundwater monitoring of the seven monitoring wells ' Before sampling was attempted the wells weie sounded for depth to water and then a clear disposable bailer was used to determine if floating product was present 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 stabilized (<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 All water purged from each monitoring well and not used as a sample was placed in a properly labeled 55 gallon DOT approved container and stored on site until its proper disposition can be arranged ' Groundwater monitoring g field logs are included in Appendix C 4 "t