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CJeo(ogicaf?ufnrts lac Page 4 Sod Groundwater Investisation Report Georges Service Project No 425 2 November 30, 1998 • feet above the 0 020 inch screened interval and was topped by a two to three foot weighted bentonite pellet transition seal installed on top of the filter pack A surface seal was achieved by pumping a neat cement grout (augmented with <4% bentonite) on top of the transition seal via a tremie pipe The wells were secured with locking watertight caps encased in flush mounted traffic rated well boxes Deeper Well The deeper monitoring well was constructed using 2 0-inch diameter PVC casing with flush threads The screened intervals extended from 79 to 81 5 feet bgs Groundwater was encountered at approximately 7 to 8 feet below grade A 43 sand filter pack surrounded and extended two feet above the 0 020 inch screened interval and was topped by a two foot weighted bentonite pellet transition seal installed on top of the filter pack A surface seal was achieved by pumping a neat cement grout (augmented with <4% bentonite) via a tremie tube The well was secured with a locking watertight cap encased in flush mounted traffic rated well box On July 12, 1998, Don Light of Del Tech mobilized to the site to developed the new monitoring wells (using mechanical surging and pumping methods) until a clear stream of water was obtained On July 14, 1998, Don Light returned to the site to purge and collect groundwater samples from the three new monitoring wells All development and purge water was containerized in 55-gallon DOT approved containers and stored on site until its disposition could be arranged 2.2.1 Groundwater Sampling 1Proeedure The groundwater in the new well was sampled no sooner than 24 hours after well development The following was the procedure for the sampling of groundwater from the well Before sampling was attempted the well was sounded for depth to water The wells were then purged of at least 3 well volumes of stagnant water using a centrifugal pump Purging continued until the temperature, conductivity, and pH of the groundwater has stabilized (<10% variation between three readings) indicating that formation water representative of aquifer conditions was entering the well These water quality parameters were measured at Intervals of each well volume purged. A stainless steel bailer was used to collect each sample Care was taken to minimize sample agitation from the initial filling of the bailer to the transfer of the sample to the VOA vial and glass amber liter bottles Once the sample container was filled and capped, the bottle was then inverted, tapped, and checked for headspace bubbles The sample container was then identified and labeled with a unique designation, inserted into foam holders and placed in an Ice chest cooled to 4°C for transport to the laboratory All non-disposable sampling equipment was decontaminated using a steam cleaner before and between uses The effectiveness of the decontamination procedure is ensured by using the following quality control measures 0 Disposable gloves were used by the technician to collect all samples and were changed with each sampling event 0 A bailer blank for the well was collected pnor to sampling by filling the decontaminated stainless steel bailer with water (provided by the laboratory) and then filling a VOA vial (provided by the laboratory) rasing the same procedures for actual sample collection