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CJeD(ogicaCTechnics Inc. Page 5 Hunter Container Report-Soil and Groundwater Investigation Project No.397.2 October 25, 1996 The OVM is a field portable photo ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 eV (hydrocarbon range). 1.3 Monitoring Well Installation .1 One of the borings were advanced into the saturated zone and a groundwater monitoring well was installed. We propose to continuously sample this boring and retain cores for future evaluation. The monitoring well was constructed using 2.0 inch diameter schedule 40 PVC casing with j flush threads. The screened interval will extend from five feet above the water table to 10 feet below the water table. Groundwater is expected to be located between 10-30 feet below grade. If a significant clay unit is encountered while drilling the well boring, the well may be seated no greater than three feet into that fine grained unit. A #3 sand filter pack will surround and extend two feet above the 0.020" screened interval. Before installing the bentonite seal the well was surged using a clean surge block to achieve maximum filter pack density. A granular bentonite transition seal was installed above the sand filter pack and hydrated with clean tap water. A surface seal was achieved by pumping a neat cement grout (augmented with < 4% bentonite) through the augers as they are withdrawn to ensure that an integral grout seal is achieved. The well was secured with a locking watertight cap encased J in flush mounted traffic rated well box or above grade monument which ever is appropriate. J After the well sealing materials have set (>24 hours) the well was developed (using mechanical surging and pumping methods) until a clear stream of water is obtained. The well was purged and groundwater samples collected after well development. All development and purge water was containerized in 55 gallon DOT approved containers and lstored on site until their disposition can be arranged. 1.4 Groundwater Sampling Procedure i The following is a procedure for the sampling of groundwater from the well: Before sampling is attempted the well was sounded for depth to water and then a clear disposable bailer was used to determine if floating product is present. The well was purged j of at least three well volumes of stagnant water using either a submersible pump or a stainless steel bailer. Purging will continue until the temperature, conductivity, and pH of the groundwater has stabilized (<10% variation between three readings) indicating that formation water representative of aquifer conditions is entering the well. These water quality parameters are measured at intervals of each well volume purged. A stainless steel or disposable plastic 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 is filled and capped, the bottle was inverted, tapped, and checked for head space bubbles. The sample container is 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 is decontaminated using a steam cleaner before and between uses. The effectiveness of the decontamination procedure is ensured by using the following quality control measures: