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Geological Technks Inc. Page 4 Monitoring Well Installation Work Plan Valley Wholesale Drug Co.,Inc. Project No. 989.2 November 21, 2001 2.4 Groundwater Monitoring Protocol 2.4.1 Well Purging and Sampling The groundwater in the new well will be sampled no sooner than 48 hours after well development and from there after on a quarterly basis. The following is a procedure for the sampling of groundwater from the well: Before sampling is attempted the well will be sounded for depth to water and then a clear disposable bailer will be used to determine if floating product is present. The well will be purged of at least 3 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 will be used to collect each sample. Care will be 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 will be inverted, tapped, and checked for headspace 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. Using the following quality control measures ensures the effectiveness of the decontamination procedure: • Disposable gloves will be used by the technician to collect all samples and will be changed with each sampling event. • A bailer blank for each well will be collected prior 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) using the same procedures for actual sample collection. -` Bailer blanks for each sample, along with a field blank (prepared from water provided by the laboratory poured into a VOA vial on site), will accompany the samples to the laboratory and serve as checks against cross contamination. A chain of custody document, listing all samples collected, accompanies the samples from field to laboratory, thereby providing a means to track their movement and ensure their integrity. All water purged from each monitoring well and not used as a sample, will be placed in a 55 gallon DOT approved container, properly labeled and stored on site. 2.4.2 Groundwater Sample Analysis One groundwater sample from each well will be submitted to Sherwood Laboratories of Hilmar (State Certified Laboratory #1400) and analyzed for benzene, toluene, ethylbenzene and xylene (BTEX) by EPA method 8020, Gasoline range petroleum hydrocarbons (TPH-