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CJeoCogica(7echnics Inc. %001 \..o� Additional Site Characterization Work Plan Page 3 Marci's Property March 21, 2000 t � 2.3 Monitoring Well Sampling Procedure After the well sealing materials have set (>24 hours) the well will be developed using mechanical surging and pumping methods until a clear stream of water is obtained. Before y any future 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. V 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 head-space bubbles. The sample container will be 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 will be decontaminated using a steam cleaner before and between uses. The following quality control .measures will ensure the effectiveness of the decontamination procedure: • The technician will use disposable gloves to collect all samples and will change gloves 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. Ld 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. All development and purged water will be containerized in 55 gallon DOT approved containers and stored on site until their disposition can be arranged. V 2.4 Laboratory Analysis Soil samples collected during drilling and groundwater samples collected after well installation will be submitted to Sherwood Laboratories of Hilmar(State Certified Laboratory 41400). They will be analyzed for the following analysis: • benzene, toluene, ethylbenzene and xylene (BTEX by EPA method 8020) '-' • diesel range petroleum hydrocarbons (TPH-Diesel by EPA method 3540/8015m). • total lead by EPA method AA 7420. • The detection limits for these compounds are listed below. A Chain of Custody will be +.• completed for all samples collected and tracked to ensure sample integrity. etectionLimits: 13 I'Ex TPH-Diesel Totalea �. Water 50 - ot (µg/Kg5,000 w