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Bank of Stockton - Cutter Lumber Site Page 3 Quarterly Groundwater Monitoring Report ' Project No 102 2 April 23, 2003 ' 2 0 GROUNDWATER MONITORING ' The following sections describe the procedures associated with the completion of groundwater monitoring at the site along with documenting the disposal of the well purge water associated with groundwater monitoring activity 2.1 Groundwater Sample Collection On March 24, 2003, Del-Tech Geotechnical Services of Oakdale, CA mobilized to the site to complete groundwater monitoring The groundwater monitoring procedure was as follows Upon arrival, each well was opened and the water level allowed to equilibrate As each well was opened, and prior to taking the depth to groundwater measurement, a PID organic vapor meter was used to ' screen for VOC's in the head space of the well The depth to groundwater was then measured by lowering an electronically actuated air / water interface detector suspended from a polyethylene measuring tape calibrated to the nearest ' 0 01 foot (see groundwater monitoring data sheets in Appendix B) A careful notation made of the depth to groundwater as measured by the device No measurable free product was observed in the wells '0 Each well was pumped with a Wattera pump and dedicated vinyl tubing lowered to bottom Well water was containerized in 55-gallon DOT approved polyethylene drums, properly labeled, and temporarily stored on-site The rate of well purging was monitored, and each well was purged of at least three casing volumes or until the groundwater parameters (temperature, conductivity, and ' pH) had stabilized indicating that water representative of actual aquifer conditions was entering the well Groundwater parameter stabilization was ' characterized by three successive readings within 10 percent After the wells had been allowed to recharge to at least 80 percent of their original volume, samples were collected from them using methods described below IAfter purging was completed, the Wattera pump was used to produce a water sample directly into the sample containers Before and in between uses, all ' sampling equipment was washed using a portable steam cleaner Disposable gloves were worn by the sampling technician while collecting all samples The gloves were changed between the collection of each sample to reduce the ' potential for cross-contamination Extreme care was exercised while collecting samples to prevent agitation of the water while filling the sample containers Water samples were transferred from . the bailer into 40 ml VOA vials preserved with hydrochloric acid (provided by ' 2937 Veneman Ave ,#B240 Geo-Phase Environmental. Inc Phone (209) 569-0293 Modesto, CA 95356 Fax (209) 569-0293