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1 Bank of Stockton - Cutter Lumber Site Page 3 Quarterly Groundwater Monitoring Report Project No. 102.2 October 20, 2005 ' 2.0 GROUNDWATER MONITORING The following sub-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 September 19, 2005, 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. ' • 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. After 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 the analytical laboratory). All samples were checked for head space bubbles, 2937 Veneman Ave.,#B240 Geo-Phase Environmental Inc. Phone (209) 569-0293 Modesto, CA 95356 Fax(209) 569-0293 1