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' Bank of Stockton Page 2 Autumn 1996 Quarterly Monitoring Report Project No 102 2 December 27, 1996 ' 1.2 Groundwater Sampling ' On December 12, 1996, depth to groundwater in four of the five monitoring wells was measured and three of the monitoring wells were purged and groundwater samples were collected as directed by Mr Harlan Knoll of the San Joaquin County PHS/EHD Depth ' to groundwater in monitoring well MW-3 was not measured because recent flooding had left several inches of standing water over the well box The well was not opened in order to prevent surface water from entering it The depth to water in MW-2 was measured but ' the well was not sampled During the purging of MW-1 4, and 5, groundwater quality parameters were recorded are tabulated in the groundwater monitoring field notes (Appendix C) provided by Del-Tech Geotechnical Services ' 1.3 Groundwater Sampling Procedure ' On December 12, 1996, Del-Tech Geotechnical Support arrived on-site, opened the all the wells, and measured the depth to water with an electrically actuated sounding tape in MW-1, MW-2, MW-4, and MW-5 The water level reading was recorded to an accuracy of 0 01 foot No floating product was observed during this sampling event 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 Stagnant water in the well casing was purged using a stainless steel bailer belayed with a servo actuated electric reel The rate of well purging was monitored, and the well was purged of at least three casing volumes until the groundwater parameters (temperature, conductivity, and pH) had stabilized (Appendix C ) indicating that water, representative I of actual aquifer conditions, was entering the well Groundwater parameter stabilization was characterized by three successive readings within 10 percent Before a sample was collected, the well's water level was allowed to recharge to at least 80% of it's initial level All water removed from the monitoring well and not used as a sample, was placed in a 55 gallon DOT (Department of Transportation 17-H) approved container, properly labeled, and temporally stored on-site A stainless steel bailer was used to collect each sample Bailer cleanliness was verified by collecting a bailer blank (pouring distilled water through the bailer and collecting it in a VOA vial) prior to collecting the analytical sample 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 2937 Veneman Ave ,#B240 Phase One Environmental Inc Phone (209) 569-0293 Modesto, CA 95356 Fax (209) 569-0295 I