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CWto9kaI Tedinics lne. Page 2 Additional Site Characterization and 3d Quarter Groundwater Monitoring Project No. 989.2 October 3l,'2002 The average groundwater elevation has decreased 0.26 feet since the previous monitoring event in June of 2002. The elevation is consistent with previous elevations recorded at the site. Gradient bearing is N22°W with a slope of 0.0054 ft/ft. These results are consistent with previous groundwater monitoring events. ' 1.0 BACKGROUND On October 5, 2001, Paul Souva of Valley Wholesale Drug Company, Inc.. (VWDC), received a directive from Jeffrey Wong, Senior REBS of the San Joaquin County Department of Public Health Services Environmental Health Division (SJCPHS-EHD). The letter required VWDC to define the extent of the contamination plume and submit a work plan to SJCPHS-EHD by November 20, 2001. On November 1, 2001, Geological Technics requested an extension for the work plan ' submittal. On November 5, 2001, Mr. Wong granted the extension to December 5, 2001. The work plan was submitted on November 21, 2001 and was approved by Mr. Wong in a letter dated February 27, 2002. Beginning in July of 2002, Geological Technics Inc. performed the following scope of work: • Installed one deep monitoring well to 42 feet below grade (MW-101) • Installed three shallow monitoring wells to 22 feet below grade (MW-7. MW-8 and MW-9) ' • Field screened soil samples and collected samples for laboratory analysis. • Developed the new monitoring wells. • Measured depth to water, purged wells and collected groundwater samples for laboratory analysis. • GPS Survey of all monitoring wells on and off site as required under AB2886. 2.0 MONITORING WELL INSTALLATION 2.1 Monitoring Well Installation Deep Monitoring WeII On July 30, 2002, Geological Technics Inc. supervised the installation of a deep groundwater-monitoring well. The well was installed near the vicinity of the former gasoline UST (Figure 2) to determine the extent of vertical migration of gasoline range petroleum hydrocarbons. ' Monitoring well permits were secured from the San Joaquin County Public Health Services/Environmental Health Department (SJC PHS/EHD). The local regulatory agency was notified 48 hours prior to commencing work. The subsurface was cleared of ' underground utilities by notifying Underground Service Alert. On July 30, 2002, the monitoring well was installed to a depth of 42 feet bgs using an 8- inch outside diameter (o.d.), hollow stem auger drill rig owned and operated by V&W