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1 Quarter Monitoring Report ' January through March 2005 • 8200 N Highway 99, Stockton, CA Page 5 of 8 ' 4.0 ADDITIONAL SITE WORK ' 4.1 Vapor Well Installation On January 18, 2005, Ground Zero personnel supervised the drilling and installation of vapor ' extraction well VW2 The well was completed to a depth of approximately 47 feet below ground surface (bgs) The well was completed of 4-inch diameter, schedule 40 PVC casing The lowermost 25 feet of PVC casing installed in the well is slotted screen (0 10-inch slot size) The ' filter pack consists of pea gravel from the bottom of the well to approximately 2 feet above the slotted interval The annular seal consists of two feet of hydrated bentonite pellets at the top of the filter pack, then neat cement grout to the ground surface The well was completed with a grade ' level traffic rated well box and a locking well cap The well was installed by V&W Drilling, Inc (C57-720904) under the supervision of a Ground Zero geologist A Copy of the boring/well log is included in Attachment G Well locations including the new well VW2 can be seen on Figure 2 ' Soil samples were collected at 5-foot intervals for soil characterization and possible laboratory analysis Soil encountered consisted primarily of silty sand (SM) and sand with silt (SP-SM), ' although silt was encountered from approximately 8-10 feet and 20-30 feet bgs, and clay was encountered at the bottom of the borehole Groundwater was not encountered during drilling Soil • samples collected at depths of approximately 10 5 feet bgs, 15-45 feet bgs. (at 5-foot intervals), and 47 feet bgs (bottom of the hole) were submitted to Argon Laboratones for analysis of gasoline constituents Benzene was not detected in any of the soil samples collected from VW2 TPHg was detected in all samples collected at levels ranging from 2 7 parts per million(ppm.) in sample VW2-15 to 5,600 ppm in VW2-35 Ethylbenzene and xylenes were also detected in all soil samples collected MTBE was detected in all except samples collected, t for those at 10 5 and 20 feet bgs MTBE in the P P soil ranged from 0 14 ppm in VW2-15 to 14 ppm in VW2-45 Table 6 summarizes the analytical tresults of soil samples collected from well VW2 Copies of laboratory results are included in Attachment H 4.2 Well Destruction ' On February 28, 2005, a Ground Zero technician supervised the destruction of the groundwater monitoring well MW2 in response to a letter dated February 15, 2005, sent by EHD requesting well destruction Well destruction was requested because well MW2 infringes on the Highway 99 Interchange Protect being directed by CalTrans V&W Drilling (C57 License #720904) destroyed well MW2 under the supervision of Ground Zero personnel The well was destroyed by overdrilling with 8-inch diameter hollow stem augers to a total ' depth of 78 feet The borehole was then backfilled to the surface with neat cement grout Approximately 175 gallons of neat cement grout were used to fill the well borehole Figure 2 shows the locations of site wells GIGROUNDZEITULEBURG\Reports\QMR1200511QM2005 doc