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' 12 December 2006 <br /> AGE-NC Project No 01-0827 <br />' Page 7 of 14 <br />' The rise in the water table from a depth of 45 feet to 25 feet bsg currently has created a smear <br /> zone at a depth of 25 to 40 feet bsg and contributed to the dissolved contamination at the site <br /> The contribution of impacted silt and clay, surrounding the coarse sand and gravel <br />' encountered from 25 to 30 feet bsg <br />' 5.0 PROCEDURES <br /> Field work was conducted in accordance with guidelines established by the CVRWQCB for the <br />' investigation of UST sites and the EHD for sampling of ground water monitoring wells The field <br /> work was performed under procedures outlined within the work plan Confirmation Soil Sampling <br />' Work Plan , dated 17 August 2006 and approved by the EHD by letter dated 06 September 2006 <br />' 5 1 QUARTERLY AND MONTHLY WELL MONITORING <br /> On 21 July,the depth to ground water was measured in monitoring wells MW-2, MW-4 and RW-1 <br /> 5 1 1 Well Monitoring and Evacuation <br /> A Solinst water level meter was used to measure the depth to ground water in each well After water <br /> levels were gauged, a Waterra inertial tubing pump was used to purge monitoring wells MW-2, <br />' MW-4 and RW-1 The wells were purged and sampled with a dedicated Waterra inertia pump and <br /> dedicated tubing A minimum of three casing-water volumes (between 16 5 and 125 gallons) of <br /> ground water were removed from all wells Temperature, pH, and conductivity were measured at <br />' regular intervals during purging using an Oakton model water analyzer Purged water from impacted <br /> wells was stored on-site in 55-gallon drums The field data sheets are included in Appendix B <br />' 5 12 Ground Water Sample Collection and Analysis <br />' After allowing the wells to achieve a minimum 80% recovery of the pre-purge water volume, a <br /> ground water sample was collected using the dedicated purge tubing The samples were transferred <br />' into three 40-milliliter(ml)VOA vials, one liter amber bottles,properly labeled, stored in a chilled <br /> container, and transported under chain of custody to Cal Tech Environmental Laboratories(CTEL), <br /> a California Department of Health Services (DHS)-certified analytical laboratory <br />' Advanced GeoEnvzronmental,Inc <br />